OPTIMIZING CATFISH/WATER QUALITY INTERACTIONS TO INCREASE CATFISH PRODUCTION
Location: Catfish Genetics Research
Title: Pushing the Envelope - What's Possible?
Submitted to: Catfish Farmers of America Research Symposium
Publication Type: Abstract Only
Publication Acceptance Date: December 1, 2005
Publication Date: February 23, 2006
Citation: Torrans, E.L., Hogue, C. 2006. Pushing the Envelope - What's Possible? [Abstract]. In: Research and Review; A Compilation of Abstracts of Research on Channel Catfish. Catfish Farmers of America Catfish Research Workshop, February 23-24, 2006, San Antonio, Texas, p. 33-34.
There is a tremendous range in catfish production rates across the industry. Some farmers are satisfied with production of three tons per acre while others have reportedly tripled that. Given that increasing yield doesn’t necessarily equate to increasing profit, what are the technical constraints to increasing catfish production? What is possible?
One of the first steps usually taken to increase production is to increase the stocking rate, but that also means a reduced growth rate and a longer time to market. Every day that a fish is in the pond it is at risk from poor water quality, disease, and bird predation. Mortality may average 12-24% annually and this impacts both production and food conversion. The key then is to: 1) grow fish to market size as quickly as possible, and 2) do this with as many fish/acre as possible.
Maximizing feed input is essential. The “feed-man” should have a vested interest in the profitability of the farm. Every two pounds not fed is a pound of lost production. All-weather access is important for feeding, harvesting, and even nightly oxygen checks. We can only feed about 40 lbs per acre per day without aeration. Feeding rates above that are almost directly proportional to available aeration. Some farmers have tried up to 5-6 hp per acre in smaller (2-7 acre) ponds and have achieved production in excess of the theoretical limit. While this may not be economical with some electric rates, it does demonstrate that we can feed far more than we believed possible only a few years ago. As we increase aeration, we should not increase stocking rates proportionally, but try to maintain a higher dissolved oxygen concentration (DO) as well. By maintaining a low DO in the mid-“two’s” instead of the mid-“one’s”, or “points”, both feed consumption and growth may nearly double, reducing the production cycle by up to a year. This can be accomplished easier in smaller ponds. In many cases water depth must also increase.
Many factors impact fish growth rate and production. Stocking and harvesting frequencies, off-flavor management, use of secondary species, circulators, bird density and harassment, farm layout, skill and equipment of the harvest crew, relationship with the processors, soil type, latitude, disease management (recording mortalities, diagnostic examinations, spring prophylactic treatments, prophylactic salt, treating correctable conditions, etc), and record keeping all affect production and/or food conversion. While we generally consider the economy of scale to favor larger farms, this may not hold true with intensifying production. Ponds must be managed as individual units as we intensify production, and this is much more difficult to accomplish on a larger farm where the labor force is generally stretched thinner than on a smaller farm.