Aquatic Update 2011-2 by Scott Parker

Ministry of Natural Resources

Whitefish Lake open-water creel survey: 2008 Scott Parker

Introduction Fishing effort, catch, and harvest information can be used to investigate the effect of fishing on a target fish species as well as support resource management decisions. Information collected during creel surveys, such as angler demographics, are useful when considering the effect of potential regulation changes on both the fish community and anglers.

Whitefish Lake is a 3,015 ha waterbody located 60 km southwest of the city of Thunder Bay. The lake has a mean depth of 1.8 m, a maximum depth of 6.4 m, 0.027 mg/L total phosphorus, 66 mg/L total dissolved solids, and a Secchi depth of 1.5 m. The fish of primary importance to anglers in the lake include walleye (Sander vitreus) and yellow perch (Perca flavescens).

Northern pike (Esox lucius) and smallmouth bass (Micropterus dolomieu) represent a small proportion of the total angling effort on the lake. Walleye, yellow perch, and smallmouth bass are not native to the lake and were introduced in the 1940s, 1960s, and 1990s respectively (Amtstaetter 2007). Lake whitefish (Coregonus clupeaformis) populations collapsed in the 1950s and never recovered (MacCallum 1983).

Several fish regulations have been applied to Whitefish Lake in the past several years because of a concern that the recreational harvest of yellow perch was potentially unsustainable. A reduction in the catch and possession limit of yellow perch, from unlimited to 100 fish in a day, was implemented on Whitefish Lake in 1999.

In 2002, the catch limit was again reduced to 50 fish in one day, with a possession limit of 100 for a sport fish licence, and a catch and possession limit of 25 for a conservation licence. A reduction in the catch and possession limit to 50 and 25 for sport and conservation licences respectively was implemented provincewide in 2000. A reduction in the possession limit from 6 to 4 walleye, and a limit of one walleye greater than 46 cm total length (TL), were implemented in 1999. The 1999 walleye regulation changes were not specific to Whitefish Lake, but applied to all waterbodies across Northwest Region. This update documents the results of the 2008 open-water roving creel survey conducted on Whitefish Lake and compares them to results of previous surveys for a better understanding of angler demographics and resource user patterns in the

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recreational fishery. A review of the status of species targeted by anglers is included to provide context for the creel survey results.

Methods An open-water, stratified roving creel survey was conducted on Whitefish Lake from May 17 to September 07, 2008. The period of sampling occurred from 07:30 to 22:30 and was divided such that 60% of the creel survey was conducted between 07:30–15:00 and 40% was conducted between 15:00–22:30. This was done to reflect historical usage patterns on Whitefish Lake and to closely replicate previous open-water creel surveys.

The survey was also stratified by day type (workday or non-workday). There were 75 workdays and 39 non-workdays surveyed. Sample dates were randomly selected for each day type.

Angler interviews included questions about each an angler’s or party’s fishing trip, and related socioeconomic information. The following information, collected on standard Ministry of Natural Resource (MNR) creel interview forms, was recorded during the survey: date, interview time, fishing start time, number of anglers, fishing method (still, jig, drift, troll, combination/other), angler origin, accommodation type, species sought, whether a guide was employed, and the number of each species harvested and released. The following questions were also asked about each party’s fishing trip: how many walleye greater than 46 cm (18 inches) were harvested; how many walleye greater than 46 cm (18 inches) were released; how many anglers had a conservation fishing licence; did you stop fishing at any time and for how long; and did you have a shore lunch? Each day, fish were sampled during the angler interviews at the commercial resorts between 11:30– 12:30 and 20:30–22:30. Fish were measured for length (mm) and weight (g), and structures for age assessment were collected. Effort, catch, and harvest estimates for creel survey data were generated using FISHNET v2.0 (Lester and Korver 1996). The total harvest weight of each species was estimated by summing the products of estimated harvest and mean weight of sampled fish. The number of walleye that were released due to compliance with fishery regulations was determined from observed values.

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Several creel and netting surveys have been conducted on Whitefish Lake over the past several decades. Most recent of these are the open-water roving creel surveys conducted on the lake in 1995 and 2001 to which this creel survey was compared.

Results Estimated effort directed at walleye during the 2008 open-water fishery was 43,067 angler-hours or 14.3 angler-hours/ha. Estimated catch-per-unit-effort (CUE) for anglers targeting walleye was 0.26 fish/angler-hour.

The estimated total catch of walleye was 12,931 with 6, 384, or 49% harvested. Estimated effort directed at yellow perch was 40,316 angler-hours or 13.4 anglerhours/ha. Estimated CUE for anglers targeting perch was 3.11 fish/angler-hour. The estimated effort directed at northern pike was only 3, 733 angler-hours, which accounted for very little of the total effort relative to walleye and yellow perch (Figure 1). Smallmouth bass accounted for only 433 angler-hours in this survey. The total estimated effort for all species was 69,210 anglerhours or 23.0 angler-hours/ha during the 2008 openwater creel survey.

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harvested 798, and reportedly released 830. Fish greater than 46 cm made up 14% of the catch, with 233 caught, 94 kept, and 139 released. Of the walleye released, only 11 could be considered forced due to the size regulation restricting anglers to the possession of only one walleye greater than 46 cm (anglers already possessed their limit of walleye greater than 46 cm). Yellow perch made up the majority of the catch, with 17,073 caught (observed).

In total, 7, 683 perch were observed harvested and 9, 390 were reportedly released during the 2008 open-water creel survey.

Figure 2. Estimated number of fish caught, harvested, and released during the 2008 open-water creel survey.

During the 2008 Whitefish Lake open-water creel survey, 203 walleye and 343 yellow perch were sampled.

The mean weight of walleye harvested was 472 g, and the mean total length was 363 mm (Table 1). The mean weight of perch harvested in Whitefish Lake during the 2008 open-water creel survey was 128 g, and the mean total length was 218 mm (Table 2).

Table 1. Relative mean size of walleye among open-water creel survey years.

Walleye Figure 1. Estimated effort (angler-hours) directed at each species during the 2008 open-water creel survey.

Yellow perch accounted for the majority of the catch and harvest of any species on Whitefish Lake (Figure 2). The estimated total catch of perch was 135,503 with 60,357, or 45% harvested. Northern pike accounted for 5% of the total catch and contributed very little (2%) to the overall harvest from the fishery. All other species combined accounted for < 0.5% of the total catch during the open-water fishery. The estimated total catch for smallmouth bass was 826. Most angling parties (956), representing 2, 231 anglers, were seeking or had caught walleye and/or yellow perch and answered the survey questions relating to the size of walleye harvested and released. These anglers caught 1, 628 walleye (observed),

Weight (g) Total length (mm)

1995

2001

2008

-

731

472

325

418

363

Table 2. Relative mean size of yellow perch among openwater creel survey years.

Yellow perch Weight (g) Total length (mm)

1995

2001

2008

-

173

128

224

230

218

Most anglers (86%) on Whitefish Lake used commercial accommodations while the majority of the remainder being local day-use anglers (6%), cottagers (4%), permanent lake residents (2.3%), and provincial park and Crown land campers (1.7%) (Figure 3). All anglers

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surveyed possessed a standard angling licence with none holding a conservation licence.

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was significantly lower than in the two previous roving open-water creel surveys (Figure 5). The proportion of estimated catch to harvest for walleye remained the same between the previous creel survey with 48% of the total catch harvested in 2001, and 49% of the total catch harvested in 2008. Only 33% of the walleye caught in 1995 were harvested.

Figure 3. Relative percentage of resource users on Whitefish Lake during the 2008 open-water creel survey.

Discussion The majority of angling activity during the 2008 openwater fishery on Whitefish Lake was directed relatively evenly between walleye and perch providing 13.4 and 14.3 angler-hours/ha of fishing effort, respectively. The total effort expended during the 2008 summer fishery was significantly less than the level of effort observed during the 1995 and 2001 open-water creel surveys.

Correspondingly, the estimated angler effort for walleye in the 2008 fishery was also lower than in the 1995 and 2001 surveys (Figure 4), which accounted for only 43,067 angler-hours or 13.9 angler-hours/ha. The effort directed at walleye during the 1995 and 2001 openwater creel surveys were 32.1 and 28.0 angler-hours/ ha, respectively. The total effort directed at perch in the 2008 open-water fishery was 40,316 angler-hours or 13.4 angler-hours/ha. The effort directed at perch during the 1995 and 2001 open-water creel surveys were 27.7 and 24.1 angler-hours/ha, respectively. The estimated total catch and harvest of walleye in the 2008 fishery

Figure 4. Relative estimated total effort (angler-hours) and effort targeting only walleye during the 1995, 2001, and 2008 open-water creel surveys.

Figure 5. Relative number of walleye caught, harvested, and released during the 1995, 2001, and 2008 open-water creel surveys.

The estimated total catch of yellow perch remained relatively consistent since 1995 (Figure 6). However, the estimated harvest of perch fluctuated between a high of 81,â&#x20AC;&#x160;007 fish in 1995 and a low of 50,â&#x20AC;&#x160;711 in 2001, despite recording the highest total catch of the three creel survey years. Similar to previous survey years, northern pike accounted for only 5% of the total catch and contributed very little (2%) to the overall harvest from the fishery in 2008. In 1995 and 2001, northern pike accounted for approximately 3% and 2% of the total catch and 2% and 1% of the overall harvest from the fishery, respectively. The total effort directed at northern pike during the 2008 creel survey was 3,â&#x20AC;&#x160;733 angler-

Figure 6. Relative number of yellow perch caught, harvested, and released during the 1995, 2001, and 2008 open-water creel surveys.

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hours and was substantially lower compared to 11,144 in 1995 and 20,297 angler-hours in 2001 (Table 1).

Smallmouth bass were only targeted for an estimated 433 angler-hours in the 2008 creel survey compared to an estimated 11,976 angler-hours of effort in 2001.

In 2001, only 21 fish were caught with approximately 20% of those harvested, whereas in 2008, 88 fish were caught incidentally despite little to no targeted effort.

Regardless of the level of effort or harvest, if smallmouth bass populations continue to expand, they will ultimately have some impact on the overall ecological structure and equilibrium of the lakes native and naturalized fish populations (Kerr and Grant 2000).

In contrast to the winter fishery where the majority of walleye were harvested (72%, 2001 winter creel survey), only 49% of walleye caught during the 2008 open-water fishery were harvested. Of the 830 walleye released, 128 fish greater than 46 cm in length were legally harvestable, but were released. Another notable difference between the summer and winter recreational fisheries on Whitefish Lake is the angler demographics.

Similar to previous open-water creel surveys, nonresident anglers accounted for the majority (86%) of the angling effort on Whitefish Lake in 2008, whereas, only 51% of the anglers were non-residents during the 2001 winter creel survey.

The annual yield of walleye in 2008 from Whitefish Lake is moderate to high relative to other walleye fisheries in Ontario (Lester et al. 2004). The 2008 openwater fishery supported an estimated harvest of 3, 015 kg or 1.0 kg/ha of walleye; whereas the 2001 openwater fishery supported an estimated harvest of 6,896 kg or 2.3 kg/ha of walleye and an estimated 2.5 kg/ha in 1995. Very few Ontario walleye lakes support yields in excess of 2.0 kg/ha with most located in southern Ontario and typically in areas with greater productivity relative to the northern Ontario (Lester et al. 2004).

Whitefish Lake has supported yields in excess of 2.0 kg/ ha when measured. However, it is unknown what the maximum sustainable yield is or what maximum level of effort this lake can support. The 2008 open-water fishery also supported an estimated harvest of 7, 709 kg or 2.6 kg/ha of yellow perch. In 2001, 8, 793 kg or 2.9 kg/ha of perch was harvested. An estimated 9, 646 more yellow perch were harvested in 2008; however, the mean round weight of perch was approximately 46 g less than in 2001, which accounts for the lower estimated yield.

The level of effort for walleye in 2008 was approximately half of that observed during the 2001 open-water creel survey (Figure 4) and an estimated 3, 052 fewer walleye

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were harvested (Figure 5). However, despite the lower estimated effort and yield in 2008, the estimated CUE for walleye remained consistent between 2008 and 2001: 0.26 and 0.23 fish/hour, respectively. The mean catch of walleye captured during fall walleye index netting (FWIN) in Whitefish Lake has also remained relatively stable between 1995 and 2005 (Amtstaetter 2007). Thus, the lower yield observed in 2008 is likely a result of lower effort and harvest of walleye and does not necessarily reflect a decline in the walleye population.

Several commercial resorts on Whitefish Lake had indicated that occupancy was down substantially (some approximately 50% or more) (Lorne Kraft, pers. comm.).

Since the majority of anglers on Whitefish Lake are non-resident (predominantly from the upper midwest United States), the high cost of fuel (in excess of 1.40/L), the high Canadian dollar (at par or higher with the U.S. dollar), and poor economic conditions are likely causes of this downturn in travel and may be reflected in the decreased effort and subsequent lower yield of walleye observed on Whitefish Lake in 2008.

The status of the Whitefish Lake fishery is of primary importance to both resource users and fisheries managers due to its high level of exploitation and its contribution to the local economy. The lake has numerous commercial lodges and private cottages and supports an economically important recreational fishery for walleye and perch. The Whitefish Lake fishery has been sustainable based on the status assessment of game fish species in the lake; however, the walleye population is likely being harvested close to its maximum potential (Fruetel 1994, Amtstaetter 2007). Despite the continued high walleye yield and level of effort/ha, the status of the walleye population can be considered stable due to relatively high abundance and average growth of fish up to approximately six years of age (Amtstaetter 2007).

However, continued close monitoring of the status of the walleye and yellow perch populations in Whitefish Lake is necessary given the level of exploitation on these two species.

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Acknowledgements

References

Several individuals contributed to the development of this report. Foremost, I would like to thank K. Armstrong for providing his guidance, insight, and review. I would also like to thank M. Friday, M. Rawson, and T. Mosindy for their reviews. Thank you to NWSI and district field staff who collected the 2008 summer creel survey data on Whitefish Lake. And finally, thanks go to J. Gagnon, and A. McColm for desktop publishing

Amtstaetter, F. 2007. Fall walleye index netting summary for Whitefish Lake: 1995 to 2005. Ontario Ministry of Natural Resources, Northwest Science and Information, Aquatics Update 2007–1. 5 pp.

Fruetel, M. 1994. Whitefish Lake: a summary of creel surveys and assessment of programs from 1963 to 1990 with an evaluation of walleye, yellow perch, and northern pike population status. Ontario Ministry of Natural Resources, Quetico-Mille Lacs Fisheries Assessment Unit Report 1994–1. 67 pp.

Kerr, S. J. and R.E. Grant. 2000. Ecological Impacts of Fish Introductions: Evaluating the Risk. Fish and Wildlife Branch, Ontario Ministry of Natural Resources, Peterborough, Ontario, 473 pp.

Kraft, Lorne. 2008. Personal Communication. Northwest Science and Information, Ontario Ministry of Natural Resources. Thunder Bay, Ontario.

Lester, N.P. and R. Korver. 1996. FISHNET v2.0 analyses of index fishing and creel surveys. Part B. Fish Statistics. Ontario Ministry of Natural Resources, Maple, Ontario. 23 pp.

MacCallum, M.E. 1983. Whitefish Lake: Part 2. Collapse of the Lake whitefish population. Ontario Ministry of Natural Resources, Quetico–Mille Lacs Fisheries Assessment Unit, Fisheries Special Employment Program.

Parker, S. 2011. Whitefish Lake open-water creel survey: 2008. Ont. Min. Natur. Resour., Northwest Sci. & Info, NWSI Aquatics Update 2011–2. 5 pp.

© 2011, Queen’s Printer for Ontario 62726 ISBN 978–1–4435–6979–8 (PDF)

Quetico-Mille Lacs Fisheries Assessment Unit Northwest Science and Information Science and Information Branch Ontario Ministry of Natural Resources 173 25th Side Road Rosslyn [Thunder Bay], Ontario P7K 0B9 Tel: 807 939-2501 Website: ontario.ca/nwsi Cette publication spécialisée n’est disponible qu’en anglais