The four major states (Mississippi, Alabama, Arkansas and Texas) accounted for 97% of total US sales. With support from the USDA National Institute of Food and Agriculture, Land-grant Universities researchers conduct research that supports the catfish industry (the largest component of aquaculture US) and help build a more resilient food system.
Understanding the Effect of High Water Hardness in Catfish Aquaculture
In Arkansas, home of the commercial catfish industry, scientists from the University of Arkansas at Pine Bluff have discovered the level of water hardness that is lethal to catfish. Hardness is one of the integral water quality parameters that determines the success of aquaculture efforts. Adequate water hardness is necessary for bone development, blood clotting, enzyme activity, eggshell integrity, and embryonic development in fish. Most species of fish perform well over a wide range of hardness values, but can suffer when hardness values are too low or too high. Optimal requirements are often species-specific.
In southern states, including Arkansas, fish producers experience significant changes in total hardness due to water evaporation during the summer months or pond water dilution. during periods of heavy rainfall. This ends up affecting the overall productivity of the fish. For successful fish farming, it is important that the high hardness remains within the safe range of the farmed fish species. However, information regarding the maximum safe hardness tolerance level is lacking for catfish or any other fish.
Researchers found that although channel catfish have ways to cope with high hardness, exposure to calcium carbonate levels of 1500 mg/L and above was detrimental. The results provide a guideline for the “maximum level” of toughness a breeder can safely increase in a catfish aquaculture system. As such, the result of this work can be applied to aquaculture worldwide.
Improve catfish health
Researchers at Mississippi State University are studying diseases that limit the production efficiency of commercially farmed catfish. Scientists are developing rapid molecular diagnostic tests for use in disease surveillance, disease treatment and prevention, and best management practices that mitigate the impact of infectious and non-infectious diseases.
The research focuses on practical catfish health or disease issues that limit catfish production in the southeastern United States. These include identifying emerging pathogens and developing disease diagnostic methodologies for field surveillance studies; develop primary catfish cell lines for the identification and confirmation of fish viruses; determine the distribution of channel catfish virus (CCV) and assess trends in occurrence and virulence of different genetic strains of CCV in channel catfish and hybrid channel catfish; and optimizing vaccine delivery and evaluating the economic impact of a live attenuated vaccine.
Preventing losses in catfish aquaculture due to algal toxicosis
Fish losses attributed to toxic algae outbreaks continue to be a significant problem facing Arkansas aquaculture. In the late 1990s, catfish producers in Arkansas lost approximately $900,000 worth of catfish annually attributed to this problem. Today, those losses would amount to $1.68 million.
Taking a proactive approach, the Aquaculture and Fisheries Program at the University of Arkansas at Pine Bluff instituted an algae monitoring program. This program continues to the present day. An extension specialist visits farms weekly during the production season, for 40 weeks or more. Algae samples are taken weekly from approximately 166 ponds. The samples are examined under a microscope with the presence and abundance of the algae, Aphanocapsa, noted. When the algae population exceeds approximately 5 million cells per litre, treatment with an approved algaecide is recommended. In some cases, flushing affected ponds with massive amounts of water from adjacent ponds has also reduced culprit algae numbers.
Over 2,800 algae samples were processed during the 2021 production season. Pond owners were asked to process algae 10 times. The program was successful in 2021 – there were no economic losses attributed to algal toxicosis. Treating the affected ponds saved about $200,000 worth of catfish.