Particle-size-conversion Efficiency, Invertebrate Production, and Potential Fish Production in Lake Ontario

1994 ◽  
Vol 51 (3) ◽  
pp. 693-700 ◽  
Author(s):  
U. Borgmann ◽  
D. M. Whittle
Keyword(s):  
Particle Size ◽  
Body Size ◽  
Conversion Efficiency ◽  
Lake Trout ◽  
Lake Ontario ◽  
Contaminant Concentration ◽  
Fish Production ◽  
Rainbow Smelt ◽  
Pelagic Species ◽  
Size Relationship

The relationships between body size and p,p′-DDE and total PCB concentration in Zooplankton, mysids, amphipods, slimy sculpin (Cottus cognatus), rainbow smelt (Osmerus mordax), alewife (Alosa pseudo-harengus), and lake trout (Salvelinus namayeush) in Lake Ontario were determined for samples collected from 1989 to 1992. Amphipods, and to a lesser extent sculpins, had higher DDE and PCB concentrations than predicted from the contaminant concentration – body size relationship for the pelagic species. PCB, but not DDE, concentrations in Zooplankton were also abnormally high. For the pelagic species, excluding PCB concentrations in Zooplankton, the log contaminant concentration – log body size relationship had a slope of 0.23 (95% confidence limits = ±0.014). Combined with revised estimates of the efficiency of contaminant retention from one body size to another (ε′ = 0.05–0.10), the revised estimate of particle-size-conversion efficiency (ε) for Lake Ontario falls between 0.27 and 0.35. Recent estimates of invertebrate (Zooplankton, mysid, and amphipod) annual production average 18 g/m2 (dry weight) with upper and lower limit estimates of 14–27 g/m2. Using ε to extrapolate from invertebrate to fish production results in estimates of mean potential fish production in Lake Ontario of 1–7 kg/ha (wet weight), as compared with previously published estimates of 6 and 14 kg/ha.

Particle-Size-Conversion Efficiency and Contaminant Concentrations in Lake Ontario Biota

1983 ◽  
Vol 40 (3) ◽  
pp. 328-336 ◽  
Author(s):  
Uwe Borgmann ◽  
D. M. Whittle
Keyword(s):  
Particle Size ◽  
Body Size ◽  
Conversion Efficiency ◽  
Food Chain ◽  
Lake Ontario ◽  
Dry Weight ◽  
Growth Efficiency ◽  
Fish Production ◽  
The Relationship ◽  
Zooplankton Production

The particle-size-conversion efficiency (log food consumption/production divided by log predator prey size ratio) is shown to be directly related to the relationship between the concentration of persistent contaminants accumulated primarily through the food chain and body size for organisms in pelagic ecosystems. The difference between particle-size-conversion efficiency for biomass and that for the contaminant gives the slope of the relationship between log contaminant concentration and log body size. This provides a useful theoretical framework for analyzing contaminant concentrations in aquatic biota without the need for specifying trophic level but still incorporating the idea of food chain accumulation. Concentrations of PCB, DDT, and mercury were examined in aquatic organisms from Lake Ontario, ranging in size from zooplankton to large salmonids (a 108 -fold range in dry weight). The slope of the double log plot of concentration versus weight varied from 0.20 to 0.22 for PCB and DDT and was approximately equal to 0.13 for mercury. This indicates that mercury is accumulated less efficiently through the food chain than PCB or DDT. After correcting for incomplete uptake and retention of the contaminant, an estimate of particle-size-conversion efficiency for biomass of about 0.26 was obtained, which agrees reasonably well with previous estimates obtained from growth efficiency experiments and analysis of particle-size spectra. These calculations indicate that potential fish production in Lake Ontario is ~ 120-fold lower than zooplankton production (for fish averaging 108-fold larger in body size as compared to zooplankton).Key words: particle-size-conversion efficiency, PCB, DDT, mercury, zooplankton production, fish production

Dynamics of salmonine diets and foraging in Lake Ontario, 1983-1993: a test of a bioenergetic model prediction

1998 ◽  
Vol 55 (2) ◽  
pp. 307-317 ◽  
Author(s):  
Peter S Rand ◽  
Donald J Stewart
Keyword(s):  
Lake Trout ◽  
Coho Salmon ◽  
Lake Ontario ◽  
Osmerus Mordax ◽  
Alosa Pseudoharengus ◽  
Bioenergetic Model ◽  
Rainbow Smelt ◽  
Predator Species ◽  
Mean Size ◽  
Diet Survey

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.

Prey fish exploitation, salmonine production, and pelagic food web efficiency in Lake Ontario

1998 ◽  
Vol 55 (2) ◽  
pp. 318-327 ◽  
Author(s):  
Peter S Rand ◽  
Donald J Stewart
Keyword(s):  
Food Web ◽  
Lake Michigan ◽  
Oncorhynchus Tshawytscha ◽  
Lake Trout ◽  
Coho Salmon ◽  
Lake Ontario ◽  
Osmerus Mordax ◽  
Prey Fish ◽  
Rainbow Smelt ◽  
Time Model

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.

Shifts in Depth Distributions of Alewives, Rainbow Smelt, and Age-2 Lake Trout in Southern Lake Ontario following Establishment of Dreissenids

2000 ◽  
Vol 129 (5) ◽  
pp. 1096-1106 ◽  
Author(s):  
Robert O'Gorman ◽  
Joseph H. Elrod ◽  
Randall W. Owens ◽  
Clifford P. Schneider ◽  
Thomas H. Eckert ◽  
...  
Keyword(s):  
Lake Trout ◽  
Lake Ontario ◽  
Rainbow Smelt ◽  
Depth Distributions

Recent Changes in the Aquatic Food Web of Eastern Lake Ontario

1987 ◽  
Vol 44 (S2) ◽  
pp. s37-s52 ◽  
Author(s):  
W. J. Christie ◽  
K. A. Scott ◽  
P. G. Sly ◽  
R. H. Strus
Keyword(s):  
Prey Species ◽  
Lake Trout ◽  
Prey Availability ◽  
Lake Ontario ◽  
Size Composition ◽  
Osmerus Mordax ◽  
Alosa Pseudoharengus ◽  
Rainbow Smelt ◽  
Aquatic Food ◽  
Representative Samples

During the past 10 yr there have been dramatic increases in piscivorous populations of walleye (Stizostedion vitreum) in the Bay of Quinte and of planted lake trout (Salvelinus namaycush) and double-crested cormorants (Phalacrocorax auritus) in the Kingston basin of Lake Ontario. This paper documents changes in the prey stocks shared by these piscivores, including reduction in size and abundance of the slimy sculpin (Cottus cognatus) with subsequent stock equilibration and unabated reduction in the size and abundance of rainbow smelt (Osmerus mordax), both owing to predation pressure from the lake trout. The third primary prey species, alewife (Alosa pseudoharengus), has not yet suffered severely from the depredations of the piscivores. Symptoms of the effects are discernible, however, and the implications of a possible collapse are discussed. Lake trout survival and growth have not yet been affected by the changes in prey availability, but their diet has shifted both in response to their own expanded size composition and relative abundance of the three prey species. Increased utilization of alewife makes the hunting of the trout more pelagic. Problems of obtaining representative samples of the prey are discussed.

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
Keyword(s):  
Body Size ◽  
Lake Trout ◽  
Cold Water ◽  
Wide Spectrum ◽  
Osmerus Mordax ◽  
Rainbow Smelt ◽  
Predator Species ◽  
Inland Lakes ◽  
Recruitment Failure ◽  
Indigenous Fishes

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.

Changes in the Fish Species Composition of the Great Lakes

1974 ◽  
Vol 31 (5) ◽  
pp. 827-854 ◽  
Author(s):  
W. J. Christie
Keyword(s):  
Great Lakes ◽  
Exotic Species ◽  
Lake Trout ◽  
Lake Ontario ◽  
Sea Lamprey ◽  
Turn Of The Century ◽  
The Other ◽  
Pest Species ◽  
Rainbow Smelt ◽  
Fish Species Composition

This paper is an interpretive review of the "case histories" which documented the changes in each of the Laurentian Great Lakes for the 1971 symposium on Salmonid Communities in Oligotrophic Lakes (SCOL). It suggests that lakes Huron, Michigan, and Superior passed through a parallel series of stock changes after the invasions of those lakes by the sea lamprey. First, the lake trout and burbot stocks collapsed, and then with the relaxation of predation pressure rainbow smelt, deepwater cisco, and alewife stocks increased. Lake herring stocks collapsed in apparent response to the smelt increase. Whitefish were affected by sea lamprey but recovery after the control of the lamprey in lakes Michigan and Superior suggested that the exotic species had little influence. Lake Ontario differed from the other lakes in that it was inhabited by both sea lamprey and alewife before the turn of the century, and provided the reservoir from which these species expanded to colonize the upper lakes. Alewife apparently equilibrated early, but the evidence was that more recent perturbations allowed the sea lamprey to become a significant factor in the loss of the piscivores of Lake Ontario. Subsequent proliferation of ciscoes and smelt, and collapse of the herring, followed a sequence similar to that of the upper lakes. Lake Erie seemed to be similarly affected by loss of predator stocks, but its predominantly eutrophic character made the situation more complex. Overfishing was indicted in many early stock collapses, in the early invasion of the smelt in lakes Huron and Michigan and in the recent cisco declines of lakes Ontario and Huron. Eutrophication and more direct pollution stresses had mainly inshore impacts, but the similarity in the species sequencing in the oligotrophic Great Lakes suggested that although these factors may have supplemented the other effects, their influence before about 1950 was less than that of overfishing and the invasion of exotic species. Control of sea lamprey, overfishing, and eutrophication seemed attainable in the Great Lakes, but the only defense against further invasions by pest species appeared to be maintenance of sufficiently dense piscivore stocks to assure their suppression. Determining the levels of harvest appropriate to this provision will require intensified research.

Using ratios of stable nitrogen and carbon isotopes to characterize the biomagnification of DDE, mirex, and PCB in a Lake Ontario pelagic food web

1995 ◽  
Vol 52 (12) ◽  
pp. 2660-2674 ◽  
Author(s):  
Richard M. Kiriluk ◽  
Mark R. Servos ◽  
D. Michael Whittle ◽  
Gilbert Cabana ◽  
Joseph B. Rasmussen
Keyword(s):  
Stable Isotopes ◽  
Food Web ◽  
Trophic Status ◽  
Lake Trout ◽  
Trophic Position ◽  
Lake Ontario ◽  
Osmerus Mordax ◽  
Rainbow Smelt ◽  
Slimy Sculpin ◽  
Pelagic Food Web

Stable isotopes of nitrogen (δ15N) and carbon (δ13C) were used to describe the trophic status and interactions of biota characteristic of a Lake Ontario pelagic food web. Stable isotopes of nitrogen were further used to characterize the relationship between an organism's trophic position and the biomagnification of specific hydrophobic contaminants through this food web. The δ15N defines the relative trophic status as (i) the top predator, lake trout (Saivelinus namaycush); (ii) prey species, alewife (Alosa pseudoharengus), rainbow smelt (Osmerus mordax), and slimy sculpin (Cottus cognatus); (iii) macroinvertebrates, mysids (Mysis relicta), and amphipods (Diporeia hoyi); (iv) net zooplankton, dominated by cyclopoids (Diacyclops thomasi) and cladocerans (Bosmina longirostris); and (v) net phytoplankton, dominated by diatoms (Melosira spp.). The separation of the four fish species, lake trout and associated prey items (alewife, rainbow smelt, and slimy sculpin), on the basis of their mean δ13C signatures complements what is known about the preferred diet of these fishes. The enrichment of 15N through this food web indicates that there is a strong correlation between the biomagnification of persistent lipophilic contaminants (p,p′-DDE, mirex, and PCB) and the relative trophic status of an organism as described by stable isotopes of nitrogen.

Particle-Size-Conversion Efficiency and Total Animal Production in Pelagic Ecosystems

1982 ◽  
Vol 39 (5) ◽  
pp. 668-674 ◽  
Author(s):  
Uwe Borgmann
Keyword(s):  
Particle Size ◽  
Conversion Efficiency ◽  
Animal Production ◽  
Size Spectrum ◽  
Fish Production ◽  
Pelagic Ecosystem ◽  
Simple Equations ◽  
Zooplankton Production ◽  
Pelagic Ecosystems

A method is described for defining conversion efficiency in pelagic ecosystems on the basis of particle size, rather than trophic level, this permits calculation of a size-corrected biomass function which can be used to describe total animal production by taking into account biomass losses resulting from carnivorous feeding in multitrophic level systems. This, in turn, permits the determination of potential fish production, for any given size fish, from experimental data on zooplankton production using simple equations. Little knowledge of trophic interactions is required. The potential fish production resulting from microzooplankton production in the Burlington Canal is calculated. Keywords: conversion efficiency, production, pelagic ecosystem, particle-size spectrum

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