Preliminary observations on fish pen culture in a lagoon at Mandapam

Abstract

The large fish pens were fabricated in the Pillaimadam lagoon near Mandapam for culturing fishes. The fish pens were made of Palmyra poles and nylon webbing. Based on the topography of the lagoon, it was divided into 3 zones. The chemical,biological and hydrological parameters of each zones were charecterised. Chanos fingerlings measuring 90-150 mm were transferred to the fish pen. The 3 fish pens of 0.25 ha area each were stocked with 1000, 1500 and 2000 chanos fingerlings at the rate of 4000, 6000 and 8000 number/ha respectively. The chanos fingerlings attained a length of 200 mm, weighing 63 g in 30 days in a 0.25 ha pen with the stocking rate of 4000/ha. The growth rate was more or less same in the pen with the stocking of 8000/ha. The average growth was 1.5 mm/day. In 6000/ha, the fingerlings of length 74 mm in a 0.06 pen attained length of 405 mm weighing 400 g in 234 days. The study also revealed the adverse effect of high salinity in influence of growth of the milkfish fingerlings.It is disclosed that the large areas of water spread in this lagoon could be utilised for culturing valuable fishes like milkfish and mullets using the fabrication of fish pens.