Open AccessImpact of Double‐Crested Cormorant Depredations on Channel Catfish Farms
Author(s) -
Stickley Allen R.,
Warrick Gordon L.,
Glahn James F.
Publication year - 1992
Publication title -
journal of the world aquaculture society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.655
H-Index - 60
eISSN - 1749-7345
pISSN - 0893-8849
DOI - 10.1111/j.1749-7345.1992.tb00768.x
Subject(s) - catfish , dorosoma , ictalurus , cormorant , gizzard shad , fishery , biology , barbel , population , fish <actinopterygii> , ecology , predation , demography , sociology
Resurgent wintering populations of double‐crested cormorants in the past 10 years have caused serious depredation problems for commercial channel catfish ( Ictalurus punctarus ) growers in Mississippi. Catch rates of catfish by cormorants were found to average 5 catfish per cormorant‐hour. Catfish taken averaged 12 cm in length. However, cormorants took fingerling catfish at rates as high as 28 per cormorant‐hour. The average number of cormorants found feeding on a single pond in this study was 30.5. If this number (but not necessarily the same individuals) fed all day in an 8 ha pond stocked at 51,000 fishlha, the fish population would be halved in 30 days. Further, using this example, the cost of harassment patrols on a 200 ha catfish farm complex over a 5 month period would be exceeded in 22 days by the losses in this one pond. Wild gizzard shad ( Dorosoma cepedianum ) occurred in some ponds, and seem to be preferred by cormorants over caffish.