A P Lipton, M Thangaraj and M Selvakku
Manonmaniam Sundaranar University, India
Posters & Accepted Abstracts: Oceanography
Sea horse, Hippocampus trimaculatus obtained as by-catch from the shallow coastal habitats in the Gulf of Mannar and Palk Bay coast of India and maintained in laboratory were observed for courtship and egg transfer. Spherical eggs measured 2.12├?┬▒0.019 mm in length and 1.97├?┬▒0.045 mm in width weighing 2.94├?┬▒0.3 mg. After egg transfer, male├ó┬?┬?s pouch became watertight and pregnancy lasted for 12 to 14 days. The mean brood size of H. trimaculatus was 389├?┬▒56.11. Newborn seahorses were 7.0├?┬▒0.05 mm in length and 0.97├?┬▒0.08 mg in weight. Feeding regimens were standardized. Juvenile sea horses captive-bred and were collar tagged, released in the natural habitat and wide publicity was given to return the tagged seahorses. Data revealed an average growth of 4.15 mm/month in the natural habitat. Sacred conch, Turbinella (=Xancus) pyrum collected from sea bed up to 20 meters depth in the Gulf of Mannar, India and maintained in rectangular tanks containing sand substratum with adequate sea water flow through were used for breeding trials. Brooders were fed ad libitum with live clams Donax cuneatus and Donax faba. The release of egg capsules and the number of baby conches were recorded. Baby conches started growing from an initial 9.09 mm length to 62.23 mm in length with an increase in shell diameter of 31.47 mm from 4.07 mm in 360 days. After tagging, the baby conches were sea-ranched in Gulf of Mannar with wide publicity for returning the recaptured tagged conches. The recovery was14.6% and the average breadth-wise growth was 8.0 mm/year in nature.
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