OPTIMIZING PAT TECHNIQUES
Optimizing periphyton production to increase fish yields
Note - Periphyton is the naturally occurring community of algae, bacteria and detritus that grows on submerged surfaces. It is a preferred source of food for tilapia and, depending on a variety of factors; amount of sunlight, available nutrients in the water, and the substrate, periphyton can meet 100% of tilapia’s dietary needs.
Maximizing fish production methods using the Periphyton Aquaculture Technique (PAT) is contingent upon many factors, primarily the quantity and quality of the periphyton produced. Research conducted in various parts of the world have shown that enhancing periphyton communities within fish ponds can reduce the amount of supplemental feed needed by 40% or more (Milstein, Wahab, 1990).
Haiti has an excellent climate for using the PAT method but sources of nutrients to fertilize the ponds are limited and the type of substrate available varies throughout the country. Our research to date has shown that providing nitrogen and phosphate at a ratio of 6:1 seems to be optimal but more work needs to be done to ascertain what local materials (valueless by-products) are available to maintain these ratios, what is the best method of controlling the balance of these elements, and what is the best material for stimulating the growth of these periphyton communities.
A summary of our current research and techniques can be found here.