Recent Changes in Lake Michigan's Fish Community and Their Probable Causes, With Emphasis on the Role of the Alewife (Alosa pseudoharengus)

1987 ◽  
Vol 44 (S2) ◽  
pp. s53-s60 ◽  
Author(s):  
Gary W. Eck ◽  
Larue Wells

Major changes in fish populations occurred in Lake Michigan between the early 1970s and 1984. The abundance of lake trout (Salvelinus namaycush) and several nonnative species of salmonines increased greatly as a result of intensive stocking. The exotic alewife (Alosa pseudoharengus), which had proliferated to extremely high levels of abundance in the mid-1960s, declined, particularly in the early 1980s. We believe that the sharp decline in alewives in the 1980s was caused primarily by poor recruitment during the colder than normal years of 1976–82. Several of Lake Michigan's endemic species of fish appeared to be adversely affected by alewives: bloater (Coregonus hoyi), lake herring (C. artedii), emerald shiner (Notropis atherinoides), yellow perch (Perca flavescens), and deepwater sculpin (Myoxocephalus thompsoni), and possibly spoonhead sculpin (Cottus ricei). All declined when alewives were abundant, and those that did not become rare, i.e. the bloater, perch, and deepwater sculpin recovered when alewives declined. We present evidence suggesting that the mechanism by which alewives affect native species is not by competition for food, as has often been hypothesized, and discuss the possibility that it is predation on early life stages. Despite the decreased availability of alewives in the early 1980s, salmonines continued to eat mainly alewives. The highly abundant alternate prey species were eaten only sparingly, but alewives still may have been abundant enough to meet the forage requirements of salmonines. Two new exotics, the pink salmon (Oncorhynchus gorbuscha) and threespine stickleback (Gasterosteus aculeatus), increased in abundance in the 1980s, and could become detrimental (particularly the salmon) to other species.

2006 ◽  
Vol 63 (11) ◽  
pp. 2434-2446 ◽  
Author(s):  
David B Bunnell ◽  
Charles P Madenjian ◽  
Randall M Claramunt

We used our long-term annual bottom trawl survey (1973–2004) in Lake Michigan to reveal the response of the native fish community to the biological control of a dominant exotic fish, alewife (Alosa pseudoharengus), as well as to changes in total phosphorus and salmonine biomass. Through nonmetric multidimensional scaling, we documented a 1970s community largely dominated by alewife, and then a shift to a community dominated by several native species during the 1980s through 1990s, when alewife remained at relatively low levels. We argue that the recovery of burbot (Lota lota), deepwater sculpin (Myoxocephalus thompsonii), and yellow perch (Perca flavescens) was partially or fully aided by the alewife reduction. We argue that changes in phosphorus or salmonines were not directly related to abundance increases of native species. An additional community shift occurred during 1999–2004, which coincided with a reduction in species richness and total fish biomass in our trawl. The mechanisms underlying this latest shift may be related to reductions in nutrients, but further research is required. The restoration of the native fish community has been incomplete, however, as emerald shiner (Notropis atherinioides), cisco (Coregonus artedii), and lake trout (Salvelinus namaycush) have yet to demonstrate recovery.


2003 ◽  
Vol 60 (4) ◽  
pp. 471-490 ◽  
Author(s):  
E L Mills ◽  
J M Casselman ◽  
R Dermott ◽  
J D Fitzsimons ◽  
G Gal ◽  
...  

We examined stressors that have led to profound ecological changes in the Lake Ontario ecosystem and its fish community since 1970. The most notable changes have been reductions in phosphorus loading, invasion by Dreissena spp., fisheries management through stocking of exotic salmonids and control of sea lamprey (Petromyzon marinus), and fish harvest by anglers and double-crested cormorants (Phalacrocorax auritus). The response to these stressors has led to (i) declines in both algal photosynthesis and epilimnetic zooplankton production, (ii) decreases in alewife (Alosa pseudoharengus) abundance, (iii) declines in native Diporeia and lake whitefish (Coregonus clupeaformis), (iv) behavioral shifts in alewife spatial distribution benefitting native lake trout (Salvelinus namaycush), threespine stickleback (Gasterosteus aculeatus), and emerald shiner (Notropis atherinoides) populations, (v) dramatic increases in water clarity, (vi) predation impacts by cormorants on select fish species, and (vii) lake trout recruitment bottlenecks associated with alewife-induced thiamine deficiency. We expect stressor responses associated with anthropogenic forces like exotic species invasions and global climate warming to continue to impact the Lake Ontario ecosystem in the future and recommend continuous long-term ecological studies to enhance scientific understanding and management of this important resource.


1981 ◽  
Vol 38 (6) ◽  
pp. 662-668 ◽  
Author(s):  
Larry B. Crowder ◽  
John J. Magnuson ◽  
Stephen B. Brandt

The potential for ecological segregation of Lake Michigan fishes was examined by comparing diets and thermal habitat use of common species. Samples were collected by bottom trawling (N = 68) off Grand Haven, Michigan, September 7–13, 1977. Five common species exhibited complementarity in the use of food and thermal habitat resources. During the day, adult alewife (Alosa pseudoharengus), and rainbow smelt (Osmerus mordax) had similar diets but occupied somewhat different thermal habitats. Young-of-the-year (YOY) alewives segregated from adult alewife and rainbow smelt on both habitat and food. Spottail shiner (Notropis hudsonius), YOY alewives, and yellow perch (Perca flavescens) used similar thermal habitats but fed on different prey. Trout-perch (Percopsis osmiscomaycus) tended to segregate from the others based on both food and thermal habitat but may experience diffuse competition. Adults of the three native species consume entirely different prey than exotic alewife and rainbow smelt. The native species which declined during the invasion of alewife and rainbow smelt were those with apparently similar habitat and food requirements to the exotics. These data suggest that competition is important in maintaining the structure of the Lake Michigan fish community.Key words: competition, fishes, food, habitat, Lake Michigan, predation, temperature


1983 ◽  
Vol 40 (6) ◽  
pp. 681-698 ◽  
Author(s):  
Donald J. Stewart ◽  
David Weininger ◽  
Donald V. Rottiers ◽  
Thomas A. Edsall

An energetics model is implemented for lake trout, Salvelinus namaycush, and applied to the Lake Michigan population. It includes an egestion function allowing any proportional mix of fish and invertebrates in the diet, a growth model accounting for both ontogenetic and seasonal changes in energy-density of predator and prey, a model for typical in situ swimming speed, and reproductive energy losses due to gametes shed. Gross conversion efficiency of energy by lake trout over their life (21.8%) is about twice the efficiency of converting biomass to growth because they store large amounts of high-energy fats. Highest conversion efficiencies are obtained by relatively fast-growing individuals, and over half the annual energy assimilated by older age-classes may be shed as gametes. Sensitivity analysis indicates a general robustness of the model, especially for estimating consumption by fitting a known growth curve. Largest sensitivities were for the intercept and weight dependence coefficients of metabolism. Population biomass and associated predatory impact of a given cohort increase steadily for about 3.5 yr then decline steadily after fishing mortality becomes important in the fourth year in the lake. This slow response time precludes manipulation of lake trout stocking densities as a means to control short-term prey fluctuations. Predation by lake trout on alewife, Alosa pseudoharengus, has been increasing steadily since 1965 to about 8 400 t∙yr−1, and is projected to rise to almost 12 000 t∙yr−1 by 1990.


1982 ◽  
Vol 39 (12) ◽  
pp. 1563-1568 ◽  
Author(s):  
John H. Hartig ◽  
David J. Jude ◽  
Marlene S. Evans

Cyclopoid predation on fish larvae, as evidenced by copepods attached to larvae in field collections, was quantitatively investigated during 1975–76 in southeastern Lake Michigan. Although six species of fish larvae were collected, predation occurred primarily (98%) on alewife (Alosa pseudoharengus); 2% of the predators were attached to spottail shiner (Notropis hudsonius) larvae. No cyclopoids were observed on rainbow smelt (Osmerus mordax), yellow perch (Perca flavescens), common carp (Cyprinus carpio), or sculpin (Cottus spp.) larvae. Most alewife larvae attacked were 3–8 mm long; older larvae and larvae of more robust species, such as yellow perch and spottail shiner, are apparently immune to such predation. Most predation (99%) occurred in July when alewife larvae were numerous and cyclopoids abundant. Fish larvae with attached copepods were found only in night collections. Most cyclopoid predators (99%) were adult female Diacyclops thomasi and Acanthocyclops vernalis. Other predaceous species of zooplankton, that occurred in close temporal and spatial proximity to fish larvae, apparently were not predaceous on these organisms.Key words: Alosa pseudoharengus larvae, Notropis hudsonius larvae, Diacyclops thomasi, Acanthocyclops vernalis, cyclopoid predation, Lake Michigan


2002 ◽  
Vol 59 (4) ◽  
pp. 736-753 ◽  
Author(s):  
Charles P Madenjian ◽  
Gary L Fahnenstiel ◽  
Thomas H Johengen ◽  
Thomas F Nalepa ◽  
Henry A Vanderploeg ◽  
...  

Herein, we document changes in the Lake Michigan food web between 1970 and 2000 and identify the factors responsible for these changes. Control of sea lamprey (Petromyzon marinus) and alewife (Alosa pseudoharengus) populations in Lake Michigan, beginning in the 1950s and 1960s, had profound effects on the food web. Recoveries of lake whitefish (Coregonus clupeaformis) and burbot (Lota lota) populations, as well as the buildup of salmonine populations, were attributable, at least in part, to sea lamprey control. Based on our analyses, predation by salmonines was primarily responsible for the reduction in alewife abundance during the 1970s and early 1980s. In turn, the decrease in alewife abundance likely contributed to recoveries of deepwater sculpin (Myoxocephalus thompsoni), yellow perch (Perca flavescens), and burbot populations during the 1970s and 1980s. Decrease in the abundance of all three dominant benthic macroinvertebrate groups, including Diporeia, oligochaetes, and sphaeriids, during the 1980s in nearshore waters ([Formula: see text]50 m deep) of Lake Michigan, was attributable to a decrease in primary production linked to a decline in phosphorus loadings. Continued decrease in Diporeia abundance during the 1990s was associated with the zebra mussel (Dreissena polymorpha) invasion, but specific mechanisms for zebra mussels affecting Diporeia abundance remain unidentified.


1987 ◽  
Vol 44 (S2) ◽  
pp. s10-s14 ◽  
Author(s):  
Bryan A. Henderson ◽  
F. E. J. Fry

Of the nine species caught in pound and gill nets in South Bay, Lake Huron (lake whitefish (Coregonus clupeaformis), rainbow smelt (Osmerus mordax), lake trout (Salvelinus namaycush), splake (S. namaycush × S. fontinalis), burbot (Lota lota), lake hering (Coregonus artedii), alewife (Alosa pseudoharengus), white sucker (Catostomus commersoni), and yellow perch (Perca flavescens)), only yellow perch, white sucker, and lake whitefish were significantly related to the abundances of all other fish species (multiple regression) from 1965 to 1984. For the longer period (pound nets 1949–84), all but smelt, burbot, and white sucker were dependent upon variations in the abundance of the nine other species. For the same period (1965–84) and species (nine), the abundances only of yellow perch and white suckers were significantly and positively related in two basins of the Bay. None of the inverse correlations between species abundances was significant in both basins. Within the Outer Basin, only the correlations between alewife and lake herring (r = −0.49, r = −0.45) and yellow perch and white sucker (r = +0.55, r = +0.47) were significant in the same direction for both time periods (1949–64 and 1965–84, respectively). We concluded that there was little evidence that the abundances of species were affected significantly by interspecific influences.


1986 ◽  
Vol 43 (1) ◽  
pp. 154-159 ◽  
Author(s):  
Marlene S. Evans

Summer Zooplankton communities in the inshore region of southeastern Lake Michigan were dominated by small species during the 1970s, suggesting that size-selective fish predation pressures were intense. Abundances of alewife (Alosa pseudoharengus), the dominant planktivore in the 1970s, declined in recent years, especially over 1982–84. Despite decreased alewife predation, small zooplankton taxa continued to predominate. Moreover, zooplankton standing stocks declined 10-fold during 1982–84, suggesting that predatory pressures had intensified. Concurrent with the alewife population decrease was a major increase in yellow perch (Perca flavescens) abundances. As a probable consequence of intense predation pressures exerted by abundant yellow perch, zooplankton standing stocks were severely reduced. Yellow perch populations may have been adversely affected by food limitation, especially in summer 1984 when zooplankton standing stocks were only 3% of their average level over 1975–81.


2016 ◽  
Vol 73 (12) ◽  
pp. 1750-1758 ◽  
Author(s):  
Karen M. Dunmall ◽  
Neil J. Mochnacz ◽  
Christian E. Zimmerman ◽  
Charles Lean ◽  
James D. Reist

Distributional shifts of biota to higher latitudes and elevations are presumably influenced by species-specific physiological tolerances related to warming temperatures. However, it is establishment rather than dispersal that may be limiting colonizations in these cold frontier areas. In freshwater ecosystems, perennial groundwater springs provide critical winter thermal refugia in these extreme environments. By reconciling the thermal characteristics of these refugia with the minimum thermal tolerances of life stages critical for establishment, we develop a strategy to focus broad projections of northward and upward range shifts to the specific habitats that are likely for establishments. We evaluate this strategy using chum salmon (Oncorhynchus keta) and pink salmon (Oncorhynchus gorbuscha) that seem poised to colonize Arctic watersheds. Stream habitats with a minimum temperature of 4 °C during spawning and temperatures above 2 °C during egg incubation were most vulnerable to establishments by chum and pink salmon. This strategy will improve modelling forecasts of range shifts for cold freshwater habitats and focus proactive efforts to conserve both newly emerging fisheries and native species at northern and upper distributional extremes.


1991 ◽  
Vol 48 (5) ◽  
pp. 909-922 ◽  
Author(s):  
Donald J. Stewart ◽  
Myriam Ibarra

A marked decline of alewife (Alosa pseudoharengus) in Lake Michigan during 1981–83 led to diet shifts by coho (Oncorhynchus kisutch) and chinook salmon (O. tshawytscha) from feeding primarily on large alewife to eating proportionately more immature alewives and other prey. Diets of lake trout (Salvelinus namaycush) did not change greatly during that period. Population biomass conversion efficiency averaged 24.5% for coho and 16.6% for lake trout. Chinook salmon suffered an apparent 20% decline in gross conversion efficiency of biomass (25.1 to 20.8%) and a 25% decline in average weight of sport-caught fish. We infer that chinook salmon growth was inhibited by insufficient forage available to them. A simulation of chinook salmon feeding on bloater (Coregonus hoyi) at 8 °C suggested that such behavior could lead to further declines in growth rates. Extension of modeling results to include approximations for brown trout (Salmo trutta) and rainbow trout (O. mykiss) revealed peaks in total annual salmonine predation of 71 000 t in 1983 and 76 000 t in 1987. The alewife was 70% of all prey eaten by salmonines in 1987–88. Lakewide gross production by salmonines was 15 300 t (or 0.27 g∙m−2) in 1987. Ratios of annual gross production to average monthly population biomass were 1.6 for chinook, 1.15 for coho, and only 0.6 for lake trout.


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