ChesMMAP Final Report 2006

ANNUALPROGRESS REPORT Data collection and analysis in support of single and multispecies stock assessments in Chesapeake Bay: The Chesapeake Bay Multispecies Monitoring and Assessment Program School of Marine Science College of William and Mary Virginia Institute of Marine Science Gloucester Point, VA 23062

Christopher F. Bonzek Robert J. Latour, Ph.D James Gartland

June 2007

ANNUAL PROGRESS REPORT

Data collection and analysis in support of single and multispecies stock assessments in Chesapeake Bay: The Chesapeake Bay Multispecies Monitoring and Assessment Program

U.S. Fish and Wildlife Service Sportfish Restoration Project F-130-R-2 April 2006 – March 2007

Submitted June 2007

Prepared by: Christopher F. Bonzek Robert J. Latour, Ph.D James Gartland

School of Marine Science College of William and Mary Virginia Institute of Marine Science Gloucester Point, VA 23062

Submitted to: Virginia Marine Resources Commission United States Fish and Wildlife Service

ChesMMAP Staff: Principal Investigators:

Robert J. Latour, Ph.D. Christopher F. Bonzek

Project Manager:

James Gartland

Field and Laboratory Staff: Eric Brasseur Melanie Chattin RaeMarie Johnson Graduate Students:

Andre Buchheister Andrij Horodysky Patrick Lynch Kathleen McNamee

Introduction Historically, fisheries management has been based on the results of single-species stock assessment models that focus on the interplay between exploitation level and sustainability. There currently exists a suite of standard and accepted analytical frameworks (e.g., virtual population analysis (VPA), biomass dynamic production modeling, delay difference models, etc.) for assessing the stocks, projecting future stock size, evaluating recovery schedules and rebuilding strategies for overfished stocks, setting allowable catches, and estimating fishing mortality or exploitation rates. A variety of methods also exist to integrate the biological system and the fisheries resource system, thereby enabling the evaluation of alternative management strategies on stock status and fishery performance. These well-established approaches have specific data requirements involving biological (life history), fisheries-dependent, and fisheries-independent data (Table 1). From these, there are two classes of stock assessment or modeling approaches used in fisheries: partial assessment based solely on understanding the biology of a species, and full analytical assessment including both biological and fisheries data.

Table 1. Summary of biological, fisheries-dependent and fisheries-independent data requirements for single-species analytical stock assessment models.

Data Category Biological / Life History

Assessment Type Partial

Fishery-Dependent Data

Analytical

Fishery-Independent Data

Analytical

Data Description Growth (length / weight) Maturity schedule Fecundity Partial recruitment schedules Longevity Life history strategies (reproductive and behavioral) Catch, landings, and effort Biological characterization of the harvest (size, sex, age) Gear selectivity Discards/bycatch Biological characterization of the population (size, sex, age) Mortality rates Estimates of annual juvenile recruitment

Although single-species assessment models are valuable and informative, a primary shortcoming is that they generally fail to consider the ecology of the species under management (e.g., habitat requirements, response to environmental change), ecological interactions (e.g., predation, competition), and technical interactions (e.g.,

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discards, bycatch) (NMFS 1999, Link 2002a,b). However, inclusion of ecological processes into fisheries management plans is now strongly recommended (NMFS 1999, NRC 1999, Pew Commission 2003, U.S. Oceans Commission 2004) and in some cases even mandated (NOAA 1996). Multispecies assessment models have been developed to move towards an ecosystem-based approach to fisheries management (Hollowed et al. 2000, Whipple et al. 2000, Link 2002a,b). Although such models are still designed to yield information about sustainability, they are structured to do so by explicitly incorporating the effects of ecological processes among interacting populations.

Over the past several years, the number and type of multispecies models designed to provide insight about fisheries questions has grown significantly (Hollowed et al. 2000, Whipple et al. 2000). This growth has been fueled by the need to better inform fisheries policy makers and managers, however, recent concerns about effects of fishing on the structure of ecosystems have also prompted research activities on multispecies modeling and the predator-prey relationships that are implied. From a theoretical perspective, basing fisheries stock assessments on multispecies rather than singlespecies models certainly appears to be more appropriate, since multispecies approaches allow a greater number of the processes that govern population abundance to be modeled explicitly. However, this increase in realism leads to an increased number of model parameters, which in turn, creates the need for additional types of data.

In the Chesapeake Bay region, there has been a growing interest in ecosystem-based fisheries management, as evidenced by the recent development of fisheries steering groups (e.g., ASMFC multispecies committee), the convening of technical workshops (Miller et al. 1996; Houde et al. 1998), publication of the Fisheries Ecosystem Planning document (Chesapeake Bay Fisheries Ecosystem Advisory Panel 2006), and the goals for ecosystem-based fisheries management set by the Chesapeake Bay 2000 (C2K) Agreement. In many respects, it can be argued that the ecosystem-based fisheries mandates inherent to the C2K Agreement constitute the driving force behind this growing awareness. The exact language of the C2K agreement, as it pertains to multispecies fisheries management, reads as follows: 1. By 2004, assess the effects of different population levels of filter feeders such as menhaden, oysters and clams on Bay water quality and habitat.

2. By 2005, develop ecosystem-based multispecies management plans for targeted species.

3. By 2007, revise and implement existing fisheries management plans to incorporate ecological, social and economic considerations, multispecies fisheries management and ecosystem approaches.

If either single-species or ecosystem-based management plans are to be developed, they must be based on sound stock assessments. In the Chesapeake Bay region,

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however, the data needed to perform single and multispecies assessments is either partially available or nonexistent.

The Chesapeake Bay Multispecies Monitoring and Assessment Program (ChesMMAP) was developed to assist in filling these data gaps, and ultimately to support bay-specific stock assessment modeling activities at both single and multispecies scales. While no single gear or monitoring program can collect all of the data necessary for both types of assessments, ChesMMAP was designed to maximize the biological and ecological data collected for several recreationally, commercially, and ecologically important species in the bay.

In general, ChesMMAP is a large-mesh bottom trawl survey designed to sample late juvenile-to-adult fishes in Chesapeake Bay. This field program currently provides data on relative abundance, length, weight, age, and trophic interactions for several important fish species seasonally inhabiting the bay. This report summarizes the field, laboratory, and preliminary data.

Among the research agencies in the Chesapeake Bay region, only VIMS has a program focused on multispecies issues involving the adult/harvested components of the exploited fish species that seasonally inhabit the bay. The multispecies research program at VIMS is comprised of three main branches: field data collection (ChesMMAP and the VIMS Seagrass Trammel Net Survey), laboratory processing (The Chesapeake Trophic Interactions Laboratory Services – CTILS, and ChesMMAP), and data analysis and multispecies modeling (The Fisheries Ecosystem Modeling and Assessment Program - FEMAP). In this report, we summarize the field, laboratory, and data analysis activities associated with the 2006 sampling year.

The following Jobs are addressed in this report: • Job 1 – Conduct research cruises • Job 2 – Synthesize data for single species analyses • Job 3 – Quantify trophic interactions for multispecies analyses • Job 4 – Estimate abundance Methods Job 1 – Conduct research cruises In 2006, five research cruises were conducted bimonthly from March to November in the mainstem of Chesapeake Bay. The timing of the cruises was chosen to adequately characterize the seasonal abundances of fishes in the bay. The R/V Bay Eagle, a 19.8m aluminum hull, twin diesel vessel owned and operated by VIMS, served as the sampling platform for this survey. The trawl net is a 13.7m (headrope length) 4-seam balloon trawl manufactured by Reidar’s Manufacturing Inc. of New Bedford, MA. The wings and body of the net are constructed of #21 cotton twine (15.2cm mesh), and the codend is constructed of #48 twine (7.6cm mesh). The legs of the net are 6.1m and connected directly to 1.3m x 0.8m steel-V trawl doors weighing 83.9kg each. The trawl

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net is deployed with a single-warp system using 9.5mm steel cable with a 37.6m bridle constructed of 7.9mm cable.

For each cruise, the goal was to sample 80 stations distributed in a stratified random design throughout the mainstem of Chesapeake Bay. The Bay was stratified by dividing the mainstem into five regions of 30 latitudinal minutes each (the upper and lower regions being slightly smaller and larger than 30 minutes, respectively). Within each region, three depth strata ranging from 3.0m-9.1m, 9.1m-15.2m, and >15.2m were defined. A grid of 1.9km2 cells was superimposed over the mainstem, where each cell represented a potential sampling location. The number of stations sampled in each region and in each stratum was proportional to the surface area of water represented.

Stations were sampled without replacement and those north of Pooles Island (latitude 39o 17’) have not been sampled since July 2002 due to repeated loss of gear. In the future, sidescan sonar will be used to identify potential sampling locations in this area.

Tows were conducted in the same general direction as the tidal current (pilot tows conducted using the net monitoring gear in November 2001 indicated that the gear performed most consistently when deployed with the current rather than against the current). The net was generally deployed at a 4:1 scope, which refers to the amount of cable deployed relative to depth. For shallow stations, however, the bridle was always deployed beyond the vessel’s tow-point, implying that the scope ratio could be quite high. The target tow speed was 6.5 km/h but occasionally varied depending on wind and tidal conditions. Based on data collected from the net monitoring gear, tow speed and scope were also adjusted occasionally to ensure that the gear was deployed properly. Tows were 20 minutes in duration, unless obstructions or other logistical issues forced a tow to be shortened (if the duration of a tow was at least 10 minutes, it was considered complete). Computer software was used to record data from the net monitoring gear (i.e., wingspread and headrope height) as well as a continuous GPS stream during each tow. On occasions when the monitoring gear failed, the trawl geometry was assumed to follow cruise averages and beginning and ending coordinates were taken from the vessel’s GPS system.

Job 2 – Synthesize data for single species analyses Once onboard, the catch from each tow is sorted and measured by species or sizeclass if distinct classes within a particular species are evident. A subsample of each species or size-class is further processed for weight determination, stomach contents, ageing, and determination of sex and maturity stage. In addition, surface and bottom temperature, salinity, and dissolved oxygen readings are also recorded at each sampling location.

Single-species assessment models typically require information on (among others) agelength-, and weight-structure, sex ratio, and maturity stage. Data were synthesized to characterize age-, length-, and weight-frequency distributions across a variety of spatial

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and temporal scales (e.g., by year, season, or region of the bay) for each species. Sex ratio and maturity data are also be available to support sex-specific analyses.

Job 3 – Quantify trophic interactions for multispecies analyses In addition to the population-level information described under Task 3, multispecies assessment models require information on predator-prey interactions across broad seasonal and spatial scales. In general, these procedures involve identifying each prey item to the lowest possible taxonomic level (Hyslop 1980). Several diet indices were calculated to identify the main prey types for each species: %weight, %number, and %frequency-of-occurrence. These indices were coupled with the information generated from Task 3 and age-, length-, and sex-specific diet characterizations were developed for each species. Efforts also focused on characterizing spatial and temporal variability in these diets.

Diet index values were calculated to identify the main prey in the diet of predators in the mainstem Chesapeake Bay. Since trawl collections essentially yield a cluster of fish at each sampling location, the aforementioned indices were calculated using a cluster sampling estimator (Buckel et al. 1999).

The contribution of each prey type to the diet (%Qk, where Qk is any of the aforementioned index types) is given by: n

%Qk =

∑M q i =1 n

i ik

∑M i =1

,

(1)

i

where

qik =

wik * 100 , wi

and where n is the number of trawls containing the predator of interest, Mi is the number of that predator collected at sampling site i, wi is the total weight, number, or frequency of all prey items encountered in the stomachs of that predator collected from sampling location i, and wik is the total weight, number, or frequency of prey type k in those stomachs. Accordingly, stomachs collected in the field were processed following standard diet analysis procedures (Hyslop 1980).

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Job 4 – Estimate abundance Time-series of relative abundance information can easily be generated from the basic catch data of a monitoring survey. For each species, a variety of relative abundance trends can be generated according to year, season, and location within the Bay. Absolute abundance estimates can be generated for each species by combining relative abundance data with area swept and gear efficiency information. Area swept was calculated for each tow by multiplying tow distance (provided by GPS equipment) by average wingspread (provided by net monitoring gear). Gear efficiency estimates are being derived by comparing the number of fish that encounter the gear (from the hydroacoustic data) with the fraction captured (from the catch data). To develop species-specific efficiency estimates, the hydroacoustic data will be partitioned according to the target strength distribution for each species. These distributions will be determined through ongoing cage experiments.

ChesMMAP utilizes two types of hydroacoustic gear in an effort to convert relative indices of abundance into estimates of total abundance. The equation necessary for this conversion is: cA N= , (1) a e where N is total population size measured in numbers (or biomass), c is the mean number (or weight) of fish captured per tow, a is the area swept by one trawl tow, A is the total survey area, and e is the net efficiency (dimensionless). Given that c is observed and A is easily determined, the hydroacoustic equipment is used to derive estimates of a and e. Estimation of the parameter e for a variety of species is a mid-tolong term goal. Until then, removal of that parameter from Equation 1 results in relative estimates of ‘minimum trawlable abundance.’ These estimates represent the smallest number (or biomass) of fish present within the sampling area that are susceptible to the sampling gear.

Results Job 1 – Conduct Research Cruises Throughout the five years of sampling, the number of fish collected each year by the ChesMMAP survey was fairly consistent and ranged from approximately 31,000 (in 2003) to 48,000 (in 2004 – Table 1). Each year, between 3,900 and 6,000 pairs of otoliths have been collected, the majority of which have been processed for age determination. Similar numbers of stomach have been collected and processed for diet composition information annually.

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Table 1. The number of specimens collected, measured and processed for age determination and diet composition information from ChesMMAP 2002 – 2006.

Year Fish Fish Otoliths Otoliths Stomachs Stomachs collected measured collected processed collected processed 2002 32,018 23,605 5,487 4,382 4,555 2,638 2003 30,925 20,828 3,913 2,934 3,250 2,220 2004 47,623 31,245 5,169 3,431 4,271 3,137 2005 45,206 36,906 6,064 4,694 5,064 3,170 2006 43,959 31,239 5,412 In process 4,391 2,640 Jobs 2-4 – Data Summaries The data summaries in this report essentially represent biological and ecological profiles of those species well sampled by the ChesMMAP survey. Our intent with these profiles is to maximize the amount of information available to fishery managers. The profiles that follow are organized first by species and then by type of analysis (‘Task’). Each Task element (single-species stock parameter summarizations, trophic interaction summaries, and estimates of abundance) is included but is not labeled with a Task number and is not necessarily shown in Task number order (note also that not all analysis types are available for all species).

The species profiles contain the following information (note that some data/analyses may not be available for all species): 1) estimates of abundance, both in numbers and biomass, by year, month, and region within the bay 2) site-specific abundance maps (number per area swept) for each cruise, overlaid on depth strata 3) length-frequency data by year 4) age-class distributions by year (for those species where appreciable numbers have been captured and otoliths have been processed) 5) sex-ratio by year and where appropriate, by region, month, and/or by age.

6) statistically determined length-weight relationships for sexes combined and separately 7) sex-specific maturity ogives along with a single diet summary Following the species profiles figures are a series of figures for each cruise containing data describing the following water quality parameters: 1) Water temperature at the surface and at the bottom.

2) Salinity at the surface and at the bottom.

3) Dissolved oxygen at the surface and at the bottom.

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List of Figures Atlantic Croaker (pages 17 – 27) Figure 1. Atlantic croaker minimum trawlable abundance estimates in Chesapeake Bay, 2002-2006.

Figures 2 – 6. Site-specific Atlantic croaker abundance figures, 2002-2006.

Figure 7. Atlantic croaker length-frequency distribution in Chesapeake Bay, 2002-2006.

Figure 8. Atlantic croaker age-frequency distribution in Chesapeake Bay, 2002-2005 (2006 ages not yet assigned).

Figure 9. Atlantic croaker sex-ratios in Chesapeake Bay, 2002-2006, by (A) region, and (B) age.

Figure 10. Atlantic croaker length-weight relationships in Chesapeake Bay, 2002-2006 for (A) sexes combined, and (B) males and females separated.

Figure 11. Atlantic croaker maturity schedule in Chesapeake Bay, 2002-2006 for sexes combined.

Figure 12. Atlantic croaker diet composition in Chesapeake Bay, 2002-2006.

Black Seabass (pages 29 – 35) Figure 13. Black seabass minimum trawlable abundance estimates in Chesapeake Bay, 2002-2006.

Figure 14. Black seabass length-frequency distribution in Chesapeake Bay, 2002-2006.

Figure 15. Black seabass age-frequency distribution in Chesapeake Bay, 2002-2003.

Figure 16. Black seabass sex-ratios in Chesapeake Bay, 2002-2006, by (A) year and (B) month.

Figure 17. Black seabass length-weight relationships in Chesapeake Bay, 2002-2006 for (A) sexes combined and (B) males and females separated.

Figure 18. Black seabass maturity schedule for females in Chesapeake Bay, 20022006.

Figure 19. Black seabass diet composition in Chesapeake Bay 2002-2006.

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Bluefish (pages 37 – 47) Figure 20. Bluefish minimum trawlable abundance estimates in (A) numbers and (B) biomass in Chesapeake Bay, 2002-2006.

Figures 21 – 25. Site-specific bluefish abundance figures, 2002-2006.

Figure 26. Bluefish length-frequency distribution in Chesapeake Bay 2002-2006.

Figure 27. Bluefish age-frequency distribution in Chesapeake Bay, 2002-2004 (20052006 ages not yet assigned).

Figure 28. Bluefish sex-ratios in Chesapeake Bay 2002-2006, by year.

Figure 29. Bluefish length-weight relationships in Chesapeake Bay, 2002-2006 for (A) sexes combined and (B) males and females separated.

Figure 30. Bluefish maturity schedule in Chesapeake Bay, 2002-2006, for sexes combined.

Figure 31. Bluefish diet composition in Chesapeake Bay, 2002-2006.

Butterfish (pages 49 – 56) Figure 32. Butterfish minimum trawlable abundance estimates in (A) numbers and (B) biomass in Chesapeake Bay, 2002-2006.

Figures 33 – 37. Site-specific butterfish abundance figures, 2002-2006.

Figure 38. Butterfish length-frequency distribution in Chesapeake Bay, 2002-2006.

Figure 39. Butterfish length-weight relationship in Chesapeake Bay, 2002-2006.

Figure 40. Butterfish diet composition in Chesapeake Bay, 2002-2006.

Northern Kingfish (pages 57 – 66) Figure 41. Northern kingfish minimum trawlable abundance estimates in (A) numbers and (B) biomass in Chesapeake Bay, 2002-2006.

Figures 42 – 46. Site-specific northern kingfish abundance figures, 2002-2006.

Figure 47. Northern kingfish length-frequency distribution in Chesapeake Bay 20022006.

Figure 48. Northern kingfish sex-ratios in Chesapeake Bay, 2002-2006, by (A) year and (B) month.

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Figure 49. Northern kingfish length-weight relationships in Chesapeake Bay, 20022006, for (A) sexes combined and (B) males and females separated.

Figure 50. Northern kingfish maturity schedule in Chesapeake Bay, 2002-2006, for sexes combined.

Figure 51. Northern kingfish diet composition in Chesapeake Bay, 2002-2006.

Northern Puffer (pages 68 – 73) Figure 52. Northern puffer minimum trawlable abundance estimates in (A) numbers and (B) biomass (B) in Chesapeake Bay, 2002-2006.

Figure 53. Northern puffer length-frequency distribution in Chesapeake Bay, 20022006.

Figure 54. Northern puffer sex-ratios in Chesapeake Bay, 2002-2006, by (A) year and (B) month.

Figure 55. Northern puffer length-weight relationships in Chesapeake Bay, 2002-2006, for (A) sexes combined and (B) males and females separated.

Figure 56. Northern puffer maturity schedule in Chesapeake Bay, 2002-2006, for sexes combined.

Figure 57. Northern puffer diet composition in Chesapeake Bay, 2002-2006.

Scup (pages 75 – 84) Figure 58. Scup minimum trawlable abundance estimates in (A) numbers and (B) biomass in Chesapeake Bay, 2002-2006.

Figures 59 – 63. Site-specific scup abundance figures, 2002-2006.

Figure 64. Scup length-frequency distribution in Chesapeake Bay, 2002-2006.

Figure 65. Scup sex-ratios in Chesapeake Bay, 2002-2006, by (A) year and (B) month.

Figure 66. Scup length-weight relationships in Chesapeake Bay, 2002-2006, for (A) sexes combined and (B) males and females separated.

Figure 67. Scup maturity schedule in Chesapeake Bay, 2002-2006, for sexes combined.

Figure 68. Scup diet composition in Chesapeake Bay, 2002-2006.

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Spot (pages 85 – 95) Figure 69. Spot minimum trawlable abundance estimates in (A) numbers and (B) biomass in Chesapeake Bay, 2002-2006.

Figures 70 – 74. Site-specific spot abundance figures, 2002-2006.

Figure 75. Spot length-frequency distribution in Chesapeake Bay, 2002-2006.

Figure 76. Spot age-frequency distribution in Chesapeake Bay, 2002-2006.

Figure 77. Spot sex-ratios in Chesapeake Bay, 2002-2005, by (A) year and (B) month.

Figure 78. Spot length-weight relationships in Chesapeake Bay 2002-2006 for (A) sexes combined and (B) males and females separated.

Figure 79. Spot maturity schedule in Chesapeake Bay, 2002-2006, for sexes combined.

Striped Bass (pages 97 – 107) Figure 80. Striped bass minimum trawlable abundance estimates in (A) numbers and (B) biomass in Chesapeake Bay, 2002-2006.

Figures 81 – 85. Site-specific striped bass abundance figures, 2002-2006.

Figure 86. Striped bass length-frequency distribution in Chesapeake Bay, 2002-2006.

Figure 87. Striped bass age-frequency distribution in Chesapeake Bay. 2002-2006.

Figure 88. Striped bass sex-ratios in Chesapeake Bay. 2002-2006, by (A) year, (B), month, and (C) age.

Figure 89. Striped bass length-weight relationships in Chesapeake Bay, 2002-2006, for (A) sexes combined and (B) males and females separated.

Figure 90. Striped bass maturity schedule in Chesapeake Bay, 2002-2006, for sexes combined.

Figure 91. Striped bass diet composition in Chesapeake Bay, 2002-2006.

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Summer Flounder (pages 109 – 119) Figure 92. Summer flounder minimum trawlable abundance estimates in (A) numbers and (B) biomass in Chesapeake Bay, 2002-2006.

Figures 93 – 97. Site-specific summer flounder abundance, 2002-2006.

Figure 98. Summer flounder length-frequency distribution in Chesapeake Bay, 20022006.

Figure 99. Summer flounder age-frequency distribution in Chesapeake Bay, 20022006.

Figure 100. Summer flounder sex-ratios in Chesapeake Bay, 2002-2006, by (A) month, (B) region and (C) age.

Figure 101. Summer flounder length-weight relationships in Chesapeake Bay, 20022005 for (A) sexes combined and (B) males and females separated.

Figure 102. Summer flounder maturity schedule in Chesapeake Bay, 2002-2006, for sexes combined.

Figure 103. Summer flounder diet composition in Chesapeake Bay 2002-2006.

Weakfish (pages 121 – 131) Figure 104. Weakfish minimum trawlable abundance estimates in (A) numbers and (B) biomass (B) in Chesapeake Bay, 2002-2006.

Figures 105 – 109. Site-specific weakfish abundance, 2002-2006.

Figure 110. Weakfish length-frequency distribution in Chesapeake Bay, 2002-2006.

Figure 111. Weakfish age-frequency distribution in Chesapeake Bay, 2002-2006.

Figure 112. Weakfish sex-ratios in Chesapeake Bay, 2002-2005, by (A) year, (B) region and (C) age.

Figure 113. Weakfish length-weight relationships in Chesapeake Bay, 2002-2006, for (A) sexes combined and (B) males and females separated.

Figure 114. Weakfish maturity schedule in Chesapeake Bay, 2002-2006, for sexes combined.

Figure 115. Weakfish diet composition in Chesapeake Bay, 2002-2006.

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White Perch (pages 133 – 143) Figure 116. White perch minimum trawlable abundance estimates in (A) numbers and (B) biomass in Chesapeake Bay, 2002-2006.

Figures 117 – 121. Site-specific white perch abundance, 2002-2006.

Figure 122. White perch length-frequency distribution in Chesapeake Bay, 2002-2006.

Figure 123. White perch age-frequency distribution in Chesapeake Bay, 2002-2005.

Figure 124. White perch sex-ratios in Chesapeake Bay 2002-2005, by (A) year and (B) age.

Figure 125. White perch length-weight relationships in Chesapeake Bay, 2002-2006 for (A) sexes combined and (B) males and females separated.

Figure 126. White perch maturity schedule in Chesapeake Bay, 2002-2006, for sexes combined.

Figure 127. White perch diet composition in Chesapeake Bay, 2002-2006.

Water Temperature (pages 144 – 153) Figure 128. Surface temperature in Chesapeake Bay, 2002.

Figure 129. Bottom temperature in Chesapeake Bay, 2002.

Figure 130. Surface temperature in Chesapeake Bay, 2003.

Figure 131. Bottom temperature in Chesapeake Bay, 2003.

Figure 132. Surface temperature in Chesapeake Bay, 2004.

Figure 133. Bottom temperature in Chesapeake Bay, 2004.

Figure 134. Surface temperature in Chesapeake Bay, 2005.

Figure 135. Bottom temperature in Chesapeake Bay, 2005.

Figure 136. Surface temperature in Chesapeake Bay, 2006.

Figure 137. Bottom temperature in Chesapeake Bay, 2006.

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Salinity (pages 154 – 163) Figure 138. Surface salinity in Chesapeake Bay, 2002.

Figure 139. Bottom salinity in Chesapeake Bay, 2002.

Figure 140. Surface salinity in Chesapeake Bay, 2003.

Figure 141. Bottom salinity in Chesapeake Bay, 2003.

Figure 142. Surface salinity in Chesapeake Bay, 2004.

Figure 143. Bottom salinity in Chesapeake Bay, 2004.

Figure 144. Surface salinity in Chesapeake Bay, 2005.

Figure 145. Bottom salinity in Chesapeake Bay, 2005.

Figure 146. Surface salinity in Chesapeake Bay, 2006.

Figure 147. Bottom salinity in Chesapeake Bay, 2006.

Dissolved Oxygen (pages 164 – 173) Figure 148. Surface dissolved oxygen in Chesapeake Bay, 2002.

Figure 149. Bottom dissolved oxygen in Chesapeake Bay, 2002.

Figure 150. Surface dissolved oxygen in Chesapeake Bay, 2003.

Figure 151. Bottom dissolved oxygen in Chesapeake Bay, 2003.

Figure 152. Surface dissolved oxygen in Chesapeake Bay, 2004.

Figure 153. Bottom dissolved oxygen in Chesapeake Bay, 2004.

Figure 154. Surface dissolved oxygen in Chesapeake Bay, 2005.

Figure 155. Bottom dissolved oxygen in Chesapeake Bay, 2005.

Figure 156. Surface dissolved oxygen in Chesapeake Bay, 2006.

Figure 157. Bottom dissolved oxygen in Chesapeake Bay, 2006.

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Additional Work Performed – Serve as sampling platform for bay studies Since its inception, ChesMMAP has strived to be not just a state-of-the-art monitoring survey, but equally, a research platform from which numerous projects can benefit. We have participated in fish disease, tagging, and habitat related studies that otherwise either could not have been conducted, or would have had very substantially increased costs. For example, since 2003 ChesMMAP personnel have been collecting additional samples from striped bass to support a mycobacteriosis prevalence study conducted by scientists in the Fisheries and Environmental and Aquatic Animal Health (EAAH) Departments at VIMS. Specifically, spleen samples from these striped bass were analyzed histologically for the presence of granulomas, which are evident in diseased fish. The apparent prevalence data set derived from these samples is the most comprehensive apparent prevalence data set collected for striped bass in the bay.

Subsequent modeling of those prevalence data has shown 1) the force-of-infection (rate of which disease-negative fish become disease positive) is age-dependent, 2) covariates sex and season are significant explanatory variables, and 3) that there is appreciable disease-associated mortality.

In 2006, ChesMMAP personnel collected 536 striped bass tissue samples to support a trophic ecology project led by members of the Center for Quantitative Fisheries Ecology (CQFE) at Old Dominion University. Stable isotope analysis is being used to investigate the trophic interactions and position of striped bass; ultimately these data will be compared to data from traditional stomach content analysis to provide a more comprehensive description of the predatory impacts of striped bass.

The costs associated with conducting both the disease monitoring and stable isotope studies in the absence of a sampling platform such as the ChesMMAP trawl survey would likely have been prohibitive.

In addition to the aforementioned striped bass projects, ChesMMAP also supported the Environmental Protection Agency’s National Coastal Assessment (NCA) program by sampling 11 additional sites during the September 2006 survey. At each of these stations, up to 10 specimens of each of a number of species of interest were sacrificed for chemical and pathological analysis. Overall, 96 specimens were taken for this effort.

Again, by contracting the ChesMMAP survey to conduct this relatively small amount of sampling, the cost of obtaining the resulting information was reduced substantially. And finally, ChesMMAP’s sampling efforts supported four master’s theses and a doctoral dissertation in 2006.

Literature Cited Buckel, J.A., D.O. Conover, N.D. Steinberg, and K.A. McKown. 1999a. Impact of age-0 bluefish (Pomatomus saltatrix) predation on age-0 fishes in Hudson River Estuary: evidence for density-dependant loss of juvenile striped bass (Morone saxatilis). Canadian Journal of Fisheries and Aquatic Sciences 56:275-287.

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Chesapeake Bay Fisheries Ecosystem Advisory Panel. 2006. Fisheries ecosystem planning for Chesapeake Bay. American Fisheries Society, Trends in Fisheries Science and Managemen 3, Bethesda, Maryland.

Hollowed, A.B., N. Bax, R. Beamish, J. Collie, M. Fogarty, P. Livingston, J. Pope, and J.C. Rice. 2000. Are multispecies models an improvement on single-species models for measuring fishing impacts on marine ecosystems? ICES Journal of Marine Science 57:707-719.

Houde, E.D., M.J. Fogarty and T.J. Miller (Convenors). 1998. STAC Workshop Report: Prospects for Multispecies Fisheries Management in Chesapeake Bay. Chesapeake Bay Program, Scientific Technical Advisory Committee.

Hyslop, E.J. 1980. Stomach content analysis – a review of methods and their application. Journal of Fish Biology 17:411-429.

Link, J.S. 2002a. Ecological considerations in fisheries management: when does it matter? Fisheries 27(4):10-17.

Link, J.S. 2002b. What does ecosystem-based fisheries management mean? Fisheries 27:18-21.

NMFS (National Marine Fisheries Service). 1999. Ecosystem-based fishery management. A report to Congress by the Ecosystems Principles Advisory Panel. U. S. Department of Commerce, Silver Spring, Maryland.

Miller, T.J., E.D. Houde, and E.J. Watkins. 1996. STAC Workshop Report: Prospectives on Chesapeake Bay fisheries: Prospects for multispecies fisheries management and sustainability. Chesapeake Bay Program, Scientific Technical Advisory Committee.

NOAA (National Oceanic and Atmospheric Administration). 1996. Magnuson-Stevens Fishery Management and Conservation Act amended through 11 October 1996.

NOAA Technical Memorandum NMFS-F/SPO-23. U. S. Department of Commerce.

Pew Oceans Commission. 2003. America’s Living Oceans: Charting a Course for Sea Change. A Report to the Nation. May 2003. Pew Oceans Commission, Arlington, Virginia.

U.S. Commission on Ocean Policy. An Ocean Blueprint for the 21st Century. Final Report. Washington, DC, 2004 Whipple, S. J., J. S. Link, L. P. Garrison, and M. J. Fogarty. 2000. Models of predation and fishing mortality in aquatic ecosystems. Fish and Fisheries 1:22-40.

16

Figure 1. Atlantic croaker minimum trawlable abundance estimates in numbers (A) and biomass (B) in Chesapeake Bay 2002-2006.

R e g io n

Va -L o w

Va -U p p

M d -L o w

M d -M id

M d -U p p

5 0 ,0 0 0 ,0 0 0

A. Minimum Trawlable Number

4 0 ,0 0 0 ,0 0 0

3 0 ,0 0 0 ,0 0 0

2 0 ,0 0 0 ,0 0 0

1 0 ,0 0 0 ,0 0 0

0 M ar

M ay

Ju l

Se p

No v

M ar M ay

2002

R e g io n

Ju l

Se p

No v

2003

V a -L o w

M ar

M ay

Ju l

Se p

No v

M ar

M ay

2004

V a -U p p

M d -L o w

Ju l

Se p

No v

2005

M d - M id

M ar M ay

Ju l

Se p

No v

M o n th

Y e ar

2006

M d -U p p

1 9 ,0 0 0 ,0 0 0 1 8 ,0 0 0 ,0 0 0 1 7 ,0 0 0 ,0 0 0

B.

1 6 ,0 0 0 ,0 0 0

Minimum Trawlable Biomass (kg)

1 5 ,0 0 0 ,0 0 0 1 4 ,0 0 0 ,0 0 0 1 3 ,0 0 0 ,0 0 0 1 2 ,0 0 0 ,0 0 0 1 1 ,0 0 0 ,0 0 0 1 0 ,0 0 0 ,0 0 0 9 ,0 0 0 ,0 0 0 8 ,0 0 0 ,0 0 0 7 ,0 0 0 ,0 0 0 6 ,0 0 0 ,0 0 0 5 ,0 0 0 ,0 0 0 4 ,0 0 0 ,0 0 0 3 ,0 0 0 ,0 0 0 2 ,0 0 0 ,0 0 0 1 ,0 0 0 ,0 0 0 0

M ar M ay Jul Sep Nov

M ar M ay Jul Sep Nov

M ar M ay Jul S ep Nov

M ar M ay Jul S ep Nov

M ar M ay Jul Sep Nov

2002

2003

2004

2005

2006

17

M o n th Ye a r

18

March

May July

September

Figure 2. Abundance (number per hectare swept) of Atlantic croaker in Chesapeake Bay, 2002.

November

19

March May July

September

Figure 3. Abundance (number per hectare swept) of Atlantic croaker in Chesapeake Bay, 2003.

November

20

March

May July

September

Figure 4. Abundance (number per hectare swept) of Atlantic croaker in Chesapeake Bay, 2004.

November

21

March

May July

September

Figure 5. Abundance (number per hectare swept) of Atlantic croaker in Chesapeake Bay, 2005.

November

22

March May July

September

Figure 6. Abundance (number per hectare swept) of Atlantic croaker in Chesapeake Bay, 2006.

November

Figure 7. Atlantic croaker length-frequency in Chesapeake Bay 2002-2006.

2002 1 1 1 1

6 4 2 0 8 6 4 2

0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0 0 0

50

100

150

200

250

300

350

400

450

350

400

450

350

400

450

350

400

450

350

400

450

T o t a 2l 0L 0e 3n g t h ( m m ) 2000 1500 1000 500 0

Expanded Number

0

50

100

150

200

250

300

T o t a 2l 0L 0e 4n g t h ( m m ) 4000 3000 2000 1000 0 0

50

100

150

200

250

300

T o t a 2l 0L 0e 5n g t h ( m m ) 1 1 1 1

6 4 2 0 8 6 4 2

0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0 0 0

50

100

150

200

250

300

T o t a 2l 0L 0e 6n g t h ( m m ) 1200 1000 800 600 400 200 0 0

50

100

150

200

250

300

T o ta l L e n g th (m m )

23

24

Age (Year Class)

1

)

16

(1 9

88

89

)

)

70

89

(1 9

16

15

(1 9

(1 9

(1 9

87

88

89

90

)

)

)

)

0

(1 9

15

)

14

(1 9

16

15

14

13

12

(1 9

(1 9

(1 9

(1 9

(1 9

(1 9

(1 9

86

87

88

89

90

91

92

)

)

)

)

)

)

)

0

16

)

90

239

90

(1 9

13

)

8

(1 9

14

)

91

11

10

)

1

15

10

)

91

146

91

(1 9

(1 9

)

21

(1 9

13

)

12

92

)

(1 99 3

)

23

14

5

)

92

71

92

(1 9

(1 9

93

65

(1 9

12

)

11

(1 9

9

(1 99 4

)

46

13

4

)

93

223

93

(1 9

10

135

(1 9

11

)

)

8

(1 99 5

)

)

111

12

1

)

94

202

94

(1 9

(1 99 4

)

43

(1 9

10

)

9

(1 99 5

7

(1 99 6

(1 99 7

)

77

11

)

193

95

95

8

)

98

(1 9

(1 9

)

(1 99 6

6

5

(1 99 8

)

)

174

10

1000 9

96

495

)

(1 9

)

7

)

)

30

(1 99 6

477

8

97

(1 99 7

(1 99 8

4

(1 99 9

(2 00 0

)

)

84

9

640

)

(1 9

2000

(1 99 7

7

)

6

5

)

3

2

(2 00 1

(2 00 2 0

8

)

98

3000

(1 99 8

(1 9

)

(1 99 9

2000

7

6

99

232

)

(1 9

716

(1 99 9

5

)

4

)

)

1

0

4000

6

4000

)

00

(2 00 0

(2 00 1

208

(2 00 0

(2 0

)

3

2

)

)

2000

5

4

01

)

11000

)

(2 0

02

(2 00 2

(2 00 3

1000

(2 00 1

3

(2 0

1

0

487

4

3000

)

2

)

)

57

(2 00 2

)

03

04

1000

3

(2 00 3

(2 0

(2 0 51

2

0 1

0

0

)

)

0

(2 00 4

(2 00 5

0

1

0

Expanded Number Figure 8. Atlantic croaker age-structure in Chesapeake Bay 2002-2005 (2006 ages not yet assigned).

2002 3993

3000 3030

1819

1330

1000 555

0 0

Age (Year Class) 2003

7000

6000 6521

5000

4000

3000

1494

1983

672

467

0 0

Age (Year Class) 2004

10000 10726

9000

8000

7000

6000

5000

4000

1199

2352

1741

665

0 0

Age (Year Class) 2005

3955

2857

2000

2135

553

965

287

111

0

0

Figure 9. Atlantic croaker sex-ratios in Chesapeake Bay 2002-2006, by region (A), age (B).

n=

93

100

A.

209

100.0

386

1450

100.1

100.1

100.1

9.6

53.3

54.3

40.7

32.3

90

1710

100.0

44.6

80

Percent Percent

70 63.8

60

58.7

50 40

45.8

44.9

44.9

2 Md-Mid

3 Md-Low

4 Va-Upp

Sex

F M U

Sex

F M U

30 20 10 0 1 Md-Upp

5 Va-Low

Region

n = 72

Percent SUM

100

B.

99.9 97.2

475 427

335 391 349 284 214 152

61

38

25

15

12

2

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

53.3

38.4

48.6

44.8

58.3

34.8

45.9

29.4

50.0

25.0

47.6

22.9

31.7

98.1

90 80

Percent

77.1

75.0

70

70.6

68.3

65.1

60

60.5

54.5

50

54.1

52.4

50.3

50.0

45.0

40

41.7

30 20 10 0 0

1

2

3

4

5

6

7

8

AGE 25

9

10

11

12

13

14

Figure 10. Atlantic croaker length-weight relationships in Chesapeake Bay 2002-2006 as calculated by power regression for sexes combined (A) and separately (B).

3000

A.

Weight(g)

2000

W e i g h t ( g ) = 0 .0 0 6 6 * L e n g t h ( c m ) * * 3 .1 8 3 4 ( n = 3 9 5 5 )

1000

0 0

10

20

30

40

50

T o ta l L e n g th (c m ) 3000

B.

Weight(g)

2000

Males - Weight(g) = 0.0072 * Length(cm)**3.1573 (n = 1674) Females - Weight(g) = 0.0067 * Length(cm)**3.1818 (n = 2117)

1000

0 0

10

20

30 Total Length(cm)

26

40

50

Figure 11. Atlantic croaker maturity schedule in Chesapeake Bay 2002-2006 combined, by sex.

1 .0 9 9 % m a t u r it y

0 .9

0 .8

Probability of Maturity

0 .7

0 .6

0 .5 5 0 % m a t u r it y

0 .4

0 .3

0 .2

0 .1

SEX

F M

0 .0

0

10

20

30

T o ta l L e n g th (c m )

Figure 12. Atlantic croaker diet in Chesapeake Bay 2002-2006 combined*.

*All samples not analyzed.

27

40

50

28

Figure 13. Black seabass minimum trawlable abundance estimates in numbers (A) and biomass (B) in Chesapeake Bay 2002-2006 (Note: abundance estimates for this species not considered reliable).

R e g io n

V a -L o w

V a -U p p

M d -L o w

M d - M id

M d -U p p

1 2 0 ,0 0 0

1 1 0 ,0 0 0

A.

1 0 0 ,0 0 0

Minimum Trawlable Number

9 0 ,0 0 0

8 0 ,0 0 0

7 0 ,0 0 0

6 0 ,0 0 0

5 0 ,0 0 0

4 0 ,0 0 0

3 0 ,0 0 0

2 0 ,0 0 0

1 0 ,0 0 0

0

M ar M ay Jul S ep Nov

M ar M ay Jul Sep Nov

M ar M ay Jul Sep Nov

M ar M ay Jul Sep Nov

M ar M ay Jul Sep Nov

2002

2003

2004

2005

2006

Ye a r

M o n th

R e g io n

V a -L o w

V a -U p p

M d -L o w

M d - M id

M o n th

M d -U p p

8 0 ,0 0 0

B. Minimum Trawlable Biomass (kg)

7 0 ,0 0 0

6 0 ,0 0 0

5 0 ,0 0 0

4 0 ,0 0 0

3 0 ,0 0 0

2 0 ,0 0 0

1 0 ,0 0 0

0

M ar M ay Jul Sep Nov

M ar M ay Jul Sep Nov

M ar M ay Jul Sep Nov

M ar M ay Jul Sep Nov

M ar M ay Jul Sep Nov

2002

2003

2004

2005

2006

29

Ye a r

Note: This species is not captured in enough abundance to create meaningful abundance maps.

30

Figure 14. Black seabass length-frequency in Chesapeake Bay 2002-2006.

2002 8 7 6 5 4 3 2 1 0 0

50

100

150

200

250

300

200

250

300

200

250

300

200

250

300

200

250

300

T o t a l2L0e0n3g t h ( m m )

7 6 5 4 3 2 1 0

Expanded Number

0

50

100

150

T o t a l2L0e0n4g t h ( m m )

4 3 2 1 0 0

50

100

150

T o t a l2L0e0n5g t h ( m m )

3

2

1

0 0

50

100

150

T o t a l2L0e0n6g t h ( m m )

3

2

1

0 0

50

100

150

T o ta l L e n g th (m m )

31

Figure 15. Black seabass age-structure in Chesapeake Bay 2002-2003 (2004-2006 ages not yet assigned).

2 0 0 2 4 0 3 5

3 0

2 0

1 0 6 2

0 7) 5

4

(1

(1

99

99

9)

8)

0

99 (1 3

2

(2

00 1

0

(2

(2

00

1)

2) 00

0)

0

0

A g e2 ( 0 Y 0 e a3 r C l a s s ) 3 0 2 7

2 0

1 0

2

(Y e a r C la s s )

32

8)

9)

0

(1

(1 4

99

99

0) (2 3

A g e

0

00

1) 00 2

(2

00 (2 1

0

(2

00

2)

3)

0

5

1

0

Figure 16. Black seabass sex-ratios in Chesapeake Bay 2002-2006, by year (A), month (B).

n= 100

A.

48

32

100.1

100.0

18.8

96.9

14

13

17

100.0

100.0

99.9

28.6

7.7

90

7.7

80

84.6

90.9

77.1

Percent

70

14.3

60 57.1

50

Sex

40

F M U

30 20 10 0 2002

2003

2004

2005

2006

Year

n= 100

B.

25

21

71

100.0

1

100.0

6

100.0

100.0

99.9

100

17

20

19

7

90

6

87

83

80 70 Percent

81

8

72

60 50

Sex

40 30 20 10 0 03-Mar

05-May

07-Jul Month 33

09-Sep

11-Nov

F M U

Figure 17. Black seabass length-weight relationships in Chesapeake Bay 2002-2006 as calculated by power regression for sexes combined (A) and separately (B).

400

A. 300

Weight(g)

W e ig h t(g ) = 0 .0 2 0 9 * L e n g th (c m )* * 2 .9 2 8 1 (n = 1 2 4 )

200

100

0 7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

T o ta l L e n g th (c m ) 400 M a le s

- W e ig h t(g ) = 0 .0 4 8 4 * L e n g th (c m )**2 .6 5 6 (n = 6 )

F e m a le s - W e ig h t(g ) = 0 .0 1 9 8 * L e n g th (c m )**2 .9 5 0 3 (n = 1 0 2 )

B.

Weight(g)

300

200

100

0 7

8

9

10

11

12

13

14

15

16

17

18

19

T o ta l L e n g th (c m )

34

20

21

22

23

24

25

26

27

Figure 18. Black seabass maturity schedule in Chesapeake Bay 2002-2006 combined (females only).

0 .9

9 9 % m a tu r it y

0 .8

Probability of Maturity

0 .7

0 .6

0 .5

5 0 % m a tu r it y 0 .4

0 .3

0 .2

0 .1

SEX

F

0 .0 8

9

10

11

12

13

14

15

16

17

18

19

T o ta l L e n g th (c m )

Figure 19. Black seabass diet in Chesapeake Bay 2002-2006 combined.

35

20

21

22

23

24

25

26

27

36

Figure 20. Bluefish minimum trawlable abundance estimates in numbers (A) and biomass (B) in Chesapeake Bay 2002-2006 (Note: abundance estimates for this species not considered reliable).

R e g io n

V a -L o w

V a -U p p

M d -L o w

M d - M id

M d -U p p

5 0 0 ,0 0 0

A.

Minimum Trawlable Number

4 0 0 ,0 0 0

3 0 0 ,0 0 0

2 0 0 ,0 0 0

1 0 0 ,0 0 0

0

M ar M ay Jul S ep Nov

M ar M ay Jul Sep Nov

M ar M ay Jul Sep Nov

M ar M ay Jul Sep Nov

M ar M ay Jul Sep Nov

2002

2003

2004

2005

2006

R e g io n

V a -L o w

V a -U p p

M d -L o w

M d - M id

M o n th Ye a r

M d -U p p

4 0 0 ,0 0 0

Minimum Trawlable Biomass (kg)

B. 3 0 0 ,0 0 0

2 0 0 ,0 0 0

1 0 0 ,0 0 0

0

M ar M ay Jul S ep Nov

M ar M ay Jul Sep Nov

M ar M ay Jul Sep Nov

M ar M ay Jul Sep Nov

M ar M ay Jul Sep Nov

2002

2003

2004

2005

2006

37

M o n th Ye a r

38

March May July

Figure 21. Abundance (number per hectare swept) of bluefish in Chesapeake Bay, 2002.

September November

39

March May

July

Figure 22. Abundance (number per hectare swept) of bluefish in Chesapeake Bay, 2003.

September November

40

March May July

Figure 23. Abundance (number per hectare swept) of bluefish in Chesapeake Bay, 2004.

September November

41

March May July

Figure 24. Abundance (number per hectare swept) of bluefish in Chesapeake Bay, 2005.

September November

42

March May

July

Figure 25. Abundance (number per hectare swept) of bluefish in Chesapeake Bay, 2006.

September November

Figure 26. Bluefish length-frequency in Chesapeake Bay 2002-2006.

2002 6 5 4 3 2 1 0 0

50

100

150

200

250

300

350

400

450

500

550

400

450

500

550

400

450

500

550

400

450

500

550

400

450

500

550

F o r k 2L0e0n3 g th (m m ) 20

10

0

Expanded Number

0

50

100

150

200

250

300

350

F o r k 2L0e0n4g th (m m ) 4 3 2 1 0 0

50

100

150

200

250

300

350

5 g th (m m ) F o r k2 L0 e0 n 30 20 10 0 0

50

100

150

200

250

300

350

F o r k 2L0e0n6g th (m m ) 3 2 1 0 0

50

100

150

200

250

300

350

F o r k L e n g th (m m )

43

Figure 27. Bluefish age-structure in Chesapeake Bay 2002-2004 (2005-2006 ages not yet assigned).

2002 19

20 18 16 14 12 10 8 6 4 2 0

15

2Age 0 0(Year 3

99

7)

8)

0

4

5

(1

(1

99

9) (1 3

2

1

0

99

00 (2

00 (2

00 (2 0

0

0)

1)

2)

0

Class)

96

99

9)

5

4

(1

(1

99

00 3

0 8)

0

0)

1) 00 2

(2 1

0

(2

00

00 (2 0

6

2)

3)

10

(2

100 90 80 70 60 50 40 30 20 10 0

Age C lass) 200(Year 4 19

20 18 16 14 12 10 8 6 4 2 0

6 2

99

0)

(1 5

(2 4

3

44

00

00 (2

(2 2

Age (Year C lass)

0 9)

0

1)

2) 00

00 (2 1

0

(2

00

3)

4)

0

Figure 28. Bluefish sex-ratios in Chesapeake Bay 2002-2006, by year.

n= 100

34

68

27

71

100

100

100

100

100

17.6

16.6

14.3

10.0

8.7

44.2

34.8

90 80

23

41.2

36.6

27.1

Percent

70 60 58.6

56.5

50

Se x

46.8

40

45.8

41.2

30 20 10 0 2002

2003

2004

2005

Y ear

45

2006

F M U

Figure 29. Bluefish length-weight relationships in Chesapeake Bay 2002-2006 as calculated by power regression for sexes combined (A) and separately (B).

3000

A.

2000 Weight(g)

We ig h t(g ) = 0 .0 0 4 4 * L e n g th (c m )**3 .3 4 3 3 (n = 2 2 9 )

1000

0

10

20

30

40

50

60

F o rk L e n g th (c m )

3000 Males

- W eight(g) = 0.0039 * Length(cm)**3.3846 (n = 86)

Females - W eight(g) = 0.0049 * Length(cm)**3.3166 (n = 111)

B.

Weight(g)

2000

1000

0

10

20

30

40

F o rk L e n g th (c m )

46

50

60

Figure 30. Bluefish maturity schedule in Chesapeake Bay 2002-2006 combined, by sex.

1 .0 9 9% ma tu r ity

0 .9

0 .8

Probability of Maturity

0 .7

0 .6

0 .5 5 0% ma tu r ity

0 .4

0 .3

0 .2

0 .1

SE X

F M

0 .0

10

20

30

40

Fork Le ngth (cm )

Figure 31. Bluefish diet in Chesapeake Bay 2002-2006 combined.

47

50

60

48

Figure 32. Butterfish minimum trawlable abundance estimates in numbers (A) and biomass (B) in Chesapeake Bay 2002-2006.

R e g io n

V a -L o w

V a -U p p

M d -L o w

M d - M id

M d -U p p

3 ,0 0 0 ,0 0 0

Minimum Trawlable Number

A.

2 ,0 0 0 ,0 0 0

1 ,0 0 0 ,0 0 0

0

M ar M ay Jul Sep Nov

M ar M ay Jul S ep Nov

M ar M ay Jul S ep Nov

M ar M ay Jul Sep Nov

M ar M ay Jul Sep Nov

2002

2003

2004

2005

2006

Ye a r

M o n th

R e g io n

V a -L o w

V a -U p p

M d -L o w

M d - M id

M o n th

M d -U p p

3 0 0 ,0 0 0

Minimum Trawlable Biomass (kg)

B.

2 0 0 ,0 0 0

1 0 0 ,0 0 0

0

M ar M ay Jul S ep Nov

M ar M ay Jul Sep Nov

M ar M ay Jul Sep Nov

M ar M ay Jul Sep Nov

M ar M ay Jul Sep Nov

2002

2003

2004

2005

2006

49

Ye a r

50

March May

July

Figure 33. Abundance (number per hectare swept) of butterfish in Chesapeake Bay, 2002.

September November

51

March May

July

Figure 34. Abundance (number per hectare swept) of butterfish in Chesapeake Bay, 2003.

September November

52

March May July

Figure 35. Abundance (number per hectare swept) of butterfish in Chesapeake Bay, 2004.

September November

53

March May July

Figure 36. Abundance (number per hectare swept) of butterfish in Chesapeake Bay, 2005.

September November

54

March May

July

Figure 37. Abundance (number per hectare swept) of butterfish in Chesapeake Bay, 2006.

September November

Figure 38. Butterfish length-frequency in Chesapeake Bay 2002-2006.

2002 60 50 40 30 20 10 0 0

50

100

150

200

250

300

2 50

30 0

2 5 0

3 0 0

250

300

250

300

3 g th (m m ) T o t a l2 L0 e0 n 3 00 2 00 1 00 0 0

50

1 00

1 50

2 00

Expanded Number

00 T o ta 2 l L e4 n g th (m m ) 3 0 0 2 0 0 1 0 0 0 0

5 0

1 0 0

1 5 0

20 0

T o t a l 2L0e0n5g t h ( m m ) 100 80 60 40 20 0 0

50

100

150

200

T o t a l 2L0e0n6 g t h ( m m ) 8 7 6 5 4 3 2 1

0 0 0 0 0 0 0 0 0 0

50

100

150

200

T o ta l L e n g th (m m )

55

Figure 39. Butterfish length-weight relationship in Chesapeake Bay 2002-2006 as calculated by power regression.

300

Weight(g)

200

We ight(g) = 0.0146 * Le ngth(cm )**3.1672 (n = 1408)

100

0

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

Fork Le ngth(cm )

Figure 40. Butterfish diet in Chesapeake Bay 2002-2006 combined (Note: nearly all samples from 2002).

56

21

22

Figure 41. Northern kingfish minimum trawlable abundance estimates in numbers (A) and biomass (B) in Chesapeake Bay 2002-2006.

R e g io n

V a -L o w

V a -U p p

M d -L o w

M d - M id

M d -U p p

5 0 0 ,0 0 0

A. Minimum Trawlable Number

4 0 0 ,0 0 0

3 0 0 ,0 0 0

2 0 0 ,0 0 0

1 0 0 ,0 0 0

0

M ar M ay Jul S ep Nov

M ar M ay Jul Sep Nov

M ar M ay Jul Sep Nov

M ar M ay Jul Sep Nov

M ar M ay Jul Sep Nov

2002

2003

2004

2005

2006

R e g io n

V a -L o w

V a -U p p

M d -L o w

M d - M id

M o n th Ye a r

M d -U p p

1 8 0 ,0 0 0 1 7 0 ,0 0 0 1 6 0 ,0 0 0

B.

1 5 0 ,0 0 0

Minimum Trawlable Biomass (kg)

1 4 0 ,0 0 0 1 3 0 ,0 0 0 1 2 0 ,0 0 0 1 1 0 ,0 0 0 1 0 0 ,0 0 0 9 0 ,0 0 0 8 0 ,0 0 0 7 0 ,0 0 0 6 0 ,0 0 0 5 0 ,0 0 0 4 0 ,0 0 0 3 0 ,0 0 0 2 0 ,0 0 0 1 0 ,0 0 0 0

M ar M ay Jul S ep Nov

M ar M ay Jul Sep Nov

M ar M ay Jul Sep Nov

M ar M ay Jul Sep Nov

M ar M ay Jul Sep Nov

2002

2003

2004

2005

2006

57

M o n th Ye a r

58

March May July

September

Figure 42. Abundance (number per hectare swept) of northern kingfish in Chesapeake Bay, 2002.

November

59

March May July

September

Figure 43. Abundance (number per hectare swept) of northern kingfish in Chesapeake Bay, 2003.

November

60

March May

July

September

Figure 44. Abundance (number per hectare swept) of northern kingfish in Chesapeake Bay, 2004.

November

61

March May

July

September

Figure 45. Abundance (number per hectare swept) of northern kingfish in Chesapeake Bay, 2005.

November

62

March May

July

September

Figure 46. Abundance (number per hectare swept) of northern kingfish in Chesapeake Bay, 2006.

November

Figure 47. Northern kingfish length-frequency in Chesapeake Bay 2002-2006.

2 0 0 2 1 1 1 1

6 4 2 0 8 6 4 2 0 0

5 0

1 0 0

1 5 0

2 0 0

2 5 0

3 0 0

3 5 0

4 0 0

4 5 0

3 5 0

4 0 0

4 5 0

3 5 0

4 0 0

4 5 0

3 5 0

4 0 0

4 5 0

3 5 0

4 0 0

4 5 0

T o t a l 2L 0e0n3g t h ( m m ) 1 0 8 6 4 2 0

Expanded Number

0

5 0

1 0 0

1 5 0

2 0 0

2 5 0

3 0 0

T o t a l 2L 0e0n4g t h ( m m ) 1 4 1 2 1 0 8 6 4 2 0 0

5 0

1 0 0

1 5 0

2 0 0

2 5 0

3 0 0

T o ta l L e n g th (m m ) 2 0 0 5 1 0 8 6 4 2 0 0

5 0

1 0 0

1 5 0

2 0 0

2 5 0

3 0 0

T o t a l 2L 0e0n6g t h ( m m ) 2 0 1 5 1 0 5 0 0

5 0

1 0 0

1 5 0

2 0 0

2 5 0

3 0 0

T o ta l L e n g th (m m ) 63

Figure 48. Northern kingfish sex-ratios in Chesapeake Bay 2002-2006, by year (A), month (B).

n= 100

A.

90

73

55

55

71

100.1

100.0

100.1

100.0

100.0

9.7

34.3

9.0

20.2

49.7

35.5

39.4

Percent

80

21.7

70 64.2

60

58.1

55.6

50

51.0

49.2

Sex

40

F M U

30 20 10 0 2002

2003

2004

2005

2006

Year

n= 100

B.

51

63

130

100

100

100

100

42.7

53.7

6.0

27.3

76

33.0

90 80 70

Percent Percent

Percent

66

20.7

60

61.0

57.3

50

52.0

45.2

40 30 20 10 0 05-May

07-Jul

09-Sep Month 64

11-Nov

Sex

F M U

Figure 49. Northern kingfish length-weight relationships in Chesapeake Bay 2002-2006 as calculated by power regression for sexes combined (A) and separately (B).

700

A.

600

Weight(g)

500

400 W e ig h t ( g ) = 0 .0 0 6 8 * L e n g t h ( c m ) * * 3 .1 4 5 ( n = 3 3 9 )

300

200

100

0

0

10

20

30

40

Total Length(cm )

700

B.

600

M a le s

500

- W e ig h t ( g ) = 0 .0 1 0 9 * L e n g t h ( c m ) * * 2 .9 9 9 ( n = 1 1 0 )

Weight(g)

F e m a le s - W e ig h t ( g ) = 0 .0 0 6 4 * L e n g t h ( c m ) * * 3 .1 6 6 ( n = 1 7 9 )

400

300

200

100

0

10

20

30 Total Length(cm ) 65

40

Figure 50. Northern kingfish maturity schedule in Chesapeake Bay 2002-2006 combined, by sex.

1 .0 9 9 % m a t u r it y

0 .9

0 .8

Probability of Maturity

0 .7

0 .6

0 .5 5 0 % m a t u r it y

0 .4

0 .3

0 .2

0 .1

S E X 20. Northern F Figure kingfish diet in Chesapeake Bay 2002-2005 combined*.

M

0 .0

10

20

30

T o ta l L e n g th (c m )

Figure 51. Northern kingfish diet in Chesapeake Bay 2002-2006 combined.

66

40

67

Figure 52. Northern puffer minimum trawlable abundance estimates in numbers (A) and biomass (B) in Chesapeake Bay 2002-2006.

R e g io n

V a -L o w

V a -U p p

M d -L o w

M d - M id

M d -U p p

6 0 0 ,0 0 0

A. Minimum Trawlable Number

5 0 0 ,0 0 0

4 0 0 ,0 0 0

3 0 0 ,0 0 0

2 0 0 ,0 0 0

1 0 0 ,0 0 0

0

M ar M ay Jul S ep Nov

M ar M ay Jul Sep Nov

M ar M ay Jul Sep Nov

M ar M ay Jul Sep Nov

M ar M ay Jul Sep Nov

2002

2003

2004

2005

2006

R e g io n

V a -L o w

V a -U p p

M d -L o w

M d - M id

M o n th Ye a r

M d -U p p

1 6 0 ,0 0 0 1 5 0 ,0 0 0 1 4 0 ,0 0 0

B.

Minimum Trawlable Biomass (kg)

1 3 0 ,0 0 0 1 2 0 ,0 0 0 1 1 0 ,0 0 0 1 0 0 ,0 0 0 9 0 ,0 0 0 8 0 ,0 0 0 7 0 ,0 0 0 6 0 ,0 0 0 5 0 ,0 0 0 4 0 ,0 0 0 3 0 ,0 0 0 2 0 ,0 0 0 1 0 ,0 0 0 0

M ar M ay Jul S ep Nov

M ar M ay Jul Sep Nov

M ar M ay Jul Sep Nov

M ar M ay Jul Sep Nov

M ar M ay Jul Sep Nov

2002

2003

2004

2005

2006

68

M o n th Ye a r

Note: This species is not captured in enough abundance to create meaningful abundance maps.

69

Figure 53. Northern puffer length-frequency in Chesapeake Bay 2002-2006.

2 0 0 2 3 0 2 0 1 0 0

0

5 0

1 0 0

1 5 0

2 0 0

2 5 0

3 0 0

2 5 0

3 0 0

2 5 0

3 0 0

2 5 0

3 0 0

2 5 0

3 0 0

T o t a l 2L0 e0 n3 g t h ( m m ) 4 0 3 0 2 0 1 0 0

Expanded Number

0

5 0

1 0 0

1 5 0

2 0 0

T o t a l 2L 0e 0n4g t h ( m m ) 7 6 5 4 3 2 1 0

0

5 0

1 0 0

1 5 0

2 0 0

T o t a l 2 L0 e0 n5 g t h ( m m ) 3 0 2 0 1 0 0

0

5 0

1 0 0

1 5 0

2 0 0

T o t a l 2L0 e0 n6 g t h ( m m ) 1 2 1 0 8 6 4 2 0

0

5 0

1 0 0

1 5 0

2 0 0

T o ta l L e n g th (m m )

70

Figure 54. Northern puffer sex-ratios in Chesapeake Bay 2002-2006, by year (A), month (B).

n= 100

A.

134

97

31

84

9 9 .9

1 0 0 .1

1 0 0 .0

1 0 0 .0

1 0 0 .1

1 3 .3

3 1 .6

1 8 .0

1 3 .5

3 4 .5

51

90 4 6 .2

3 6 .9

2 7 .0

70 6 7 .9

60

6 3 .1

5 5 .0

50

S ex

4 9 .7

40

F M U

4 0 .4

30 20 10 0 2002

2003

2004

2005

2006

Year

n= 100

B.

14

76

105

202

1 0 0 .0

1 0 0 .1

1 0 0 .0

1 0 0 .0

2 1 .4

6 2 .3

2 0 .7

8 .0

90

2 2 .9

80

3 6 .7

2 8 .6

70 6 9 .1

Percent Percent

Percent

Percent

80

60 50

S ex

5 0 .0

40

4 2 .6 3 6 .0

30 20 10 0 0 5 -M a y

0 7 -J u l

0 9 -S e p

M o n th 71

1 1 -N o v

F M U

Figure 55. Northern puffer length-weight relationships in Chesapeake Bay 2002-2006 as calculated by power regression for sexes combined (A) and separately (B).

600

A. 500

Weight(g)

400

300

W e i g h t ( g ) = 0 .0 3 7 * L e n g t h ( c m ) * * 2 .8 8 5 8 ( n = 4 4 3 )

200

100

0 0

10

20

30

T o ta l L e n g th (c m ) 600

B. 500

400

M a le s

- W e i g h t ( g ) = 0 .0 3 3 2 * L e n g t h ( c m ) * * 2 .9 0 3 9 ( n = 1 3 7 )

Weight(g)

F e m a l e s - W e i g h t ( g ) = 0 .0 5 5 7 * L e n g t h ( c m ) * * 2 .7 5 6 9 ( n = 2 2 1 ) 300

200

100

0 0

10

20 T o ta l L e n g th (c m )

72

30

Figure 56. Northern puffer maturity schedule in Chesapeake Bay 2002-2006 combined, by sex.

1 .0

9 9 % m a tu r it y 0 .9

0 .8

Probability of Maturity

0 .7

0 .6

0 .5

5 0 % m a tu r it y 0 .4

0 .3

0 .2

0 .1

SEX 0 .0 0

F M 10

20

T o ta l L e n g th (c m )

Figure 57. Northern puffer diet in Chesapeake Bay 2002-2006 combined.

73

30

74

Figure 58. Scup minimum trawlable abundance estimates in numbers (A) and biomass (B) in Chesapeake Bay 2002-2006.

R e g io n

V a -L o w

V a -U p p

M d -L o w

M d - M id

M d -U p p

4 ,0 0 0 ,0 0 0

A. Minimum Trawlable Number

3 ,0 0 0 ,0 0 0

2 ,0 0 0 ,0 0 0

1 ,0 0 0 ,0 0 0

0

M ar M ay Jul Sep Nov

M ar M ay Jul S ep Nov

M ar M ay Jul S ep Nov

M ar M ay Jul Sep Nov

M ar M ay Jul Sep Nov

2002

2003

2004

2005

2006

Ye a r

M o n th

R e g io n

V a -L o w

V a -U p p

M d -L o w

M d - M id

M o n th

M d -U p p

2 0 0 ,0 0 0 1 9 0 ,0 0 0 1 8 0 ,0 0 0

B.

1 7 0 ,0 0 0

Minimum Trawlable Biomass (kg)

1 6 0 ,0 0 0 1 5 0 ,0 0 0 1 4 0 ,0 0 0 1 3 0 ,0 0 0 1 2 0 ,0 0 0 1 1 0 ,0 0 0 1 0 0 ,0 0 0 9 0 ,0 0 0 8 0 ,0 0 0 7 0 ,0 0 0 6 0 ,0 0 0 5 0 ,0 0 0 4 0 ,0 0 0 3 0 ,0 0 0 2 0 ,0 0 0 1 0 ,0 0 0 0

M ar M ay Jul S ep Nov

M ar M ay Jul Sep Nov

M ar M ay Jul Sep Nov

M ar M ay Jul Sep Nov

M ar M ay Jul Sep Nov

2002

2003

2004

2005

2006

75

Ye a r

76

March May

July

Figure 59. Abundance (number per hectare swept) of scup in Chesapeake Bay, 2002.

September November

77

March May

July

Figure 60. Abundance (number per hectare swept) of scup in Chesapeake Bay, 2003.

September November

78

March May July

Figure 61. Abundance (number per hectare swept) of scup in Chesapeake Bay, 2004.

September November

79

March May July

Figure 62. Abundance (number per hectare swept) of scup in Chesapeake Bay, 2005.

September November

80

March May

July

Figure 63. Abundance (number per hectare swept) of scup in Chesapeake Bay, 2006.

September November

Figure 64. Scup length-frequency in Chesapeake Bay 2002-2006.

2 0 0 2 4 0 3 0 2 0 1 0 0

0

5 0

1 0 0

1 5 0

2 0 0

2 5 0

3 0 0

3 5 0

2 5 0

3 0 0

3 5 0

2 5 0

3 0 0

3 5 0

2 5 0

3 0 0

3 5 0

2 5 0

3 0 0

3 5 0

F o r k 2L0e0n3g t h ( m m ) 7 6 5 4

0 0 0 0

3 0 2 0 1 0 0

Expanded Number

0

5 0

1 0 0

1 5 0

2 0 0

F o r k 2 L0 e0 n4 g t h ( m m ) 1 1 1 1

6 4 2 0 8 6 4 2

0 0 0 0 0 0 0 0 0 0

5 0

1 0 0

1 5 0

2 0 0

F o r k 2 L0 e0 n5 g t h ( m m ) 3 0 0

2 0 0

1 0 0

0 0

5 0

1 0 0

1 5 0

2 0 0

F o r k 2L0e0n6g t h ( m m ) 8 7 6 5 4 3 2 1

0 0 0 0 0 0 0 0 0 0

5 0

1 0 0

1 5 0

2 0 0

F o rk L e n g th (m m )

81

Figure 65. Scup sex-ratios in Chesapeake Bay 2002-2005, by year (A) and month (B).

n= 100

A.

40

97

1 0 0 .0

1 0 0 .0

155 1 0 0 .1

1 0 0 .0

85

115 9 9 .9

2 3 .3

3 1 .8

4 9 .5

3 7 .0

7 6 .8

90 80

2 7 .5 2 9 .5

60 50

1 0 .7

40

4 0 .7

Se x

F M U

3 9 .9 3 3 .5

30

2 9 .9

20

8 .5

10

1 4 .6

0 2002

2003

2004

2005

2006

Year

n= 100

B.

34

124

255

79

100

100

100

100

8 6 .2

6 4 .4

4 0 .0

1 5 .4

90 2 8 .8

80 70 Percent Percent

Percent

Percent

4 6 .8

70

60

2 8 .0 5 5 .8

50

Se x

40 5 .6

30

3 2 .0

3 0 .0

20 10

1 3 .8

0 0 5 -M a y

0 7 -J u l

0 9 -S e p M o n th

82

1 1 -N o v

F M U

Figure 66. Scup length-weight relationships in Chesapeake Bay 2002-2006 as calculated by power regression for sexes combined (A) and separately (B).

300

A.

Weight(g)

200

W e ig h t(g ) = 0 .0 2 3 6 * L e n g th (c m )**2 .9 8 0 6 (n = 4 9 6 )

100

0 6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

T o ta l L e n g th (c m ) 300

B. 200

M a le s

- W e ig h t(g ) = 0 .0 4 0 1 * L e n g th (c m )**2 .7 9 9 (n = 1 0 4 )

Weight(g)

F e m a le s - W e ig h t(g ) = 0 .0 2 4 3 * L e n g th (c m )**2 .9 7 4 6 (n = 1 8 4 )

100

0 8

9

10

11

12

13

14

15

16

17

T o ta l L e n g th (c m )

83

18

19

20

21

22

23

Figure 67. Scup maturity schedule in Chesapeake Bay 2002-2006 combined, by sex.

1 .0

9 9 % m a tu r it y 0 .9

0 .8

Probability of Maturity

0 .7

0 .6

0 .5

5 0 % m a tu r it y 0 .4

0 .3

0 .2

0 .1

SEX

F M

0 .0 8

9

10

11

12

13

14

15

16

F o r k L e n g th (c m )

Figure 68. Scup diet in Chesapeake Bay 2002-2006 combined.

84

17

18

19

20

21

22

23

Figure 69. Spot minimum trawlable abundance estimates in numbers (A) and biomass (B) in Chesapeake Bay 2002-2006.

R e g io n

V a -L o w

V a -U p p

M d -L o w

M d - M id

M d -U p p

1 9 ,0 0 0 ,0 0 0 1 8 ,0 0 0 ,0 0 0 1 7 ,0 0 0 ,0 0 0 1 6 ,0 0 0 ,0 0 0

A.

1 5 ,0 0 0 ,0 0 0

Minimum Trawlable Number

1 4 ,0 0 0 ,0 0 0 1 3 ,0 0 0 ,0 0 0 1 2 ,0 0 0 ,0 0 0 1 1 ,0 0 0 ,0 0 0 1 0 ,0 0 0 ,0 0 0 9 ,0 0 0 ,0 0 0 8 ,0 0 0 ,0 0 0 7 ,0 0 0 ,0 0 0 6 ,0 0 0 ,0 0 0 5 ,0 0 0 ,0 0 0 4 ,0 0 0 ,0 0 0 3 ,0 0 0 ,0 0 0 2 ,0 0 0 ,0 0 0 1 ,0 0 0 ,0 0 0 0

M ar M ay Jul Sep Nov

M ar M ay Jul Sep Nov

M ar M ay Jul S ep Nov

M ar M ay Jul S ep Nov

M ar M ay Jul Sep Nov

2002

2003

2004

2005

2006

R e g io n

V a -L o w

V a -U p p

M d -L o w

M d - M id

M o n th Ye a r

M d -U p p

2 ,0 0 0 ,0 0 0 1 ,9 0 0 ,0 0 0 1 ,8 0 0 ,0 0 0

B.

1 ,7 0 0 ,0 0 0

Minimum Trawlable Biomass (kg)

1 ,6 0 0 ,0 0 0 1 ,5 0 0 ,0 0 0 1 ,4 0 0 ,0 0 0 1 ,3 0 0 ,0 0 0 1 ,2 0 0 ,0 0 0 1 ,1 0 0 ,0 0 0 1 ,0 0 0 ,0 0 0 9 0 0 ,0 0 0 8 0 0 ,0 0 0 7 0 0 ,0 0 0 6 0 0 ,0 0 0 5 0 0 ,0 0 0 4 0 0 ,0 0 0 3 0 0 ,0 0 0 2 0 0 ,0 0 0 1 0 0 ,0 0 0 0

M ar M ay Jul Sep Nov

M ar M ay Jul S ep Nov

M ar M ay Jul S ep Nov

M ar M ay Jul Sep Nov

M ar M ay Jul Sep Nov

2002

2003

2004

2005

2006

85

M o n th Ye a r

86

March May

July

Figure 70. Abundance (number per hectare swept) of spot in Chesapeake Bay, 2002.

September November

87

March May

July

Figure 71. Abundance (number per hectare swept) of spot in Chesapeake Bay, 2003.

September November

88

March May July

Figure 72. Abundance (number per hectare swept) of spot in Chesapeake Bay, 2004.

September November

89

March May

July

Figure 73. Abundance (number per hectare swept) of spot in Chesapeake Bay, 2005.

September November

90

March May

July

Figure 74. Abundance (number per hectare swept) of spot in Chesapeake Bay, 2006.

September November

Figure 75. Spot length-frequency in Chesapeake Bay 2002-2006.

2 0 0 2 5 0 0 4 0 0 3 0 0 2 0 0 1 0 0 0

0

5 0

1 0 0

1 5 0

2 0 0

2 5 0

3 0 0

3 5 0

2 5 0

3 0 0

3 5 0

2 5 0

3 0 0

3 5 0

2 5 0

3 0 0

3 5 0

2 5 0

3 0 0

3 5 0

F o r k 2 L0 e0 n3 g t h ( m m ) 7 6 5 4 3 2 1

0 0 0 0 0 0 0

0 0 0 0 0 0 0 0

Expanded Number

0

5 0

1 0 0

1 5 0

2 0 0

F o r k 2 L0 e0 n4 g t h ( m m ) 7 6 5 4 3 2 1

0 0 0 0 0 0 0

0 0 0 0 0 0 0 0

0

5 0

1 0 0

1 5 0

2 0 0

F o r k 2 L0 e0 n5 g t h ( m m ) 1 4 0 0 1 2 0 0 1 0 0 0 8 0 0 6 0 0 4 0 0 2 0 0 0

0

5 0

1 0 0

1 5 0

2 0 0

F o r k2 0L 0e 6n g t h ( m m ) 1 1 1 1

6 4 2 0 8 6 4 2

0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0 0

0

5 0

1 0 0

1 5 0

2 0 0

F o rk L e n g th (m m )

91

Figure 76. Spot age-structure in Chesapeake Bay 2002-2006.

2 0 0 2 1 8 0 0

1 6 5 1

1 6 0 0 1 4 0 0 1 2 0 0 9 5 4

1 0 0 0 8 0 0 6 0 0 4 0 0

2 0 0( Y3 e

A g e

0 7

)

)

99

99

5

4

(1

(1

99 (1

2

3

(2

(2 1

1

9

)

00

00

1

0

)

) 2 00 (2 0

2 4

)

8 4

0

8

2 0 0

a r C la s s )

3 0 0 0

2 2 8 0

2 0 0 0

1 2 7 2

0( Y4e

8

9

99

99

5

4

(1

(1

00 (2

A2g 0 e

0

)

) 0

) 2

1

3

(2

(2

00

00

2

1

)

) 3 00 (2 0

2

0

)

3 1

0

a r C la s s )

3 0 0 0 2 6 2 2

2 0 0 0

1 2 6 5

1 0 0 0

1 8 6 ) 9 99 5

4

3

2

0( Y5 e

(1

00 (2

00 (2

00 (2

00 (2 1

2 g0e A

0

0

) 1

) 2

) 3

) 4 00 (2 0

0 )

2

0

a r C la s s )

8 0 0 0 7 1 2 3

7 0 0 0 6 0 0 0 5 0 0 0 4 0 7 2

4 0 0 0 3 0 0 0 2 0 0 0 1 0 0 0 )

)

00

1

(2 5

4

2

3

(2

(2

00

00 (2

00 (2 1

A g e

2006

0

00

2

3

)

)

) 4

) 5 00 (2 0

2

2 0

0

1 5 3

0

( Y e a r C la s s )

3865

4000

2835

3000 2000 1000

89

0

0

0

92

1) 00 (2

(2

00

5

3

A g e (Y e a r C la s s )

4

(2

00

2)

3)

4) 00 2

(2

00 (2 1

(2

00

5)

6)

0

0

Expanded Number

1 0 0 0

Figure 77. Spot sex-ratios in Chesapeake Bay 2002-2005, by year (A), month (B).

n= 100

A.

672

380

617

1023

100

100

100

100

1 3 .8

6 .5

1 7 .4

1 3 .6

100

4 0 .9

4 8 .3

90

680

3 9 .3

4 4 .8

80

3 8 .2

Percent Percent

70 60 5 5 .3

50 40

Se x

4 5 .2

4 4 .4

2003

2004

4 1 .4

4 7 .1

F M U

30 20 10 0 2002

2005

2006

Y ear

n= 100

B.

4

433

802

1304

100

100

100

100

100

100

19

11

7

15

90

829

46

42 34

80

39

Percent Percent

70 60 50

51

40

47

47

0 7 -J u l

0 9 -S e p

43

30 20 10 0 0 3 -M a r

0 5 -M a y

M o n th 93

1 1 -N o v

Se x

F M U

Figure 78. Spot length-weight relationships in Chesapeake Bay 2002-2006 as calculated by power regression for sexes combined (A) and separately (B).

600

A. 500

Weight(g)

400

W e ig h t(g ) = 0 .0 0 8 * L e n g th (c m )**3 .2 5 8 (n = 3 4 1 3 )

300

200

100

0 0

10

20

30

40

F o r k L e n g th (c m )

600 M a le s

- W e ig h t ( g ) = 0 .0 0 8 7 * L e n g t h ( c m ) * * 3 . 2 2 9 6 ( n = 1 2 9 9 )

F e m a le s - W e ig h t ( g ) = 0 .0 0 7 6 * L e n g t h ( c m ) * * 3 . 2 7 4 2 ( n = 1 5 7 9 )

500

B.

Weight(g)

400

300

200

100

0 0

10

20 F o r k L e n g th (c m )

94

30

40

Figure 79. Spot maturity schedule in Chesapeake Bay 2002-2006 combined, by sex.

1 .0

9 9 % m a t u r it y 0 .9

0 .8

Probability of Maturity

0 .7

0 .6

0 .5

5 0 % m a t u r it y 0 .4

0 .3

0 .2

0 .1

SEX

F M

0 .0 0

10

20

F o r k L e n g th (c m )

95

30

40

96

Figure 80. Striped bass minimum trawlable abundance estimates in numbers (A) and biomass (B) in Chesapeake Bay 2002-2006.

R e g io n

V a -L o w

V a -U p p

M d -L o w

M d - M id

M d -U p p

4 ,0 0 0 ,0 0 0

A. Minimum Trawlable Number

3 ,0 0 0 ,0 0 0

2 ,0 0 0 ,0 0 0

1 ,0 0 0 ,0 0 0

0

M ar M ay Jul Sep Nov

M ar M ay Jul S ep Nov

M ar M ay Jul S ep Nov

M ar M ay Jul Sep Nov

M ar M ay Jul Sep Nov

2002

2003

2004

2005

2006

R e g io n

V a -L o w

V a -U p p

M d -L o w

M d - M id

M o n th Ye a r

M d -U p p

3 ,0 0 0 ,0 0 0

Minimum Trawlable Biomass (kg)

B.

2 ,0 0 0 ,0 0 0

1 ,0 0 0 ,0 0 0

0

M ar M ay Jul Sep Nov

M ar M ay Jul S ep Nov

M ar M ay Jul S ep Nov

M ar M ay Jul Sep Nov

M ar M ay Jul Sep Nov

2002

2003

2004

2005

2006

97

M o n th Ye a r

98

March May

July

September

Figure 81. Abundance (number per hectare swept) of striped bass in Chesapeake Bay, 2002.

November

99

March May

July

September

Figure 82. Abundance (number per hectare swept) of striped bass in Chesapeake Bay, 2003.

November

100

March May

July

September

Figure 83. Abundance (number per hectare swept) of striped bass in Chesapeake Bay, 2004.

November

101

March May

July

September

Figure 84. Abundance (number per hectare swept) of striped bass in Chesapeake Bay, 2005.

November

102

March May July

September

Figure 85. Abundance (number per hectare swept) of striped bass in Chesapeake Bay, 2006.

November

Figure 86. Striped bass length-frequency in Chesapeake Bay 2002-2006.

2002 30 20 10 0 0

50

100

150

200

250

300

350

400

450

500

550

600

650

700

750

800

850

900

950

1000

700

750

800

850

900

950

1000

700

750

800

850

900

950

1000

700

750

800

850

900

950

1000

700

750

800

850

900

950

1000

F o r k 2L0e0n3g t h ( m m ) 50 40 30 20 10 0

Expanded Number

0

50

100

150

200

250

300

350

400

450

500

550

600

650

F o r k 2L0e0n4g t h ( m m ) 50 40 30 20 10 0 0

50

100

150

200

250

300

350

400

450

500

550

600

650

5 g th (m m ) F o r k 2 L0 e0 n

200 150 100 50 0 0

50

100

150

200

250

300

350

400

450

500

550

600

650

F o r k 2L0e0n6g t h ( m m ) 7 6 5 4 3 2 1

0 0 0 0 0 0 0 0 0

50

100

150

200

250

300

350

400

450

500

550

600

650

F o rk L e n g th (m m )

103

104

A g e (Y e a r C la s s )

0)

1

9

1 6 (1 9

9

8

9

9)

0)

0

9

(1

1

1

6

5

(1

(1

(1

98

98

99

8)

9)

0)

1)

1

(1

5

1)

4

99

1

1

1

1

1

6

5

4

3

2

(1

(1

(1

(1

(1

(1

98

98

98

99

99

99

7)

8)

9)

0)

1)

2)

3)

0

6

1

9

1

(1

2)

1

99

1

1

1

1

1

1

1

6

5

4

3

2

1

0

9

(1

(1

(1

(1

(1

(1

(1

(1

98

98

98

98

99

99

)

)

)

)

)

6)

7)

8)

9)

0)

1)

2)

93

94

95

96

99

9

9

9

9

97

)

)

0

1

1)

4

9

9

0

9

(1

3

99

0

(1

4

2)

1

(1

3)

(1

3

5

1

9

2

99

1

0

)

(1

(1

(1

9

98

99

)

0

1

2)

9

9

9

4

9

(1

1

(1

1

(1

3

3)

1

4)

94

0

4

1

9

1

99

9

8

7

6

(1

9

9

00

2

1

6

3)

1 9

9

9

2

9

(1

4)

(1

9

(1

2

9

0

(1

)

)

1

3

1

9

1

1

9

95

96

)

5

(1

(1

0

)

)

2

1

4)

(1

7

9

1

5)

)

7

9

1

9

95

9

9

97

10

(1

5)

9

9

(1

(1

9

)

4

3

(2

01

02

1

2

9

(1

(1

)

8

7

(1

98

)

)

2

0

0

9

1

9

1 0

(1

0

1 4

1

1

9

96

)

8

1

5

6)

1 3 )

4

9

0 6

9

97

2

9

99

(1

9

6

9

99

00

)

21

(1

(1

8

(1

)

(1

9

0

01

(2

(2

3

0

9

)

7

98

)

5

(1

(2

0

1

0

13

1

0( Y0 e6 a

)

7

1 4

7

99

)

9

99

21

99

(1

8

(1

9

)

4

3

(2

)

)

22

(1

8

99

6

(1

00

)

2

02

03

4

9

)

1 9

8

A g2 e

99

(1

6

(1

7

)

5

0

01

18

8

1 3

)

9

1

9

99

2 5

99

(1

)

(2

0

19

(1

6

0

4

(2

)

0

0

18

7

5 0

)

5 0

0

00

)

5 0

00

(2

1

3

02

(2

(2

5

(2

5

00

)

0

)

1

0

0

6

2 5

)

(2

2

1 5 0

1

4

00

(2

03

)

93

00

)

(2

2

0

04

100

(2

2

3

)

(2

0

34

5

00

6 0 0

(2

)

3

1 0 0

4

3

00

1 8 0 0

00

(2

1

(2

100

(2

)

)

0

163

3

4

4

)

7 5

00

00

5

300

(2

2

(2

00

2

2

)

(2

0

5

1

0

0

00

0

)

0

(2

6

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

1

00

7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1

(2

1 1 1 1 1 1 1 1

0

Expanded Number Figure 87. Striped bass age-structure in Chesapeake Bay 2002-2006.

2002

157

28 51

0 0

A2g 0e 0( Y3e a r C l a s s )

300

254

200

167

76 42 25 0 0

0 e4a r C l a s s ) A g2e 0( Y

273 290

200

96

25 2 2

2 g0e 0( Y5e a r C l a s s ) A

1 7 0 0 1 7 3 4

2 0 0

1 7 5

1 4 9

1 2 5

7 3 9 9

5 0

0 0

r C la s s )

5 0 0

5 5 1

2 0 0

1 7 5

1 5 0

1 5 0

1 2 5

1 0 0

7 5

4 7

0

0

Figure 88. Striped bass sex-ratios in Chesapeake Bay 2002-2006, by year (A), month (B), age (C).

n= 100

467

584

724

100.0

100.0

99.9

100.0

100.0

4.8

59.3

6.0

53.2

67.3

63.3

90

A.

337

535

53.0

80 70

Percent

Percent

60 50

Sex

F M U

Sex

F M U

Sex

F M U

45.2

40

40.9

39.2

30

31.9

31.6

20 10 0 2002

2003

2004

2005

2006

Year

n=

1137

B.

350

100.0

100

211

100.0

48.1

149

99.9

77.0

68.2

90

800

100.1

100.0

66.0

60.9

80

Percent

Percent

70 60 50 48.3

40 38.5

30

32.4

27.6

20 19.3

10 0 03-Mar

05-May

07-Jul

09-Sep

11-Nov

Month

n=

Percent SUM

100

5

263 725 363 256 83

57

73

44

100.0

100.0

100.1

100.0

100.0

100.0

100.0

100.0

100.0

58

19

52

52

77

88

93

81

72

48

48

38 100.0

30

2

2

100.0

14 100.0

7 100.0

3 100.0

1 100.0

100.0

100.0

78

64

71

100

100

50

50

50

50

15

16

83

90

C.

80

41

70 60

Percent

50 40

23

40 36

30 29

28

20

23

22

19

19 15

10

12 7

0 0

1

2

3

4

5

6

7

8

9

AGE

105

10

11

12

13

14

Figure 89. Striped bass length-weight relationships in Chesapeake Bay 2002-2006 as calculated by power regression for sexes combined (A) and separately (B).

16000 15000 14000

A.

13000 12000 11000

W e ig h t(g ) = 0 .0 0 9 3 * L e n g th (c m )**3 .0 6 6 2 (n = 2 6 8 9 )

Weight(g)

10000 9000 8000 7000 6000 5000 4000 3000 2000 1000 0 0

10

20

30

40

50

60

70

80

90

100

110

80

90

100

110

F o rk L e n g th (c m )

16000 M a le s

15000

- W e ig h t(g ) = 0 .0 0 9 3 * L e n g th (c m )**3 .0 6 8 1 (n = 1 6 2 4 )

F e m a le s - W e ig h t(g ) = 0 .0 0 8 5 * L e n g th (c m )**3 .0 8 5 5 (n = 9 6 6 )

14000 13000

B.

12000 11000

Weight(g)

10000 9000 8000 7000 6000 5000 4000 3000 2000 1000 0 0

10

20

30

40

50

60

F o rk L e n g th (c m )

106

70

Figure 90. Striped bass maturity schedule in Chesapeake Bay 2002-2006 combined, by sex.

1 .0

9 9 % m a tu r ity 0 .9

0 .8

Probability of Maturity

0 .7

0 .6

0 .5

5 0 % m a tu r ity 0 .4

0 .3

0 .2

0 .1

SEX

F M

0 .0 0

10

20

30

40

50

60

F o r k L e n g th (c m ) Figure 40. Striped bass diet in Chesapeake Bay 2002-2005 combined.

Figure 91. Striped bass diet in Chesapeake Bay 2002-2006 combined.

107

70

80

90

100

110

108

Figure 92. Summer flounder minimum trawlable abundance estimates in numbers (A) and biomass (B) in Chesapeake Bay 2002-2006.

R e g io n

V a -L o w

V a -U p p

M d -L o w

M d - M id

M d -U p p

1 ,6 0 0 ,0 0 0 1 ,5 0 0 ,0 0 0

A.

1 ,4 0 0 ,0 0 0 1 ,3 0 0 ,0 0 0

Minimum Trawlable Number

1 ,2 0 0 ,0 0 0 1 ,1 0 0 ,0 0 0 1 ,0 0 0 ,0 0 0 9 0 0 ,0 0 0 8 0 0 ,0 0 0 7 0 0 ,0 0 0 6 0 0 ,0 0 0 5 0 0 ,0 0 0 4 0 0 ,0 0 0 3 0 0 ,0 0 0 2 0 0 ,0 0 0 1 0 0 ,0 0 0 0

M ar M ay Jul Sep Nov

M ar M ay Jul S ep Nov

M ar M ay Jul S ep Nov

M ar M ay Jul Sep Nov

M ar M ay Jul Sep Nov

2002

2003

2004

2005

2006

R e g io n

V a -L o w

V a -U p p

M d -L o w

M d - M id

M o n th Ye a r

M d -U p p

1 ,0 0 0 ,0 0 0

9 0 0 ,0 0 0

B.

Minimum Trawlable Biomass (kg)

8 0 0 ,0 0 0

7 0 0 ,0 0 0

6 0 0 ,0 0 0

5 0 0 ,0 0 0

4 0 0 ,0 0 0

3 0 0 ,0 0 0

2 0 0 ,0 0 0

1 0 0 ,0 0 0

0

M ar M ay Jul Sep Nov

M ar M ay Jul S ep Nov

M ar M ay Jul S ep Nov

M ar M ay Jul Sep Nov

M ar M ay Jul Sep Nov

2002

2003

2004

2005

2006

109

M o n th Ye a r

110

March May

July

Figure 93. Site-specific summer flounder abundance (number per hectare swept), 2002.

September November

111

March May

July

Figure 94. Site-specific summer flounder abundance (number per hectare swept), 2003.

September November

112

March May

July

Figure 95. Site-specific summer flounder abundance (number per hectare swept), 2004.

September November

113

March May July

Figure 96. Site-specific summer flounder abundance (number per hectare swept), 2005.

September November

114

March May July

Figure 97. Site-specific summer flounder abundance (number per hectare swept), 2007.

September November

Figure 98. Summer flounder length-frequency in Chesapeake Bay 2002-2006.

2002 60 50 40 30 20 10 0 0

50

100

150

200

250

300

350

400

450

500

550

600

650

700

750

800

550

600

650

700

750

800

550

600

650

700

750

800

550

600

650

700

750

800

550

600

650

700

750

800

00 T o ta l2 L e3 n g th (m m ) 50 40 30 20 10 0

Expanded Number

0

50

100

150

200

250

300

350

400

450

500

T o ta 2l 0L0e4n g th (m m ) 120 100 80 60 40 20 0 0

50

100

150

200

250

300

350

400

450

500

00 T o t a l2 L e5 n g th (m m ) 60 50 40 30 20 10 0 0

50

100

150

200

250

300

350

400

450

500

T o ta2l 0L0e6n g th (m m ) 120 100 80 60 40 20 0 0

50

100

150

200

250

300

350

400

450

500

T o ta l L e n g th (m m )

115

Figure 99. Summer flounder age-structure in Chesapeake Bay 2002-2006.

2 0 0 2 4 0 0

3 7 7

3 0 0

2 0 0 1 1 5

9 1

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

) 0 99

1

(1 12

(1 11

(1 10

(1 9

8

0

)

) 2

4) 99 (1

99 (1 7

0

C la s s )

6 9 4 5

3 2

)

)

0 1

2

3 99

99 12

(1

(1 11

(1 10

(1 9

8

0

)

0

4)

5) 99 (1

99 (1 7

6 Y e a r 2 0A g 0e ( 4

0

99

2

6)

7) 99 (1

99 5

(1

(1 4

5

99

9

8)

9) 99

0) 00 3

(2

(2 2

(2 1

0

(2

00

00

2)

1)

1 3

C la s s )

5 0 0 4 1 1

4 0 0

3 0 0

2 0 0 1 1 4

1 0 0

1 0 0

7 1

) 2

)

99 12

10

11

(1

(1

(1

99

99

3

4

5) (1

8

2

0

)

0

9

(1

99 (1 7

6

2 A0g e 0( Y 5e a r

1

6)

7)

8) 99 (1

99 (1 5

6

2

99

1 3

9)

0) 4

3

(2

(2

00

00

1)

2) 00 (2 2

(2 1

0

(2

00

00

3)

4)

0

99

3 6

2 7

C la s s )

2 9 3

3 0 0

2 0 2

2 0 0

8 8

7 8

2 4

2 1 3

)

)

0

11

12

(1

(1

99

99

4

5 (1 10

(1 9

8

0

)

0 99

7) 99 (1

99 (1 7

6

2 0A g0e 6( Y e a r

5

2

8)

9) (1

00 5

(2

(2 4

99

0)

1) 00

2) 3

(2

(2 2

(2 1

00

00

00

4)

5) 00 (2 0

3)

4

6)

2 8

0

99

1 0 0

C la s s )

5 0 0 4 4 6

4 0 0

3 0 0

2 0 0 1 4 9

9 7

7 0

) 99 (1 12

11

(1

99

4

)

0

5

) (1 10

9

(1

99

99

6

7)

8)

1

2

1

99 8

(1

99

A g e ( Y e a r C la s s )

116

3

9)

0) 00 6

(2

00 5

(2

00 (2 4

1 7

1 5

1)

2)

3) 3

(2

00 (2 2

(2 1

00

5) 00

6) 00 (2

4)

2 4

0

(1

6 0

7

1 0 0

0

Expanded Number

0

1 5 3

1 5 0

3)

6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1

00

1 1 1 1 1 1 1

5)

6) 6

4

5

(1

(1

99

99

7)

8) (1

99 3

(1

(2 2

(2 1

99

9)

0) 00

00

1)

2) 00 (2 0

Y e a r 2 0A g 0e ( 3

2

1

1

99

2 0

99

2 2

3)

2 6

0

99

8 6

1 0 0

Figure 100. Summer flounder sex-ratios in Chesapeake Bay 2002-2006, by month (A), region (B), age (C).

n=

242 7.4

90

A.

336

100

100

473

959

1028

100

100

100

100

20.1

20.6

29.0

37.9

77.2

76.3

15.7

80 76.9

70

Percent

68.0 Percent

60 58.9

50

Sex

F M U

Sex

F M U

Sex

F M U

40 30 20 10 0 03-M ar

05-M ay

07-Jul

09-Se p

11-Nov

M onth

n= 100

Percent

Percent

B.

14

163

285

100.0

100.0

100.1

99.9

48.9

4.9

37.1

5.0

1012

36.8

90

1564 100.0

28.8

27.8

80 70 68.7

67.1

60

61.3

58.3

50

51.1

40 30 20 10 0 1 M d-Upp

2 M d-M id

3 M d-Low

4 Va-Upp

5 Va-Low

Re gion

n = 1114 716

Percent SUM

100 90

100.0 5

47

100.1 4

354

276

100.0

100.0

7

4

96

32 93

194 100.0 5

95

114 100.0 4

78

28

14

9

2

1

100.0

100.0

100.0

100.0

100.0

100.0

100.0

2

8

100

7

11

100

100

50

96 93

92

89

Percent

C.

80 70 64

60 50

50

48

40 30 20 10 0 0

1

2

3

4

5

6 AGE

117

7

8

9

10

11

12

Figure 101. Summer flounder length-weight relationships in Chesapeake Bay 2002-2005 as calculated by power regression for sexes combined (A) and separately (B).

6000

A.

5000

Weight(g)

4000

Weight(g) = 0.004 * Length(cm )**3.2528 (n = 3078)

3000

2000

1000

0

10

20

30

40

50

60

70

80

Fork Length(cm )

6000 Males

- W eight(g) = 0.006 * Length(cm)**3.1414 (n = 854)

Females - W eight(g) = 0.0038 * Length(cm)**3.2678 (n = 2115)

5000

B. Weight(g)

4000

3000

2000

1000

0

10

20

30

40

50

Fork Length(cm )

118

60

70

80

Figure 102. Summer flounder maturity schedule in Chesapeake Bay 2002-2006 combined, by sex.

1.0 99% matu rity

0.9

0.8

Probability of Maturity

0.7

0.6

0.5 50% matu rity

0.4

0.3

0.2

0.1

SEX

F M

0.0

10

20

30

40

50

Figure 47. Summer flounder diet in Chesapeake BayLe2002-2005 Total ngth (cm )combined.

Figure 103. Summer flounder diet in Chesapeake Bay 2002-2006 combined.

119

60

70

80

120

Figure 104. Weakfish minimum trawlable abundance estimates in numbers (A) and biomass (B) in Chesapeake Bay 2002-2006.

R e g io n

V a -L o w

V a -U p p

M d -L o w

M d - M id

M d -U p p

5 ,0 0 0 ,0 0 0

A. Minimum Trawlable Number

4 ,0 0 0 ,0 0 0

3 ,0 0 0 ,0 0 0

2 ,0 0 0 ,0 0 0

1 ,0 0 0 ,0 0 0

0

M ar M ay Jul Sep Nov

M ar M ay Jul S ep Nov

M ar M ay Jul S ep Nov

M ar M ay Jul Sep Nov

M ar M ay Jul Sep Nov

2002

2003

2004

2005

2006

R e g io n

V a -L o w

V a -U p p

M d -L o w

M d - M id

M o n th Ye a r

M d -U p p

1 ,0 0 0 ,0 0 0

9 0 0 ,0 0 0

B.

Minimum Trawlable Biomass (kg)

8 0 0 ,0 0 0

7 0 0 ,0 0 0

6 0 0 ,0 0 0

5 0 0 ,0 0 0

4 0 0 ,0 0 0

3 0 0 ,0 0 0

2 0 0 ,0 0 0

1 0 0 ,0 0 0

0

M ar M ay Jul Sep Nov

M ar M ay Jul S ep Nov

M ar M ay Jul S ep Nov

M ar M ay Jul Sep Nov

M ar M ay Jul Sep Nov

2002

2003

2004

2005

2006

121

M o n th Ye a r

122

March May

July

Figure 105. Site-specific weakfish abundance (number per hectare swept), 2002.

September November

123

March May July

Figure 106. Site-specific weakfish abundance (number per hectare swept), 2003.

September November

124

March May

July

Figure 107. Site-specific weakfish abundance (number per hectare swept), 2004.

September November

125

March May July

Figure 108. Site-specific weakfish abundance (number per hectare swept), 2005.

September November

126

March May July

Figure 109. Site-specific weakfish abundance (number per hectare swept), 2006.

September November

Figure 110. Weakfish length-frequency in Chesapeake Bay 2002-2006.

2002 140 120 100 80 60 40 20 0 0

50

100

150

200

250

300

350

400

450

500

550

600

650

700

500

550

600

650

700

500

550

600

650

700

500

550

600

650

700

500

550

600

650

700

T o t a2l 0L0e3n g t h ( m m ) 300 200 100 0

Expanded Number

0

50

100

150

200

250

300

350

400

450

T o t a 2l 0L0e4n g t h ( m m ) 500 400 300 200 100 0 0

50

100

150

200

250

300

350

400

450

T o t a 2l 0L0e5n g t h ( m m ) 300 200 100 0 0

50

100

150

200

250

300

350

400

450

T o t a 2l 0L0e6n g t h ( m m ) 180 160 140 120 100 80 60 40 20 0 0

50

100

150

200

250

300

350

400

450

T o ta l L e n g th (m m )

127

Figure 111. Weakfish age-structure in Chesapeake Bay 2002-2006.

2002 700

629 600

519 500 400

291

300 200

132 100

62 9

3 6)

7)

99 (1

(1

6

5

4

3

(1

(1

99

99

8)

9) 99

0) 00 (2 2

0

1

(2

(2

00

00

2)

1)

0

A 2g0e 0( Y3e a r C l a s s ) 800

709 700

577

600 500

441

400 300 200

103 100

6

0

7)

8)

0

6

5

(1

(1

99

99

9) 4

3

(2

(1

00

99

0)

1) 00 (2 2

2A0g e0 (4Y e a r

C la s s )

1961

2000 1800 1600 1400 1200 1000

886

800 600

405

395

400 200

1

1200

6

4

5

(2

(1

(1

99

99

9)

0) 00

1) 3

1

2

(2

(2

(2

00

00

2)

3) 00

4) 00 (2 0

2A0g 0e 5( Y e a r

0 8)

0

0

C la s s )

1142

1100 1000 900 800

694

661

700 600 500 400 300

185

8

0

2A g0 e0 (6Y e a r

0

0)

1)

5

6

(2

(1

00

00 4

2

3

(2

(2

00

00 (2

(2 1

2)

4) 00

5) 00 (2 0

3)

0

9)

100

99

200

C la s s )

600 528

506

500 400 325

300 200 98

4

128

5

(2

(2

00

00

1)

2) 4

(2

00

00 (2 3

(2 2

(2 1

3)

4)

5) 00

6) 00 (2

00

A g e ( Y e a r C la s s )

0 0)

0

0

6

100

0

Expanded Number

0

1

(2

(2

00

00

2)

3)

0

Figure 112. Weakfish sex-ratios in Chesapeake Bay 2002-2005, by year (A), region (B), age (C).

n=

803

100

626

99.9

100.0

8.6

7.5

43.5

42.7

1108

1115

100.0

728

100.0

100.0

7.3

10.4

40.7

A.

90

38.0

37.0

Percent

Percent

80 70 60 55.9

50

54.7

52.6

49.8

47.8

Sex

F M U

Sex

F M U

40 30 20 10 0 2002

2003

2004

2005

2006

Year

n= 100

B. Percent

264

532

1830

99.9

100.1

99.9

100.0

20.4

20.9

16.5

4.9 39.2

4.8 41.7

47.0

35.9

90

1664

40.1

80

Percent

90 100.0

70 60 55.8

50 43.1

43.5

2 Md-Mid

3 Md-Low

40 30

53.5

32.6

20 10 0 1 Md-Upp

4 Va-Upp

5 Va-Low

Region

n=

Percent SUM

100

C.

1112

1170

964

231

34

9

3

100.0

100.1

100.0

100.0

100.0

100.0

100.0

24.5

40.6

44.5

55.4

61.9

33.3

66.7

90 80 33.0

Percent

70 66.7

60

59.2 55.4

50 40

Sex 44.6

42.5

38.1 33.3

30 20 10 0 0

1

2

3

4

AGE

129

5

6

F M U

Figure 113. Weakfish length-weight relationships in Chesapeake Bay 2002-2006 as calculated by power regression for sexes combined (A) and separately (B).

3000

A.

2000 Weight(g)

We ig h t(g ) = 0 .0 0 5 6 * L e n g th (c m )**3 .1 6 6 2 (n = 4 4 5 9 )

1000

0 0

10

20

30

40

50

60

70

50

60

70

T o ta l L e n g th (c m )

3000 Males

- W eight(g) = 0.007 * Length(cm)**3.1006 (n = 1630)

Females - W eight(g) = 0.0053 * Length(cm)**3.1854 (n = 2355)

B. Weight(g)

2000

1000

0 0

10

20

30

40

T o ta l L e n g th (c m )

130

Figure 114. Weakfish maturity schedule in Chesapeake Bay 2002-2006 combined, by sex.

1.0

99% matu r ity 0.9

0.8

Probability of Maturity

0.7

0.6

0.5

50% matu r ity 0.4

0.3

0.2

0.1

SEX

Figure 53. Weakfish diet in Chesapeake Bay 2002-2005 combined.

0.0 0

10

20

30

40

T o ta l L e n g th (c m )

Figure 115. Weakfish diet in Chesapeake Bay 2002-2006 combined.

131

50

60

F M 70

132

Figure 116. White perch minimum trawlable abundance estimates in numbers (A) and biomass (B) in Chesapeake Bay 2002-2006.

R e g io n

V a -L o w

V a -U p p

M d -L o w

M d - M id

M d -U p p

4 0 ,0 0 0 ,0 0 0

A. Minimum Trawlable Number

3 0 ,0 0 0 ,0 0 0

2 0 ,0 0 0 ,0 0 0

1 0 ,0 0 0 ,0 0 0

0

M ar M ay Jul Sep Nov

M ar M ay Jul Sep Nov

M ar M ay Jul S ep Nov

M ar M ay Jul S ep Nov

M ar M ay Jul Sep Nov

2002

2003

2004

2005

2006

R e g io n

V a -L o w

V a -U p p

M d -L o w

M d - M id

M o n th Ye a r

M d -U p p

3 5 ,0 0 0 ,0 0 0

Minimum Trawlable Biomass (kg)

3 0 ,0 0 0 ,0 0 0

B.

6 ,0 0 0 ,0 0 0

5 ,0 0 0 ,0 0 0

4 ,0 0 0 ,0 0 0

3 ,0 0 0 ,0 0 0

2 ,0 0 0 ,0 0 0

1 ,0 0 0 ,0 0 0

0

M ar M ay Jul Sep Nov

M ar M ay Jul Sep Nov

M ar M ay Jul S ep Nov

M ar M ay Jul S ep Nov

M ar M ay Jul Sep Nov

2002

2003

2004

2005

2006

133

M o n th Ye a r

134

March May

July

September

Figure 117. Figures 117. Site-specific white perch abundance (number per hectare swept), 2002.

November

135

March May

July

Figure 118. Site-specific white perch abundance (number per hectare swept), 2003.

September November

136

March May

July

Figure 119. Site-specific white perch abundance (number per hectare swept), 2004.

September November

137

March May

July

Figure 120. Site-specific white perch abundance (number per hectare swept), 2005.

September November

138

March May

July

Figure 121. Site-specific white perch abundance (number per hectare swept), 2006.

September November

Figure 122. White perch length-frequency in Chesapeake Bay 2002-2006.

2002 1200 1000 800 600 400 200 0 0

50

100

150

200

250

300

350

300

350

400

F o r k2 0L0e3n g t h ( m m ) 600 500 400 300 200 100 0

Expanded Number

0

50

100

150

200

250

400

Fork 2 0L0e4n g t h ( m m ) 1600 1400 1200 1000 800 600 400 200 0 0

50

100

150

200

250

300

350

400

300

350

400

F o r2k 0L0e5n g t h ( m m ) 1200 1000 800 600 400 200 0 0

50

100

150

200

250

F o r2k0 L0 e6 n g t h ( m m ) 2000 1500 1000 500 0 0

50

100

150

200

250

F o r k L e n g th (m m ) 139

300

350

400

140

A g e (Y e a r C la s s )

98

9)

28

(1

0)

16

15

14

(1

(1

(1

98

98

99

99

8)

9)

0)

1)

2)

16

15

14

13

12

(1

(1

(1

(1

(1

98

98

98

99

99

99

7)

8)

9)

0)

1)

2)

4

16

99

4

(1

1)

(1

99

(1

28

15

99

27

(1

2)

(1

11

4

14

99

538

(1

13

12

3)

16

13

3)

200

99

99

)

)

)

)

)

3)

94

95

96

97

99

9

9

(1

(1

(1

9

9

98

3

(1

(1

10

9

8

(1

(1

9

)

100

12

11

4)

)

)

0

4)

99

95

96

7

6

(1

99

)

)

0

99

(1

9

9

)

)

5

9

00

01

)

)

900

(1

5)

10

(1

(1

97

98

)

(1

0

0

02

03

16

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

(1

(1

(1

(1

(1

(1

98

98

98

98

99

99

)

)

)

)

)

)

)

)

)

)

6)

7)

8)

9)

0)

1)

2)

93

94

95

96

97

98

99

00

01

02

99

9

9

9

9

9

9

9

0

0

0

(1

(1

(1

(1

(1

(1

(1

(1

(2

(2

(2

1700 1600 1500 1400 1300 1200 1100 1000 900 800 700 600 500 400 300 200 100 0

11

99

924

(1

)

9

8

9

9

99

4

(2

(2

0

0

258

10

96

)

708

9

97

(1

(1

9

)

3

2

(2

(2

261

(1

9

)

700

(1

98

7

6

(1

00

)

)

1

0

700

9

8

9

)

600

(1

99

5

0

01

02

)

)

262

7

9

)

913

(1

00

(2

0

0

03

04

233

6

0

)

900

(2

01

4

(2

(2

0

0

400

5

0

)

800

(2

02

3

2

(2

(2

500

4

0

1000

(2

)

1

0

300

3

03

)

)

0

0

04

05

100

(2

0

0

4

2

(2

(2

0

1

0

Expanded Number Figure 123. White perch age-structure in Chesapeake Bay 2002-2005 (2006 ages not yet assigned).

2002

A g 2e 0( Y 0 e3a r C l a s s )

800 840

600 647

433

384

290

200

0 0

A2g 0 e 0( Y4e a r C l a s s )

3000

2000

1000

Ag 2 e0 (0Y 5e a r C l a s s )

824 925

616

722

500

517

400

300

91

196

2

0

Figure 124. White perch sex-ratios in Chesapeake Bay 2002-2005, by year (A), age (B).

n=

A.

100

551

177

356

419

100.0

100.0

99.9

100.0

100.0

28.9

31.2

20.5

24.8

31.8

90 80

79.3 74.9

70 Percent Percent

385

70.5

68.5

68.2

60 50

Sex

40

F M U

30 20 10 0 2002

2003

2004

2005

2006

Year

n=

Percent SUM

B.

100

6

33

95

79

118 114 219 132 136 248 72 103

100.1

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

5

12

23

42

24

28

19

27

31

30

31

68

8

8

2

100.0

100.0

100.0

100.0

100.0

8

15

100

100

100

84

90

92

34 85

80

81

76

76

70

73

72

70

70

69

Percent

60 58

55

50

Sex

40 30 20 10

11

0 0

1

2

3

4

5

6

7

8

AGE 141

9

10

11

12

13

14

15

F M U

Figure 125. White perch length-weight relationships in Chesapeake Bay 2002-2006 as calculated by power regression for sexes combined (A) and separately (B).

800

A.

700

600

W e ig h t(g ) = 0 .0 0 8 9 * L e n g th (c m )**3 .2 2 3 1 (n = 1 8 8 6 ) Weight(g)

500

400

300

200

100

0 0

10

20

30

40

F o r k L e n g th (c m )

800 Males

- W eight(g) = 0.0087 * Length(cm)**3.2227 (n = 464)

Females - W eight(g) = 0.0097 * Length(cm)**3.1949 (n = 1403)

700

600

B.

Weight(g)

500

400

300

200

100

0 0

10

20 F o r k L e n g th (c m )

142

30

40

Figure 126. White perch maturity schedule in Chesapeake Bay 2002-2006 combined, by sex.

1 .0

9 9 % m a tu r ity 0 .9

0 .8

Probability of Maturity

0 .7

0 .6

0 .5

5 0 % m a tu r ity 0 .4

0 .3

0 .2

0 .1

SEX

F M

0 .0 0

10

20

F o r k L e n g th (c m )

Figure 127. White perch diet in Chesapeake Bay 2002-2006 combined.

143

30

40

144

March

Figure 128. Surface temperature in Chesapeake Bay, 2002.

July

September November

145

March

Figure 129. Bottom temperature in Chesapeake Bay, 2002.

July

September November

146

March May

Figure 130. Surface temperature in Chesapeake Bay, 2003.

July

September November

147

March May

Figure 131. Bottom temperature in Chesapeake Bay, 2003.

July

September November

148

March May

Figure 132. Surface temperature in Chesapeake Bay, 2004.

July

September November

149

March May

Figure 133. Bottom temperature in Chesapeake Bay, 2004.

July

September November

150

March May

Figure 134. Surface temperature in Chesapeake Bay, 2005.

July

September November

151

March May

Figure 135. Bottom temperature in Chesapeake Bay, 2005.

July

September November

152

March May

Figure 136. Surface temperature in Chesapeake Bay, 2006.

July

September November

153

March May

Figure 137. Bottom temperature in Chesapeake Bay, 2006.

July

September November

154

March

Figure 138. Surface salinity in Chesapeake Bay, 2002.

July

September November

155

March

Figure 139. Bottom salinity in Chesapeake Bay, 2002.

July

September November

156

March May

Figure 140. Surface salinity in Chesapeake Bay, 2003.

July

September November

157

March May

Figure 141. Bottom salinity in Chesapeake Bay, 2003.

July

September November

158

March May

Figure 142. Surface salinity in Chesapeake Bay, 2004.

July

September November

159

March May

Figure 143. Bottom salinity in Chesapeake Bay, 2004.

July

September November

160

March May

Figure 144. Surface salinity in Chesapeake Bay, 2005.

July

September November

161

March May

Figure 145. Bottom salinity in Chesapeake Bay, 2005.

July

September November

162

March May

Figure 146. Surface salinity in Chesapeake Bay, 2006.

July

September November

163

March May

Figure 147. Bottom salinity in Chesapeake Bay, 2006.

July

September November

164

March July

Figure 148. Surface dissolved oxygen in Chesapeake Bay, 2002.

September November

165

March July

Figure 149. Bottom dissolved oxygen in Chesapeake Bay, 2002.

September November

166

March May July

Figure 150. Surface dissolved oxygen in Chesapeake Bay, 2003.

September November

167

March May

July

Figure 151. Bottom dissolved oxygen in Chesapeake Bay, 2003.

September November

168

March May

July

Figure 152. Surface dissolved oxygen in Chesapeake Bay, 2004.

September November

169

March May

July

Figure 153. Bottom dissolved oxygen in Chesapeake Bay, 2004.

September November

170

March May

July

Figure 154. Surface dissolved oxygen in Chesapeake Bay, 2005.

September November

171

March May

July

Figure 155. Bottom dissolved oxygen in Chesapeake Bay, 2005.

September November

172

March May

July

Figure 156. Surface dissolved oxygen in Chesapeake Bay, 2006.

September November

173

March May

July

Figure 157. Bottom dissolved oxygen in Chesapeake Bay, 2006.

September November