Size Structure of a Lake Trout (Salvelinus namaycush) Population an Arctic Lake: Influence of Angling and Implications for Fish Community Structure

1989 ◽  
Vol 46 (12) ◽  
pp. 2153-2156 ◽  
Author(s):  
Michael E. McDonald ◽  
Anne E. Hershey
Keyword(s):  
Community Structure ◽  
Fish Community ◽  
Lake Trout ◽  
Size Structure ◽  
Salvelinus Namaycush ◽  
Fish Community Structure ◽  
Median Length ◽  
Arctic Alaska ◽  
Gill Net ◽  
Toolik Lake

The lake trout (Salvelinus namaycush) population in Toolik Lake in arctic Alaska was assessed by gill net during 1977, prior to exploitation. In 1986 we replicated the gill net study to determine the effects of recent angling pressure on the fish community. Relative composition of the catch varied between samples. Round whitefish (Prosopium cylindraceum), which are not susceptible to angling, made up 42% of the catch in 1986 and 28% in 1977. Significant reductions in the median length and weight of lake trout between the sampling periods were observed. The median size of lake trout in 1986 was below the minimum 1977 reproductive size. Differences in median length and weight of grayling (Thymallus arcticus) and of round whitefish during this period were not significantly different. The condition factor of lake trout was significantly higher in 1986. We suggest that large lake trout in Toolik Lake control salmonid recruitment and determine community structure. With continued fishing pressure further changes in the fish community and lake trophic dynamics may result.

Evaluation of the Effects of Fish Community Structure on Observed Yields of Lake Trout (Salvelinus namaycush)

1987 ◽  
Vol 44 (S2) ◽  
pp. s239-s248 ◽  
Author(s):  
C. I. Goddard ◽  
D. H. Loftus ◽  
J. A. MacLean ◽  
C. H. Olver ◽  
B. J. Shuter
Keyword(s):  
Community Structure ◽  
Fish Community ◽  
Lake Trout ◽  
Salvelinus Namaycush ◽  
Lake Area ◽  
Fish Community Structure ◽  
Extrinsic Factors ◽  
Potential Yield ◽  
Factors Affecting ◽  
Intrinsic Factors

Creel and lake survey data from 87 Ontario lakes with self-sustaining lake trout (Salvelinus namaycush) populations were analysed to determine the effect of intrinsic factors, such as fish community structure, and extrinsic factors, such as angling-effort, on the observed yields of lake trout. Multiple regression analyses showed that angling-effort and lake area, in order of importance, explained almost 82% of the variation in annual catches. Analyses of covariance were used to test a variety of hypotheses about how community structure — the presence of forage, competitors, or alternate sports species — affected the catch of lake trout. No significant differences among groups were detected, which suggests that fish community structure has little or no effect on actual yield of lake trout. The difficulties inherent in using catch and effort data alone to evaluate the importance of factors affecting productivity (or potential yield) are discussed.

Changes in the Zoobenthos Community of Acidified Bowland Lake after Whole-Lake Neutralization and Lake Trout (Salvelinus namaycush) Reintroduction

1990 ◽  
Vol 47 (2) ◽  
pp. 440-445 ◽  
Author(s):  
W. Keller ◽  
Lewis A. Molot ◽  
Ronald W. Griffiths ◽  
N. D. Yan
Keyword(s):  
Water Quality ◽  
Fish Community ◽  
Lake Trout ◽  
Size Structure ◽  
Salvelinus Namaycush ◽  
Total Abundance ◽  
Insufficient Time

The zoobenthos of Bowland Lake is described prior to, and for 2 yr after, neutralization of the lake from pH 4.9 to > 6.0 and reintroduction of lake trout (Salvelinus namaycush). Observed changes in the total abundance, biomass, and size structure of shallow and profundal zoobenthos assemblages were attributable to changes in the fish community, not to improvements in water quality. A shift toward increased importance of oligochaetes, more representative of nonacidic conditions, occurred. However, many common, acid-sensitive taxa of zoobenthos which were absent prior to neutralization had not appeared within 2 yr after treatment, indicating insufficient time for recolonization.

Prediction of Lake Trout (Salvelinus namaycush) Presence in Low-Alkalinity Lakes near Sudbury, Ontario

1992 ◽  
Vol 49 (S1) ◽  
pp. 95-101 ◽  
Author(s):  
Michael Conlon ◽  
John M. Gunn ◽  
J. Robert Morris
Keyword(s):  
Water Quality ◽  
Fish Community ◽  
Acidic Deposition ◽  
Lake Trout ◽  
Salvelinus Namaycush ◽  
Species Assemblages ◽  
Fish Community Structure ◽  
The Status ◽  
Measured Water ◽  
Correct Discrimination

Surveys of 30 low-alkalinity lake trout (Salvelinus namaycush) lakes near Sudbury, Ontario, were conducted to assess factors that affect lake trout presence under acidification stress. At the time of the surveys the lakes varied widely in pH (4.5–6.9), concentrations of toxic metals (Al 12–300 μg∙L−1), and the status of lake trout populations (extinct–abundant). Fish community structure (species richness, species assemblages) reflected and was readily predicted from measured water quality variables. A PCA factor composed of pH, alkalinity, and conductivity was the variable that best predicted lake trout presence (correct discrimination (> 92%). The results of this study provide managers with easily obtainable predictors for monitoring lake trout status under changing levels of acidic deposition.

Consequences of prey fish community dynamics on lake trout (Salvelinus namaycush) foraging efficiency in Lake Superior

1998 ◽  
Vol 55 (5) ◽  
pp. 1273-1284 ◽  
Author(s):  
Doran M Mason ◽  
Timothy B Johnson ◽  
James F Kitchell
Keyword(s):  
Fish Community ◽  
Community Dynamics ◽  
Lake Trout ◽  
Size Structure ◽  
Lake Superior ◽  
Salvelinus Namaycush ◽  
Foraging Efficiency ◽  
Prey Fish ◽  
Rainbow Smelt ◽  
Lake Herring

We used a size-structured model, indexed by age, that combines bioenergetics and foraging theory to evaluate the effects of prey fish community structure (species dominance, size structure, and density) on the diet and net foraging efficiency of lake trout (Salvelinus namaycush) in Lake Superior. Prey size structure was important for young lake trout but decreased in importance for older lake trout, especially with increasing prey density. The model predicted that rainbow smelt (Osmerus mordax) should dominate the diet of young lake trout due to the size-dependent capture limitations of larger prey. In contrast, lake herring (Coregonus artedi) should dominate the diet of oldest lake trout owing to a higher net energy return than rainbow smelt. Model results are consistent with age-specific diet and size-at-age of lake trout during the last 40 years. Diets of intermediate-sized lake trout do not reflect the recent resurgence of lake herring populations. Absence of a dietary switch is probably due to higher capture probability for rainbow smelt. Lake trout growth and production will likely be highest with a mixed prey species assemblage of young rainbow smelt and older lake herring.

Fish community structure, habitat complexity, and soundscape characteristics of patch reefs in a tropical, back-reef system

2019 ◽  
Vol 609 ◽  
pp. 33-48 ◽  
Author(s):  
RP Lyon ◽  
DB Eggleston ◽  
DR Bohnenstiehl ◽  
CA Layman ◽  
SW Ricci ◽  
...  
Keyword(s):  
Community Structure ◽  
Habitat Complexity ◽  
Fish Community ◽  
Back Reef ◽  
Fish Community Structure ◽  
Patch Reefs ◽  
Reef System

Dissolved oxygen and temperature best predict deep-sea fish community structure in the Gulf of California with climate change implications

2020 ◽  
Vol 637 ◽  
pp. 159-180
Author(s):  
ND Gallo ◽  
M Beckwith ◽  
CL Wei ◽  
LA Levin ◽  
L Kuhnz ◽  
...  
Keyword(s):  
Climate Change ◽  
Community Structure ◽  
Community Composition ◽  
Environmental Conditions ◽  
Deep Sea ◽  
Gulf Of California ◽  
Fish Community ◽  
Demersal Fish ◽  
Fish Community Structure ◽  
Explained Variance

Natural gradient systems can be used to examine the vulnerability of deep-sea communities to climate change. The Gulf of California presents an ideal system for examining relationships between faunal patterns and environmental conditions of deep-sea communities because deep-sea conditions change from warm and oxygen-rich in the north to cold and severely hypoxic in the south. The Monterey Bay Aquarium Research Institute (MBARI) remotely operated vehicle (ROV) ‘Doc Ricketts’ was used to conduct seafloor video transects at depths of ~200-1400 m in the northern, central, and southern Gulf. The community composition, density, and diversity of demersal fish assemblages were compared to environmental conditions. We tested the hypothesis that climate-relevant variables (temperature, oxygen, and primary production) have more explanatory power than static variables (latitude, depth, and benthic substrate) in explaining variation in fish community structure. Temperature best explained variance in density, while oxygen best explained variance in diversity and community composition. Both density and diversity declined with decreasing oxygen, but diversity declined at a higher oxygen threshold (~7 µmol kg-1). Remarkably, high-density fish communities were observed living under suboxic conditions (<5 µmol kg-1). Using an Earth systems global climate model forced under an RCP8.5 scenario, we found that by 2081-2100, the entire Gulf of California seafloor is expected to experience a mean temperature increase of 1.08 ± 1.07°C and modest deoxygenation. The projected changes in temperature and oxygen are expected to be accompanied by reduced diversity and related changes in deep-sea demersal fish communities.

Keystone species of fish community structure in the Bohai Sea

2018 ◽  
Vol 25 (2) ◽  
pp. 229
Author(s):  
Zhongyi LI ◽  
Qiang WU ◽  
Xiujuan SHAN ◽  
Tao YANG ◽  
Fangqun DAI ◽  
...  
Keyword(s):  
Community Structure ◽  
Fish Community ◽  
Bohai Sea ◽  
Keystone Species ◽  
Fish Community Structure ◽  
The Bohai Sea
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