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Use of a Minimum Length Limit to Manage Walleyes in Lake Francis Case, South Dakota
Author(s) -
Stone Clifton,
Lott John
Publication year - 2002
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(2002)022<0975:uoamll>2.0.co;2
Subject(s) - stizostedion , fishing , fishery , population , drainage basin , abundance (ecology) , catch and release , environmental science , geography , biology , fish <actinopterygii> , recreational fishing , demography , sociology , cartography
Walleyes Stizostedion vitreum are the primary predator fish in Lake Francis Case, a Missouri River impoundment located in south‐central South Dakota. Because of increasing angling pressure in the mid‐1980s, this walleye sport fishery was nearing the point of overharvest. In 1990, angling regulations were changed to address management concerns. A partial‐year (April–June), 356‐mm minimum length limit was implemented, the daily bag limit was reduced from 6 to 4, and the possession limit was reduced from 12 to 8. We evaluated the effects of the length limit regulation on recruitment, population structure, growth, and angler use and harvest by comparing a 5‐year preregulation period with a 9‐year postregulation period. Walleye recruitment, growth, condition, and abundance did not change significantly from preregulation to postregulation periods. Abundance of 356‐mm and longer walleyes and proportional stock density increased significantly in the years following implementation of the minimum length limit. Angler use and harvest declined in the first 2 years after imposition of the regulation; however, by the third year, angling pressure and harvest estimates were similar to those preceding the regulation. Angler use and harvest continued to increase throughout the postevaluation period. The reduction in the daily creel limit appeared to have minimal effects on the population, but the evaluation was confounded by large changes in water yield in the Missouri River basin during the evaluation period.