Habituation performance of two percids under turbid and clear water culture.

摘要

Advanced walleye (Sander vitreus) and yellow perch (Perca flavescens) fingerlings are produced by habituating pond-reared fingerlings to commercial feed. Success of the habituation phase depends on many variables. Among these, diet contrast/visibility is an important variable for habituation success. The objective of this study was to compare the effect of turbid water (greater than or equal to 100 nephelometric turbidity unit, NTU) and clear water culture conditions during the habituation phase for these two species. In 2005, 12 150 L black-cuboidal tanks with in-tank lighting were stocked at a rate of 2 g/L age 0 of either walleye or yellow perch fingerlings with half of the tanks receiving turbidity (clay slurry) and cultured for 28 d. All fish were fed a commercial diet every 5 min during a 16 h daylight interval at 10% body weight/d. Walleye in the clear treatment had higher survival (83 pl 2.0%) than the turbid treatment (57 pl 6.0%). The yellow perch exhibited opposite survival results: turbid treatment rates at 79 pl 2.1% and clear treatment rates at 54 pl 9.2%. These results demonstrate that the addition of clay may enhance the contrast of the feed and thus improve the habituation phase for yellow perch.