An Energetics Model for Lake Trout, Salvelinus namaycush: Application to the Lake Michigan Population

1983 ◽  
Vol 40 (6) ◽  
pp. 681-698 ◽  
Author(s):  
Donald J. Stewart ◽  
David Weininger ◽  
Donald V. Rottiers ◽  
Thomas A. Edsall
Keyword(s):  
Lake Michigan ◽  
Lake Trout ◽  
Salvelinus Namaycush ◽  
High Energy ◽  
Alosa Pseudoharengus ◽  
Fishing Mortality ◽  
Age Classes ◽  
Short Term ◽  
Conversion Efficiencies

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.

Accumulation of PCBs by Lake Trout (Salvelinus namaycush): An Individual-Based Model Approach

1993 ◽  
Vol 50 (1) ◽  
pp. 97-109 ◽  
Author(s):  
Charles P. Madenjian ◽  
Stephen R. Carpenter ◽  
Gary W. Eck ◽  
Michael A. Miller
Keyword(s):  
Uncertainty Analysis ◽  
Lake Michigan ◽  
Lake Trout ◽  
Salvelinus Namaycush ◽  
Prey Fish ◽  
Age Classes ◽  
Individual Based Model ◽  
Trout Population ◽  
Different Levels ◽  
Model Approach

To explain the variation in growth and in concentration of polychlorinated biphenyls (PCBs) among individual fish, an individual-based model (IBM) was applied to the lake trout (Salvelinus namaycush) population in Lake Michigan. The IBM accurately represented the variation in growth exhibited by the different age classes of lake trout. Uncertainty analysis of the IBM revealed that mean PCB concentration for the lake trout population was most sensitive to PCB concentration in their prey. The variability in PCB concentration among lake trout individuals was not adequately explained by the IBM, unless variation in prey fish PCBs was included in the model. To accomplish this, the simulated lake trout population was divided into subsets subjected to different levels of PCB concentration in the prey fish. Thus, model results indicated that variability in prey fish PCB concentration was an important component of the variation in PCB concentration observed among individual lake trout comprising the Lake Michigan population.

Lake Michigan's Capacity to Support Lake Trout (Salvelinus namaycush) and Other Salmonines: An Estimate Based on the Status of Prey Populations in the 1970s

1985 ◽  
Vol 42 (3) ◽  
pp. 449-454 ◽  
Author(s):  
G. W. Eck ◽  
Edward H. Brown Jr.
Keyword(s):  
Lake Michigan ◽  
Lake Trout ◽  
Physiological Stress ◽  
Total Mortality ◽  
Salvelinus Namaycush ◽  
Predatory Fish ◽  
Natural Mortality ◽  
Alosa Pseudoharengus ◽  
Mass Balance Equation ◽  
The Status

We used a mass balance equation relating total mortality of age II and older alewives (Alosa pseudoharengus) to their removals by predatory fish and other sources of mortality as the basis for estimating that the forage base in Lake Michigan could support an additional 13 000 to 21 000 t of lake trout (Salvelinus namaycush) or a total lake trout biomass between 15 000 and 23 000 t. This biomass estimate is projected with biomasses of other trout and salmon held at 1979 levels. Major premises of this approach are that (1) the sustained availability of age II and older alewives to salmonines will ultimately limit the expansion of salmonine stocks, (2) the alewife population was oscillating without trend during 1973–80, and (3) additional limited predation on alewives would be compensated by a reduction in natural mortality caused by physiological stress and disease.

In situ measurement of tissue turnover and energy conversion efficiencies in lake trout (Salvelinus namaycush) using a novel toxicokinetic approach

2005 ◽  
Vol 62 (2) ◽  
pp. 464-471 ◽  
Author(s):  
Gordon Paterson ◽  
Susan Y Huestis ◽  
D Michael Whittle ◽  
Kenneth G Drouillard ◽  
G Douglas Haffner
Keyword(s):  
Energy Conversion ◽  
Lake Trout ◽  
Polychlorinated Biphenyl ◽  
Food Limitation ◽  
Lake Ontario ◽  
Salvelinus Namaycush ◽  
Turnover Rates ◽  
Tissue Turnover ◽  
Conversion Efficiencies

We determined polychlorinated biphenyl (PCB) elimination patterns in lake trout (Salvelinus namaycush) from Lake Ontario using biomonitoring data collected from 1977 to 1993. The in situ elimination rates of these persistent pollutants were found to describe tissue turnover rates in lake trout. A model relating tissue turnover rates and endogenous energy conversion efficiencies revealed that chemical elimination in larger organisms is primarily regulated by food limitation and bioenergetic mechanisms rather than chemical kinetics. Lake trout approximately 2500 g and larger were observed to have higher PCB elimination rates than smaller fish as a result of increased lipid mobilization to supplement metabolic demands due to increased time spent foraging. This study concludes that the growth and production of large predators in Lake Ontario are regulated by the bioenergetic constraints of searching for prey in a food-limited environment. We also demonstrate that persistent organic pollutant kinetics can describe the proportion of endogenous energy required to support metabolism and production, thus providing important in situ measurements of bioenergetic processes.

An examination of the PCB: lipid relationship among individual fish

1997 ◽  
Vol 54 (5) ◽  
pp. 1031-1038
Author(s):  
C A Stow ◽  
L J Jackson ◽  
J F Amrhein
Keyword(s):  
Salmo Trutta ◽  
Lake Michigan ◽  
Oncorhynchus Tshawytscha ◽  
Lake Trout ◽  
Coho Salmon ◽  
Salvelinus Namaycush ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Strong Linear Correlation ◽  
Brown Trout Salmo Trutta ◽  
The Relationship

We examined data from 1984 to 1994 for five species of Lake Michigan salmonids to explore the relationship between total PCB concentration and percent lipid. When we compared mean species lipid and PCB values, we found a strong linear correlation. When we compared values among individuals, we found modest positive PCB:lipid associations in brown trout (Salmo trutta), chinook salmon (Oncorhynchus tshawytscha), coho salmon (Oncorhynchus kisutch), and rainbow trout (Oncorhynchus mykiss) collected during spawning, but positive associations were not apparent among nonspawning individuals. Lake trout (Salvelinus namaycush) exhibited no discernible PCB:lipid relationship. Our results are not incompatible with previous observations that contaminants are differentially partitioned into lipids within a fish, but these results do suggest that lipids are not a major factor influencing contaminant uptake.

In Situ Determination of the Annual Thermal Habitat Use by Lake Trout (Salvelinus namaycush) in Lake Huron

2003 ◽  
Vol 29 ◽  
pp. 347-361 ◽  
Author(s):  
Roger A. Bergstedt ◽  
Ray L. Argyle ◽  
James G. Seelye ◽  
Kim T. Scribner ◽  
Gary L. Curtis
Keyword(s):  
Habitat Use ◽  
Lake Trout ◽  
Salvelinus Namaycush ◽  
Lake Huron ◽  
Thermal Habitat

Optimal Use of Creel Survey Data in Assessing Population Behaviour: Lake Opeongo Lake Trout (Salvelinus namaycush) and Smallmouth Bass (Micropterus dolomieui), 1936–83

1987 ◽  
Vol 44 (S2) ◽  
pp. s229-s238 ◽  
Author(s):  
B. J. Shuter ◽  
J. E. Matuszek ◽  
H. A. Regier
Keyword(s):  
Lake Trout ◽  
Total Mortality ◽  
Salvelinus Namaycush ◽  
Fish Population ◽  
Smallmouth Bass ◽  
Fishing Mortality ◽  
Assessment Data ◽  
Creel Survey ◽  
Micropterus Dolomieui ◽  
Independent Assessment

Creel survey and independent assessment data on the lake trout (Salvelinus namaycush) and smallmouth bass (Micropterus dolomieui) populations of Lake Opeongo were evaluated. Annual estimates of total mortality, fishing mortality, and abundance were generated for each population over the period 1936–83. Large variations in survey efficiency, angler efficiency, fishing mortality, and abundance were identified over this period. We argue that a creel survey, which is expected to provide reliable information on fish population dynamics, requires an overall study design which includes collection of data on the number and relative efficiency of different kinds of anglers and periodic assessment studies aimed at providing independent checks on both survey effectiveness and population behaviour.

Bioenergetics and PCB, DDE, and Mercury Dynamics in Lake Ontario Lake Trout (Salvelinus namaycush): A Model based on Surveillance Data

1992 ◽  
Vol 49 (6) ◽  
pp. 1086-1096 ◽  
Author(s):  
U. Borgmann ◽  
D. M. Whittle
Keyword(s):  
Gastrointestinal Tract ◽  
Lake Trout ◽  
Prey Selection ◽  
Lake Ontario ◽  
Salvelinus Namaycush ◽  
Whole Body ◽  
Alosa Pseudoharengus ◽  
Assimilation Rate ◽  
Feeding Rates ◽  
Dynamics Model

Lake trout (Salvelinus namaycush) ingestion rates in a bioenergetics and contaminant dynamics model were estimated directly from contaminant concentrations in lake trout and their prey, rather than from the sum of growth and predicted metabolism. Elimination rates for PCB and DDE, but not for mercury, were dependent on either body mass or lipid content. Concentrations in lake trout responded rapidly to changes in concentration of their prey. This was due primarily to growth dilution and not contaminant elimination, especially for DDE and PCB. Changes in lipid concentrations, therefore, have only minor effects on final concentrations in lake trout, and it is not appropriate to lipid normalize PCB or DDE concentrations when examining trends in whole-body concentrations for this species. Concentrations of PCBs and lipids have declined in lake trout from 1977 to 1988. The drop in PCB concentrations is probably not caused primarily by the lowered lipid concentrations but is the result of either a reduction in feeding rates and improved growth efficiencies, a reduction in PCB concentrations in alewife (Alosa pseudoharengus), or an undocumented change in prey selection. Models based on chemical kinetics across the gastrointestinal tract are more consistent with observed data than models based on a constant contaminant assimilation rate and direct excretion.

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
Keyword(s):  
Native Species ◽  
Yellow Perch ◽  
Gasterosteus Aculeatus ◽  
Lake Michigan ◽  
Lake Trout ◽  
Pink Salmon ◽  
Oncorhynchus Gorbuscha ◽  
Alosa Pseudoharengus ◽  
Poor Recruitment ◽  
Emerald Shiner

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.

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