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Walleye Mortality during Live‐Release Tournaments on Lake Oahe, South Dakota
Author(s) -
Fielder David G.,
Johnson Bruce A.
Publication year - 1994
Publication title -
north american journal of fisheries management
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.587
H-Index - 72
eISSN - 1548-8675
pISSN - 0275-5947
DOI - 10.1577/1548-8675(1994)014<0776:wmdlrt>2.3.co;2
Subject(s) - stizostedion , fish <actinopterygii> , mortality rate , fishery , catch and release , range (aeronautics) , biology , tournament , toxicology , geography , demography , mathematics , recreational fishing , materials science , combinatorics , sociology , composite material
Mortality of walleyes Stizostedion vitreum was estimated during two live‐release tournaments held in May 1990 and May 1991 on Lake Oahe, South Dakota. Mortality was divided into three components: weigh‐in, delayed, and total. Weigh‐in mortality was the percentage of walleyes that could not be released alive. Delayed mortality was calculated from walleyes that died in submersed cages after 3 d. Total mortality was determined by adding weigh‐in deaths and delayed deaths, after applying the delayed mortality to all released fish. Weigh‐in mortality averaged 18.4% in 1990 and 13.2% in 1991. Delayed mortality was estimated to be 5.5% for 1990 and 8.4% in 1991. Total mortality was 22.8% in 1990 and 20.5% in 1991. These rates were similar to results under similar conditions reported by other researchers. Released walleyes were tagged to monitor their later contribution to the creel. Returns of tags from tournament‐released walleyes averaged 29.5% compared with 12.4% for walleyes tagged during annual spawning runs. Higher exploitation of tournament‐released walleyes suggests increased vulnerability, possibly caused by displacement from their home range. When weather variables are favorable, live‐release tournaments can safely return a high proportion of walleyes compared with harvest events.