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.

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.

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.

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.

scholarly journals Appraising the Status of Fish Community Structure in the Yellow Sea Based on an Indicator-Testing Framework

2021 ◽  
Vol 8 ◽  
Author(s):  
Yuru Li ◽  
Shuyang Ma ◽  
Caihong Fu ◽  
Yongjun Tian ◽  
Jianchao Li ◽  
...  
Keyword(s):  
Climate Change ◽  
Fisheries Management ◽  
Fish Community ◽  
Large Scale ◽  
The Yellow Sea ◽  
Total Catch ◽  
Fish Community Structure ◽  
Testing Framework ◽  
The Status ◽  
Ecosystem Based Fisheries Management

Fish community structure (FCS) of the Yellow Sea (YS) is affected by multiple pressures. Quantifying the responses of indicators of FCS (IFCSs) to pressures is a key aspect of ecosystem-based fisheries management. Quantitative methodology has hitherto been rarely applied to evaluate the performance of ecological indicators in response to physical and anthropogenic pressures and management actions. In this study, we adopted a quantitative and flexible framework to quantify the performance of IFCSs in the YS as well as to identify a suite of operational IFCSs to evaluate the status of the FCS via two state-space approaches. A total of 22 IFCSs were tested for their responses to three types of pressures including anthropogenic activities (fishing), large-scale climate change, and regional environmental variables. Our results indicate that the majority of IFCSs have good performance in terms of sensitivity in their responses to pressures, but weak performance in terms of robustness. The IFCSs tend to respond stronger to fishing than to large-scale climatic indices and regional environmental indices both in terms of sensitivity and robustness. A final indicator suite of five best-performing IFCSs was identified. The five IFCSs include total catch (ToC), mean trophic level (MTL), the ratio of catch of large predatory groups to total catch (LPC/ToC), mean temperature of catch (MTC) [or alternatively catch of small pelagic groups (SPC)], and functional evenness based on thermal groups (T-J′FD), all of which show regime shift patterns consistent with climate change. Compared to a reference period (1960–1964), the status of the current FCS has been obviously changed, and the long-term trajectories of the final indicator suite is consistent with that of fishing pressure. This study demonstrates the applicability of the indicator-testing framework in appraising the status of FCS, and facilitates moving towards ecosystem-based fisheries management in the YS.

Changes in the Georgian Bay fish community, with special reference to lake trout (Salvelinus namaycush) rehabilitation

Hydrobiologia ◽  
1988 ◽  
Vol 163 (1) ◽  
pp. 179-194 ◽  
Author(s):  
Bryan A. Henderson ◽  
N. Robert Payne
Keyword(s):  
Special Reference ◽  
Fish Community ◽  
Lake Trout ◽  
Salvelinus Namaycush ◽  
Georgian Bay

Dynamics in Year-Class Strength, Growth, and Calcified-Structure Size of Native Lake Trout (Salvelinus namaycush) Exposed to Moderate Acidification and Whole-Lake Neutralization

1992 ◽  
Vol 49 (S1) ◽  
pp. 102-113 ◽  
Author(s):  
John M. Casselman ◽  
John M. Gunn
Keyword(s):  
Water Quality ◽  
Direct Effect ◽  
Lake Trout ◽  
Calcium Content ◽  
Salvelinus Namaycush ◽  
Ambient Water ◽  
Intraspecific Interaction ◽  
Relative Growth ◽  
Class Strength

Accurate age-interpretation techniques were developed, using scales and otoliths, to examine the role of whole-lake neutralization in the resurgence of a lake trout (Salvelinus namaycush) fishery in Nelson Lake (pH 5.7) near Sudbury, Ontario. Calcified structures and data from 860 lake trout were collected from 1972 to 1987. The population was characterized by the regular cyclic occurrence of strong year classes, which were probably an effect of pulse angling, cyclic food abundance, and possibly intraspecific interaction. The majority (65.8%) of the lake trout caught in the exceptional winter fishery of 1980 (3.3 kg∙ha−1) were in the lake prior to liming in 1975–76. Young lake trout (up to age 4) of the 1975 and 1976 year classes grew bigger and had larger scales than other year classes from 1973 to 1977, coinciding with an increase in hypolimnetic zooplankton, probably related to improved water quality. Otoliths grew significantly larger and more translucent and exceeded relative growth of scales and body for all ages in 1976 (18% greater) and for the 1976 year class, confirming that otolith accretion can come from the ambient water because liming increased the calcium content by 33% that year, the only observed direct effect of the treatment.

Predation by Freshwater Seals on the Fish Community of Lower Seal Lake, Quebec

1978 ◽  
Vol 35 (6) ◽  
pp. 844-850 ◽  
Author(s):  
G. Power ◽  
Jean Gregoire
Keyword(s):  
Brook Trout ◽  
Fish Community ◽  
Lake Trout ◽  
Fork Length ◽  
Salvelinus Namaycush ◽  
Phoca Vitulina ◽  
Unit Weight ◽  
Potential Yield ◽  
Spawning Period ◽  
Show Evidence

The presence of freshwater harbor seals (Phoca vitulina) in Lower Seal Lake, Quebec, has drastically modified the lake's fish community. Lake trout (Salvelinus namaycush) are the most affected; they are small (rarely exceed 55 cm fork length), their growth rate is faster than in neighboring lakes, their longevity is greatly reduced, the age at sexual maturity has been halved, and individual fecundity per unit weight has increased at the expense of egg diameter. Brook trout (S. fontinalis), the dominant fish species in the lake, show evidence of high mortality rates in the lake, but are protected during the vulnerable spawning period because their spawning sites are dispersed in tributary streams. Rough calculation suggests the seal population is small and that it consumes the lake's potential yield of fish annually. Key words: predation, freshwater seals, Phoca vitulina, Salvelinus namaycush, Salvelinus fontinalis

scholarly journals Assessment of fish community structure along the Jakarta Bay–Pulau Seribu reef complex

2018 ◽  
Vol 99 (2) ◽  
pp. 503-516
Author(s):  
A.R.M. Polónia ◽  
D.F.R. Cleary ◽  
A.A. Duine ◽  
J. Van Dijk ◽  
N.J. De Voogd
Keyword(s):  
Remote Sensing ◽  
Water Quality ◽  
Community Structure ◽  
Fish Community ◽  
Remotely Sensed ◽  
Fish Biomass ◽  
Fish Community Structure ◽  
Remotely Sensed Data ◽  
Poor Water Quality ◽  
Reef Degradation

Coastal ecosystems have been increasingly subjected to poor water quality. Remote sensing has been used to monitor water quality, but few studies have integrated remotely sensed data with compositional and/or abundance data of coral reef taxa. In the present study, fish biomass was assessed along the Jakarta Bay Thousand Island reef system and variation in the biomass of selected fish families related to substrate cover and remotely sensed data. Overall, fish biomass and the biomass of each of the families Acanthuridae, Apogonidae, Caesionidae, Chaetodontidae, Ephippidae, Pomacentridae, Labridae and the subfamily Scaridae were much higher mid- and offshore than inshore. Substrate cover and chlorophyll-a concentrations proved to be significant predictors of spatial variation in fish biomass, suggesting an important impact of reef degradation and eutrophication on reef fish abundance.

Recovery of Planted Brook Trout, Splake, and Rainbow Trout from Selected Ontario Lakes

1972 ◽  
Vol 29 (2) ◽  
pp. 129-142 ◽  
Author(s):  
J. M. Fraser
Keyword(s):  
Rainbow Trout ◽  
Brook Trout ◽  
Fish Community ◽  
Lake Trout ◽  
Salvelinus Namaycush ◽  
Low Fertility ◽  
Salmo Gairdneri ◽  
White Sucker ◽  
The Mean ◽  
Brook Stickleback

Recoveries of hatchery-reared brook trout (Salvelinus fontinalis), splake (Salvelinus namaycush × S. fontinalis), and rainbow trout (Salmo gairdneri), planted in lakes having different resident fishes, were highest (9–30%) in a lake in which minnows and the brook stickleback were the only other fishes. Recoveries, by angling and gillnetting, were considerably lower (2–15%) in two lakes containing the white sucker and minnows, and still lower (0.5–5%,) in two lakes containing spiny-rayed species as well. Recoveries were lowest (< 0.5%) in a lake having a complex fish community that included native brook and lake trout. Planted splake and rainbow trout generally yielded higher returns, in weight, than brook trout in comparable situations.The low survival of planted fish was apparently due to the low fertility of the waters and to competition with, or predation by, resident fish species. Predation by fish-eating birds and mammals may also have had an effect.The weight of the catch of salmonids exceeded the weight planted in only one lake. Here, the mean yield of planted salmonids was 8.4 kg/ha per year in comparison with 2.6 to < 0.5 kg/ha per year in the five other study lakes.

Sign in / Sign up

Export Citation Format

Share Document