Some aspects of the biology and fishery of Sarinella sirm off the coast of Negambo, Sri Lanka

Abstract

Some aspects of the fishery, biology and population dynamics of Sardinella sirm off the coast of Negombo was studied. Sampling was carried out approximately once every five days for six months, January to June 1985, at the landing site at Kuttiduwa in Negombo. There is a continuous year round fishery for this species. Catch and effort analysis of the fishery revealed maximum production being recorded in June. This fishery is very much weather dependent and the fishery practically comes to a halt on days of stormy weather. A wide range of mesh sizes are used in the fisheries with the 1 1/2" , mesh size being most commonly used. The number of nets carried by these boats very often consisted" of twenty pieces and the fishery was conducted both at dawn and at night. Fishing and sailing times show wide fluctuations. Length frequency distribution of the catches indicate two cohorts or two year classes being exploited. A protracted spawning season was observed and mature fish were sampled in all the months of study. The regression equation for length-weight relationship was obtained, which indicates that Sardinella sirm does not change the shap~ of its body as it grows.