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

2005 ◽  
Vol 62 (10) ◽  
pp. 2254-2264 ◽  
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·m–2) were twice those in Lake Champlain or Parry Sound (6 ± 1 predators·m–2). Densities of eggs were higher in Lake Champlain (2994.1 ± 398.3 eggs·m–2) 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·predator–1·m–2. Ratios may help establish target egg densities for restoration efforts and the concentration of spawning adults required to allow survival to the fry stage.

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

1985 ◽  
Vol 42 (4) ◽  
pp. 737-743 ◽  
Author(s):  
William H. Horns
Keyword(s):  
Great Lakes ◽  
Lake Michigan ◽  
Lake Trout ◽  
Lake Superior ◽  
Relevant Information ◽  
Salvelinus Namaycush ◽  
The Other ◽  
Morphological Development ◽  
Green Lake ◽  
The Times

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.

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.

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

1980 ◽  
Vol 37 (11) ◽  
pp. 1989-2006 ◽  
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

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.

Effects of coancestry on accuracy of individual assignments to population of origin: examples using Great Lakes lake trout (Salvelinus namaycush)

Genetica ◽  
2006 ◽  
Vol 127 (1-3) ◽  
pp. 329-340 ◽  
Author(s):  
Bruno Guinand ◽  
Kim T. Scribner ◽  
Kevin S. Page ◽  
Kristi Filcek ◽  
Laura Main ◽  
...  
Keyword(s):  
Great Lakes ◽  
Lake Trout ◽  
Salvelinus Namaycush

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

1980 ◽  
Vol 37 (11) ◽  
pp. 2133-2145 ◽  
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

Paenibacillus thiaminolyticus is not the cause of thiamine deficiency impeding lake trout (Salvelinus namaycush) recruitment in the Great Lakes

2012 ◽  
Vol 69 (6) ◽  
pp. 1056-1064 ◽  
Author(s):  
Catherine A. Richter ◽  
Allison N. Evans ◽  
Maureen K. Wright-Osment ◽  
James L. Zajicek ◽  
Scott A. Heppell ◽  
...  
Keyword(s):  
Great Lakes ◽  
Thiamine Deficiency ◽  
Lake Trout ◽  
Bacterial Species ◽  
Primary Source ◽  
Salvelinus Namaycush ◽  
Trophic Levels ◽  
Thiaminase I ◽  
Global Concern ◽  
Paenibacillus Thiaminolyticus

Thiamine (vitamin B1) deficiency is a global concern affecting wildlife, livestock, and humans. In Great Lakes salmonines, thiamine deficiency causes embryo mortality and is an impediment to restoration of native lake trout ( Salvelinus namaycush ) stocks. Thiamine deficiency in fish may result from a diet of prey with high levels of thiaminase I. The discoveries that the bacterial species Paenibacillus thiaminolyticus produces thiaminase I, is found in viscera of thiaminase-containing prey fish, and causes mortality when fed to lake trout in the laboratory provided circumstantial evidence implicating P. thiaminolyticus. This study quantified the contribution of P. thiaminolyticus to the total thiaminase I activity in multiple trophic levels of Great Lakes food webs. Unexpectedly, no relationship between thiaminase activity and either the amount of P. thiaminolyticus thiaminase I protein or the abundance of P. thiaminolyticus cells was found. These results demonstrate that P. thiaminolyticus is not the primary source of thiaminase activity affecting Great Lakes salmonines and calls into question the long-standing assumption that P. thiaminolyticus is the source of thiaminase in other wild and domestic animals.

New insight into the spawning behavior of lake trout, Salvelinus namaycush, from a recovering population in the Laurentian Great Lakes

2014 ◽  
Vol 98 (1) ◽  
pp. 173-181 ◽  
Author(s):  
T. R. Binder ◽  
H. T. Thompson ◽  
A. M. Muir ◽  
S. C. Riley ◽  
J. E. Marsden ◽  
...  
Keyword(s):  
Great Lakes ◽  
Lake Trout ◽  
Salvelinus Namaycush ◽  
Laurentian Great Lakes ◽  
Spawning Behavior ◽  
Insight Into
Sign in / Sign up

Export Citation Format

Share Document