Factors affecting the growth and condition of lake whitefish (Coregonus clupeaformis)

2009 ◽  
Vol 66 (12) ◽  
pp. 2096-2108 ◽  
Author(s):  
Michael D. Rennie ◽  
W. Gary Sprules ◽  
Timothy B. Johnson
Keyword(s):  
Growth Rates ◽  
Environmental Variables ◽  
Comprehensive Evaluation ◽  
Early Growth ◽  
Coregonus Clupeaformis ◽  
Lake Whitefish ◽  
Catch Per Unit Effort ◽  
Factors Affecting ◽  
Biological Variables ◽  
Alternative Hypotheses

Though declines in the growth and condition of Great Lakes lake whitefish ( Coregonus clupeaformis ) have been largely attributed to food web disruptions caused by invasive dreissenid mussels, a comprehensive evaluation of alternative hypotheses is currently lacking. Using various statistical approaches, we evaluated 69 years of data from the inner basin of South Bay, Lake Huron, considering the role of biological variables (food availability as Diporeia abundance and lake whitefish relative abundance as catch per unit effort, CPUE) versus environmental variables (climate change as growing degree days >5 °C and productive habitat capacity as percent epilimnetic volume, EV) on the condition and early growth rates of resident lake whitefish. Consistently, biological variables (Diporeia abundance, CPUE) best explained changes in lake whitefish growth and condition, respectively, in years when Diporeia data were available. In their absence, environmental variables (EV) best explained early growth rates of lake whitefish, whereas CPUE again best explained lake whitefish condition. Our analysis revealed that environmental change contributed significantly but alone was not sufficient to explain declines in lake whitefish growth after dreissenid establishment, whereas biological variables considered here could account for the majority of growth and condition changes observed in this population.

Recent Rapid Climate Changes in Antarctic and their Influence on Low Diversity Ecosystems

2010 ◽  
Vol 17 (1) ◽  
pp. 17-30 ◽  
Author(s):  
Katarzyna J. Chwedorzewska
Keyword(s):  
Environmental Variables ◽  
Climate Changes ◽  
Biological Significance ◽  
Global Changes ◽  
Factors Affecting ◽  
Low Diversity ◽  
Main Factors ◽  
The Antarctic ◽  
High Diversity ◽  
Temperature Water

ABSTRACTThe geographic position, astronomic factors (e.g. the Earth’s maximum distance from the Sun during winter), ice cover and altitude are the main factors affecting the climate of the Antarctic, which is the coldest place on Earth. Parts of Antarctica are facing the most rapid rates of anthropogenic climate change currently seen on the planet. Climate changes are occurring throughout Antarctica, affecting three major groups of environmental variables of considerable biological significance: temperature, water, UV-B radiation.Low diversity ecosystems are expected to be more vulnerable to global changes than high diversity ecosystems

Ecological and environmental factors affecting the foraging activity of the White-bellied Heron Ardea insignis (Hume, 1878) in Bhutan

2021 ◽  
pp. 1-18
Author(s):  
PEMA KHANDU ◽  
GEORGE A. GALE ◽  
SARA BUMRUNGSRI
Keyword(s):  
Relative Abundance ◽  
Habitat Restoration ◽  
Prey Species ◽  
Catch Per Unit Effort ◽  
Factors Affecting ◽  
Prey Biomass ◽  
Gravel Mining ◽  
Unit Effort ◽  
Prey Preferences ◽  
The Government

Summary White-bellied Heron Ardea insignis (WBH) is critically endangered, but we lack data on many aspects of its basic ecology and threats to the species are not clearly understood. The goal of this study was to analyse WBH foraging microhabitat selection, foraging behaviour, and prey preferences in two river basins (Punatsangchhu and Mangdechhu) in Bhutan which are likely home to one of the largest remaining populations of WBH. We also explored the relationship between the relative abundance of the WBH and prey biomass catch per unit effort within four foraging river microhabitats (pool, pond, riffle and run). Prey species were sampled in 13 different 100-m thalweg lengths of the rivers using cast nets and electrofishing gear. Riffles and pools were the most commonly used microhabitats; relative abundance was the highest in riffles. The relative abundance of WBH and prey biomass catch per unit effort (CPUE) also showed a weak but significant positive correlation (rs = 0.22). The highest biomass CPUE was observed in riffles while the lowest was found in the ponds. From the 97 prey items caught by the WBH, 95% of the prey were fish. The WBH mainly exploited three genera of fish (Garra, Salmo, and Schizothorax) of which Schizothorax (64%) was the most frequently consumed. This study provides evidence in support of further protection of critical riverine habitat and fish resources for this heron. Regular monitoring of sand and gravel mining, curbing illegal fishing, habitat restoration/mitigation, and developing sustainable alternatives for local people should be urgently implemented by the government and other relevant agencies. Further study is also required for understanding the seasonal variation and abundance of its prey species in their prime habitats along the Punatsangchhu and Mangdechhu basins.

The Winter Flounder (Pseudopleuronectes americanus) in Long Pond, Conception Bay, Newfoundland

1971 ◽  
Vol 28 (8) ◽  
pp. 1153-1165 ◽  
Author(s):  
V. S. Kennedy ◽  
D. H. Steele
Keyword(s):  
Food Intake ◽  
Growth Rates ◽  
Plant Material ◽  
Early Growth ◽  
Winter Flounder ◽  
Pseudopleuronectes Americanus ◽  
Food Items ◽  
Fish Remains ◽  
Males And Females ◽  
Conception Bay

Monthly samples of winter flounder taken in Long Pond from November 1962 to October 1963 indicated that the flounder moved into deeper water (7–10 m) during the summer and returned to shallow water (1–2 m) from September to June. These movements corresponded to the end of the spawning season and the ripening of the gonads respectively. Spawning occurred from March until early June, most of it in May and early June. Most males were mature at age 6 and most females at age 7. Fifty percent of the males and females were mature at 21 and 25 cm respectively. The growth rates of the males and females were similar until the age of 8, after which the females apparently outgrew the males. Early growth and fecundity were similar to those reported for other areas. No feeding took place in December or January but the flounder fed in March and continued to feed throughout the summer; food intake decreased in the fall. They were omnivorous and the type of food eaten varied with the locality. Polychaetes, plant material, and molluscs were the most common food items throughout the year. Capelin eggs and fish remains were found only during a few months of the year but were eaten in great quantities.

Development of the embryonic heat shock response and the impact of repeated thermal stress in early stage lake whitefish ( Coregonus clupeaformis ) embryos

2017 ◽  
Vol 69 ◽  
pp. 294-301 ◽  
Author(s):  
Lindy M. Whitehouse ◽  
Chance S. McDougall ◽  
Daniel I. Stefanovic ◽  
Douglas R. Boreham ◽  
Christopher M. Somers ◽  
...  
Keyword(s):  
Thermal Stress ◽  
Heat Shock ◽  
Heat Shock Response ◽  
Early Stage ◽  
Coregonus Clupeaformis ◽  
Lake Whitefish ◽  
Shock Response ◽  
The Impact

Factors affecting levels and growth rates in the wage rates of women: evidence from nursing

1998 ◽  
Vol 30 (6) ◽  
pp. 727-739 ◽  
Author(s):  
David E. Ault ◽  
Gilbert L. Rutman
Keyword(s):  
Growth Rates ◽  
Factors Affecting ◽  
Wage Rates

Fecundity Comparisons for Various Stocks of Lake Whitefish, Coregonus clupeaformis

1975 ◽  
Vol 32 (3) ◽  
pp. 404-407 ◽  
Author(s):  
M. C. Healey ◽  
C. W. Nicol
Keyword(s):  
Northwest Territories ◽  
Lake Erie ◽  
Fork Length ◽  
Nonlinear Relationship ◽  
Coregonus Clupeaformis ◽  
Lake Whitefish ◽  
Limited Data ◽  
Relative Fecundity ◽  
Great Slave Lake ◽  
The Relationship

We found no significant differences in slope or intercept for the regression of loge fecundity on loge fork length among samples of whitefish from four lakes near Yellowknife in the Northwest Territories. The equation describing the relationship between fecundity and fork length for these populations was:[Formula: see text]Five other populations for which length–fecundity relationships could be calculated had length exponents ranging from 3.20 to 4.38, suggesting a nonlinear relationship between weight and fecundity. Six of the nine populations as well as four others for which limited data were available all had similar relative fecundities. Fish from Buck Lake in Alberta and from Lake Erie had high relative fecundities while fish from Great Slave Lake had low relative fecundity.

Occurrence of the eyefluke, Diplostomum (Diplostomum) baeri bucculentum Dubois et Rausch, 1948, in salmonid fishes of northern British Columbia

1985 ◽  
Vol 63 (2) ◽  
pp. 396-399 ◽  
Author(s):  
Hilda Lei Ching
Keyword(s):  
Rainbow Trout ◽  
Chinook Salmon ◽  
Sockeye Salmon ◽  
Lake Trout ◽  
Infected Fish ◽  
Salmo Gairdneri ◽  
Coregonus Clupeaformis ◽  
Lake Whitefish ◽  
Dolly Varden Salvelinus Malma ◽  
Prosopium Williamsoni

As a result of experimental infections in chicks, diplostomula found in the retina of chinook salmon from the Nechako River were identified as Diplostomum (Diplostomum) baeri bucculentum. Eyeflukes in other salmonids were considered to be the same species based on similar measurements and site in the eyes. These eyeflukes varied in prevalence and mean intensity in seven salmonid species surveyed in nine localities in 1979–1981. The following fish were sampled: rainbow trout (Salmo gairdneri), 505; mountain whitefish (Prosopium williamsoni), 334; lake whitefish (Coregonus clupeaformis), 32; Dolly Varden (Salvelinus malma), 66; lake trout (S. namaycush), 13; kokanee or sockeye salmon (Oncorhynchus nerka), 323; and chinook salmon (O. tshawytscha), 164. Eyeflukes had prevalences ranging from 84 to 100% in six lakes, 64% in the river, 53% in one reservoir site, and a prevalence of 15% in the other reservoir site. Mountain and lake whitefishes had high mean intensities while kokanee had low mean intensities. Correlation of increased intensity with increased fish size was significant for 6 of 27 samples. Four samples of lake whitefish, mountain whitefish, rainbow trout, and chinook salmon showed significant asymmetry when numbers of diplostomula were compared between eyes. More of the heavily infected fish showed asymmetry than did the lightly infected fish.

Sign in / Sign up

Export Citation Format

Share Document