DEPLETION AS A TECHNIQUE TO ESTIMATE COMMERCIAL POND INVENTORIES OF CHANNEL CATFISH

A depletion population estimation method was tested in three trials in experimental ponds and in 19 commercial ponds that held channel catfi sh Ictalurus punctatus. Estimates of population numbers in experimenta l ponds differed from measured population numbers by +6.5%, -3.8%, and -18.4%, respectively. Estimates of population weights differed from m easured population weights by -0.1%, 0%, and -7.7%, respectively. Esti mated population numbers in two commercial ponds in 1995 differed from measured population numbers by -0.3% to -2.4%, and estimated populati on weights differed from measured population weights by -3.5% to -6.1% . In 1996, depletion estimates of population weight from 17 commercial channel catfish ponds differed from measured weights by -1.4 +/- 13.7 %. A fourth sampling point (tested in five commercial ponds) did not s ignificantly (P greater than or equal to 0.05) improve the accuracy of population estimates. The depletion method appears to have potential as an alternative management tool that could be used periodically by c hannel catfish farmers.