Cage culture of the spiny lobster Panulirus homarus (Linnaeus) at Vizhinjam, Trivandrum along the south-west coast of India

Abstract

The potential for using floating sea cage for the aquaculture of spiny lobster, Panulirus homarus was assessed by rearing them in two different holding systems such as land-based FRP tanks and a large floating cage moored at Vizhinjam Bay along the south-west coast of India. Lobsters were reared for a period of 120 and 135 days in the tanks and cage, respectively and regularly fed on small/medium sized live mussels (Perna indica), in order to evaluate their growth, survival and feasibility for culture. Juvenile lobsters with average weight of 114.8± 25.67 g in the cage grew to an average weight of 225.95±42.7 g in 135 days. The weight increase recorded was 0.82 g day-1 with a percentage weight gain of 96.68 in the cage whereas juvenile lobsters in tanks with an average weight of 77.87±15.87 g attained 137.35±30.07 g with a weight increase of 0.48 g day-1 and percentage weight gain of 69.2%. The specific growth rates achieved in lobsters maintained in FRP tanks and in the sea cage were 0.45% and 0.50% of the body weight per day respectively. The hydrological parameters viz., temperature, pH, salinity, dissolved oxygen and microbial load recorded were at the optimal levels for normal growth of lobsters. Bio-foulers on the cage unit were represented by ascidians, barnacles, sponges, polychaetes, brown mussels, oysters and seaweeds, which did not affect the performance of the lobsters as indicated by the significant growth advantages and better survival (75%) of juvenile spiny lobsters in the cage over the tank systems (71%).