Historical and contemporary movement and survival rates of walleye (Sander vitreus) in Lake Winnipeg, Canada

2021 ◽  
Author(s):  
Nicole A. Turner ◽  
Colin Charles ◽  
Douglas A. Watkinson ◽  
Eva C. Enders ◽  
Geoff Klein ◽  
...  
Keyword(s):  
Survival Rates ◽  
Sander Vitreus ◽  
Lake Winnipeg

Contrasting strategies of ova lipid provisioning in relation to maternal characteristics in three walleye (Sander vitreus) populations

2007 ◽  
Vol 64 (4) ◽  
pp. 700-712 ◽  
Author(s):  
M D Wiegand ◽  
T A Johnston ◽  
W C Leggett ◽  
K E Watchorn ◽  
A J Ballevona ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Lipid Content ◽  
Maternal Age ◽  
Lake Ontario ◽  
The Other ◽  
Sander Vitreus ◽  
Selection Pressures ◽  
Lake Winnipeg ◽  
Maternal Characteristics ◽  
Nutrient Reserves

We examined how the lipid content and fatty acid composition of walleye (Sander vitreus) ova varied with respect to maternal characteristics, particularly indices of body nutrient reserves, within three spawning populations that varied in maternal age, size, and somatic lipid reserves. We also compared the variability in ova lipid composition among three populations with that observed among spawning years within one of these populations. Maternal characteristics had little influence on ova lipid content. In Lake Ontario, percentages of docosahexaenoic acid (22:6(n-3), DHA) and arachidonic acid (20:4(n-6), AA) increased with maternal length, while those of eicosapentaenoic acid (20:5(n-3), EPA) declined. In Lake Nipissing, maternal age had similar effects on AA and EPA, but not DHA. The Lake Winnipeg population did not conform to the trends of the other two populations, and ova from this population had very low levels of AA. We hypothesize that there are similar selection pressures on the Lake Ontario and Lake Nipissing populations with respect to desirable ova fatty acid profiles. Lake Winnipeg walleye may experience different selection pressures or may be unable to conform to the trends observed in the other two lakes.

Growth rate and condition of walleye (Sander vitreus), sauger (Sander canadensis), and dwarf walleye in a large Canadian lake

2018 ◽  
Vol 96 (7) ◽  
pp. 739-747 ◽  
Author(s):  
K.T. Sheppard ◽  
B.J. Hann ◽  
G.K. Davoren
Keyword(s):  
Dreissena Polymorpha ◽  
Sander Vitreus ◽  
Osmerus Mordax ◽  
Bythotrephes Longimanus ◽  
The South ◽  
Rainbow Smelt ◽  
Lake Winnipeg ◽  
South Basin ◽  
The North ◽  
North And South

The second largest inland walleye (Sander vitreus (Mitchill, 1818)) and sauger (Sander canadensis (Griffith and Smith, 1834)) fishery in Canada is found in Lake Winnipeg, Manitoba. To manage the fishery for a sustainable future, the growth and condition of these fish must be understood. Objectives were to (1) examine baseline growth and condition of walleye and sauger in Lake Winnipeg, (2) evaluate variation between the North and South basins, and (3) contribute observational findings on the distribution of dwarf walleye. Gill nets were set to catch walleye, sauger, and dwarf walleye throughout both basins at various locations and in all seasons during 2010 and 2011. North Basin walleye and sauger had higher growth rates and condition relative to the South Basin. This may be due to differential exploitation rates or diets such as the consumption of invasive rainbow smelt (Osmerus mordax (Mitchell, 1814)) in the North Basin and not in the South Basin. Dwarf walleye were observed more frequently in the South Basin than in the North Basin. Overall, this study provides important baseline data on the growth and condition of walleye and sauger populations prior to invasion of the spiny waterflea (Bythotrephes longimanus Leydig, 1860) and zebra mussels (Dreissena polymorpha (Pallas, 1771)).

Reproductive divergence between growth forms of Lake Winnipeg walleye (Sander vitreus)

2010 ◽  
Vol 20 (1) ◽  
pp. 52-66 ◽  
Author(s):  
M. D. Moles ◽  
T. A. Johnston ◽  
B. W. Robinson ◽  
A. M. Bernard ◽  
C. C. Wilson ◽  
...  
Keyword(s):  
Sander Vitreus ◽  
Growth Forms ◽  
Lake Winnipeg

scholarly journals Morphology and blood metabolites reflect recent spatial and temporal differences among Lake Winnipeg walleye, Sander vitreus

2020 ◽  
Author(s):  
Matt J. Thorstensen ◽  
Lilian M. Wiens ◽  
Jennifer D. Jeffrey ◽  
Geoffrey M. Klein ◽  
Ken M. Jeffries ◽  
...  
Keyword(s):  
Blood Metabolites ◽  
Sander Vitreus ◽  
Lake Winnipeg ◽  
Temporal Differences

scholarly journals Genomic signals found using RNA sequencing support conservation of walleye (Sander vitreus) in a large freshwater ecosystem

2020 ◽  
Author(s):  
Matt J. Thorstensen ◽  
Jennifer D. Jeffrey ◽  
Jason R. Treberg ◽  
Douglas A. Watkinson ◽  
Eva C. Enders ◽  
...  
Keyword(s):  
Rna Sequencing ◽  
Messenger Rna ◽  
Population Genomics ◽  
Large Female ◽  
Population Divergence ◽  
Freshwater Ecosystem ◽  
Sander Vitreus ◽  
Freshwater Species ◽  
Lake Winnipeg ◽  
Outlier Loci

AbstractRNA sequencing is an effective approach for studying an aquatic species with little prior molecular information available, yielding both physiological and genomic data, but its genetic applications are not well-characterized. We investigate this possible role for RNA sequencing for population genomics in Lake Winnipeg, Manitoba, Canada, walleye (Sander vitreus). Lake Winnipeg walleye represent the largest component of the second-largest freshwater fishery in Canada. In the present study, large female walleye were sampled via nonlethal gill biopsy over two years at three spawning sites representing a latitudinal gradient in the lake. Genetic variation from sequenced messenger RNA was analyzed for neutral and adaptive markers to investigate population structure and possible adaptive variation. We find low population divergence (FST = 0.0095), possible northward gene flow, and outlier loci that vary latitudinally in transcripts associated with cell membrane proteins and cytoskeletal function. These results indicate that Lake Winnipeg walleye may be effectively managed as a single demographically connected metapopulation with contributing subpopulations, and suggest genomic differences possibly underlying observed phenotypic differences. Because RNA sequencing data can yield physiological in addition to genetic information discussed here, we argue that it is useful for addressing diverse molecular questions in the conservation of freshwater species.

scholarly journals Morphology and Blood Metabolites Reflect Recent Spatial Differences Among Lake Winnipeg Walleye, Sander vitreus

2020 ◽  
Author(s):  
Matt J. Thorstensen ◽  
Lilian M. Wiens ◽  
Jennifer D. Jeffrey ◽  
Geoffrey M. Klein ◽  
Ken M. Jeffries ◽  
...  
Keyword(s):  
Large Scale ◽  
Fork Length ◽  
Essential Amino Acids ◽  
Relative Mass ◽  
Sander Vitreus ◽  
Rainbow Smelt ◽  
Data Set ◽  
Lake Winnipeg ◽  
Index Data ◽  
The North

AbstractThe invasive rainbow smelt (Osmerus mordax) was an abundant food source for Lake Winnipeg walleye (Sander vitreus), especially in the north basin of the lake, until the smelt’s collapse in approximately 2013. We quantified changing length-at-age (≈ growth rates) and relative mass (≈ body condition) in Lake Winnipeg walleye caught for a gillnet index data set. Here, walleye showed smaller length-at-age, particularly in the north basin with young fish, over time. This approach to assessing growth suggests a constraint in the north basin fish, possibly a nutritional limitation between 2017 and 2018, that was not present in the south. We then analyzed a separate group of walleye (≥452 mm in fork length) sampled in 2017 as part of a large-scale tracking study, which had a similar slope in length-mass relationship to large walleye caught in that year for the gillnet index data. A panel of metabolites associated with amino acid metabolism and protein turnover was compared in whole blood. These metabolites revealed elevated essential amino acids and suggest protein degradation may be elevated in north basin walleye. Therefore, based on both growth estimates and metabolites associated with protein balance, we suggest there were spatially distinct separations affecting Lake Winnipeg walleye with decreased nutritional status of walleye in the north basin of Lake Winnipeg being of particular concern.

scholarly journals Morphological and trophic differentiation of growth morphotypes of walleye (Sander vitreus) from Lake Winnipeg, Canada

2010 ◽  
Vol 88 (10) ◽  
pp. 950-960 ◽  
Author(s):  
M. D. Moles ◽  
B. W. Robinson ◽  
T. A. Johnston ◽  
R. A. Cunjak ◽  
T. D. Jardine ◽  
...  
Keyword(s):  
Life History ◽  
Normal Form ◽  
Isotope Analysis ◽  
Normal Growth ◽  
Fish Populations ◽  
Sander Vitreus ◽  
Growth Forms ◽  
Resource Polymorphism ◽  
Lake Winnipeg ◽  
Juvenile Habitat

Ecologically related polymorphisms occur in many northern freshwater fish populations and are distinguished by alternate phenotypes consistently associated with differential use of habitats or resources. We tested for polymorphism in walleye (Sander vitreus (Mitchill, 1818)) in the south basin of Lake Winnipeg, where evidence suggests that “dwarf” and “normal” growth forms may coexist. Morphometric comparisons of these growth forms at similar size demonstrated significant differences in the relative sizes of head, snout, eye, and mouth, collectively suggesting dwarf individuals inhabit a more benthic niche than normal morphs. Stable isotope analysis did not support this morphometric interpretation, however, as δ13C and δ15N isotope signatures were similar between similar-sized individuals of both forms, but differed from those of large normal walleye. Walleye from Lake Winnipeg do not seem to exhibit a simple resource polymorphism where different ecotypes are associated with alternate habitats throughout their life history, nor do they exhibit characteristics of a simple mating polymorphism. We suggest the walleye from Lake Winnipeg represent two growth forms sharing a common juvenile habitat followed by the normal form shifting into an alternative adult niche.

Ultrastructural Changes in Three Different Mammalian Cells Following Ultraviolet Laser Irradiation

1972 ◽  
Vol 30 ◽  
pp. 350-351
Author(s):  
K. Shankar Narayan ◽  
Kailash C. Gupta ◽  
Tohru Okigaki
Keyword(s):  
Ultraviolet Light ◽  
Mammalian Cells ◽  
Biological Effects ◽  
Survival Rates ◽  
Chinese Hamster ◽  
Cell Types ◽  
Differential Sensitivity ◽  
Ultrastructural Changes ◽  
Ultraviolet Laser

The biological effects of short-wave ultraviolet light has generally been described in terms of changes in cell growth or survival rates and production of chromosomal aberrations. Ultrastructural changes following exposure of cells to ultraviolet light, particularly at 265 nm, have not been reported.We have developed a means of irradiating populations of cells grown in vitro to a monochromatic ultraviolet laser beam at a wavelength of 265 nm based on the method of Johnson. The cell types studies were: i) WI-38, a human diploid fibroblast; ii) CMP, a human adenocarcinoma cell line; and iii) Don C-II, a Chinese hamster fibroblast cell strain. The cells were exposed either in situ or in suspension to the ultraviolet laser (UVL) beam. Irradiated cell populations were studied either "immediately" or following growth for 1-8 days after irradiation.Differential sensitivity, as measured by survival rates were observed in the three cell types studied. Pattern of ultrastructural changes were also different in the three cell types.

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