LIFE CYCLE STUDY OF RAGGED SEA HARE, BURSATELLA LEACHII (BLAINVILLE, 1817) INHABITING THE INTER-TIDAL WATERS OF PULICAT LAKE, TAMIL NADU, INDIAMahadev Rama Kokane, V Anuradha, K. Revathi, S.N. Sethi , Karthikeyan P., Marigoudar S.R., Surender C., Rajkumar Rajan and S.Y. Metar
The species Bursatella leachii was collected from the intertidal waters of Pulicat Lake. The study was carried out at controlled room temp. in glass aquaria's; the mating occurred in the form of unilateral copulating with chain formation. Only the first animal acted as receptor, the second and succeeding animals acted as donors. It releases the fertilized eggs like spaghetti, packaged in capsules to form a cylindrical string called an egg mass. The number of capsule per cm of the egg masses varies from 25 to 55 capsules and each capsule contained 5 to 19 eggs. After spawning, the egg masses were light yellowish greenish, it changed to golden brown. The embryo developed into trochophore stage and began to rotate within the egg capsule in first 4-5 days; 6-8 days onwards it develops the precursor of the velum called prevelum. At 7- 8 days after spawning, the prevelum is transformed into the velum and attend veliger stage. Between 8-12 days the veligers hatched as free-swimming larvae. Metamorphic stage began: on 16 to 19 days shell get detached and villae start appearing whole body like spines, 19th to 20th days larvae become benthic and 30th to 40th days it transformed to adult stag.