Vulnerability of Arctic Zooplankton Species to Predation by Small Lake Trout (Salvelinus namaycush)

1978 ◽  
Vol 35 (11) ◽  
pp. 1495-1500 ◽  
Author(s):  
Dean Kettle ◽  
W. John O'Brien
Keyword(s):  
Key Words ◽  
Lake Trout ◽  
Salvelinus Namaycush ◽  
Zooplankton Species ◽  
Small Lake ◽  
Visual Predation ◽  
Reactive Distance

The susceptibility of arctic zooplankton species to small lake trout (Salvelinus namaycush) was investigated by measuring both the reactive distance of fish to prey and the success with which prey were captured. Species common to ponds without fish were found to be more vulnerable to lake trout than lake species, several of which appear to have developed adaptations to reduce visual predation. Key words: lake trout, zooplankton, predation, reactive distance

Fecundity Changes in Exploited Populations of Lake Whitefish (Coregonus clupeaformis) and Lake Trout (Salvelinus namaycush)

1978 ◽  
Vol 35 (7) ◽  
pp. 945-950 ◽  
Author(s):  
M. C. Healey
Keyword(s):  
Key Words ◽  
Lake Trout ◽  
Salvelinus Namaycush ◽  
Coregonus Clupeaformis ◽  
Lake Whitefish ◽  
Northern Canada ◽  
Average Fecundity ◽  
Individual Fecundity

This report considers the possibility that exploited populations of lake whitefish (Coregonus clupeaformis) and lake trout (Salvelinus namaycush) may show increased individual fecundity. Average fecundity of both species in three exploited lakes varied significantly between 1972 and 1976, while fecundity in an adjacent unexploited lake did not vary. Changes in the fecundity of whitefish and trout in the exploited lakes were not clearly related to the pattern and intensity of exploitation, but fecundity of both species increased in all exploited lakes after exploitation, with trout showing the greater response. Key words: fecundity, lake whitefish, lake trout, exploitation, northern Canada

Joint Segregation of Biochemical Loci in Salmonidae: Results from Experiments with Salvelinus and Review of the Literature on Other Species

1979 ◽  
Vol 36 (9) ◽  
pp. 1114-1128 ◽  
Author(s):  
Bernie May ◽  
James E. Wright ◽  
Mark Stoneking
Keyword(s):  
Key Words ◽  
Brook Trout ◽  
Lake Trout ◽  
Salvelinus Namaycush ◽  
Pairwise Comparisons ◽  
Duplicate Genes ◽  
Single Pair ◽  
Review Of The Literature ◽  
Uniform System ◽  
Joint Segregation

An extensive survey of joint segregation is described involving 37 pairwise comparisons of 12 biochemical loci in 11 single pair matings of brook trout (Salvelinus fonlinalis) and 38 pairwise comparisons of 9 loci in an F1 splake (lake trout, Salvelinus namaycush × brook trout) backcross to brook trout mating. We report pseudolinkage of two duplicated malate dehydrogenase loci (MDH-3 and MDH-4) and statistically highly significant nonrandom segregation of MDH-1 with an alphaglycerophosphate dehydrogenase locus (AGP-1). Several additional cases of aberrant joint segregation are described. All known examinations of joint segregation in Salmonidae are reviewed. A uniform system of nomenclature and guidelines for future investigations are discussed. Key words: joint segregation, brook trout, splake hybrid, inheritance, electrophoresis, pseudolinkage, duplicate-genes

scholarly journals Food Web Structure Informs Potential Causes of Bimodal Size Structure in a Top Predator

2018 ◽  
Vol 11 (1) ◽  
pp. 36-45 ◽  
Author(s):  
Peter C. Searle ◽  
Joshua A. Verde ◽  
Mark C. Belk
Keyword(s):  
Body Size ◽  
Yellow Perch ◽  
Lake Trout ◽  
Large Body ◽  
Somatic Growth ◽  
Salvelinus Namaycush ◽  
Trophic Niche ◽  
Competitive Interactions ◽  
Large Body Size ◽  
Small Lake

Background: Assemblages of fishes in lakes and reservoirs in the western USA are dominated by non-native, large-bodied, piscivorous fishes that lack a shared evolutionary history. Top predators in these crowded systems are often characterized by unstable population dynamics and poor somatic growth rates. One such assemblage is in Fish Lake, located in southern Utah, USA, in which introduced lake trout (Salvelinus namaycush, Walbaum) exhibit a bimodal growth pattern. A few lake trout in Fish Lake grow rapidly to large size typical of the species; whereas, most never grow beyond 600 mm total length. Objective: To inform competitive interactions in this evolutionarily novel fish assemblage that might cause the low recruitment to large body size in lake trout, we characterized trophic niche (from stable isotope analysis of C and N) of all fishes in the lake. Methods: We used a Bayesian mixing model to describe the trophic niche and infer diet of lake trout and their potential prey, and we used Bayesian ellipse analysis to identify potential areas of high competition within the food web. Large lake trout feed mostly on small lake trout and splake (Salvelinus namaycush, Walbaum x Salvelinus fontinalis, Mitchill) despite availability of abundant yellow perch. (Perca flavescens, Mitchill). Small lake trout and splake feed mostly on zooplankton and exhibit substantial overlap of their trophic niche implying competition for food. Yellow perch and Utah chub (Gila atraria, Girard; formerly an important food item for lake trout in Fish Lake) exhibit extreme overlap of their trophic niche implying strong competitive interactions. Results: Our data suggest that lack of recruitment to large body size in lake trout may result from a reduction in availability of Utah chub resulting from competitive interactions with yellow perch, and increased competition from introduced splake for available prey. Conclusion: Management actions that may help ameliorate the poor somatic growth rates of most lake trout include efforts to reduce perch populations or increase vulnerability of perch to predation by lake trout, and removal of splake as a competitor of small lake trout.

Effects of large lake trout (Salvelinus namaycush) on the dietary habits of small lake trout: a comparison of stable isotopes (δ15N and δ13C) and stomach content analyses

Hydrobiologia ◽  
2006 ◽  
Vol 579 (1) ◽  
pp. 175-185 ◽  
Author(s):  
Matthew D. Keyse ◽  
Kenneth Fortino ◽  
Anne E. Hershey ◽  
W. John O’Brien ◽  
Philip W. Lienesch ◽  
...  
Keyword(s):  
Stable Isotopes ◽  
Stomach Content ◽  
Dietary Habits ◽  
Lake Trout ◽  
Salvelinus Namaycush ◽  
Large Lake ◽  
Small Lake ◽  
Content Analyses ◽  
Δ15n And Δ13c

Evidence of successful river spawning by lake trout (Salvelinus namaycush) in the Lower Niagara River, Lake Ontario

2021 ◽  
Author(s):  
Alexander Gatch ◽  
Dimitry Gorsky ◽  
Zy Biesinger ◽  
Eric Bruestle ◽  
Kelley Lee ◽  
...  
Keyword(s):  
Lake Trout ◽  
Lake Ontario ◽  
Salvelinus Namaycush ◽  
Niagara River

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

Impact of Diet on Metabolism and Swimming Performance in Juvenile Lake Trout, Salvelinus namaycush

1989 ◽  
Vol 46 (3) ◽  
pp. 384-388 ◽  
Author(s):  
F. W. H. Beamish ◽  
J. C. Howlett ◽  
T. E. Medland
Keyword(s):  
Oxygen Consumption ◽  
Swimming Speed ◽  
Lake Trout ◽  
Swimming Performance ◽  
Salvelinus Namaycush ◽  
Feeding Trial ◽  
Direct Association ◽  
Feeding Trials ◽  
Velocity Increments ◽  
Isocaloric Diets

Juvenile lake trout, Salvelinus namaycush, of similar size were fed one of three isocaloric diets, each differing in protein and lipid content. Oxygen consumption and swimming performance were measured in a recirculating water flume at intervals throughout the 70-d feeding trials (10 °C). Swimming speed was increased by stepwise velocity increments (5 cm∙s−1) and oxygen consumption was measured at each velocity between 20 and 45 cm∙s−1. Oxygen consumption for a given speed did not differ significantly throughout the feeding trial nor among the diets implying a similarity in the quality and quantity of substrate catabolized for energy. Basal metabolism (0 cm∙s−1) was also independent of diet and feeding interval. Critical swimming speed increased with dietary and carcass protein content to suggest a direct association with muscle mass and number of myofilaments.

Land water linkages: influences of riparian deforestation on lake thermocline depth and possible consequences for cold stenotherms

1997 ◽  
Vol 54 (6) ◽  
pp. 1299-1305 ◽  
Author(s):  
Robert France
Keyword(s):  
Thermal Stratification ◽  
Lake Trout ◽  
Salvelinus Namaycush ◽  
Thermocline Depth ◽  
Experimental Lakes Area ◽  
Northwestern Ontario ◽  
Riparian Trees ◽  
Tree Removal ◽  
Riparian Tree ◽  
Land Water

The purpose of the present study was to determine if riparian deforestation would expose lake surfaces to stronger winds and therefore bring about deepening of thermoclines and resulting habitat losses for cold stenotherms such as lake trout (Salvelinus namaycush). Removal of protective riparian trees through wind blowdown and two wildfires was found to triple the overwater windspeeds and produce thermocline deepening in two lakes at the Experimental Lakes Area. A survey of thermal stratification patterns in 63 northwestern Ontario lakes showed that lakes around which riparian trees had been removed a decade before through either clearcutting or by a wildfire were found to have thermocline depths over 2 m deeper per unit fetch length compared with lakes surrounded by mature forests. Riparian tree removal will therefore exacerbate hypolimnion habitat losses for cold stenotherms that have already been documented to be occurring as a result of lake acidification, eutrophication, and climate warming.

scholarly journals Genetic and phenotypic variation along an ecological gradient in lake trout Salvelinus namaycush

2016 ◽  
Vol 16 (1) ◽  
Author(s):  
Shauna M. Baillie ◽  
Andrew M. Muir ◽  
Michael J. Hansen ◽  
Charles C. Krueger ◽  
Paul Bentzen
Keyword(s):  
Phenotypic Variation ◽  
Lake Trout ◽  
Salvelinus Namaycush ◽  
Ecological Gradient
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