March 10, 2021 CAC packet

Community Advisory Committee 7:00 PM, Wednesday, March 10, 2021 – Held Electronically Until further notice Community Advisory Committee meetings will only be available via telephone and/or the web-based application Go To Meeting. You will not be able to attend meetings in person. You can join the meeting electronically by clinking on this link https://global.gotomeeting.com/join/396102957 and following the directions or dial in using your phone: +1 (224) 501-3412 Access Code: 396-102-957 Please visit www.capitolregionwd.org to get additional CRWD COVID-19 information.

Agenda

Materials Enclosed

7:00

I)

Welcome, Announcements, Updates, and Introductions

7:05

II)

Public Comment for Issues Not on the Agenda (3 minutes per person)

7:08

III)

Approval of the Agenda

7:09

IV)

Approval of Minutes A) Approval of the February 10, 2021 Minutes

7:10

V)

District Initiatives for Review, Comment and Recommendations A) Como Lake Fishery Management Plan Update (Houle)

7:50

VI)

CAC Initiatives A) CAC Recruiting Update (Gardner) B) 2020 Watershed Steward Awards Program Debrief (Bromelkamp)

8:30

VII)

Project and Program Updates A) Communications and Engagement Update (Bromelkamp)

8:50

VIII) CAC Observer Update

8:55

IX)

Discussion A) New & Old Issues B) CAC Observer for March 17, 2021 and March 31, 2021 Board of Managers Meeting

9:00

X)

Adjourn

Our mission is to protect, manage and improve the water resources of Capitol Region Watershed District.

Community Advisory Committee Meeting Wednesday, February 10, 2021 7:00 p.m.

CAC Members Present: Nicole Soderholm, remote Bob Simonet, remote David Arbeit, remote Mary Lilly, remote Mike MacDonald, remote Richard Weil, remote Cheryl Braun, remote Steve Duerre, remote Gwen Willems, remote Michelle Ulrich, remote Tom Elko, remote

Others Present: Mark Doneux, CRWD Mary Texter, CRWD, remote Jessica Bromelkamp, CRWD, remote Mark Houle, CRWD, remote Bob Fossum, CRWD, remote

CAC Members Absent: Pat Cavanaugh, excused

I. Welcome, Announcements, and Updates Ms. Willems opened the meeting at 7:00 p.m. by videoconference. Ms. Willems asked for any announcements or updates. Mr. Doneux announced two new members will be joining the CAC: Lauren Wheeler and Devin Driscoll. Ms. Soderholm added that regarding CAC recruitment measures the Ramsey Washington Metro Watershed District has enlisted targeted social media adds for recruitment of CAC members in that watershed district.

II. Public Comment for Issues Not on the Agenda Ms. Willems asked for comments not on the agenda. There were none.

III. Approval of Agenda CAC 21-006 Motion: To approve the CAC February 10, 2021 agenda

“Our mission is to protect, manage, and improve the water resources of the Capitol Region Watershed District.” 1

Simonet/MacDonald Unanimously approved.

IV. Approval of Minutes A. January 13, 2021 CAC Meeting Minutes CAC 21-007 Motion: To approve the January 13, 2021 CAC Meeting Minutes.

Weil/Duerre Unanimously approved.

V. District Initiatives for Review, Comment and Recommendations A) 2020 Lakes Update (Houle) Mr. Houle presented an update on the District’s 2020 monitoring results for each of the five lakes within the District’s boundaries. As part of his report Mr. Houle reviewed the District’s Monitoring Methods, 2020 Climate, Results from Monitoring, Accomplishments in 2020 and 2021 Initiatives. There are five lakes within the District’s boundaries: Como Lake, Crosby Lake, Little Crosby Lake, Loeb Lake in St. Paul and Lake McCarrons in Roseville. Each lake is collaboratively monitored by Ramsey County Public Works, Ramsey County Soil and Water Conservation Division, the Department of Natural Resources and the Capital Region Watershed District, to evaluate overall health, assess compliance with water quality standards, and determine if each lake supports its designated uses for swimming, fishing and/or aesthetics.

Mr. Houle explained that in 2020 the District and its collaborators collected chemical, physical and biological data from all five District lakes. In response to Ms. Lilly’s question, Mr. Houle clarified that this data is specific to the District’s geographical area, or established watershed district boundary. Regarding climate results Mr. Houle reported that 2020 was drier than normal, with fewer intense precipitation events, and lower than average snowfall. Regarding 2020 lake monitoring results Houle stated that although Como Lake did not meet state standards, it has made significant improvement. In response to Mr. MacDonald’s question if this improvement trend will continue, Mr. Houle responded that he expects to see lower phosphorous levels going forward in Como Lake. Crosby and Little Crosby did not meet state standards, most likely an effect of Mississippi River flooding. The 2020 monitoring results show that Loeb Lake and McCarrons Lake met state standards. Regarding 2020 accomplishments Mr. Houle highlighted the Lake Como water quality projects, adoption of Lake McCarrons’ management plan, and sampling for hypolimnetic chloride in Como Lake. Lake initiatives for 2021 include: expanding lake data accessibility, implementation of Como Lake and Lake McCarrons’ management plans. Mr. Arbeit joined by all CAC members thanked Mr. Houle for his presentation.

VI. CAC Initiatives A. Final Revisions to CAC Bylaws (Doneux)

“Our mission is to protect, manage, and improve the water resources of the Capitol Region Watershed District.” 2

Mr. Doneux explained the Board of Managers approved the CAC’s updated Bylaws, with a request for the CAC to adopt the updated Bylaws with minor clarifications as now proposed by the Board. Upon motion by Ms. Soderholm, seconded by Mr. Weil, the CAC unanimously voted to adopt the Bylaws as amended.

B. 2020 Watershed Steward Awards Update (Doneux) Mr. Doneux provided an update of the 2020 Watershed Steward Awards upcoming ceremony on February 25, 2021. Mr. Arbeit has volunteered to facilitate the virtual awards ceremony. CAC members are encouraged to attend and RSVP to obtain the link for virtual attendance.

VII. Project and Program Updates Mr. Doneux provided a program update regarding a townhome development proposal on McCarrons’ Lake.

District review of this permit application indicates none of the run-off from the proposed project will go to the lake. Mr. Doneux will email CAC members a status update on the District’s review process for this proposed project. Mr. Doneux advised the CAC of additional program updates including revising the District’s employee policy manual, implementing a “crisis go” app for District staff, updating the District’s document management system and District contracting and procurement guidelines.

VIII. CAC Observer Update CAC Observer Mr. MacDonald reported on attending the Board’s January 20, 2021 regular meeting, pointing out the Board closed out a number of permits at this meeting as well as engaged in a discussion of the upcoming Steward Awards ceremony.

Mr. Simonet reported on attending the Board’s February 3, 2021 regular meeting, highlighting the 2020 Lakes update report provided by Mr. Houle and appointment of new CAC member Lauren Wheeler.

IX. Discussion A. New & Old Issues None B. CAC Observer for February 17, 2021 and March 3, 2021 Board of Managers Meetings.

Ms. Lilly volunteered to attend the February 17, 2021 meeting; Mr. Weil volunteered to attend the March 3, 2021 meeting.

X. Adjourn

“Our mission is to protect, manage, and improve the water resources of the Capitol Region Watershed District.” 3

CAC 21-008 Motion: To adjourn the February 10, 2021 CAC Meeting.

Arbeit/Lilly Unanimously approved.

The meeting was adjourned at 8:45 p.m.

Respectfully submitted, Michelle Ulrich

W:\05 Citizen Advisory Committee\Minutes\2020\February 10, 2021.doc

“Our mission is to protect, manage, and improve the water resources of the Capitol Region Watershed District.” 4

March 10, 2021 CAC Meeting V. District Initiatives for Review, Comment and Recommendations— A) Como Lake Fishery Management Plan(Houle)

DATE: TO: FROM: RE:

March 4, 2021 CRWD Community Advisory Committee Mark Houle, Water Resource Technician and Britta Belden, Water Resource Project Manager Como Lake Fishery Management Plan

Background The Como Lake Management Plan (CLMP) was adopted by the Board of Managers on May 15, 2019 and outlines an adaptive management plan for achieving water quality goals for Como Lake over the next 20 years.

As part of the CLMP, actions for fisheries management (Actions L8 and L9) were recommended to assist in meeting the objectives of Goal 1, to manage Como Lake as an ecologically healthy shallow lake: L8. Develop long-term targets for a balanced fishery. Develop and implement a “Como Lake Fishery Management Plan” that defines long-term targets for a diverse, ecologically balanced fishery that can also support and sustain recreational fishing for the community.

L9. Conduct fish surveys. Complete regular fish surveys every 2-3 years or as need to determine species abundance and diversity, and to measure progress of efforts to meet and sustain long-term targets for a balanced fishery.

Actions L8 and L9 were recommended in the CLMP because of the current imbalance between predatory fish and planktivorous fish (e.g. sunfish). Como Lake has few predatory fish to keep the planktivorous fish in check, which can cause a trophic cascade of effects that can influence lake water quality.

Issues The Como Lake Fishery Management Plan was developed by CRWD and Wenck Associates in collaboration with the Minnesota DNR. The overall goal of the plan is to manage the Como Lake’s fish community to complement water quality improvement efforts and aquatic plant initiatives while enhancing the lake’s value as an urban recreational fishery. The plan sets forth an adaptive management framework for shifting the lake to a largemouth bass fishery over time. Increasing the abundance of the largemouth bass population in Como Lake would have multiple benefits, including improving recreational fishing opportunities and improving trophic balance through predator control. In the plan, improving the largemouth bass population is viewed as a longterm goal, with shorter-term goals set forth as part of the adaptive management approach (i.e. water quality improvements, restoration of the vegetation community, evaluation and removal of excess rough fish).

Management tools are provided in the plan to achieve both short-term and long-term goals. The plan also provides guidance for routine monitoring of the fish populations so the data can inform decision making.

Requested Action None. enc: Como Lake Fishery Management Plan (dated: 2/11/2021) W:\06 Projects\Como Lake Projects\Fisheries Mgmt\2021 Como Fishery Mgmt Plan\Board & CAC\CAC Memo_Fishery Mgmt Plan_3-4-21.docx

Our Mission is to protect, manage and improve the water resources of Capitol Region Watershed District

Como Lake Fishery Management Plan Capitol Region Watershed District Saint Paul, MN February 11, 2021 Prepared by: Wenck Associates, Inc. now part of Stantec

Table of Contents EXECUTIVE SUMMARY ............................................................................................. 1 1.0

INTRODUCTION .......................................................................................... 1-1 1.1 1.2 1.3 1.4

2.0

COMO LAKE FISH COMMUNITY ................................................................... 2-1 2.1 2.2

2.3 2.4 2.5 3.0

Introduction ....................................................................................... 2-1 Como Lake Fisheries Surveys................................................................ 2-1 2.2.1 Recent Trap and Gill Net Surveys .............................................. 2-3 2.2.2 Nearshore Survey ................................................................. 2-13 2.2.3 Supplemental Electrofishing Surveys ....................................... 2-13 Current Fisheries Management ............................................................ 2-14 Recreational Fishing .......................................................................... 2-15 Summary Of the Current Fishery ......................................................... 2-16

FISHERY MANAGEMENT .............................................................................. 3-1 3.1 3.2

3.3

3.4

3.5

4.0

Purpose ............................................................................................. 1-1 The Importance of the Fish Community in Shallow Lake Ecology ............... 1-1 Summary of Issues and Objectives ........................................................ 1-1 Fish Management Approach and Tools ................................................... 1-3

Introduction ....................................................................................... 3-1 Current Stressors To the Como Lake Fishery........................................... 3-1 3.2.1 Water Quality ......................................................................... 3-2 3.2.2 Limited Submerged Aquatic Vegetation Habitat ........................... 3-2 3.2.3 Overabundance of Planktivorous Fish ......................................... 3-2 3.2.4 Imbalanced Zooplankton Community ......................................... 3-3 3.2.5 Limited and Altered Nearshore Habitat ....................................... 3-3 Fishery Management ........................................................................... 3-3 3.3.1 Short- and Long-Term Goals ..................................................... 3-3 3.3.2 Potential Tools ........................................................................ 3-3 3.3.3 Evaluating the Fish Community ................................................. 3-4 3.3.4 Managing Fish Habitat ............................................................. 3-4 3.3.5 Manipulating the Fish Community .............................................. 3-4 3.3.6 Managing Fishing Pressure ....................................................... 3-4 Como Lake Fishery Management Implementation Plan ............................. 3-9 3.4.1 Evaluating the Fish Community ............................................... 3-10 3.4.2 Managing Fish Habitat ........................................................... 3-10 3.4.3 Manipulating the Fish Community ............................................ 3-10 3.4.4 Managing Fish Pressure .......................................................... 3-10 Summary of Next Steps ..................................................................... 3-14 3.5.1 Year 1.................................................................................. 3-14 3.5.2 Year 2.................................................................................. 3-15 3.5.3 Years 3 and beyond:.............................................................. 3-15

REFERENCES ............................................................................................... 4-1

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TABLES Table 2.1.

Table 2.2.

Table 2.3.

Table 3.1.

Table 3.2.

Table 3.3.

Fish species found in Como Lake 1976-2017.1 ............................................. 2-2 Fish survey results 2010-2020. .................................................................. 2-3 DNR stocking efforts on Como Lake 2010-2020.......................................... 2-15 Stressors affecting the fishery in Como Lake................................................ 3-1 Fishery management tools. ....................................................................... 3-5 Fishery restoration implementation plan for Como Lake. ............................. 3-11

FIGURES Figure 1-1: A stepwise approach to fishery management. ............................................ 1-3 Figure 2-1: A stepwise approach to fishery management. ............................................ 2-1 Figure 2-2. Como Lake trap/gill net survey compared to other Lake Class 40 lakes.......... 2-7 Figure 2-3. Como Lake trap/gill net survey compared to other Lake Class 40 lakes.......... 2-8 Figure 2-4. Primary trophic categories commonly sampled in Como Lake. ...................... 2-9 Figure 2-5. Como Lake relative catch per unit effort by trophic category. ..................... 2-12 Figure 2-6. Como Lake relative biomass by trophic category. ...................................... 2-12 Figure 2-7. Largemouth bass (LMB) electrofishing survey results ................................ 2-14 Figure 3-1. A stepwise approach to fishery management. ............................................. 3-1 Figure 3-2. Generalized fishery management action plan.............................................. 3-9

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Executive Summary The Capitol Region Watershed District (CRWD) has placed a high priority on improving Como Lake, as it is one of the most recognizable and well-loved water resources in the watershed and the City of Saint Paul. For decades the District has been actively managing Como Lake to improve its historically poor water quality, address invasive submersed aquatic vegetation (SAV), and together with the Minnesota Department of Natural Resources (DNR), enhance its fishery. The Como Lake Management Plan was updated in 2019 and sets forth measurable objectives and management actions for Como Lake. The goal is to achieve an urban shallow lake that is ecologically healthy and supports a variety of year-round recreational opportunities, where phosphorus levels are maintained at sufficiently low levels to minimize algae nuisances; the aquatic plant community is dominated by a diverse assemblage of native species; and a balanced aquatic food web is maintained.

The District is currently undertaking various projects to improve water quality and increase water clarity by reducing sediment and nutrients to the lake from both the watershed and internal sources. Chemical treatments are underway to reduce the incidence of invasive curly-leaf pondweed, which will allow the beneficial native SAV to thrive in the increasingly clear lake.

This Como Lake Fishery Management Plan is the third component in this integrated approach. A review of existing data reveals that in addition to poor water quality and invasive SAV, the fishery and other biotic communities are unbalanced. There is a lack of top predator fish and an overabundance of fish that feed on zooplankton, which would typically graze on algae and keep it in check. This allows for increased phytoplankton growth, resulting in more frequent and more widespread algal blooms and reduced clarity.

The goal of the Como Lake Fishery Management Plan is to manage the lake’s resident fish community to complement water quality improvement and SAV initiatives while enhancing Como Lake’s value as an urban recreational fishery. This Management Plan sets forth a systematic plan to manage Como Lake to shift the lake over time to a largemouth bass (LMB) fishery. Increasing the abundance of the LMB population in Como Lake would have multiple benefits – most importantly improving recreational fishing opportunities and improving trophic balance through predator control.

Improving the LMB population will be viewed as a long-term goal, with shorter-term goals being restoration of the vegetation community, evaluation and removal (if needed) of excess rough fish biomass and establishing a more balanced fishery. LMB establishment success will likely take longer since it is heavily tied to improving water quality, SAV community, and nearshore habitat features.

Threaded through this implementation is ongoing monitoring and assessment to determine progress towards interim milestones and long-term goals and to identify any needed interim course corrections. This adaptive management approach is a stepwise, iterative process of implementation that establishes interim milestones that must be met prior to moving on to the next management action. Because fishery management is just one facet of the overall improvement of Como Lake, this approach ensures that all the parts are moving forward toward the District’s goals.

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1.0 Introduction 1.1

PURPOSE

The goal of the Como Lake Fishery Management Plan is to manage the lake’s resident fish community to complement water quality improvement and submersed aquatic vegetation (SAV) initiatives while enhancing Como Lake’s value as an urban recreational fishery.

Accomplishing this requires an appreciation for the dynamic nature of lake and fish population ecology as well as the important social components and feasibility considerations of effectively managing fish populations. Thus, a successful plan requires a structured adaptive approach driven by robust monitoring data. The plan also recognizes the existing recreational uses of Como Lake and the need to maintain recreational opportunities appropriate for a shallow urban lake. The plan aims to move beyond “put-and-take” based on stocking adult top predators to managing for self-sustaining populations.

1.2

THE IMPORTANCE OF THE FISH COMMUNITY IN SHALLOW LAKE ECOLOGY

Shallow lakes in the American Midwest are frequently inhabited by a modest diversity of fish species. This diversity represents an important component of the lake ecosystem and the relative abundance of fishes has cascading effects on the trophic food web. Shallow lakes in this region often present alternative stable states where the clear, biologically diverse state is dominated by emergent and submerged aquatic vegetation and the turbid water, low diversity state is dominated by algae. Fish populations can affect the dynamics of trophic cascade in shallow lake ecology in strong ways depending on their abundance and other factors leading to persistence of the turbid state. Therefore, shallow lake management/ restoration often includes biomanipulation of fish populations through various methods (Noonan 1994). Usually these methods focus on actively managing an apex predator species for high abundance and size.

1.3

SUMMARY OF ISSUES AND OBJECTIVES

The issues identified with the Como Lake fish community that are relevant to the management plan include: 1. Put-and-take fisheries are not representative of ecologically balanced fish communities that would naturally occur in a shallow lake like Como: a. Hyperdynamic, exhibiting boom/bust swings in fish abundance tied to successful year classes that have cascading effects through the lake ecosystem. b. Cost-inefficient compared to fisheries sustained by natural reproduction.

2. Relatively poor fish habitat quality due to: a. Highly urban watershed delivering high nutrient and chloride loadings. b. Nuisance curly-leaf pondweed dominance of the submersed aquatic vegetation community and associated herbicide treatments that negatively affect non-target vegetation. c. Disturbed riparian near-shore and emergent vegetation zones with low diversity of vegetation. d. An apparent lack of significant coarse woody debris.

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e. Potentially limited spawning habitat for largemouth bass. f. Potential periodic anoxia mitigated by a winter aeration system. g. Potential for summer kill of predator species, such as northern pike, due to high water temperature and low dissolved oxygen.

3. High predation pressure on zooplankton by small-bodied “forage” fishes as well as juveniles of naturally produced species that drive algal dominated primary production and poor water quality sometimes called the “turbid” state (Noonan 1994).

4. Moderate to high abundance (quantity) but relatively low quality (size) of bluegill sunfish and black crappie, which is an issue occurring in many lakes in Minnesota.

5. Current presence of prolific benthivorous (bottom feeding) species known to affect water quality through bioturbation when hyperabundant (black bullhead and common carp). Surveyed black bullhead relative abundance is consistently above normal ranges for ecological class 40 lakes. Common carp relative abundance in Como Lake is low based on historic DNR trap/gill net catch rates, however specific carp population estimates have not been attempted for the lake. Some research has documented that carp recruitment can be controlled by other fish species, such as bluegill, eating the eggs (Silbernagel and Sorensen 2013). Common carp are extremely tolerant species and therefore often have successful recruitment immediately following significant winterkill of less tolerant species such as bluegill.

The bluegill population and lack of winterkill in Como Lake may be limiting the abundance of common carp through their feeding activities.

With these issues in mind, the 2019 Como Lake Management Plan (CRWD 2019) sets forth a set of measurable objectives and actions for Como Lake. The Goals and Objectives that are relevant to the Fishery Management Plan include: Goal 1: Como Lake will be managed as an ecologically healthy, shallow lake.

An ecologically healthy, shallow lake is one where phosphorus levels are maintained at sufficiently low levels (60 µg/L or lower) to minimize algae nuisances; the rooted aquatic plant community is dominated by a diverse assemblage of native species; and a balanced aquatic food web is maintained. Relevant to the fish community, the long-term goal is to achieve natural in-lake fish reproduction.

• •

Objective 1F: Establish and maintain native aquatic vegetation to exceed these criteria: species richness > 8 with at least 3 species where the Frequency of Occurrence (FOC) > 20%.

Objective 1G: Establish and maintain a fishery with balanced populations of piscivorous, planktivorous, and benthivorous fish.

Goal 2: Maintain healthy shoreline areas that can support a variety of wildlife and contribute to the ecological health of Como Lake.

•

Objective 2A: Maintain areas of native vegetation along the shoreline to capture surface runoff, minimize shoreline erosion, and promote wildlife habitat.

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Goal 3: Maintain a variety of year-round recreational opportunities that are appropriate for a shallow urban lake.

• 1.4

Objective 3A: Continue to provide fishing opportunities.

FISH MANAGEMENT APPROACH AND TOOLS

In considering how best to proceed with Como Lake, the USEPA guidance document Fish and Fisheries Management in Lakes and Reservoirs (Baker et al. 1993) was utilized to set forth a systematic and comprehensive approach to lake management. This considers not only fish but other biota, water quality, habitat, and watershed characteristics that provide for a more integrated approach.

In general, this approach is similar to the familiar model of Adaptive Management: Assess ► Design ► Implement ► Monitor ► Evaluate ► Adjust Figure 1.1 illustrates the USEPA approach. Section 2 of this report addresses the first four steps in this process; section 3 discusses potential implementation actions and monitoring recommendations.

Assess current status

Characterize lake users and values

Establish priority management objectives

Identify problems, causes, and limiting factors

Figure 1-1: A stepwise approach to fishery management.

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Select and implement actions

Monitor results

2.0 Como Lake Fish Community 2.1

INTRODUCTION

This section will focus on the first four steps of the USEPA approach as shown in Figure 2.1.

We will analyze the available data for Como Lake to assess its current status and problems and discuss fishery management objectives. In Section 3 we will discuss the stressors that are limiting the fish community and the implementation actions that can be taken to overcome those factors and achieve management goals. The action plan also includes monitoring actions to guide implementation and assess success.

Assess current status

Characterize lake users and values

Establish priority management objectives

Identify problems, causes, and limiting factors

Select and implement actions

Monitor results

Figure 2-1: A stepwise approach to fishery management.

2.2

COMO LAKE FISHERIES SURVEYS

Fisheries surveys on Como Lake have been completed by the Minnesota Department of Natural Resources (DNR) and the Capitol Region Watershed District (CRWD). The DNR began conducting fish community surveys in Como Lake in 1976 and CRWD began conducting supplemental surveys following DNR protocols in 2014. The surveys included standard DNR trap and gill net methods and, in 2017, a nearshore fisheries survey. Each standard DNR trap/gill net survey used 3-9 trap net locations and 1-2 gill net locations. The DNR completed a total of 13 trap/gill net surveys from 1976 to 2016, approximately one survey every five years. In addition, due to high net avoidance, supplemental electrofishing surveys were conducted by the DNR in 1996, 2011, and 2017 to assess the LMB population.

The historic surveys for Como Lake reveal a fish community common for a hypereutrophic shallow lake that is heavily managed. A total of 20 species have been sampled since 1976 (Table 2.1), four of which (LMB, walleye, channel catfish, and bluegill sunfish) have been stocked into Como Lake at times from 2010-2019 (see Section 2.3), with the main stocking effort during this period being walleye. Sections 2.2.1 through 2.2.3 provide a summary and discussion of each survey method that has been conducted by the DNR and CRWD in Como Lake over the most recent 10-year period (2010-2020).

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Table 2.1. Fish species found in Como Lake 1976-2017.1 Species

1

Black bullhead (Ameiurus melas) Black crappie (Pomoxis nigromaculatus) Bluegill sunfish (Lepomis macrochirus) Brown bullhead (Ameiurus nebulosus) Channel catfish (Ictalurus punctatus) Common carp (Cyprinus carpio) Golden Shiner (Notemigonus crysoleucas) Goldfish (Carassius auratus) Green Sunfish (Lepomis cyanellus) Hybrid Sunfish (Lepomis sp.)

Largemouth bass (Micropterus salmoides) Northern pike (Esox Lucius) Pumpkinseed (Lepomis gibbosus) Rock bass (Ambloplites rupestris) Shortnose gar (Lepisosteus platostomus) Walleye (Sander vitreus) White crappie (Pomoxis annularis) White sucker (Catostomus commersonii) Yellow bullhead (Ameiurus natalis) Yellow perch (Perca flavescens)

Trophic Category

Year First Observed

Year Last Observed

Survey Type/Metho d

Invertivore-Carnivore

1976

2017

T, G

Invertivore-Carnivore

1976

2017

T, G

Invertivore

1986

2017

T, G

Invertivore-Carnivore

2001

2015

T

Invertivore-Carnivore

1996

2017

T, G2

Invertivore-Detritivore

1981

2016

T, G

Invertivore-Herbivore

1981

2017

T

Invertivore-Detritivore

1976

1981

T

Invertivore-Carnivore

1976

2006

T, G

Invertivore

1976

2017

T, G

Invertivore-Carnivore

1986

2017

T, G, E

Carnivore

1996

2017

T, G

Invertivore

1976

2017

T, G

Invertivore-Carnivore

1976

1976

G

Carnivore

1991

1991

G

Invertivore-Carnivore

1986

2017

T, G, E

Invertivore-Carnivore

1981

1981

G

Invertivore-Detritivore

1981

2015

G

Invertivore-Carnivore

1988

2017

T

Invertivore-Carnivore

1990

2017

T

Data collected from surveys conducted by the DNR, CRWD, and Wenck using standard trap and gill nets methods described in (Schlagenhaft, 1993).

2 T = standard trap net; G = standard gill net; E = electrofishing; N = nearshore methods

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2.2.1 Recent Trap and Gill Net Surveys Overview Since 2010, five standard trap net and gill net surveys have been completed: 2011, 2014, 2015, 2016, and 2017. Two of these survey efforts (2011 and 2016) were conducted by the DNR while the other surveys (2014, 2015, and 2017) were conducted by CRWD. The 2017 survey conducted by CRWD was done in conjunction with the nearshore (see Section 2.2.2).

Over the past five trap and gill net surveys, 15 fish species were sampled in Como Lake and the most dominant species in terms of total biomass were northern pike, black crappie, and black bullhead (Table 2.2). The most abundant fish sampled, in terms of total catch, was black crappie followed by bluegills and black bullhead.

Table 2.2. Fish survey results 2010-2020.

Species

Trophic Category*

Biomass (lbs)

Count (#)

Average Weight (lbs)

Black bullhead

I-C

144

458

0.31

Black crappie

I-C

148

1,023

0.15

Bluegill sunfish

I

65.5

473

0.14

Brown bullhead

I-C

0.37

1

0.37

Channel catfish

I-C

66.1

35

1.89

Common Carp

I-D

7.04

1

7.04

Golden shiner

I-H

4.54

34

0.13

Hybrid sunfish

I

3.11

13

0.24

Largemouth Bass

I-C

2.73

4

0.68

Northern pike

C

329

95

3.46

Pumpkinseed sunfish

I

6.16

61

0.10

Walleye

I-C

55.7

37

1.51

White sucker

I-D

12.7

6

2.11

Yellow bullhead

I-C

20.7

46

0.45

Yellow perch I-C 8.39 39 * C = carnivore; I = invertivore; H = herbivore; D = detrivore

0.22

Comparisons to Similar Lakes The DNR uses the Schupp Lake Class system (Schupp 1992) to classify every lake in Minnesota into 44 ecological lake classes. Each lake class grouping varies based on physical and chemical characteristics such as lake size, lake depth, water chemistry, and geographical location within the state since these factors can influence fish species and community assemblages. Fish survey data within each class can be compared to develop normal ranges and assess current/historic fisheries conditions and trends. Como Lake falls into Schupp Lake Class 40, which is generally characterized by shallow (less than 15 feet deep), productive lakes with simple shoreline complexity in the central part of the state.

Figures 2.2 and 2.3 show Como Lake’s trap and gill net CPUE and average weight results for the four species with the highest total biomass during recent surveys: black bullhead, black crappie, bluegill, and northern pike. Also shown on these figures are the median (dotted

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black line), upper (dotted red line), and lower (dotted blue line) normal range CPUE and average weight values for other Lake Class 40 lakes. Below is a brief discussion of each individual species.

Black Bullheads Since 2011, black bullheads have, on average, accounted for 32% of the trap/gill net CPUE and 16% of the total biomass. Compared to other Lake Class 40 lakes, Como Lake black bullhead CPUEs were near the median and lower normal ranges in 2011 and 2014, then increased closer to the upper normal range in 2015 and 2016, before falling back close to the lower normal range in 2017. Bullhead average weights have consistently exceeded the median range with a high in 2014 that was well above the upper normal range. These results tend to suggest that while bullhead numbers in Como Lake fluctuate year to year, average size is typically on the higher end compared to similar shallow lakes.

Black bullheads are tolerant of low oxygen environments and are often associated with shallow, turbid lakes with low bluegill CPUEs and little to no submerged aquatic vegetation (SAV) (Drake and Pereira 2002; Bajer et al. 2018). Bullheads typically feed on zooplankton and small fish in addition to benthic invertebrates (Repsys et al. 1976; Leunda et al. 2008).

Compared to other species, black bullheads are relatively short lived and their biomass rarely ‘‘builds up’’ in lakes over time (Bajer et al. 2018). This likely explains the fluctuations in bullhead numbers observed in Como Lake. There appears to be strong bullhead year classes in which recruitment was very successful, and other years where mortality rates were higher and/or recruitment was less successful. The up and down year classes are likely the result of environmental conditions (e.g. DO levels, temperature, vegetation coverage, habitat conditions) as well as interactions with other fish species and trophic levels.

Both common carp and bullhead can disturb SAV during spawning - carp by thrashing in vegetation and bullheads by removing plants from nest sites (Bajer et al. 2018). However, black bullheads are believed to have lesser ability to uproot SAV or drive large increases in turbidity compared to carp (Braig & Johnson 2003; Fischer et al. 2013). Bajer et al. (2018) suggested that management thresholds for bullheads may be higher than for carp (e.g. 200 kg/ha for severe ecological damage) but this needs to be further verified using controlled experiments. Given the lack of a true black bullhead population estimate for Como Lake and uncertainties in a management threshold, it is difficult at this time to evaluate Como Lake’s bullhead population and if they are impacting vegetation and/or turbidity levels.

Black Crappies Black crappies have averaged 43% of the trap/gill net CPUE and 20% of the total biomass over the past 10 years. Como Lake’s black crappie CPUE consistently exceeds the Lake Class 40 median value and has exceeded the upper normal range on three of the past five surveys (Figure 2.4). Average weight has been at or below the Lake Class 40 median during the past surveys indicating an abundance of small crappies in the system. Of the 528 crappies sampled in 2011 and 2016, only 11 (2%) measured 8-9 inches and only 2 (<1%) measured 10-11 inches. Most of the crappies measured between 0-5 inches (31%) and 6-7 inches (66%).

Compared to bluegill and other sunfish species, black crappies are more adapted to open water environments. Vegetation abundance, while important to all fish species, is less important to black crappies compared to species such as bluegills and largemouth bass

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(Dibble et al. 1996; Cross and McInerny 2001). Black crappie under 7 inches typically feed on zooplankton and other small aquatic invertebrates, while adult crappie greater than 7 inches primarily eat small fish. Typically, black crappie greater than 10 inches are considered harvestable. Thus, Como Lake’s current black crappie population offers limited opportunity for harvest due to their small size structure. It is not clear what is prohibiting black crappies from reaching full maturity and larger sizes, however possibilities include environmental stressors, limited/poor habitat conditions, lack of food and/or overcompetition with other fish for food and resources. It is possible, although unlikely, that fishing pressure is also a driver of crappie size structure as we would expect some larger individuals desired by anglers to be caught in the trap/gill nets if there were catchable size fish in the lake.

Bluegills Bluegill trap/gill net CPUE and biomass for Como Lake has averaged 7% and 11%, respectively, over the past five surveys. Similar to other species, Como Lake’s bluegill CPUE has fluctuated over the most recent surveys. Bluegill CPUE peaked in 2011, then fell below the Lake Class 40 lower normal range in 2014 and 2015, and then increased close to median values in 2016 and 2017. Average weight of bluegills has been between the median and lower normal range in three of the past five surveys (2011, 2016, and 2017) and between the median and upper normal range in the two surveys with the lowest CPUEs (2014 and 2015). Of the 342 bluegills sampled in 2011 and 2016, 264 (77%) measured 0-5 inches and 77 (23%) measured 6-7 inches. Only one fish (<1%) measured greater than 7 inches.

Submerged aquatic vegetation is extremely important to bluegills as they depend on SAV throughout their life cycle for spawning, refuge, and foraging (Valley et al. 2004). Young of year bluegill remain in SAV and choose the densest available vegetation to reduce predation risk (Werner et al. 1983; Werner and Hall 1988; Shoup et al. 2003). Bluegill up to 3 inches in length feed primarily on vegetation-dwelling invertebrates. Bluegills longer than 5 inches typically feed on zooplankton (Mittelbach 1981; Werner and Hall 1988), while bluegills in the 3-5 inch range will consume a combination of vegetation-dwelling invertebrates and zooplankton (Werner and Hall 1988). Bluegill 6-8 inches in size are considered desirable by anglers, and therefore Como Lake’s bluegill population offers limited opportunities for harvest of bluegill by anglers. Since bluegill population dynamics are strongly related to SAV abundance and density, it is likely that Como Lake’s current SAV community is a limiting factor to bluegill growth rates, size, and success of certain year classes. Studies have found that the probability of finding a quality largemouth bass or bluegill population is highest between 10% and 60% total cover of SAV. When vegetation covers less than 10% of a waterbody (e.g., turbid systems), bass/bluegill are scarce and production is typically low (Durocher et al. 1984; Bettoli et al. 1992; Maceina 1996; Wrenn et al. 1996; Miranda and Pugh 1997). When vegetation coverage exceeds 40-60% of the entire waterbody, low feeding rates and/or poor growth by these species can occur (Colle and Shireman 1980; Bettoli et al. 1992; Maceina 1996; Wrenn et al. 1996; Miranda and Pugh 1997).

Northern Pike Since 2011, northern pike have averaged only 5% of the trap/gill net CPUE but 33% of the total biomass. Como Lake’s northern pike trap/gill net CPUE has declined in recent years from above the upper normal range in 2011, to below the lower normal range in 2017.

However, northern pike CPUEs were above the median range in 2014, 2015, and 2016, so

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more data will need to be collected to determine if this is part of a long-term trend.

Northern pike average weights have remained near or slightly above the upper normal range indicating that good size pike are surviving and flourishing in the lake. A total of 55 northern pike were sampled in the 2011 and 2016 trap/gill net surveys, of which 4 (7%) measured 15-19 inches, 38 (69%) measured 20-24 inches, 11 (20%) measured 25-29 inches, and 2 (4%) measured 30-34 inches. Typically, pike greater than 24 inches present a fun catch for anglers and pike over 30 inches are considered high quality and desirable.

Therefore, based on the trap/gill net surveys, Como Lake offers a good northern pike fishing opportunity for anglers.

Northern pike are considered ambush predators that feed primarily on other fish, however they will also pursue any living thing up to a third its body length that they are able to consume such as small ducks, mice, rats, frogs, snakes, and crayfish. Since northern pike represent the top of the food chain in most lakes, sustaining healthy numbers and sizes can be an important component in maintaining a balanced fish population and trophic structure.

However, research has shown that northern pike do not typically feed on black bullheads (Sammons 1994) and that northern pike are not likely as effective in controlling over abundant centrarchids (i.e. bluegills). In a shallow lake such as Como, an over-abundance of northern pike can create problems with the balance in the fish community. As a result, efforts to alter or enhance the northern pike population within Como Lake are not recommended. Instead, efforts should focus on the establishment of LMB as the top predator within the lake.

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Figure 2-2. Como Lake trap/gill net survey compared to other Lake Class 40 lakes.

Note: Black bullhead (left) and black crappie (right) CPUE (top) and average fish weight (bottom).

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Figure 2-3. Como Lake trap/gill net survey compared to other Lake Class 40 lakes.

Note: Bluegill (left) and northern pike (right) CPUE (top) and average fish weight (bottom).

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Trophic Structure When reviewing fish survey data, it is often helpful to group individual species into trophic categories. Analyzing the data by trophic categories allows lake managers to assess the fish community as a whole and evaluate potential food web interactions and dynamics. For the purposes of this plan, Como Lake’s fish community was broken into five trophic groups as presented in Goldstein and Simon (1999) and modified in Miranda et. al. (2008). These five categories include: • • • • •

Carnivores which consume whole bodies of other fish Invertivores which consume invertebrates such as midges, zooplankton, and mollusks Planktivores which consume plankton suspended in the water column Herbivores which consume plants including phytoplankton, epilithic algae (i.e. attached algae), or macrophytes Detritivores which consume nonliving organic matter and associated microflora accumulated in the sediment

Figure 2-4. Primary trophic categories commonly sampled in Como Lake.

Note: Individual fish drawings by Duane Raver were downloaded from the US Fish and Wildlife Service website.

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It is important to point out that several species common to Como and other Minnesota lakes belong to more than one trophic group during their life cycles. Additionally, feeding preferences of certain species can shift based on environmental factors such as food availability, habitat conditions, and biotic stressors. Table 2.1 summarizes the individual species sampled in Como Lake and their associated trophic category.

Figures 2.5 and 2.6 show the recent community structure, as represented by trophic category, sampled by trap and gill nets in Como Lake from 2011-2017. Only relative (i.e. percent of total) catch per unit effort (CPUE) and biomass for each trophic category are presented in these figures since the number of trap nets (3-9) and gill nets (1-2) deployed during each survey event varied from survey to survey.

Northern pike is the only sampled fish species that falls entirely within the carnivore trophic category in Como Lake. Thus, carnivore CPUE is generally lower than the other trophic categories, however relative biomass can be quite high due to the large northern pike individuals that are commonly sampled in the trap/gill nets. Northern pike CPUE rates were 5-15 times higher during the 2011-2016 surveys compared to the 2017 survey. As a result, carnivore relative biomass was significantly lower in 2017 compared to previous surveys.

Most of the fish species sampled in Como Lake during recent surveys are considered invertivore-carnivores and therefore feed on both invertebrates and other fish depending on age/life cycle, size, available food, and other factors. Invertebrate-carnivore CPUE has ranged from 77% (2017) to 95% (2015) while biomass has ranged from 37% (2011) to 72% (2016). The primary invertebrate-carnivore species sampled recently in Como Lake include black bullhead and black crappie. Black bullheads have accounted for 42% of the invertebrate-carnivore CPUE and 32% of the biomass. Black crappies have accounted for 49% of the invertivore-carnivore CPUE and 33% of the biomass. As discussed in the previous section, the average weight of black bullheads sampled in Como Lake typically exceed the median range of similar lakes, while black crappie average weights are typically below the median range. Other invertebrate-carnivore species sampled in Como Lake include brown bullhead, channel catfish, largemouth bass, walleye, yellow bullhead, and yellow perch. Each of these species have individually accounted for less than 10% of the invertebrate-carnivore category average CPUE since 2011. Channel catfish (15%) and walleye (13%) are the only other invertebrate-carnivore species that accounted for greater than 10% of the invertebrate-carnivore category total biomass.

Species that fall entirely within the invertebrate category include bluegill sunfish, pumpkinseed sunfish, and hybrid sunfish. Invertivore CPUE in Como Lake has ranged from <1% (2015) to 22% (2017), while biomass has ranged from <1% (2015) to 35% (2017).

Bluegill sunfish are the dominant species within the invertivore trophic group as they have accounted for a majority of this group’s CPUE (84%) and total biomass (89%). As discussed in the previous section, bluegill CPUEs and average weights have fluctuated in Como Lake in recent years as they are highly dependent on SAV abundance/density.

Abundance and biomass of invertebrate-herbivore and invertebrate-detritivore species in Como Lake is relatively low. Golden shiner is the only invertebrate-herbivore species recently sampled in Como Lake and, except for one year (2014), has accounted for less than 2% of the annual trap/gill net CPUE and total biomass. Similarly, invertebratedetritivore CPUE and total biomass has accounted for less than 5% of the sampled population. Common carp and white suckers are the only invertebrate-detritivore species sampled in Como Lake since 2011. Common carp have only been sampled once (2015) in

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the trap/gill nets during the past five surveys for Como Lake. Common carp tend to avoid trap/gill nets and therefore it is difficult to assess their relative abundance using this gear type. White suckers have been sampled during only two of the last five surveys and, when sampled, their CPUEs are at or below the lower normal range compared to other Lake Class 40 Lakes.

Overall, the trophic category analyses presented here suggest that Como Lake’s fish community structure tends to fluctuate from survey to survey, which is quite common for shallow, hypereutrophic lakes in urban environments. There are no community structure guidelines for a healthy shallow lake fishery, however ideally a healthy system would demonstrate low (i.e. <20%) rough fish (i.e. detritivore) biomass, and relatively stable, diverse, and balanced invertivore and carnivore communities. The EPA’s Fish and Fisheries Management in Lakes and Reservoirs Guidance Manual suggests that food web stability functions best in productive, densely vegetated systems when piscivore (i.e. carnivore) ageclass and community structure are diverse and they compose at least 30% of the total fish biomass (EPA 1993). Currently, Como Lake has a high abundance of smaller invertebrate and invertebrate-carnivore individuals and is generally lacking in the number of carnivore and invertebrate-carnivore species (i.e. LMB) that can effectively feed on smaller fish. Thus, increasing the abundance of predator species that can exert top-down grazing pressure on smaller fish should create more balance in Como Lake and promote the establishment of larger fish that feed on insects and fish rather than zooplankton.

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Figure 2-5. Como Lake relative catch per unit effort by trophic category.

Figure 2-6. Como Lake relative biomass by trophic category.

Note: based on the most recent (2011-2017) trap and gill net surveys.

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2.2.2 Nearshore Survey As a supplement to their traditional standardized sampling methods, the DNR has developed nearshore survey methods to capture and identify more non-game components of the fish community (i.e. darter species, shiner species) utilizing backpack electrofishing and beach seining efforts (Bacigalupi et al. 2015). As part of the development of the DNR’s Index of Biotic Integrity (IBI) tool, fish species were grouped into five categories for scoring purposes: tolerant species, insectivores, top carnivores, small benthic dwellers, and vegetative dwellers. Lakes smaller than 100 acres in size were not used during the development of Minnesota’s IBI tool and therefore Como Lake cannot be scored using this tool. However, parts of the IBI tool and metrics can be used to qualitatively assess Como Lake’s nearshore fish community. Nearshore surveys may have value as an assessment tool within Como Lake to target certain species. However, in the absence of a specific IBI tool for small, shallow lakes less than 100 acres, the IBI is unlikely to be used to drive management activities within Como Lake.

2.2.3 Supplemental Electrofishing Surveys In addition to the trap/gill net surveys described above, the DNR conducted three supplemental electrofishing surveys in 1996, 2011, and 2017. These surveys were intended to target walleye and largemouth bass. Walleye numbers increased from one fish weighing approximately 4 pounds in 1996 to 12 fish in 2017 that weighed on average about one pound. Walleye were not collected during the 2011 electrofishing survey as the target of this survey was solely for the assessment of LMB. Walleye are currently stocked and managed in Como Lake by the DNR (see Section 2.3).

Largemouth bass electrofishing numbers have declined from a high of 11 fish sampled in 1996 (12.9 fish/hour) to one fish sampled in 2011 (2.6 fish/hour) and three fish (3.1 fish/hour) in 2017 (Figure 2.7). These numbers are well below the 50 fish/hour electrofishing target/goal the DNR commonly uses for largemouth bass managed lakes throughout Minnesota. Of the four largemouth bass sampled during the 2011 and 2017 surveys, three measured 6-7 inches and only one measured 15-19 inches. Typically, largemouth bass greater than 16 inches are sought by anglers and therefore Como Lake currently offers limited recreational opportunities for this species. As discussed above, ideal conditions to support largemouth bass are mesotrophic lakes with total SAV frequency of occurrence ranging between 10% and 60%. Thus, restoring and maintaining a healthy SAV community in Como Lake as water quality conditions improve will be critical to supporting largemouth bass.

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Figure 2-7. Largemouth bass (LMB) electrofishing survey results 2.3

CURRENT FISHERY MANAGEMENT

Historically the DNR has managed and stocked Como Lake as a so-called “put-and-take” sport fishery. The earliest records show it was stocked in 1950 and then not again until unknown persons stocked fish in 1974 (DNR Fisheries Lake Survey, 1976). Up until 1985, Como Lake frequently winterkilled, which limited fish populations to bullheads, goldfish, and occasional populations of crappies. In 1985 the DNR implemented a full lake rotenone treatment to remove all fish in the lake. An air-lifted aeration system was installed immediately following the rotenone treatment to prevent winterkill. The aeration system continues to be operated to this day by Ramsey County staff during the winter months. The DNR began a stocking program following the rotenone treatment which included LMB, bluegill, and walleye. Around this time the DNR also implemented an experimental regulation requiring the release of bass between 12 and 16 inches long. The purpose of this special regulation was to help increase the size structure of bluegills within the lake. The regulation expired in 1993. Largemouth bass abundance was relatively high when the experimental regulation was in place, however the bass population declined shortly after the regulation expired and stocking efforts shifted toward other species.

Recently, stocking efforts have been done through the DNR’s Fishing in the Neighborhood (FiN) Program, which aims to increase angling opportunities in urban lakes. As of 2016, the DNR’s primary management species for Como are bluegills and channel catfish (DNR 2016 Fisheries Survey Report), although limited bluegill stocking has occurred over the last 10 years (Table 2.3) Channel catfish are unlikely to be included in future DNR stocking efforts as there is a limited available supply of this species. The updated lake management plan in 2017 listed walleye and channel catfish as primary management species with bluegill and northern pike listed as secondary management species. In 2018, 350 adult LMB weighing on

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average just over one pound were stocked in Como Lake. No surveys have been performed since this stocking event to evaluate the LMB population and the success of these efforts.

Put-and-take fisheries are not representative of fish communities that would naturally occur in a lake like Como. These types of stocking programs can be expensive and are often variable in their effectiveness to create long term benefits beyond the season when the stocked fish are added to the lake. The FiN program stocking efforts do provide urban recreational opportunities by adding a resource that can provide a direct and immediate benefit to anglers. Based on the most recent fish community surveys in Como Lake it is not certain if recent stocking efforts are establishing a reproductive fish community that can continue on its own with less direct management. The desired goal for future stocking efforts would be to add target management species in conjunction with water quality and habitat improvements that can establish a self-sustaining fish community that is both ecologically stable for the lake while also continuing to provide recreational benefits to anglers and the local community.

Table 2.3. DNR stocking efforts Year Species Walleye 2020 Walleye Walleye 2019 Walleye Largemouth Bass 2018 Walleye Walleye Walleye 2017 Walleye 2016 Walleye Channel Catfish 2015 Walleye Channel Catfish Largemouth Bass 2014 Walleye Walleye Yellow Perch 2013 Walleye Channel Catfish 2011 Channel Catfish Walleye Bluegill Sunfish Channel Catfish 2010 Channel Catfish Walleye 2.4

on Como Lake 2010-2020.

Size Number adults 115 yearlings 320 adults 56 fingerlings 2,231 adults 350 adults 259 yearlings 102 yearlings 335 adults 111 yearlings 903 adults 181 yearlings 2,840 adults 130 adults 8 fingerlings 4,108 fry 71,000 adults 1,211 fingerlings 486 yearlings 3,900 adults 124 fingerlings 3,593 adults 24 adults 91 yearlings 3,900 yearlings 4

Pounds 130 80 48 94 467 259 34 62 111 137 302 142 195 5 78 1 284 68 666 281 129 10 286 750 1

RECREATIONAL FISHING

The community surrounding Como Lake presents ideal demographics for the DNR’s FiN program to engage residents in outdoor recreation by providing angling opportunities. A fishing pier was installed by the DNR in 1987 and replaced by a larger pier in 2006. A creel survey (i.e. angler use survey) conducted by the DNR in 1991 estimated that angler use was approximately 163 angler-hours per acre of fishing per year (DNR 2018). A second

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creel survey conducted in 2003 estimated that angler use declined significantly to approximately 39 angler-hours/acre/year (DNR 2018). The DNR has determined that Como Lake should support much higher angler use based on its location and the surrounding population. In their 2017 Lake Management Plan, the DNR identified a long-range angler use goal of 200 angler-hours/acre/year and a mid-range goal of 100 angler-hours/ acre/ year. An angler use survey was conducted by the DNR in 2016 using trail cameras to monitor and track progress toward meeting the mid- and long-range angler use goals for Como Lake.

2.5

SUMMARY OF THE CURRENT FISHERY

This section provided an analysis of the historic fish survey results and fishery management for Como Lake with a specific focus on the most recent 10-year period (2010-2020). Below is a summary of the key findings and conclusions from this section: •

Como Lake’s fish community structure (i.e. balance between carnivore, invertivore, and other trophic categories) tends to fluctuate significantly from survey to survey.

Carnivore biomass fell below 30% during recent surveys while biomass of other trophic categories have fluctuated significantly.

•

Certain invertivore and invertivore-carnivore species, particularly black bullhead, black crappie, and bluegill, exhibit strong year classes followed by periods of low numbers and recruitment. The black crappie and bluegill population is generally characterized by an abundance of small sized individuals. Small sizes and the boom-bust nature of these species is common for hypereutrophic shallow lakes and is likely the result of environmental conditions/stressors, stocking, and interactions with other fish species and trophic levels.

•

It is unclear if and to what degree species such as black bullhead and common carp are impacting turbidity levels, water quality, and SAV abundance in Como Lake. Black bullheads are typically short-lived so numbers tend to fluctuate in Como Lake, although average weights are generally above the median compared to similar shallow lakes.

Common carp trap/gill net catch rates have been low during recent surveys, with only one carp sampled during the past five surveys. Common carp tend to avoid trap and gill nets and therefore more targeted survey techniques (e.g. electrofishing) would be needed to assess carp density and their potential impact. DNR staff have indicated common carp numbers within Como Lake appear to be low and that the bluegill and sunfish populations may be limiting their numbers by consuming carp eggs.

•

Como Lake currently supports good sized northern pike; however numbers were down during the most recent trap/gill net survey. More data will be needed to determine if this is part of a long-term trend. Maintaining a healthy number and size structure of northern pike helps maintain trophic balance and provides recreational opportunities for anglers.

•

The DNR has historically managed Como Lake as a put-and-take sport fishery. Currently, primary management species are bluegills and channel catfish, however several other species are managed through stocking. It is uncertain, based on recent survey data, if stocking efforts are establishing a reproductive fish community that can sustain itself without direct management. Future stocking and management efforts should align with the goals of this plan and other management plans and initiatives currently underway for Como Lake.

•

Supplemental electrofishing surveys conducted by the DNR suggest Como Lake LMB numbers are low and well below DNR’s target for lakes that are managed for LMB.

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Improving and sustaining LMB numbers would help improve trophic balance and provide a recreational opportunity for anglers.

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3.0 Fishery Management 3.1

INTRODUCTION

Section 2 analyzed the available data for Como Lake to assess its current status and begin identifying potential fishery management objectives. In Section 3 we will discuss the stressors that are limiting the fish community and the implementation actions that can be taken to overcome those factors and achieve management goals. The action plan also includes monitoring actions to guide implementation and assess success (Figure 3.1).

Assess current status

Characterize lake users and values

Establish priority management objectives

Identify problems, causes, and limiting factors

Select and implement actions

Monitor results

Figure 3-1. A stepwise approach to fishery management.

3.2

CURRENT STRESSORS TO THE COMO LAKE FISHERY

The previously completed Como Lake Water Quality Drivers Analysis Study (LimnoTech, 2017) provides a comprehensive review and analysis of all data and management activity done in Como Lake to that date. It identified the primary drivers thought to be the cause of poor water quality and stressed biologic communities, and recommended management actions. A review of that study and the available data (in Section 2 and elsewhere) suggests five primary stressors impacting the fishery, summarized in Table 3.1 and discussed in more detail below.

Table 3.1. Stressors affecting the fishery in Como Lake.

Stressor Impacts Water Quality Limited SAV Habitat Overabundance of Planktivorous Fish Imbalanced Zooplankton Community Limited and Altered Nearshore Habitat

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Watershed disturbance and lake eutrophication can limit the fishery to species that can tolerate low oxygen, more turbid conditions.

Currently, the native SAV community in Como Lake is limited and curly-leaf pondweed (CLP) infestations may be outcompeting native macrophyte populations and leading to a decline in biodiversity and water quality.

Lack of top predators allows planktivorous fish to thrive.

Reduced efficiency of phytoplankton grazing results in more frequent and widespread algal blooms.

Eutrophication and highly managed lakeshore can impact substrate and limit the amount of submergent and emergent vegetation that is used by fish as habitat for foraging, recruitment, and reproduction.

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3.2.1 Water Quality Como Lake is an urban, shallow lake that has been designated an Impaired water by the State of Minnesota because it does not meet state nutrient concentration standards. High levels of phosphorus can cause excessive blooms of algae that can have multiple impacts on the fishery.

Algal blooms reduce water clarity, which can reduce the growth of beneficial aquatic vegetation fish use for predation and spawning. When the algae die off, the detritus is consumed by bacteria, which also consume oxygen dissolved in the water column and at the lakebed. More sensitive fish that are intolerant of nutrient-rich, murky and low oxygen conditions cannot survive. Water quality can also be impacted through bioturbation of bottom sediments due to spawning and bottom-feeding activity of fish, which contribute phosphorus loading to the lake.

Como Lake also suffers from high concentrations of chloride from road salt in stormwater runoff.

It is widely accepted within the scientific community that the first step toward improving and protecting biotic communities in lakes is through managing nutrients and water quality. In 2020 the District began a multi-year project to improve water quality in the lake through the application of aluminum sulfate, or alum, to reduce and control phosphorus release from the lake’s sediments during periods of low oxygen.

3.2.2 Limited Submerged Aquatic Vegetation Habitat Studies suggest that “ideal” SAV conditions for fish are a diverse community with variability throughout the littoral area in SAV patchiness, architecture, biovolume, plant structure, and plant form (Olson et al. 1998; Valley and Bremigan 2002; Valley et al. 2004; Tomcko and Pereira 2006). Lakes with no or minimal SAV, and lakes with excessive amounts of monodominant stands that create inhospitable foraging environments are not desirable.

Como Lake’s SAV community is dominated by curly-leaf pondweed (CLP) early in the growing season, covering as much as 80 percent of the lake’s surface area at its peak abundance.

Native SAV richness in Como Lake is limited and plant coverage and biovolume is typically low following CLP senescence in early to mid-July. CLP is an invasive species that can dominate a lake’s aquatic macrophyte community. It begins growing in late fall, continues growing under the ice, and dies back relatively early in summer. As with phytoplankton, as it decomposes dissolved oxygen is consumed, creating low oxygen or anoxic conditions. It can also outcompete desirable native plant species that typically grow in early summer. The District undertook an herbicide treatment in 2020 to begin working towards controlling CLP and promoting growth of native plants.

3.2.3 Overabundance of Planktivorous Fish Healthy shallow lakes must maintain a delicate trophic balance of piscivorous (predator) fish, planktivorous/insectivorous fish, zooplankton, and phytoplankton. When this food web becomes unbalanced the lake can experience a trophic cascade. Historic fish data suggests that this can be the case in Como Lake, particularly during periods of strong year classes. The fish community in Como Lake has few large top predators and therefore predation pressure is relatively low. As a result, there are cascading effects on the zooplankton community, which in turn becomes unbalanced.

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3.2.4 Imbalanced Zooplankton Community The zooplankton data shows a population that is dominated by small-bodied taxa. The low density of large-bodied zooplankton is likely the result of intense size-selective feeding pressure by plankton-feeding fish leading to increased abundance of small-bodied zooplankton.

Small-bodied zooplankton are less efficient grazers on phytoplankton than large-bodied zooplankton. This allows for increased phytoplankton growth, resulting in more frequent and more widespread algal blooms and reduced clarity.

3.2.5 Limited and Altered Nearshore Habitat The shoreline of Como Lake is entirely in public ownership, part of Como Regional Park. The entire shoreline up to the water’s edge has been planted and restored with native vegetation in phases and has been maintained by a combination of hand and mechanical weeding and prescribed burning. Some shoreline zones were stabilized with biologs and erosion control mats for toe and slope stabilization and protection from fluctuating water levels. A 2020 Shoreline Assessment was completed to evaluate current conditions and opportunities for additional restoration. That study also evaluated existing reptile and waterfowl habitat. There is a limited amount of information about quality near-shore emergent vegetation and a lack of information about other types of habitat in the near-shore zone, include the availability of substrate for fish spawning. Further, decades of eutrophication and poor water clarity has limited the abundance and diversity of SAV needed by fish for foraging, refuge, recruitment, and reproduction.

3.3

FISHERY MANAGEMENT

3.3.1 Short- and Long-Term Goals Largemouth bass (LMB) is a species that could thrive in Como Lake as water quality and vegetation conditions improve. Increasing the size and abundance of the LMB population in Como Lake would have multiple benefits – most importantly improving recreational fishing opportunities and improving trophic balance through predator control. Improving the LMB population is viewed as a long-term goal, with shorter-term goals being restoration of the vegetation community, evaluation and removal (if needed) of excess benthivore biomass and establishing a more balanced fishery. LMB establishment success will likely take longer since it is heavily tied to improving water quality, SAV community, and nearshore habitat features.

3.3.2 Potential Tools Table 3.2 contains brief descriptions of fish management tools that may be appropriate for achieving Como Lake goals. The tools are organized into four major fisheries management approaches as outlined in USEPA’s Fish and Fisheries Management in Lakes and Reservoirs Guidance Manual (USEPA 1993): • • • •

Evaluating the Fish Community Managing Fish Habitat Manipulating the Fish Community Managing Fish Pressure

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Each potential tool has its advantages and disadvantages and may be more appropriate or less appropriate at various stages during the short and long term. Table 3.3 later in this report proposes an implementation plan of actions and sequencing.

The District is separately tackling external and internal phosphorus loading through ongoing programs and projects, and curly-leaf pondweed and aquatic vegetation management via its Como Lake Long-Term Aquatic Vegetation Management Plan (Wenck 2020). While this Como Lake Fish Management Plan is a separate analysis, in practice all these management efforts are closely intertwined and will be ongoing simultaneously.

3.3.3 Evaluating the Fish Community Monitoring and evaluation are necessary on an ongoing basis to assess changes in the fish and zooplankton communities so that course corrections can be made if necessary. There are numerous methods for evaluating biota, and it is essential to be strategic on how they are used. Each has its advantages and disadvantage and may be appropriate at different stages of the active management process (Table 3.2).

3.3.4 Managing Fish Habitat The District is taking an integrated approach to lake management, understanding that water quality improvements and SAV management are also integral to fishery management. In urban, highly developed lakes such as Como, evaluating and enhancing disturbed near-shore areas are often important implementation actions that can bolster recruitment of desirable species.

3.3.5 Manipulating the Fish Community An impaired and stressed fish community may require active manipulation through stocking and selective harvesting to reset the fish community.

3.3.6 Managing Fishing Pressure Humans are often a source of stress to the fishery. Actions to change or limit behaviors that are stressful to the community such as catch-and-release regulations or size restrictions may be necessary to allow the fishery to establish and become naturally reproducing.

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Table 3.2. Fishery management tools.

Management Approach

Management Activity

Mode of Action

Advantages •

Trap & gill net surveys

Capture-markrecapture surveys

Standardized methods used by DNR to evaluate fish communities in lakes throughout Minnesota. Trap nets consist of placing a lead net that extends perpendicular to shore with a series of hoops and funnels at the end of the net lead that entrap fish. The gill nets consist of multi-sized mesh panels that are typically placed in deeper (~8-12 feet), open water habitats catching fish via gill entanglement.

Survey method whereby target species are captured and marked (e.g. fin clips, external tags, radio tags, passive integrated transponder (PIT) tags, etc.) and released. Recapture survey(s) are then performed and marked fish are documented and used to model target species numbers and biomass

• • • •

• •

• Evaluating the Fish Community

Special electrofishing surveys

Electrofishing in nearshore for target species in nearshore areas and specific habitats (e.g. common carp, largemouth bass)

•

•

Nearshore surveys

Survey methods developed by DNR to complete assessments of habitats along shoreline areas.

Near shore survey data is combined with trap and gill net results to conduct Index of Biotic Integrity (IBI) evaluation of lake fish community health. Near shore survey methods include use of minnow seine net and backpack electrofishing unit at distinct locations along the lake shoreline

Creel surveys

Tool used by DNR to assess angler use and or satisfaction for a water body. Can be an important management tool to gather information related to hours of angler use, harvest of target species, and angler satisfaction. Surveys can include a combination of passive observation (such as simply recording how many or how long anglers use the fishing pier) and active interviews with specific questions to collect target data

February 2021

•

•

•

• • • •

Provides a general means to qualitatively evaluate fish community structure and presence/absence of certain species Costs are reasonable compared to other survey methods DNR routinely conducts these surveys every ~5 years on recreational lakes throughout the metro and state Previous monitoring efforts can be compared to future efforts to easily track progress/changes in the fish community Results can be compared to other lakes of the same lake class for comparison and to develop reasonable goals/targets “Gold standard” survey method to estimate target species lake-wide numbers and biomass when recapture survey(s) are effective Allows better confidence in management goals, end points, and tracking progress

Disadvantages • • •

•

• • •

Ability to target species that are not collected and/or underrepresented in trap & gill nets surveys Ability to sample specific habitats and times of year when target species are using those habitats Surveys can typically be completed in one day for small/moderate sized lakes where the majority of the lakeshore areas can be surveyed and assessed

• •

Ability to target species that are not collected and/or underrepresented in trap & gill nets surveys Ability to collect young of the year fish from nearshore areas as a potential way to gage reproductive success of target management species (other methods mainly target larger or adult fish) Surveys can typically be completed in conjunction with trap & gill net surveys while adding minimal cost to that year’s field budget.

•

Surveys can be customized to collect the information specific to the goals of the entity overseeing the survey.

Once protocols are established, survey can be conducted by anyone, including summer interns to keep costs manageable Provide direct feedback from recreational users of their perspective for lake use One of the only methods to help estimate harvest of target management species

•

3-5

•

• •

• •

Certain species are not captured or are underrepresented by this gear type (e.g. common carp, largemouth bass, minnows and juvenile fish) Surveys do not provide a means to estimate lake-wide numbers and biomass of individual species, or the fish population as a whole May need to supplement more frequent surveys than DNR’s routine schedule (~5 years) to truly evaluate interannual trends and/or success of management activities Potentially high mortality in targeted fish species populations Expensive and labor intensive May require several recapture efforts to provide reliable data Large-scale recapture surveys are unpredictable and may be extremely difficult for some lakes depending on schooling behavior of target species and physical/environmental factors Requires electrofishing boat and specialized equipment Several surveys may be needed within a year or from year to year to build a reliable database and analyze trends Reliable methods, standards, and metrics for analyzing results are limited compared to other methods (i.e. for largemouth bass, may have to rely on results from other systems to establish targets/goals) IBI scoring protocols have not been developed for all Schupp Lake classifications; may need to use a modified or “closest match” scoring protocol to calculate IBI scores A relatively small percentage of shoreline is assessed compared to the special electrofishing surveys.

Surveys of this type are unlikely to provide information on adult/catchable size top predator species; therefore, this survey technique would not necessarily replace any of the above listed survey methods Results of survey is dependent on willingness of anglers to share information about their catch and experience. Some measurements can be collected by passive observation (instead of interviews) if needed Information collected is helpful to provide context but is more a qualitative assessment of fish populations compared to quantitative surveys listed above.

Can be relatively labor intensive to conduct surveys throughout the summer recreational season.

Management Approach

Management Activity

Mode of Action

Advantages

Disadvantages •

Zooplankton surveys

Evaluate and manage water quality

Zooplankton monitoring conducted in conjunction with water quality and other efforts throughout the year

Monitor and evaluate key water quality parameters that can be direct and/or indirect stressors to fish communities: • Chloride levels • Dissolved oxygen levels • Eutrophication levels (TP, Chl-a, Secchi)

Conduct surveys to evaluate current fish habitat conditions and spawning locations in nearshore areas (e.g. current status of fallen trees, drop offs, emergent vegetation, weedy shallow shorelines, nesting areas, etc.)

Evaluate, improve, and protect nearshore habitat

• • •

• Implement watershed and in-lake activities to improve/protect water quality conditions

Managing Fish Habitat

Provides a means to begin to qualitatively answer specific questions about the lake’s food web dynamics: • Do zooplankton #s and types provide adequate grazing of phytoplankton and support desired water quality goals?

• Are zooplankton numbers and types supportive of desired fish community?

• Is the fish community negatively impacting zooplankton community through grazing pressure by planktivorous fish?

•

• • •

• Implement projects (e.g. shoreline stabilization, restoring emergent vegetation, complex bundles of tree drops, addition of other course woody habitat, substrate manipulations, addition of artificial structures, lake drawdown) to improve and protect critical habitat areas identified during nearshore habitat and spawning survey

February 2021

• • •

Relatively inexpensive to collect Monitoring these parameters are often already done and supported through other programs/initiatives Provides a means to evaluate state of the lake (i.e. clearwater or turbid-water) and bottom-up pressure on fish community Widely accepted within the scientific community that the first step toward improving and protecting biotic communities in lakes is through managing nutrients and water quality Water quality improvement projects are supported through local/state/federal programs and initiatives Relatively inexpensive survey Assessment will identify current near-shore habitat locations to target for protection Identify areas with minimal and/or degraded habitat that could be target for improvements Providing area for cover, feeding, and/or spawning will directly benefit species currently in the lake as well as those targeted for continued management Materials such as woody debris or substrates (sand and gravel) are readily available and can be easily added to the lake.

Likely a relatively inexpensive option, as no direct largescale in-lake management or manipulation would occur Some artificial structures are easy to add and could potentially be removed in the future if natural habitat conditions improve.

3-6

• • •

• •

Sampling can be costly (due to lab costs) compared to other parameters and requires specific equipment (e.g. plankton nets) Zooplankton community structure can be different in different parts of a lake Analysis of results are more qualitative than quantitative Food webs are very complex and therefore data conclusions are often speculative in nature. In many cases, there are likely several potential drivers of changes in zooplankton numbers and community structure (i.e. shifts in water quality, vegetation, fish community, environmental factors, etc.) rather than a singular cause and effect relationship Although some literature and general guidelines do exist, specific metrics/goals connecting water quality and fish tolerance and community response is limited Water quality alone cannot always explain or predict changes in biotic communities

• • •

Can be very costly Limited space to implement projects Can take a long time to achieve final targets/goals

•

Limited guidance/protocols/methods currently exist to survey nearshore habitat conditions Limited guidance in literature with specific details on the appropriate amount of nearshore habitat that should be enhanced/protected

•

• • • • •

Fishing pressure could increase in and around restored areas which could lead to overharvesting if not controlled Simply adding nearshore habitat features does not guarantee that fish will use these features Other management actions such as improving water quality and establishing SAV community often have bigger effects on fish community Need to guard against homogenic substrate additions as too much clean sand or gravel could create a desert like affect in an area May require DNR permits for construction/implementation, and in the case of artificial structures, may require obtaining annual permits for deployment

Management Approach

Management Activity

Mode of Action

Conduct annual SAV point intercept surveys to evaluate SAV habitat conditions

Advantages • •

Surveys are relatively inexpensive SAV surveys are often supported through other programs/initiatives Previous surveys can be compared to future efforts as management occurs to track progress/changes in SAV habitat

Disadvantages •

•

•

Evaluate, improve, and protect SAV habitat

Establish fish exclusion plots to evaluate the impact of fish, particularly rough fish, on the SAV community

Manage (e.g. mechanical/herbicide treatments, transplanting, etc.) the SAV community as needed to create optimum SAV habitat conditions for fish, which includes: • Widespread coverage of SAV throughout littoral area • Diverse community dominated by native species • Limit excessive growth/density that creates inhospitable foraging environment

• •

Provides a potential means to evaluate to what degree rough fish may be impacting SAV, water quality, and other factors in the lake Establishing exclusion plots are relatively inexpensive

• •

• • • •

Well documented within the scientific community that a robust SAV community is one of the most critical habitat features to support healthy fish and biotic communities Vegetation management (e.g. chemical treatments and mechanical harvesting) is a common practice in Minnesota lakes Management activities are proven to provide short term control and changes to target species

• •

• •

Manipulating the Fish Community

Targeted Fish Stocking

Targeted stocking of selected adult and/or juvenile fish to support desired fish community goals (e.g. stocking piscivorous species such as largemouth bass to promote more balanced food web structure)

February 2021

• •

Addition of adult piscivorous fish to systems that lack top predators will aid in developing a naturally reproducing population.

Addition of adult piscivorous fish to systems that lack top predators could provide grazing control on planktivorous fish if stocking is successful If adult fish are protected by special fish regulations (see below) they would also be a recreational resource to lake users.

3-7

• • •

Changes in SAV can be complex and the result of various factors/drivers (e.g. water clarity, water levels, presence of rough fish, environmental factors, etc.) making it difficult to make firm conclusions.

Although some literature exists, specific metrics/goals for ideal SAV species, architecture, patchiness, biovolume, and plant structure are rather limited Will require monitoring and maintenance of plots to ensure structures are secure and fish are excluded throughout the monitoring season Other factors/drivers (e.g. water quality, environmental factors) may impact SAV growth in exclusion plots making it difficult to evaluate rough fish impacts Results may be difficult to interpret and/or compromised if large scale SAV management efforts (e.g. fluoridone treatments) are occurring Since SAV growth has various factor/drivers, managing to optimum habitat conditions for fish can be extremely difficult and may not be sustainable unless all other factors/drivers are controlled Continuous management may be needed to manage SAV to meet goals SAV management in which undesirable SAV is removed/treated but is not replaced by new SAV represents a loss of habitat and a major void for certain fish species. This can have dramatic negative effects on lake water clarity, as well as SAV and the overall fish community (Valley et al. 2004; Heiskary et al. 2012; Radomski and Perleberg 2019; Radomski et al. 2019) Stocked species may not survive/flourish/reproduce if habitat conditions are not favorable (e.g. lack of SAV or nearshore habitat) or if major stressors (e.g. water quality) to the fish community are not addressed Could be high costs to acquire adult fish and the supply may be limited at times.

Alternate could be to stock younger fish (less cost to purchase) but would need more time for fish to grow and reach reproductive age.

Multiple stocking efforts may be needed over several years to ensure a sufficient number of fish become established to create a sustainably reproducing population.

Management Approach

Management Activity

Mode of Action

Advantages

Disadvantages • •

Fish Removals

Fish removals via physical methods (e.g. openwater seining, nearshore seining, channel trapping, box netting, electrofishing), drawdowns, or chemical controls (e.g. rotenone) can be used to “reset” the fish community and/or reduce biomass of invasive and/or undesirable species that can negatively impact water quality and fish community composition

•

•

If successful, removal activities can have immediate impact on overall lake ecology as overabundance of undesirable species are no longer present, creating availability of resources for consumption /use by target species Reduction in bioturbation of sediments could have direct positive impact on in-lake water quality by reducing internal loading

• • • •

Managing Fishing Pressure

Fishing Regulations limiting or prohibiting harvest of identified species

Work with DNR to implement regulations such as: • “No Kill” rule prohibiting all harvest of specific species • Size restriction limiting harvest to a certain size range or maximum allowable size of fish • Reduce number of fish that can be harvested (i.e. 1 or 2 individuals compared to state harvest rule of 6 fish)

February 2021

•

• • •

Implementing restrictions would protect the adult fish in the lake to allow time for the species to become well established, utilize reproductive areas, grow, and begin naturally reproducing in the system Provides immediate protection for target species Costs for implementation are low, only requiring signs and publication of special regulation within State fishing regulations.

This method has proven successful to help establish target species (e.g. largemouth bass) populations in other Minnesota lakes

3-8

• • • • •

Removal activities can be labor intensive and expensive to implement Chemical controls (e.g. rotenone) would impact all species present and is not typically viewed favorably by the public or resource managers Capture and harvest of significant biomass of target species (e.g. black bullhead, common carp) is difficult to predict.

Coordination with commercial fisherman can be challenging and other removal methods (e.g. box netting) are less developed and often labor intensive May require multiple removal efforts to reduce biomass of target species Even if removal efforts are successful, future removals may be required if controls are not in place to limit recruitment and reproduction of removed species Will need DNR to consent to and approve all special regulations.

Must establish appropriate targets/measures for implementing the regulation and then also for possible removal of the regulations in the future.

Potential source of frustration among the fishing community.

Education is key – if lake users are not aware of the rules they will not be followed or may be ignored.

Enforcement can be difficult based on staff availability (either the DNR or Watershed) and unknown penalties for non-compliance.

3.4

COMO LAKE FISHERY MANAGEMENT IMPLEMENTATION PLAN

Managing the fishery in Como Lake is primarily a four-step process starting with: 1. Improving overall water quality in the lake.

2. Ensuring a healthy native vegetation community by increasing biodiversity and minimizing excessive growth of mono-dominant vegetation stands 3. Enhancing in-lake fish habitat where feasible.

4. When progress has been made with the above, undertaking biomanipulation as necessary to achieve the desired fish community.

The long-term goal for fish management in Como Lake is a self-supporting, biodiverse and healthy fish community anchored by LMB, providing plentiful opportunities for angling and supporting other shallow lake management goals in the lake. A healthy and thriving fish community is critical in maintaining a healthy shallow lake.

Figure 3.2 depicts the general approach to restoring and managing a healthy biota in Como Lake. Improving and maintaining water quality in the lake will be an ongoing effort. During the first five years or so, the District will continue efforts to manage the vegetation community and to more thoroughly document the baseline fish and zooplankton communities. There will be no active management of the fishery until further surveys/assessments have been conducted (e.g. targeted electrofishing surveys) and improvements to water quality and the SAV community have been achieved. During this time, the District will work together with the DNR to undertake more active fishery management, which may include creel surveys, planned stocking, habitat manipulation, and special regulations.

Threaded through this implementation is ongoing monitoring and assessment to determine progress towards interim milestones and long-term goals and to identify any needed interim course corrections. This adaptive management approach is a stepwise, iterative process of implementation that establishes interim milestones that must be met prior to moving on to the next management action. Because fishery management is just one facet of the overall improvement of Como Lake, this approach assures that all the parts are moving forward toward the District’s goals.

Figure 3-2. Generalized fishery management action plan.

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The following is a brief description of the focus for the first management cycle (5 years) and guidance for setting the approach for future management cycles (Table 3.3).

3.4.1 Evaluating the Fish Community A thorough monitoring program in Year 1 of implementation is essential to establish baseline conditions and obtain a thorough understanding of the community structure and food web. This includes not only trap and gill net surveys, but also zooplankton surveys, near-shore carp electrofishing, and creel surveys of local anglers to understand user experiences and expectations. Surveys in later years may be repeated at less frequent intervals.

3.4.2 Managing Fish Habitat The focus in the first five years is on improving water quality in the lake and restoring native vegetation. It will be important to assess near-shore conditions and consider habitat improvements, such as restoration of emergent vegetation and addition and/or modification of substrate. As SAV and water quality goals are achieved or are close, implementation will transition to adaptive management.

3.4.3 Manipulating the Fish Community If common carp surveys performed in Year 1 indicate that carp biomass in the lake exceeds accepted guidelines, carp removals may be necessary. The District will partner with the DNR to develop a plan to achieve the desired fishery through targeted stocking.

3.4.4 Managing Fish Pressure A targeted stocking plan may also require adopting differential regulation(s) in Como Lake until the fishery can be self-sustaining. It will also be beneficial to initiate an outreach campaign to educate anglers about the fish management plan and how special regulations can be an effective strategy in ensuring that a self-sustaining LMB fishery is achievable.

It will likely take several years for special regulations to be reviewed and approved for implementation by the DNR, therefore the District will begin discussions with the DNR regarding this process in the first year of this plan.

February 2021

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Table 3.3. Fishery restoration implementation plan for Como Lake.

Management Approach

Management Activity

Cycle 1 Actions (Years 1-5) Goal(s)

Current Condition

Year 1 •

1) Trap & gill net surveys

2) Electrofishing survey: largemouth bass (LMB)

Evaluate current structure of the fish community and changes over time as management occurs

Surveyed by DNR every 5 years

Conduct summer trap & gill net surveys to establish baseline conditions for year 1 of this plan

Evaluate LMB population; ultimate target/goal of 50 fish/hour during survey

Last surveyed by DNR in 2017

Conduct near-shore LMB electrofishing survey (spring) to establish baseline conditions for year 1 of this plan

•

• •

Implement activities #10 and #11 as necessary based on Year 1 survey results Conduct summer trap net surveys every 2-3 years as management actions are carried out. Gill net surveys will only be conducted every 5 years due to higher mortality rates of large piscivores (e.g. northern pike)

Continue trap net surveys every 2-3 years until goals are achieved. Revert back to 5-year schedule when goals are achieved and/or management actions are ended. Gill net surveys continue on 5year schedule

Implement activities #8 and #9 to evaluate and improve LMB habitat conditions Conduct follow-up surveys to track progress as management occurs

Conduct more near-shore LMB electrofishing surveys as management actions occur

Implement management activity #10 as necessary based on Year 1 survey results Conduct follow-up surveys to track progress when/if management occurs

Establish routine schedule (e.g. every 5 years) to track common carp

3) Special electrofishing survey: common carp

Evaluate common carp biomass

Never been assessed

Conduct summer common carp electrofishing surveys according to methods detailed in Bajer et al. 2009 (three events consisting of 3, 20 minute transects). Additionally, implant PIT tags in captured carp that can be used for capture-mark-recapture analyses

4) Nearshore surveys

Evaluate health of the entire fish community

Last surveyed in 2017

Conduct nearshore surveys using DNR’s IBI methods/protocols to establish baseline conditions for year 1 of this plan

None

Update nearshore survey and IBI scores to track progress after management actions occur

Conduct survey of local anglers to obtain data on fishing pressure as well as local perspective on the overall state of the fishery, fishing amenities, recreational experience, recommendations, etc.. Survey could be completed using a kiosk with comment cards to be filled out by anglers. District staff could develop survey, place cards near fishing access points, collect the cards, and record the results.

Use Year 1 creel survey results to inform and drive activities #11 and #12

None

Monitor zooplankton community using current methods/schedule to establish baseline conditions for Year 1 of this plan

Continue monitoring zooplankton community using current methods/schedule to evaluate changes in community as management occurs

Continue monitoring zooplankton community using current methods/schedule

Evaluate the Fish Community

Evaluate current fishing pressure and desired recreational fishing opportunities

Last Creel Survey in 2003

6) Zooplankton surveys

Evaluate food-web structure

Surveyed in conjunction with water quality

7a) Water quality monitoring

Monitor key water quality stressors to fish community: chloride, DO, eutrophication

5) Creel surveys

Improve Fish Habitat

Cycle 2 Actions (Years 5+)

Years 2-5

7b) Water quality improvements to support fish community

Long-term goals: i) Chloride <230 mg/L* ii) DO >3.5 (critical conditions)**; DO >6.5 (dec. production)** iii) TP = 60 ug/L* iv) Chl-a = 20 ug/L* v) Secchi = 1.0 m* * MPCA State Standard **EPA guidance (EPA 1993)

Routinely monitored throughout summer i) Chloride = will assess current conditions in Year 1 ii) DO = will assess current conditions in Year 1 iii) TP = 71 ug/L (2020) iv) Chl-a = 30 ug/L (2020) v) Secchi = 1.0 m (2020)

February 2021

Monitor water quality using current methods/schedule to establish baseline conditions for Year 1 of this plan • •

Implement activity #7a Further assess current conditions (chloride and DO) and establish realistic/achievable interim water quality goals/targets that will help set benchmarks and guide adaptive management toward the long-term WQ goals to improve fish habitat. Use the updated Como Lake water quality model to run scenarios (TP) of recent/future WQ projects

3-11

• •

• •

• • • •

Continue monitoring water quality using current methods/schedule to evaluate changes as management occurs Develop chloride impact study (per Como Lake Vegetation Mgt. Plan) Adaptive management based on outcomes of activity #7a Continue implementation of alum treatment (per Como Lake Plan) Continue implementation of watershed BMPs (per Como Lake Plan) Continually evaluate DO targets/goals as progress toward eutrophication goals is achieved

• •

Continue monitoring water quality using current methods/schedule Implement activity #7b based on results of water quality monitoring and chloride impact study

Assess data, continue monitoring, implement adaptive management • Ensure internal P load control • Continue implementation of watershed BMPs (per Como Lake Plan) • Implement chloride BMPs

Management Approach

Management Activity

Cycle 1 Actions (Years 1-5) Goal(s)

Current Condition

Year 1 •

8a) SAV surveys

Evaluate SAV habitat conditions

Routinely monitored 2X per year •

8b) Establish and maintain healthy and diverse native SAV community (per Vegetation Mgt. Plan)

9a) Evaluate nearshore habitat

i) CLP <10% FOC* ii) Species Richness >8* iii) Min 3 species with FOC >20%* iv) Overall FOC >20% & <60%** *per Vegetation Mgt. Plan **Wren et al. 1996

2020: i) CLP 35% FOC ii) Species Richness = 3 iii) 1 species (coontail) with FOC >20% iv) Overall FOC = 33%

Evaluate current fish habitat conditions and spawning locations in nearshore areas

Never been assessed

Continue SAV surveys using current methods/schedule to track SAV management activities establish baseline SAV habitat conditions for Year 1 of this plan Establish fish exclusion plot to evaluate impact of fish on SAV community

• •

Implement activity #8a Implement herbicide treatment as necessary based on results of 2020 treatments (per Vegetation Mgt. Plan)

•

Prior to conducting survey, establish nearshore habitat survey methods and habitat goals and targets through discussion with DNR, literature review, etc.

Conduct nearshore fish habitat survey to identify current habitat features to protect and potential locations for improvements (e.g. status of fallen trees, drop offs, emergent vegetation, weedy shallow shorelines, nesting areas, shoreline erosion, etc.)

•

•

Goals need to be developed (see activity #8a)

Never been assessed

•

See year 1 actions and repeat as necessary (per Vegetation Mgt. Plan)

•

Use Year 1 nearshore habitat survey results to inform and drive activity #9b Conduct hydrologic assessment of lake drawdown (per Vegetation Mgt. Plan)

•

Implement activity #9a •

10) Fish Removals

i) common carp biomass <89 lbs/acre ii) other species that can affect SAV and water quality (e.g. black bullhead) below upper quartile range for both CPUE and biomass

i) common carp biomass never been assessed ii) black bullheads below upper quartile range (2017)

11) Fish Stocking

Create a diverse, ecologically balanced fishery that can also support and sustain recreational fishing for the community (per Como Lake Plan) i) Carnivore biomass* >30%

i) Piscivores=18% biomass (2017) ii) 3 LMB caught per hour (2017) iii) see activity #10

Manipulate the Fish Community

February 2021

• • •

Implement activities #1-4 If common carp biomass >89 lbs/acre, install radio tags (~10) and additional PIT tags in fall

•

Implement year 1 actions for activities #1-6 to establish baseline conditions for year 1 of this plan Establish stocking plan in consultation with DNR to achieve stated goals

•

3-12

Continue SAV surveys using current methods/schedule to track changes as activities #7b and #10 are implemented

See Previous

•

•

9b) Implement projects to improve and protect nearshore fish habitat

Cycle 2 Actions (Years 5+)

Years 2-5

•

Implement projects and strategies to protect and improve nearshore habitat based on outcomes of activity #9a (e.g. shoreline stabilization, restoring emergent vegetation, complex bundles of tree drops, addition of other course woody habitat, substrate manipulations, addition of artificial structures, etc.)

Note: Types and amount of nearshore habitat manipulation will be tied to progress of SAV community goals (activity #8b) If common carp surveys indicate biomass >89 lbs/acre, conduct on-ice winter sein to reduce biomass If bullhead trap net surveys indicate bullheads exceed the upper quartile range, consider options to reduce biomass (e.g. onice winter sein, spring trapping)

Begin implementing fish stocking plan

•

Maintain CLP Occurrence to less than 10% (per Vegetation Mgt. Plan) Implement spot herbicide treatments (per Vegetation Mgt. Plan)

None

•

•

Protect nearshore habitat and spawning locations through signage and/or implementing recreation restriction in these areas Implement findings of lake drawdown assessment (per Vegetation Mgt. Plan)

Continue managing common carp and/or other species to achieve goals through adaptive management

Adjust stocking plan through monitoring and adaptive management

Management Approach

Management Activity

Cycle 1 Actions (Years 1-5) Goal(s)

Current Condition

ii) LMB = Min. of 50 LMB caught per hour** iii) Common carp = see goal i for activity #10 iv) Improve size structure of invertivore-carnivore and invertivore species (e.g. black crappie and bluegills) *based on EPA 2013) **based on goals established for other lakes in Minnesota

Manage Fishing Pressure

12) Implement Special Regulations

Sustain recreational fishing for the community (per Como Lake Plan). See specific goals outlined in activity #11

iv) Recent surveys indicate invertivorecarnivores and invertivores are primarily comprised of small individuals

No special regulations currently in place

February 2021

Year 1 •

Within stocking plan, establish benchmarks that must be met for specific stocking activities to proceed (e.g. activity #9 must be complete and/or goal iv for activity #8b must be met for three consecutive years prior to stocking of adult LMB)

•

Implement Year 1 actions for activity #5 (creel survey) Implement Year 1 actions for activity #11 (develop fish stocking plan) Work with DNR to evaluate and begin process of implementing minimum slot limit of LMB and/or other restrictions to protect the population.

• •

3-13

Years 2-5

• •

Begin implementing fish stocking plan Continue working with DNR on implementing LMB restriction(s)

Cycle 2 Actions (Years 5+)

Adjust stocking plan and fishing regulations through monitoring and adaptive management

3.5

SUMMARY OF NEXT STEPS

This plan presents a four-step process to manage the fishery in Como Lake to achieve the primary goals of maintaining a balanced fishery and year-around recreational fishing opportunities. The four-step process includes: 1) ensuring a healthy native vegetation community; 2) improving overall water quality; 3) enhancing in-lake fish habitat; and 4) biomanipulation of the fish community. Below is a summary and timeline of action items included in this plan for Year 1, Year 2, and Years 3 and beyond.

3.5.1 Year 1 The first year will focus on completing baseline assessments and working with the DNR to develop and implement initial fish management.

•

[Winter] District will meet with DNR to review this plan and discuss: o o o

•

Roles/responsibilities for Year 1 baseline data collection surveys and assessments Review stocking plan for Year 1 and discuss how future stocking may change once Year 1 baseline data has been collected, and reviewed Initiate the process of future regulations as necessary to limit/prohibit harvest of LMB and other target species, such as implementing a “no kill” rule, establishing size restrictions or harvest limits, etc.

[Spring/Summer] District and partners will collect Year 1 baseline habitat and fish community data by performing the following surveys and assessments: o o o o o o o o o

Trap and gill net surveys LMB targeted electrofishing survey Common carp targeted electrofishing survey(s) Nearshore fish community survey Creel survey(s) Zooplankton surveys Water quality monitoring SAV surveys Nearshore habitat survey

•

[Fall] District and partners will begin planning common carp biomass removals (if necessary) depending on results of summer surveys.

•

[Fall] District will produce an annual progress report/memorandum that summarizes the results of the Year 1 actions and surveys/assessments. The progress report will serve as an addendum to this plan and will also include a summary of the water quality and SAV management actions and outcomes.

•

[Fall/Winter] District will meet with DNR and other partners to review annual progress report and discuss Year 2 adaptive management plan and action items.

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3.5.2 Year 2 Year 2 actions will continue actions begun in Year 1 and focus on assessing conditions against the short-term milestones established for water quality, SAV, and the fishery.

•

[Winter] District and partners will lead efforts (if necessary) to conduct on-ice winter seine to reduce benthivore biomass.

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[Spring/Summer] District and partners will begin adaptive management process based on results of Year 1 baseline data. This could include, but is not limited to: o o

Continued SAV management Projects to protect and improve nearshore habitat

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[Spring/Summer] District and partners will continue performing water quality monitoring, and SAV and zooplankton surveys.

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[Fall] District will produce an annual progress report/memorandum that summarizes the results of the Year 2 actions and surveys/assessments.

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[Fall/Winter] District will meet with DNR and other partners to review annual progress report and discuss Year 3 adaptive management plan and action items.

3.5.3 Years 3 and beyond: Following the first few years of baseline monitoring and focus on water quality and SAV management, the focus will be on evaluating the impacts of shifting conditions on the fishery and other biotic communities. Progress will be evaluated annually against the shortterm benchmarks that when met will signal movement to the next phase of management.

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[Spring/Summer] District and partners will begin adaptive management process based on results of Year 1 and 2 survey/assessments and data collection.

•

[Spring/Summer] District and partners will continue performing water quality monitoring, and SAV and zooplankton surveys.

•

[Fall] District will produce an annual progress report/memorandum that summarizes the results of the Year 3+ actions and surveys/assessments.

•

[Fall/Winter] District will meet with DNR and other partners to review annual progress report and discuss Year 3+ adaptive management plan and action items.

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4.0 References Bacigalupi, J., Treml, P., and D. Staples. 2015. Lake IBI Nearshore Sampling Manual Updated May 2015, for use by MNDNR Fisheries Section. Minnesota Department of Natural Resources. Ecological and Water Resources Division. Brainerd.

Bajer, P.G., M.W. Beck, P.J. Hundt. 2018. Effect of non-native versus native invaders on macrophyte richness: are carp and bullheads ecological proxies? Hydrobiologia 817: 379-391.

Baker, J.P., H. Olem, C.S. Creagor, M.D. Marcus, and B.R. Parkhurst. 1993. Fish and fisheries management in lakes and reservoirs. EPA 841-R-93-002. Terrene Institute and US Environmental Protection Agency.

Bettoli, P.W., M.J. Maceina, R.L. Noble, and R.K. Betsill. 1992. Piscivory in largemouth bass as a function of aquatic vegetation abundance. North American Journal of Fisheries Management. 12:509-516.

Braig, E. C. & D. L. Johnson, 2003. Impact of black bullhead (Ameiurus melas) on turbidity in a diked wetland. Hydrobiologia 490: 11–21.

Colle, D. E. & J. V. Shireman, 1980. Coefficients of condition for largemouth bass, bluegill and redear sunfish in hydrilla-infested lakes. Trans. am. Fish. Soc. 109: 521–531.

Cross, T.K., and M.C. McInerny. 2001. Spatial habitat influences on inshore fish communities in a selected Minnesota ecological lake class. Minnesota Department of Natural Resources, Section of Fisheries Investigational Report 494, St. Paul.

CRWD. 2019. Como Lake Management Plan. Prepared by LimnoTech for Capitol Region Watershed District, St. Paul, MN. Dibble, E. D., K. J. Killgore, and G. O. Dick. 1996. Measurement of plant architecture in seven aquatic plants. Journal of Freshwater Ecology 11:311±318 Drake and Pereira 2002 (1997 ref in Tomcko) Durocher, P.P., W.C. Provine, and J.E. Kraai. 1984. Relationship between abundance of largemouth bass and submerged vegetation in Texas reservoirs. North American Journal of Fisheries Management 4:84-88.

Fischer, J. R., R. M. Krogman & M. C. Quist, 2013. Influences of native and non-native benthivorous fishes on aquatic ecosystem degradation. Hydrobiologia 711: 187–199.

Goldstein, R. M., and T. P. Simon. 1999. Toward a united definition of guild structure for feeding ecology of North American freshwater fishes. Pages 123–202 in T. P. Simon, editor. Assessing the sustainability and biological integrity of water resources using fish communities. CRC Press, Boca Raton, Florida.

Leunda, P. M., J. Oscoz, B. Elvira, A. Agorreta, S. Perea & R. Miranda, 2008. Feeding habits of the exotic black bullhead Ameiurusmelas (Rafinesque) in the Iberian Peninsula:

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first evidence of direct predation on native fish species. Journal of Fish Biology 73: 96–114.

LimnoTech, 2017. Como Lake: Water Quality Drivers Analysis Study. Prepared for Capitol Region Watershed District, St. Paul, MN. Maceina, M. 1996. Largemouth bass abundance and aquatic vegetation in Florida lakes: An alternative interpretation. Journal of Aquatic Plant Management 34(34):43-47.

Minnesota DNR. Multiple Years. Fisheries Lake Surveys. dnr.state.mn.us/lakefind/showreport.html?downum=62005500 Miranda, L. E. & L. L. Pugh, 1997. Relationship between vegetation coverage and abundance, size and diet of juvenile largemouth bass during winter. N. am. J. Fish.

Manage. 17: 601–610.

Miranda, L. E., M. D. Habrat, and S. Miyazono. 2008. Longitudinal gradients along a reservoir cascade. Transactions of the American Fisheries Society 137:1851–1865.

Mittelbach, G. 1981. Foraging efficiency and body size: A study of optimal diet and habitat sue by bluegills. Ecology 62(5):1370-1386.

Noonan, T. A. (1998) Como Lake, Minnesota: The Long-Term Response of a Shallow Urban Lake to Biomanipulation, Lake and Reservoir Management, 14:1, 92-109, DOI: 10.1080/07438149809354113 Olson, M. H., S. R. Carpenter, R. Cunningham, S. Gafny, B. R. Herwig, N. P. Nibbelink, T. Pellett, C. Storlie, A. S. Trebitz, and K. A. Wilson. 1998. Managing macrophytes to improve fish growth: a multi-lake experiment. Fisheries 23(2):6±12.

Radomski, P. and D. Perleberg. 2019. Avoiding the invasive trap: policies for aquatic nonindigenous plant management. Environ Values. 28(2):211–232. Journal of Aquatic Plant Management 34(34):43-47.

Radomski, P., K. Carlson D. Perleberg. 2019. Advancing aquatic vegetation management and for fish in north temperate lakes, Lake and Reservoir Management, 35(4):355363.

Repsys, A. J. R. L. Applegate, and D. C. Hales. 1976. Food and food selectivity of the black bullhead, Ictalurus melas, in Lake Poinsett, South Dakota. J. Fish. Res. Bd. Can. 33(4,1):768-775.

Sammons, S. M., C. Scalet, and R. Neumann. 1994. Seasonal and size-related changes in the diet of northern pike from a shallow prairie lake. Journal of Freshwater Ecology 9:32 1-329.

Schlagenhaft, T. 1993. Manual of instructions for lake survey. Minnesota Department of Natural Resources, Section of Fisheries Special Publication 147, St. Paul.

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Schupp, D. H. 1992. An ecological classification of Minnesota lakes with associated fish communities. Minnesota Department of Natural Resources, Fisheries Investigational Report 417, St. Paul.

Shoup, D.E., R.E. Carlson, and R.T. Heath. 2003. Effects of predation risk and foraging return on the diel use of vegetated habitat by two size-classes of bluegills.

Transactions of the American Fisheries Society 132:590-597.

Silbernagel, J.J. and P.W. Sorensen. 2013. Direct Field and Laboratory Evidence that a Combination of Egg and Larval Predation Controls Recruitment of Invasive Common Carp in Many Lakes of the Upper Mississippi River Basin, Transactions of the American Fisheries Society, 142:4, 1134-1140 Tomcko, C.M., and D.L. Pereira. 2006. The Relationship of Bluegill Population Dynamics and Submerged Aquatic Vegetation in Minnesota Lakes. Minnesota Department of Natural Resources Investigational Report 538, 2006.

Valley, R.D., and M.T. Bremigan. 2002. Effects of macrophyte bed architecture on largemouth bass foraging: implications of exotic macrophyte invasions. Transactions of the American Fisheries Society 131:234-244.

Valley, Ray, T. Cross, and P. Radomski. 2004. The role of submersed aquatic vegetation as habitat for fish in Minnesota lakes, including implications of non-native plant invasions and their management. Minnesota Department of Natural Resources Special Publication 160.

Werner, E.E., J.F. Gillian, D.J. Hall, and G.G. Mittelbach. 1983. An experimental test of the effects of predation risk on habitat use in fish. Ecology 64:1546-1548.

Werner, E. E., and D. J. Hall. 1988. Ontogenetic habitat shifts in bluegill: the foraging ratepredation risk trade-off. Ecology 69:1,352-1,366.

Wrenn, W.B., D.R. Lowery, M.J. Maceina, and W.C. Reeves. 1996. Relationships between largemouth bass and aquatic plants in Guntersville reservoir, Alabama. American Fisheries Society Symposium 16:382-393.

Wenck 2017. Como Lake Fish Community Surveying. Memo prepared for Capital Region Watershed District.

Wenck 2020. Como Lake Long-Term Aquatic Vegetation Management Plan. Report prepared for Capital Region Watershed District.

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