Location: Warmwater Aquaculture Research UnitTitle: Catfish production systems-where are we and why did it take fifty years to get here
Submitted to: Catfish Farmers of America Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 2/8/2018
Publication Date: N/A
Interpretive Summary: This abstracts discusses the changes in catfish production technology/systems in the past 50 years.
Technical Abstract: In the early days of the catfish industry there were no specialized production systems. Catfish were raised in ponds ranging from 40-acres (built with a dragline) to small watershed ponds complete with stumps. Neither could be harvested efficiently. Fish in larger ponds were often baited into a corner and caught with a cutting seine, dipped into a tub, and carried up to levee to a truck. Smaller ponds were drained and seined between the stumps. With no aeration and limited feed, annual production was less than 1,000 lbs/acre. Low production was not a bad thing since there were no established markets and, therefore, no established harvest schedules. Most fish were marketed through a combination of pay lakes, pond-bank sales and small-scale processing on small orders. Most levee-type ponds built on flat land in the 60s, 70s and even 80s were built with a minimum depth of three feet. This depth was necessary to prevent the growth of aquatic vegetation. Most of these ponds ended up with perhaps only a couple of feet of water after a few years due to erosion of the levees. Even as aeration rates increased at the turn of the 20th century, production remained low in these ponds since oxygen management was so difficult in shallow water. In the past decade or so, most ponds have been both reduced in size and deepened as they were renovated. As the industry grew, feeds were developed—first sinking pellets based on early Auburn diets, and later floating (extruded) pellets which were continually improved through research at several institutions. The use of feeds meant that more fish could be raised in smaller ponds—a good thing—but also that aeration became necessary to prevent catastrophic fish kills. A variety of emergency aerators were developed, and ultimately reliable, efficient electric floating aerators. The 10-hp electric paddlewheel aerator became the standard for the industry and is still the most common aerator in use. Increased aeration intensity (over 10-hp/acre now in some cases) allowed for greatly increased production. Harvesting technology was developed for the growing industry. The National Marine Fisheries Service Gear Research Station at Kelso Arkansas developed the first seine-puller and sock which allowed for seining and harvesting entire ponds, grading off the larger food-size fish if desired. The zipper-sock developed by Mississippi State University replaced the small square opening used to attach the sock to the seine, allowing for less stress on fish during harvest. The “panel sock” was developed at the University of Arkansas at Pine Bluff to grade hybrid catfish which tend to gill in traditional socks, and the “sock-saver” was developed by USDA-ARS at Stoneville to provide liquid oxygen to fish being held overnight in socks. While fish pumps are used in other industries, loading catfish on a truck still utilizes a boom and basket. Something as simple as having gravel on a levee can mean the difference in selling a pond of fish during rainy weather and not selling fish. Protozoan and trematode parasites were the major cause of catfish mortality in the early days. Anyone with a cheap microscope was a diagnostician. Aeromonad infections were occasionally seen in hot weather after oxygen stress. In the early 80s mortality was so low that many researchers didn’t even report survival in research studies. Things changed in the mid-80s. Enteric septicemia of catfish and proliferative gill disease came on the scene, and columnaris infections increased. Channel catfish virus disease, trematodes, winter-kill, visceral toxicosis of catfish, and a virulent aeromonas all appeared and inflicted heavy mortality at times. Mortality in mixed-batch channel catfish production ponds was so great that farmers talked about a “black hole” where only a fraction of the fingerlings stocked were harvested. Science tackled each of these prob