8.1 Island Development

Ocean Science and Technology for Islands

In the 9th Five Year Plan programme proposed by DOD for "Island Development", a special emphasis is given on building up of infrastructure and expertise in Ocean Science and Technology for Islands through development and transfer of technology in the area of marine living resources which will bring in socio-economic benefits to the island community. This programme is being implemented by the National Institute of Ocean Technology, Chennai.

In the programme on lobster resource enhancement, which is implemented from 1998-99 onwards, several experiments have already been carried out in the following areas:

1. Fattening of spiny lobster Panulirus homarus using different live feeds (mussels, clams and squids) either alone or in combination.

2. Biochemical analysis of lobsters and live feeds.

3. Water quality, disease diagnostics and preventive measures.

4. Spawning and larval rearing, and

5. Survey of lobster resources in Gulf of Mannar and Andaman & Nicobar Islands.

To give a head start to the overall programme on Ocean Science and Technology for Islands, a seafront laboratory and a marine animal grow out system have been developed near Chennai and various experimental programmes related to the development of fattening and larval rearing technology is underway. A complementary seawater recirculatory wet-lab facility is under construction at NIOT campus, Pallikaranai, in order to carry out experiments on larval rearing under controlled environmental conditions. To elucidate the various biochemical processes involved during the growth and reproduction of economically important marine organisms, an R & D has been set up at NIOT campus. A comprehensive analytical programme on nutritional and reproductive aspects of the Indian spiny lobster Panulirus homarus is presently underway. A laboratory has also been set up recently at Port Blair, Andaman & Nicobar Islands (Andaman & Nicobar Centre for Ocean Science & Technology, ANCOST) to carry out studies on marine living resources, coastal environment, ocean observation and related areas in Ocean Science and Technology.

The immediate thrust of the programme is on development of technology for:

1. Fattening of juvenile Indian spiny lobsters to cater to the needs of live lobster export trade and

2. Breeding, larval rearing and sea ranching of lobsters.

Fattening of juvenile spiny lobsters:

During the experiments on lobster fattening, maximum specific growth rate of 0.47% body weight per day was achieved in the green mussel (Perna viridis) fed animals. During the fattening of lobsters, it was observed that the maintenance of hydrobiological parameters viz. temperature, pH, salinity, dissolved oxygen, nitrite, nitrate, ammonia, phosphate and microbial loads would be very essential at optimal conditions for normal growth of the lobsters. In addition to that, the levels of total free sugars, total protein, free aminoacids, total lipids and free cholesterol in the live feeds such as green mussel, grey clam, squid and polychaete were estimated and their role in growth enhancement is being assessed.

Spawning of lobster and rearing of phyllosoma larvae:

To sustain the fattening technology in the long run, spawning of lobster and rearing of phyllosoma larvae upto juvenile stage are important imperatives. Studies on spawning behaviour, carried out by NIOT scientists at Chennai, have revealed that lobsters reared in captivity undergo normal gonadal maturation and exhibit natural spawning behaviour. Over 2.2 million phyllosoma hatched out from 12 successful spawning in the hatchery. Temperature, pH, salinity, dissolved oxygen, nitrite, nitrate, ammonia, phosphate and microbial load were regularly monitored in all larval rearing tanks. Treatment with 'treflan' at a concentration of 0.01-0.03 PPM was found to be effective in controlling protozoan and bacterial loads. The larvae reached the V stage and for the first time in India they were reared for the duration of 73 days. Attempts are on to rear them up to puerulus / juvenile stages in order to enhance the natural resources by sea farming and ranching through careful nutritional, water quality and disease management practices.

Sea ranching:

Under this project, it is also proposed to sea ranch the early life stages (phyllosoma / puerulus) of lobster in order to enhance their population in nature. For this purpose, a pre ranching survey was conducted at Minnie Bay, Port Blair, for identifying the suitable sites for sea ranching. After analyzing the water quality and distribution of surface plankton, nekton, benthos and underwater habitat, it was found that the Minnie Bay of A & N islands would be ideal for initiating experiments on sea ranching of early life stages of lobsters. Immediately after the technology for larval rearing is perfected, the sea ranching of early life stages will be initiated at Minnie Bay.

Transfer of technology to island and coastal communities:

A protocol for fattening technology developed by NIOT has entered into the stage of field demonstration and extension at A & N islands aiming at benefiting island /coastal communities. Under this program, it is shown that the juvenile lobster with a starting weight of 100g average body weights could be grown to exportable sizes of 240 to 250g within a span of 5 1/2 to 6 months. The initial estimates are that fattening technology would yield around Rs.50,000/- per family per annum when it is extended to island communities.