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Evaluation of a Mechanical Population Reduction of Black Crappie and Black Bullheads in a Small Wisconsin Lake
Author(s) -
Hanson David A.,
Belonger Brian J.,
Schoenike Dean L.
Publication year - 1983
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 - 10.1577/1548-8659(1983)3<41:eoampr>2.0.co;2
Subject(s) - ictalurus , fish <actinopterygii> , biology , hectare , population , fishery , zoology , ecology , demography , catfish , sociology , agriculture
The large populations of black crappies (Pomoxis nigromaculatus) and black bullheads (Ictalurus melas) in 20.2‐hectare English Lake, Manitowoc County, Wisconsin, had a size distribution undesirable for angling. An attempt was made to reduce the abundance of these species and improve growth rates by mechanical removal (trapping) of 2,822 black crappies per hectare and 277 black bullheads per hectare in the spring of 1977. Three growing seasons later the density of black crappies more than 120 mm long (TL) was less than 10% of the number removed; estimated density of fish more than 200 mm long increased by 430%. Similarly, the density of black bullheads after three seasons was 21% of the population prior to removal but the estimated density of fish larger than 260 mm long increased by 11 times. Mean total length of black crappies for ages I‐IV increased appreciably after removal.