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United States Department of Agriculture

Agricultural Research Service

Research Project: IMPROVING PRODUCTION EFFICIENCY IN WARM WATER AQUACULTURE THROUGH WATER QUALITY MANAGEMENT

Location: Warmwater Aquaculture Research Unit

Title: Combatting wintertime off-flavors

Author
item Tucker, Craig

Submitted to: The Catfish Journal
Publication Type: Trade Journal
Publication Acceptance Date: December 20, 2013
Publication Date: February 7, 2014
Citation: Tucker, C.S. 2014. Combatting wintertime off-flavors. The Catfish Journal. 27(5):11.

Interpretive Summary: Off-flavored catfish are not acceptable for harvest, which disrupts the orderly flow of product from farm to processing plant. Most summertime off-flavors are caused when odorous substances produced by blue-green algae are absorbed from water and deposited in the fish’s flesh. Fish can also become off-flavored when they eat unpleasant-smelling foods. Diet-related off-flavors can occur any time, but are most common in winter when fish are infrequently fed. Wintertime off-flavors are more difficult to manage than summer problems because off-flavors are slowly purged from fish in cold water. If fish are to be harvested in winter, they must be free of off-flavors before the water cools in late autumn. If odor-producing blue-green algae are present in late summer, they should be eradicated with algicides, which will allow fish to purge the offending substances while water is still relatively warm. Offering manufactured feed occasionally during warm-weather periods throughout the winter will reduce scavenging on decaying fish or plants and reduce the incidence of diet-related off-flavors. Processors should also consider increasing the number of fish flavor-tested in winter to account for increased variation in wintertime flavor quality.

Technical Abstract: Off-flavored catfish are not acceptable for harvest, which disrupts the orderly flow of product from farm to processing plant. Most summertime off-flavors are caused when odorous substances produced by blue-green algae are absorbed from water and deposited in the fish’s flesh. Fish can also become off-flavored when they eat unpleasant-smelling foods. Diet-related off-flavors can occur any time, but are most common in winter when fish are infrequently fed. Wintertime off-flavors are more difficult to manage than summer problems because off-flavors are slowly purged from fish in cold water. If fish are to be harvested in winter, they must be free of off-flavors before the water cools in late autumn. If odor-producing blue-green algae are present in late summer, they should be eradicated with algicides, which will allow fish to purge the offending substances while water is still relatively warm. Offering manufactured feed occasionally during warm-weather periods throughout the winter will reduce scavenging on decaying fish or plants and reduce the incidence of diet-related off-flavors. Processors should also consider increasing the number of fish flavor-tested in winter to account for increased variation in wintertime flavor quality.

Last Modified: 7/25/2014
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