Recent Changes in the Inshore Forage Fish of Lake Michigan

Jude, David J.; Tesar, Frank J.

doi:10.1139/f85-142

Cited by 84 publications

(40 citation statements)

References 7 publications

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“…Most studies showed that alewives were the principal prey of Lake Michigan salmon (Eck and Wells 1983, Jude and Tesar 1985, and Jude et al 1987. The chances of overstocking salmon increased since the alewife population was decreasing, and there was increasing evidence that salmon were reproducing (Trudeau 2005).…”

Section: Discussionmentioning

confidence: 99%

Diets of Lake Michigan Salmon and Maximum Size of Alewife Prey

Savitz

2009

Journal of Freshwater Ecology

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The diets of Lake Michigan salmon were determined by examining stomach contents of sport-caught salmon. The study was conducted from 2001 through 2008 when the population of principal forage (i.e., the alewife) was declining and there was a decrease in salmon stocking. The largest alewives were measured to determine upper size limits utilized by salmon. Sixty-four charter boat trips were taken with a total catch of 713 salmon (430 coho salmon, 210 chinook salmon, 34 rainbow trout, 27 lake trout, 11 brown trout, and one pink salmon). Small alewives were the predominant prey of salmon. Of the coho salmon stomachs with prey, 97.7% contained alewives, and for chinook salmon, 99.5 % contained alewives. Other occasional prey items were smelt, sticklebacks, yellow perch, and blackflies. No round gobies were found in the diet. The largest alewives in the diets were 178 mm and only 9.6% of the alewives were greater than 152 mm. Coho salmon had fewer empty stomachs (13%) than chinook salmon (51.8%), and coho salmon had a more diverse diet than chinook salmon. INTRODUCTIONThe diets of sport-caught Lake Michigan salmon were examined a s the alewife population was declining and there was a decrease in salmon stocking. There was a potential collapse of the salmon population (Madenjian et al. 2005). Since small alewives (Alosa pseudoharengus) were the principal forage of salmon (Madenjian et al. 2002), the analyses included measurement of the largest alewife in individual salmon diets in order to determine the size range of alewives that supported the salmon populations. As a response to the alewife population decline, fewer salmon were stocked (Trudeau 2005). It was hoped that with declining alewife populations and increasing round goby (Neogobius melanostomus) populations, salmon would start to forage on round gobies (Alexander, 2009). Similar declines in the alewife population had occurred in the past without resulting in salmon foraging on alternate prey (Madenjian et al. 2002); however, the round goby was not found in Lake Michigan during the previous alewife population decline.The sport-caught salmon in this study were chinook salmon (Oncorhynchus tshawytscha), coho salmon (Oncorhynchus kitsutsch), rainbow trout (Oncorhynchus mykiss), pink salmon (Oncorhynchus gorbuscha), lake trout (Saluelinus namaycush), and brown trout (Salmo trutta). The prey fishes were alewives, rainbow smelt (Osmerus mordax), yellow perch (Perca flauescens), and three-spine stickleback (Gasterosteus aculeatus). Blackflies ( Simulidae) were also in the diet.

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Section: Discussionmentioning

confidence: 99%

Diets of Lake Michigan Salmon and Maximum Size of Alewife Prey

Savitz

2009

Journal of Freshwater Ecology

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“…Since the closure of the commercial fishery in Lake Michigan in 1976, increased density-dependent growth appears to be occurring (Jude and Tesar, 1985;Brown et al, 1987;Brown and Eck, 1992). Skewed sex ratios of bloater (e.g., 80-90% females) have been hypothesized to have contributed to the decline of bloater populations in lakes Michigan and Huron from ∼1960 until 1975 Crowder, 1980;Jude and Tesar, 1985;Brown et al, 1987). The mechanism by which the skewed sex ratios occur in bloater has been hypothesized to be the result of a change in the neuroendocrine aspect of bloaters or a reduced viability of males (Philips and Ehlinger, 1995;Turgeon et al, 1999).…”

Section: Intraspecific Competitorsmentioning

confidence: 99%

The Ecology of Body Size and Depth Use by Bloater (Coregonus hoyiGill) in the Laurentian Great Lakes: Patterns and Hypotheses

Clemens¹,

Crawford²

2009

Reviews in Fisheries Science

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Deepwater ciscoes (genus Coregonus, subgenus Leucichthys) radiated into six phenotypes that occupy different depths in the Great Lakes, based upon body size and lipid content. Large, lipid-dense ciscoes occupy greater depths than small, lean ciscoes. This relationship is observed between adults and juveniles of the most prevalent deepwater cisco, the bloater (C. hoyi Gill). Lipid-dense adult bloaters are restricted to the hypolimnion, whereas lean juveniles are found primarily in the epilimnion. This article critically reviews, synthesizes, and provides hypotheses from the literature on the ecology of body size and depth use of bloater. Factors influencing depth use in bloater are categorized by Fry's (1971) environmental factors. The case is made for two parsimonious hypotheses to explain the depth distribution by body size of bloater:(1) the optimal foraging-antipredation (OFA) hypothesis, and (2) the mass-specific metabolism hypothesis. The OFA hypothesis relates abundance of piscivores with abundance and extent of diel vertical migration of bloater. The mass-specific metabolism hypothesis relates body size to density-dependent growth, metabolism, swimming activity and hence depth distribution of bloater. Follow-up hypotheses and predictions are presented and may broaden our understanding of trophic ecology and adaptive radiation of deepwater ciscoes in the Great Lakes.

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“…Fish ecology of Laurentian Great Lakes nearshore zones has been the subject of comparatively few studies (e.g., Jude and Tesar 1985;Kelso and Minns 1996;Brazner and Beals 1997;Brazner 1997;Garza and Whitman 2004;Goforth and Carman 2005;Dopazo et al, 2008), especially in exposed shore areas (Randall and Minns 2002;Mackey and Goforth 2005). The few studies that exist suggest that biological communities can become altered along shorelines with high levels of anthropogenic activity compared to intact shorelines (e.g., Brazner 1997;Brazner and Beals 1997;Goforth and Carman 2005;Meadows et al, 2005).…”

Section: Discussionmentioning

confidence: 99%