Colonization of Inland Lakes in the Great Lakes Region by Rainbow Smelt, Osmerus mordax: Their Freshwater Niche and Effects on Indigenous Fishes

1987 ◽  
Vol 44 (S2) ◽  
pp. s249-s266 ◽  
Author(s):  
David O. Evans ◽  
David H. Loftus

Rainbow smelt, Osmerus mordax, have colonized numerous inland lakes in eastern North America, primarily as a result of introductions by humans. Smelt often establish large populations in these lakes and influence indigenous fishes both directly (predation) and indirectly (competition). Smelt have a eurythermal life history, which results in spatial segregation of their larvae, juvenile, and adults, and are omnivorous feeders, eating a range of food types from zooplankton to fish. As a result, smelt interact strongly with a wide spectrum of prey and predator species. Effects on other species are mediated via food web interactions resulting in recruitment and growth changes in some species and redirection of energy flow and storage. Species most often affected are cold-water and cool-water species whose niches are most similar to juvenile and adult smelt. Increased growth rates of Atlantic salmon (Salmo salar) and lake trout (Salvelinus namaycush) and recruitment failure of lake whitefish (Coregonus clupeaformis) are the best documented responses to invasion by smelt. Many other species are probably also affected, although the effects vary greatly between lakes. Variation in the smelt metabolic niche (as expressed by relative growth efficiency) is due to variations in prey size and availability and is reflected in differences in smelt body size between lakes. Smelt body size, in turn, is related to the variable effects that they have on other species.

1998 ◽  
Vol 55 (2) ◽  
pp. 307-317 ◽  
Author(s):  
Peter S Rand ◽  
Donald J Stewart

We tested the hypotheses that (1) reductions in individual size and energy density of adult alewife (Alosa pseudoharengus) in Lake Ontario over the past decade have caused reductions in mean size of consumed alewife and compensatory increases in frequency of feeding by salmonines and (2) perceived recent reductions in the alewife and rainbow smelt (Osmerus mordax) prey base in recent years have resulted in shifts in diets of salmonines to less preferred prey items. Data from a diet survey conducted on sport-caught salmonines during 1983-1988 and 1993 indicated significant reductions in the mean size of consumed alewife across all predator species over time and an increased frequency of feeding among some predators (reflected by a decline in the proportion of empty stomachs observed). We found evidence of increased ration levels in coho salmon (Oncorhynchus kisutch) and lake trout (Salvelinus namaycush) and an increase in the number of adult alewife in stomachs of all predator species that was accurately predicted by an earlier bioenergetic model analysis. We found evidence of a shift in diet across years away from rainbow smelt and other fishes to adult alewife. Results point toward possible sources of bioenergetic stress on salmonines in Lake Ontario.


1983 ◽  
Vol 40 (2) ◽  
pp. 114-120 ◽  
Author(s):  
Hugh R. MacCrimmon ◽  
Christopher D. Wren ◽  
Barra L. Gots

Lake trout, Salvelinus namaycush, released into Tadenac Lake as juveniles, show a pronounced acceleration in growth rate, following a change in diet from benthic invertebrates to rainbow smelt, Osmerus mordax, beginning at age 6 (> 30 cm). An abrupt increase in the rate of mercury accumulation in white muscle of these fish occurs at the same time. Mercury levels in lake trout ([Formula: see text] = 0.24–3.44 μg/g) and coresident smelt ([Formula: see text] = 0.06–0.48 μg/g) from Tadenac and eight neighboring lakes reveal maximum levels reaching 10.0 and 0.84 μg/g, respectively. Mercury levels in lake trout from Tadenac Lake, an undisturbed PreCambrian Shield ecosystem without detected indigenous sources, exceed the "safe" level (0.5 μg/g) at sexual maturity and at a size less than generally acceptable for human utilization. Mercury accumulation by the trout is correlated with length (r = 0.92) in each lake population examined, but substantial among-lake differences occur in fish of comparable ages. As the growth rates are similar in various waters, differences in extent of mercury accumulation is attributed to differences in mercury availability among lakes. In view of a strong correlation (r = 0.96) between mercury levels in smelt and trout calculated at standardized length, it is proposed that the smelt is an appropriate indicator species for the ranking of cold-water lakes relative to the availability of mercury for uptake by lake trout and other living aquatic organisms.Key words: mercury uptake, lake trout, rainbow smelt, growth rate, diet


<em>Abstract</em>.—Lake trout <em>Salvelinus namaycush </em>eggs were collected from 18 separate locations in the Great Lakes and inland lakes to evaluate the relationship between diet and egg thiamine content. Thiamine concentrations in the eggs of lake trout whose diet consisted primarily of rainbow smelt <em>Osmerus mordax </em>and alewife <em>Alosa pseudoharengus </em>were one-ninth to one-seventeenth those of eggs of lake trout whose diet lacked either of these two species and was composed of lake herring <em>Coregonus artedi</em>, yellow perch <em>Perca flavescens</em>, cyprinids, or invertebrates. Within the Great Lakes, concentrations of thiamine in the eggs of lake trout increased in the order Ontario, Erie, Michigan, Huron < Superior and reflected the proportion of smelt, alewives, or both in the diet. Of the three forms of thiamine found in eggs, free thiamine was the most important and the form most affected by a diet of alewives or smelt. Collections from inland lakes were similar in terms of thiamine content and its relationship to diet composition. Average free thiamine concentrations in lake trout from Lakes Ontario, Erie, Michigan, and Huron were 1.5 to 4 times a threshold of 0.8 nmol/g that has been associated with the development of a thiamine-responsive early mortality syndrome. In contrast, the concentration of free thiamine in Lake Superior lake trout eggs was 26 times the threshold. We concluded that the reduction in egg thiamine concentrations in lake trout whose diet was primarily smelt or alewives was the result of their high thiaminase content, because published thiamine contents could not explain the patterns observed. Egg thiamine concentrations in lake trout were unaffected by maternal age.


2003 ◽  
Vol 60 (12) ◽  
pp. 1552-1574 ◽  
Author(s):  
Charles R Bronte ◽  
Mark P Ebener ◽  
Donald R Schreiner ◽  
David S DeVault ◽  
Michael M Petzold ◽  
...  

Changes in Lake Superior's fish community are reviewed from 1970 to 2000. Lake trout (Salvelinus namaycush) and lake whitefish (Coregonus clupeaformis) stocks have increased substantially and may be approaching ancestral states. Lake herring (Coregonus artedi) have also recovered, but under sporadic recruitment. Contaminant levels have declined and are in equilibrium with inputs, but toxaphene levels are higher than in all other Great Lakes. Sea lamprey (Petromyzon marinus) control, harvest limits, and stocking fostered recoveries of lake trout and allowed establishment of small nonnative salmonine populations. Natural reproduction supports most salmonine populations, therefore further stocking is not required. Nonnative salmonines will likely remain minor components of the fish community. Forage biomass has shifted from exotic rainbow smelt (Osmerus mordax) to native species, and high predation may prevent their recovery. Introductions of exotics have increased and threaten the recovering fish community. Agencies have little influence on the abundance of forage fish or the major predator, siscowet lake trout, and must now focus on habitat protection and enhancement in nearshore areas and prevent additional species introductions to further restoration. Persistence of Lake Superior's native deepwater species is in contrast to other Great Lakes where restoration will be difficult in the absence of these ecologically important fishes.


<em>Abstract</em>.—Thiamine concentrations in representative Great Lakes prey fish, including alewives <em>Alosa pseudoharengus</em>, rainbow smelt <em>Osmerus mordax</em>, slimy sculpin <em>Cottus cognatus</em>, bloater chub <em>Coregonus hoyi</em>, and lake herring <em>Coregonus artedi</em>, and their major dietary items, including mysids <em>Mysis relicta</em>, amphipods <em>Diporeia hoyi</em>, and net macroplankton, were measured to assess their potential involvement in depressed thiamine concentrations in lake trout <em>Salvelinus namaycush </em>of the Great Lakes. Mean thiamine concentrations in all biota were greater than the recommended dietary intake of 3.3 nmol/g for prevention of effects on growth, although the adequacy of these concentrations for reproduction is not known. Mean thiamine concentrations decreased in the order alewives > bloater chub, herring > smelt and differed from the order of associated egg thiamine concentrations published for lake trout feeding on these species (herring > alewives, smelt). As a result, these data strongly implicate the high thiaminase content, rather than the low thiamine content, of alewives and smelt as being responsible for the low egg thiamine concentrations of Great Lakes lake trout stocks that feed heavily on these species. Variations in thiamine content among prey species did not appear to be related to levels in their diet, because thiamine concentrations in <em>Mysis</em>, <em>Diporeia</em>, and macroplankton showed little consistency between group or between lake variation. There was no lake to lake variation in mean thiamine concentrations of prey species, but considerable within species variation occurred that was unrelated to size.


1987 ◽  
Vol 44 (S2) ◽  
pp. s417-s424 ◽  
Author(s):  
D. H. Loftus ◽  
C. H. Olver ◽  
E. H. Brown ◽  
P. J. Colby ◽  
W. L. Hartman ◽  
...  

We proposed and implemented procedures for partitioning future fish yields from the Great Lakes into taxonomic components. These projections are intended as guidelines for Great Lakes resource managers and scientists. Attainment of projected yields depends on restoration of stable fish communities containing some large piscivores that will use prey efficiently, continuation of control of the sea lamprey (Petromyzon marinus), and restoration of high-quality fish habitat. Because Great Lakes fish communities were harmonic before their collapse, we used their historic yield properties as part of the basis for projecting potential yields of rehabilitated communities. This use is qualified, however, because of possible inaccuracies in the wholly commercial yield data, the presence now of greatly expanded sport fisheries that affect yield composition and magnitude, and some possibly irreversible changes since the 1950s in the various fish communities themselves. We predict that total yields from Lakes Superior, Huron, and Ontario will be increased through rehabilitation, while those from Lakes Michigan and Erie will decline. Salmonines and coregonines will dominate future yields from the upper lakes. The Lake Erie fishery will continue to yield mostly rainbow smelt (Osmerus mordax), but the relative importance of percids, especially of walleye (Stizostedion vitreum vitreum), will increase. In Lake Ontario, yields of salmonines will be increased. Managers will have to apply the most rigorous management strictures to major predator species.


2002 ◽  
Vol 59 (1) ◽  
pp. 115-124 ◽  
Author(s):  
Chris J Harvey ◽  
Paul C Hanson ◽  
Timothy E Essington ◽  
Paul B Brown ◽  
James F Kitchell

To describe temporal dynamics of stable isotope ratios in fishes, we developed a bioenergetics-based model that links isotope ratios to growth, as influenced by fish size, temperature, diet, and prey quality. The model includes error terms for isotope ratios, diet proportions, and fractionation. The model accurately predicted temporal δ15N dynamics of lake trout (Salvelinus namaycush) in a diet-switch experiment but was less successful for δ13C, possibly because of variable fractionation. The model was then used in three heuristic applications. In a diet-validation scenario, a model derived from limited knowledge of rainbow smelt (Osmerus mordax) diet reasonably estimated δ13C and δ15N compared with a null model but inaccurately estimated prey consumption. In a scenario where adult lake trout briefly cannibalized stocked lake trout fingerlings, the detectability of a cannibalism-induced δ15N increase depended on predator size, duration of cannibalism, and sample size. In a scenario where seasonal isotopic variability occurred at the base of a food web, variation propagated to higher trophic levels depended on consumer size and diet. Our approach is most valuable when used to examine multiple diet combinations that produce observed stable isotope ratios; one can then identify the most reasonable diets through field tests or other observations.


1998 ◽  
Vol 55 (2) ◽  
pp. 318-327 ◽  
Author(s):  
Peter S Rand ◽  
Donald J Stewart

Estimates of production and predation rates from bioenergetic models of chinook salmon (Oncorhynchus tshawytscha), coho salmon (Oncorhynchus kisutch), and lake trout (Salvelinus namaycush) suggest a long-term decline in their gross conversion efficiency (gross production/prey consumption) and the gross production to biomass ratio in Lake Ontario during 1978-1994. The former pattern was caused primarily by a declining trend in adult alewife (Alosa pseudoharengus) energy density during 1978-1985; the latter pattern resulted from reductions in growth rates (coho salmon) and a buildup of the older age-classes in the population (lake trout) over time. Model results suggest that over 100 and 25% of the annual production of adult alewife and rainbow smelt (Osmerus mordax), respectively, was consumed by salmonines during 1990 in Lake Ontario; hence, we claim that recent observations of reduced salmonine growth in Lake Ontario may be a result of prey limitation. Energy transfer from primary production to salmonines appeared to be more efficient in Lake Ontario than in Lake Michigan, probably due to higher stocking levels per unit area and higher densities of preferred prey fish in Lake Ontario. Through separate analyses, we arrived at conflicting conclusions concerning the sustainability of the food web configuration in Lake Ontario during 1990.


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.


1987 ◽  
Vol 44 (S2) ◽  
pp. s23-s36 ◽  
Author(s):  
Wayne R. MacCallum ◽  
James H. Selgeby

The Lake Superior fish community has changed substantially since the early 1960s, when control of the sea lamprey (Petromyzon marinus) became effective. Self-reproducing stocks of lake trout (Salvelinus namaycush) have been reestablished in many inshore areas, although they have not yet reached pre-sea lamprey abundance; offshore lake trout are probably at or near pre-sea lamprey abundance. Stocks of lake whitefish (Coregonus clupeaformis) appear to have fully recovered; commercial catches are at or above historical levels. Lake herring (Coregonus artedii) are recovering rapidly in U.S. waters and are abundant in western Canadian waters. The population of rainbow smelt (Osmerus mordax), which declined in the 1970s, is recovering. Pacific salmon (Oncorhynchus) are becoming more abundant as a result of increased stocking in U.S. waters and are reproducing in most suitable tributaries; they have become significant in anglers' creels.


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