Differences in Early Development Among Lake Trout (Salvelinus namaycush) Populations

Genetic differences among surviving lake trout (Salvelinus namaycush) populations might be important for the reestablishment of self-sustaining populations in the Great Lakes, but little relevant information is available to guide stocking practices. I studied eggs and fry of four populations, two from Lake Superior, one from Trout Lake, and one (the Green Lake strain) derived in part from Lake Michigan. I found significant interpopulation differences in hatching and emergence times as well as in indices of morphological development rates. Interpopulation differences in morphological development at the times of emergence suggest that the Green Lake strain emerges at an earlier stage of morphological development than do the other populations. Between-lake differences are the most important sources of variability in my data; the Lake Superior populations were similar to one another, and variation among crosses within populations was small.

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Responses of Lake Trout (Salvelinus namaycush) to Harvesting, Stocking, and Lamprey Reduction

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f80-255 ◽

1980 ◽

Vol 37 (11) ◽

pp. 2133-2145 ◽

Cited By ~ 27

Author(s):

Carl J. Walters ◽

Greg Steer ◽

George Spangler

Keyword(s):

Simple Model ◽

Policy Analysis ◽

Great Lakes ◽

Population Regulation ◽

Lake Trout ◽

Normal Population ◽

Lake Superior ◽

Sea Lamprey ◽

Salvelinus Namaycush ◽

Density Dependent

Sustained yields, declines, and recovery of lake trout (Salvelinus namaycush) can be explained by a simple model that hypothesizes normal population regulation through density dependent body growth, coupled with depensatory lamprey mortality. The model indicates that either lamprey or fishing alone could have caused the Lake Superior decline, though they apparently operated in concert. The presence of depensatory lamprey mortality leads to a "cliff edge" in the system's dynamics, such that catastrophic changes may be repeated in the future. It is not unlikely that Lake Superior is on the verge of a second collapse. Options for dealing with potential disasters include conservative harvesting policies, development of more sensitive monitoring indicators, and modified stocking policies that may speed the coevolution of a viable lamprey/trout association.Key words: lake trout, sea lamprey, simulation, Great Lakes, policy analysis

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Estimates of egg deposition and effects of lake trout (Salvelinus namaycush) egg predators in three regions of the Great Lakes

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f05-141 ◽

2005 ◽

Vol 62 (10) ◽

pp. 2254-2264 ◽

Cited By ~ 29

Author(s):

Jory L Jonas ◽

Randall M Claramunt ◽

John D Fitzsimons ◽

J Ellen Marsden ◽

Brian J Ellrott

Keyword(s):

Great Lakes ◽

Lake Michigan ◽

Lake Trout ◽

Salvelinus Namaycush ◽

First Year ◽

Lake Champlain ◽

Predator Species ◽

Orconectes Propinquus ◽

Egg Deposition ◽

First Year Of Life

Excessive mortality from spawning through the first year of life is likely responsible for recruitment failures in many lake trout (Salvelinus namaycush) populations. We evaluated relationships between interstitial predator species and lake trout egg deposition in three regions of the Great Lakes. The introduced crayfish Orconectes rusticus dominated the nearshore zone in northern Lake Michigan, whereas other sites in Lake Michigan and Parry Sound were dominated by native Orconectes propinquus. In Lake Champlain, sculpin (Cottus spp.) were the most common interstitial predator, yet densities were comparable with those in Lake Michigan. Predator densities in Lake Michigan (mean ± standard error = 15.5 ± 0.4 predators·m2) were twice those in Lake Champlain or Parry Sound (6 ± 1 predators·m2). Densities of eggs were higher in Lake Champlain (2994.1 ± 398.3 eggs·m2) and Parry Sound (454.7 ± 36.3) than in Lake Michigan (7.5 ± 1.3; Kruskal-Wallis, P ≤ 0.05). Ratios of eggs to predator provide simple measures of the effectiveness of lake trout rehabilitation efforts. The average ratio calculated from 10 successful spawning locations is 190 eggs·predator1·m2. Ratios may help establish target egg densities for restoration efforts and the concentration of spawning adults required to allow survival to the fry stage.

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Movements of Hatchery-Reared Lake Trout in Lake Superior

Journal of the Fisheries Research Board of Canada ◽

10.1139/f65-093 ◽

1965 ◽

Vol 22 (4) ◽

pp. 999-1024 ◽

Cited By ~ 14

Author(s):

Richard L. Pycha ◽

William R. Dryer ◽

George R. King

Keyword(s):

Great Lakes ◽

Lake Trout ◽

Lake Superior ◽

Salvelinus Namaycush ◽

Surface Currents ◽

Gill Nets ◽

East Lake ◽

History Of ◽

Keweenaw Peninsula

The history of stocking of lake trout (Salvelinus namaycush) in the Great Lakes is reviewed.The study of movements is based on capture of 24,275 fin-clipped lake trout taken in experimental gill nets and trawls and commercial gill nets.Yearling lake trout planted from shore dispersed to 15-fath (27-m) depths in [Formula: see text]. Most fish remained within 2 miles (3.2 km) of the planting site 2 months, but within 4 months some fish had moved as much as 17 miles (27 km). The highest abundance of planted lake trout was in areas 2–4 miles (3.2–6.4 km) from the planting site even 3 years after release. Distance moved and size of fish were not correlated.Dispersal of lake trout begins at planting and probably continues until the fish are mature. Most movement was eastward in southern Lake Superior and followed the counterclockwise surface currents. Movement is most rapid in areas of strong currents and slowest in areas of weak currents or eddies. Movement to areas west of the Keweenaw Peninsula was insignificant from plantings in Keweenaw Bay and nil from other plantings farther east. Lake trout planted in the eastern third of the lake dispersed more randomly than those planted farther west. Few fish moved farther offshore than the 50-fath (91-m) contour. Lake trout planted in Canadian waters made insignificant contributions to populations in US waters.

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Lake Trout (Salvelinus namaycush) and Sea Lamprey (Petromyzon marinus) Populations in Lake Michigan, 1971–78

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f80-244 ◽

1980 ◽

Vol 37 (11) ◽

pp. 2047-2051 ◽

Cited By ~ 8

Author(s):

LaRue Wells

Keyword(s):

Regression Model ◽

Lake Michigan ◽

Lake Trout ◽

Lake Superior ◽

Petromyzon Marinus ◽

Sea Lamprey ◽

Salvelinus Namaycush ◽

Combined Effects ◽

Widespread Application ◽

Mortality Estimates

Lake trout (Salvelinus namaycush) was exterminated in Lake Michigan by the mid-1950s as a result of the combined effects of an intensive fishery and predation by the sea lamprey (Petromyzon marinus). The widespread application of lampricide in tributary streams had greatly reduced the abundance of lampreys by the early 1960s, and a program to restore self-sustaining populations of lake trout through stocking of yearlings and fingerlings was initiated in 1965. Although the hatchery-reared fish spawned widely in Lake Michigan each year after 1970, no progeny were observed except in an isolated area in Grand Traverse Bay. During 1971–78, sea lamprey abundance was generally greater in Wisconsin than in other parts of the lake. However, the rate of occurrence of sea lamprey wounds on lake trout dropped dramatically there in 1978 after the Peshtigo River, a tributary to Green Bay, was treated with lampricide. Application of Lake Michigan wounding rates to a regression model relating mortality to lamprey wounding developed from Lake Superior data, yielded lamprey-induced mortality estimates in 1977 of 5% in Michigan plus Indiana (combined) and 31% in Wisconsin; corresponding estimates for 1978 were 5 and 15%.Key words: lake trout, sea lamprey predation, abundance, Lake Michigan

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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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Classification of Sea Lamprey (Petromyzon marinus) Attack Marks on Great Lakes Lake Trout (Salvelinus namaycush)

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f80-240 ◽

1980 ◽

Vol 37 (11) ◽

pp. 1989-2006 ◽

Cited By ~ 52

Author(s):

Everett Louis King Jr.

Keyword(s):

Great Lakes ◽

Lake Trout ◽

Petromyzon Marinus ◽

Attachment Site ◽

Sea Lamprey ◽

Salvelinus Namaycush ◽

Oral Disc ◽

Field Assessment ◽

Sea Lampreys

Criteria for the classification of marks inflicted by sea lamprey (Petromyzon marinus) into nine categories were developed from laboratory studies in an attempt to refine the classification system used in field assessment work. These criteria were based on characteristics of the attachment site that could be identified under field conditions by unaided visual means and by touching the attachment site. Healing of these marks was somewhat variable and was influenced by the size of lamprey, duration of attachment, severity of the wound at lamprey detachment, season and water temperature, and by other less obvious factors. Even under laboratory conditions staging of some wounds was difficult, especially at low water temperatures. If these criteria are to be used effectively and with precision in the field, close examination of individual fish may be required. If the feeding and density of specific year-classes of sea lampreys are to be accurately assessed on an annual basis, close attention to the wound size (as it reflects the size of the lamprey's oral disc) and character of wounds on fish will be required as well as consideration of the season of the year in which they are observed.Key words: sea lamprey, attack marks, lake trout, Great Lakes

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Survey of the Genetic Variation Among Eastern Lake Superior Lake Trout (Salvelinus namaycush)

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f81-222 ◽

1981 ◽

Vol 38 (12) ◽

pp. 1738-1746 ◽

Cited By ~ 24

Author(s):

Terrence R. Dehring ◽

Anne F. Brown ◽

Charles H. Daugherty ◽

Stevan R. Phelps

Keyword(s):

Genetic Variation ◽

Gel Electrophoresis ◽

Lake Trout ◽

Lake Superior ◽

Salvelinus Namaycush ◽

Starch Gel Electrophoresis ◽

Average Heterozygosity ◽

Management Implications ◽

Salmonid Species ◽

Starch Gel

Patterns of genetic variation among lake trout (Salvelinus namaycush) of eastern Lake Superior were examined using starch gel electrophoresis. We used 484 individuals sampled from three areas, representing three morphological types (leans, humpers, and siscowets). Of 50 loci examined, 44 were monomorphic in all groups sampled. Genetic variation occurs at six loci AAT-1,2, MDH-3,4, ME-1, and SOD-1. The average heterozygosity found (H = 0.015) is low relative to other salmonid species. A significant amount of heterogeneity exists among the 10 lake trout samples. These differences are due to variation within as well as between morphological types. The significance and management implications of these data are discussed.Key words: genetic variation, lake trout, Salvelinus namaycush, Lake Superior

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Paleohydrology of the upper Laurentian Great Lakes from the late glacial to early Holocene

Quaternary Research ◽

10.1016/j.yqres.2009.01.003 ◽

2009 ◽

Vol 71 (3) ◽

pp. 397-408 ◽

Cited By ~ 25

Author(s):

Andy Breckenridge ◽

Thomas C. Johnson

Keyword(s):

Great Lakes ◽

Lake Michigan ◽

Lake Superior ◽

Late Glacial ◽

Lake Huron ◽

Michigan Basin ◽

Great Lakes Basin ◽

Lake Agassiz ◽

Sharp Drop ◽

Freshwater Fluxes

AbstractBetween 10,500 and 9000 cal yr BP, δ18O values of benthic ostracodes within glaciolacustrine varves from Lake Superior range from − 18 to − 22‰ PDB. In contrast, coeval ostracode and bivalve records from the Lake Huron and Lake Michigan basins are characterized by extreme δ18O variations, ranging from values that reflect a source that is primarily glacial (∼ − 20‰ PDB) to much higher values characteristic of a regional meteoric source (∼ − 5‰ PDB). Re-evaluated age models for the Huron and Michigan records yield a more consistent δ18O stratigraphy. The striking feature of these records is a sharp drop in δ18O values between 9400 and 9000 cal yr BP. In the Huron basin, this low δ18O excursion was ascribed to the late Stanley lowstand, and in the Lake Michigan basin to Lake Agassiz flooding. Catastrophic flooding from Lake Agassiz is likely, but a second possibility is that the low δ18O excursion records the switching of overflow from the Lake Superior basin from an undocumented northern outlet back into the Great Lakes basin. Quantifying freshwater fluxes for this system remains difficult because the benthic ostracodes in the glaciolacustrine varves of Lake Superior and Lake Agassiz may not record the average δ18O value of surface water.

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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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