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Effect of Fish Density on Growth, Survival, and Food Consumption by Juvenile Walleyes in Rearing Ponds
Author(s) -
Fox Michael G.,
Flowers David D.
Publication year - 1990
Publication title -
transactions of the american fisheries society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.696
H-Index - 86
eISSN - 1548-8659
pISSN - 0002-8487
DOI - 10.1577/1548-8659(1990)119<0112:eofdog>2.3.co;2
Subject(s) - stocking , stizostedion , biomass (ecology) , population density , biology , juvenile , zoology , population , predation , growth rate , fishery , density dependence , fish <actinopterygii> , ecology , mathematics , demography , geometry , sociology
We investigated the effect of density of young‐of‐year walleyes Stizostedion vitreum on their growth, biomass production, survival, and food consumption. We used 2‐d‐old larvae stocked at densities of 20, 40, and 60 fish/m 3 in eight drainable outdoor ponds (unbalanced design with one additional replicate for high and low densities). Growth, food consumption, and prey density were monitored weekly during the 6‐week experiment. Mean length and weight at harvest showed an inverse logarithmic relationship with initial walleye density, whereas biomass production and initial density were positively related. There was no relationship between the within‐pond variability in walleye size at harvest and either stocking density, final density, or mean harvest length and weight. The rate of survival was also unrelated to either initial density or size at harvest. Our results support the contention that growth is more important than mortality in adjusting population biomass to environmental conditions. However, among‐pond differences in growth were better explained by population density than by the biomass of food found in walleye stomachs. We hypothesize that density‐dependent growth may be due in part to density‐related differences in the activity level of the fish.