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

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

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f83-091 ◽

1983 ◽

Vol 40 (6) ◽

pp. 681-698 ◽

Cited By ~ 245

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.

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System Simulation of the Predatory Activities of Sea Lampreys (Petromyzon marinus) on Lake Trout (Salvelinus namaycush)

Journal of the Fisheries Research Board of Canada ◽

10.1139/f75-080 ◽

1975 ◽

Vol 32 (5) ◽

pp. 623-631 ◽

Cited By ~ 4

Author(s):

Patrick F. Lett ◽

F. W. H. Beamish ◽

G. J. Farmer

Keyword(s):

Lake Trout ◽

Petromyzon Marinus ◽

Salvelinus Namaycush ◽

Commercial Fishing ◽

Stochastic Dynamic ◽

Age Classes ◽

Trout Population ◽

Sea Lampreys ◽

Population Structures ◽

The Mean

A stochastic dynamic model was developed to evaluate the simulated and empirical interactions between sea lampreys (Petromyzon marinus) and two lake trout (Salvelinus namaycush) population structures, one without and the other with previous lamprey predation.An arithmetic increase in lampreys induced a geometric decline in trout, which was dependent on the number of age-classes and the mean weight of trout. Large trout, when present, were subject to most of the lamprey predation allowing survival of smaller trout. Lethality increased exponentially with lamprey size resulting in peak lake trout mortality during fall near the end of the lamprey’s feeding period. Lake trout scarring data could be used only as an index of lamprey abundance when trout:lamprey ratios and trout population structures were known. The simulation suggested that sea lampreys and lake trout could coexist if large trout are not removed by commercial fishing and if some exogenous factor controlled lamprey abundance.

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An examination of the PCB: lipid relationship among individual fish

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f97-014 ◽

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.

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Lake Trout Population Dynamics in the Northern Refuge of Lake Michigan: Implications for Future Rehabilitation

North American Journal of Fisheries Management ◽

10.1577/m09-108.1 ◽

2010 ◽

Vol 30 (3) ◽

pp. 629-641 ◽

Cited By ~ 6

Author(s):

Charles P. Madenjian ◽

Timothy J. Desorcie

Keyword(s):

Population Dynamics ◽

Lake Michigan ◽

Lake Trout ◽

Trout Population

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Depth Distribution, Diet, and Overwinter Growth of Lake Trout (Salvelinus Namaycush) in Southeastern Lake Michigan Sampled in December 1981 and March 1982

Journal of Great Lakes Research ◽

10.1016/s0380-1330(86)71726-7 ◽

1986 ◽

Vol 12 (4) ◽

pp. 263-269 ◽

Cited By ~ 23

Author(s):

Gary W. Eck ◽

LaRue Wells

Keyword(s):

Lake Michigan ◽

Depth Distribution ◽

Lake Trout ◽

Salvelinus Namaycush

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Fertilization of Eggs of Lake Michigan Lake Trout Salvelinus namaycush in Lake Water: Effect of PCBs (Aroclor 1254)

Bulletin of Environmental Contamination and Toxicology ◽

10.1007/s001289900500 ◽

1997 ◽

Vol 59 (3) ◽

pp. 460-466 ◽

Cited By ~ 1

Author(s):

N. R. Foster ◽

W. H. Berlin

Keyword(s):

Lake Water ◽

Lake Michigan ◽

Lake Trout ◽

Salvelinus Namaycush ◽

Water Effect ◽

Aroclor 1254

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

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f97-254 ◽

1998 ◽

Vol 55 (2) ◽

pp. 318-327 ◽

Cited By ~ 39

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.

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Genetic Differences in Retention of Swimbladder Gas Between Two Populations of Lake Trout (Salvelinus namaycush)

Journal of the Fisheries Research Board of Canada ◽

10.1139/f74-159 ◽

1974 ◽

Vol 31 (8) ◽

pp. 1351-1354 ◽

Cited By ~ 21

Author(s):

P. Ihssen ◽

J. S. Tait

Keyword(s):

Brook Trout ◽

Depth Distribution ◽

Lake Trout ◽

Salvelinus Namaycush ◽

Genetic Differences ◽

Trout Population ◽

Two Populations

Lake trout (Salvelinus namaycush) derived from two populations differed in retention of swimbladder gas. The two reciprocal interpopulation crosses were intermediate to the parent populations. The two F1 hybrids obtained by crossing fish from each lake trout population with brook trout (S. fontinalis) were also found different in retention. Gas retention was correlated with depth distribution of the parent populations, high retention being associated with deeper distribution.

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Quantification of historic lake trout (Salvelinus namaycush) spawning aggregations in Lake Michigan

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f97-136 ◽

1997 ◽

Vol 54 (10) ◽

pp. 2290-2302 ◽

Cited By ~ 18

Author(s):

K A Dawson ◽

R L Eshenroder ◽

M E Holey ◽

C Ward

Keyword(s):

Lake Michigan ◽

Lake Trout ◽

Salvelinus Namaycush ◽

Catch Per Unit Effort ◽

Spawning Activity ◽

Commercial Catch ◽

Northeast Section ◽

Site Specific ◽

Spawning Aggregations ◽

Made In

We used commercial catch reports to determine site-specific characteristics of lake trout (Salvelinus namaycush) spawning aggregations in Michigan's and Wisconsin's waters of Lake Michigan before reproduction ceased in the 1950s. One hundred sites where annual catches exceeded 25 kg/year were identified. Two thirds of the catch was made in offshore waters and nearly half was made in the northeast sector of the lake. Catch was a better descriptor of the size of spawning aggregations than catch per unit effort (CPUE). CPUEs were not significantly different among onshore, offshore, and southern deepwater reefs. Spawning activity as measured by CPUE had peaked by the week beginning 29 October at all locations. Spawning aggregations were strongly clustered in the northeast section of the lake where Devonian rocks were subject to brecciation, i.e., fracturing and recementing following slumping. Areas zoned as refuges in the current lake trout rehabilitation plan account for 36% of the historical catch targeted at spawning aggregations. We recommend a refocusing of rehabilitation efforts in northern waters from sites where historical catches were modest to sites that produced the largest catches of lake trout aggregated for spawning.

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