Current UGA CAES Aquaculture Projects

Aquaculture and Fish Pond Diagnostics

Blue-green Algae Control in Catfish Ponds Improves Market Timing

Aquaculture and Fish Pond Diagnostics
	SITUATION: Disease and water quality problems occur when new aquaculture facilities are started, when fish are stressed, and when adverse weather occurs. The catfish acreage in Georgia has added new acres of ponds in which disease cases have been frequently reported. Catfish diseases and catfish pond water quality problems have caused the loss catfish valued at over $300,000 in the year 2001. Freshwater prawn farms have begun to develop resulting in new demands on the county extension system for information and response to special problems. Farm pond owners contact cooperative extension agents frequently with questions about protecting their investment in pond, fish, and property associated with the pond. Cases in the area of water quality have increased due to drought conditions in Georgia. RESPONSES: County agents have been trained to utilize microscopes for capture of fish disease images that can be utilized for distance diagnostics. Workshops for catfish farmer certification and prawn farmer training have been held to train producers in management, economic, and marketing topics. These workshops were intended to provide more extensive training by meeting for three to five days per training program. Pond weed control cases are increasing as are reports of exotic and invasive species. New pond construction and renovation of existing ponds has occurred during the drought period, demanding additional attention from county agents and the specialist. RESULTS: Over 450 clients have submitted aquaculture or pond cases to Tifton during the first three quarters of 2002. The value of these cases exceeds $1,800,000 based on the savings of $4,000 in fish or operating costs per case. The first report of West Nile virus in alligators in Georgia was one of the cases. Attendance of the extended training for catfish and prawn production trained 25 clients who are now involved in catfish farm development, catfish processing plant development, or prawn farm development in areas around Albany, Atlanta, Dublin, Sparta, Sylvania, Bartow, and Nashville, GA. CONTACT: Gary J. Burtle COUNTY/DEPARTMENT: Animal & Dairy Sciences ADDRESS: P. O. Box 748, Tifton, GA 31793-0748 PHONE: (229)386-3364 FAX: (229)386-3219 EMAIL: fish@tifton.cpes.peachnet.edu
Blue-green Algae Control in Catfish Ponds Improves Market Timing
	SITUATION: Chemicals that are toxic to blue green algae are not always effective in Georgia catfish ponds. Blue-green algae can make the catfish taste like soil or musty. Catfish with earthy-musty flavor cannot be sold until the flavor returns to normal. Catfish may return to normal flavor in two weeks or may take long as 12 months from the time the off-flavor was detected unless the blue-green algae is controlled. Catfish than cannot be sold become the target of diseases, predation, and water quality deterioration. Losses due to off-flavor in Georgia can exceed $1,000,000 unless corrective measures are available. RESPONSES: Over the past three years, chemical and biological controls for blue-green algae have been studied and recommended to reduce fish losses and economic hardship. Stocking threadfin shad to eat the unwanted blue green algae is a viable alternative to chemical treatment with reduction of 60% in the blue green algal numbers in ponds with shad versus without shad. The threadfin shad is a relatively small fish and would not be expected to interfere with normal catfish harvest procedures. An emergency label exemption was granted for diuron use in catfish ponds. RESULTS: Emergency exemption for diruon use in Georgia was approved for use in catfish ponds in 2002. Catfish farms used a combination of diuron treatments, copper treatments, and threadfin shad to control off-flavor. No reports of off-flavor catfish occurred during the fall of 2002, normally the heaviest off-flavor period. CONTACT: Gary J. Burtle COUNTY/DEPARTMENT: Animal & Dairy Sciences ADDRESS: P. O. Box 748, Tifton, GA 31793-0748 PHONE: (229)386-3364 FAX: (229)386-3219 EMAIL: fish@tifton.cpes.peachnet.edu