Mud crab (Scylla serrata) culture in tidal flats with existing mangroves

Abstract

The performance of the mud crab Scylla serrata (Forsskal) in 200 m² pens installed in tidal flats with existing mangroves was determined in a factorial experiment with stocking density (0.5 or 1.5/m²) and feed (salted fish by-catch or a mixed diet of 75% salted brown mussel flesh and 25% salted fish by-catch) as main factors. Duration of the experiment was 160 days. Results showed no interaction between feed and stocking density so data were pooled for each feed and stocking density treatment. There was no significant differences in growth, feed conversion ratio (FCR), survival, and production among two types of feed. Regardless of feed, the FCR was significantly more efficient and survival significantly higher at 0.5 than at 1.5/m² stocking density. Growth, however, was not significantly different. Cost-return analysis on a per crop/200 m² basis showed that the use of either of the two stocking density levels with either of the two types of feed was economically viable with a return on capital investment of 65-87%. Partial budgeting analysis, however, revealed that net earnings were increased by P1,128.00 if crabs were stocked at 1.5/m² and P881.00 if fed a mixed diet of 75% salted brown mussel flesh and 25% salted fish by-catch compared with crabs stocked at 0.5/m² and fed salted fish by-catch alone.