8.  COASTAL COMMUNITY PROGRAMME

 

8.1  Island Development

 

In the 9th Five Year Plan programmes proposed by the Department of Ocean Development for “Island Development”, a special emphasis was 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 were carried out in the following areas during the year under report:

 

v      Fattening of spiny lobster Panulirus homarus, P. versicolor and mudcrab (Scylla serrata) using different pelletised and live feeds (mussels, clams, squids, trash fish and chicken waste) both in the main land and A&N Islands,

v      Spawning and larval rearing of lobsters,

v      Water quality, disease diagnostics and preventive measures, and

v      Biochemical analysis of lobsters and live feeds.

To achieve the overall objectives of the programme on Ocean Science and Technology for Islands, the following infrastructure facilities were developed at the National Institute of Ocean Technology:

E    A seafront laboratory and a marine animals grow out system were established at Neelankarai for carrying out various experimental programmes related to the development of fattening and larval rearing.

E    An R&D laboratory was set up at NIOT in order to elucidate various biochemical processes involved during the growth and reproduction of economically important marine organisms. A comprehensive analytical programme on nutritional and reproductive aspects of Indian spiny lobster P. homarus was initiated and is in progress.

E    A field laboratory with demonstration ponds (15 hectares) facility was set up at Port Blair under  the Andaman & Nicobar Centre for Ocean Science & Technology (ANCOST) for carrying out studies on marine living resources, coastal environment, ocean observation and related areas in Ocean Science & Technology.

 

Fattening of juvenile spiny lobsters and mud crabs:

An experiment conducted for a period of one year in order to find out the growth performance of different size group lobsters during fattening using mussel meat as feed, indicated that smaller size animals (55 – 85g) can be fattened similar to the growth rate displayed by bigger size animals (90 – 120g) within the same period.

 

Another study was carried out with a view to find out the growth performance and feeding pattern of male and female lobsters. The results revealed that the specific growth rate was higher in males as compared to females. The feeding pattern also indicated a high feed intake by males as compared to females.

Experiment on the influence of unilateral eyestalk ablation in lobsters indicated that ablated lobsters could be grown up to an average growth rate of 1.41 g.d–1 as compared to 0.83 g.d–1 exhibited by un-ablated animals. The frequency of moulting was also observed to be high in the ablated lobsters than in the un-ablated ones. A similar trend was noticed in case of bilaterally ablated lobsters as well, however, the changes were more pronounced in the bilaterally ablated animals as compared to un-ablated animals.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Well developed ovary ( orange coloured mass) in the eyestalk ablated and immature ovary (white mass) in the unablated lobsters

 

 

Studies on the efficacy of a commercially available pelletised shrimp feed, mussel meat and a semi-moist feed, consisting of soya chunk and mussel meat in the ratio 1:2 was evaluated on the basis of growth response of lobsters. The average daily growth rate exhibited by mussel meat fed lobsters was higher than that obtained by semi – moist and pelletised feed fed lobsters.

           

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


Mud-crab fattening in cane cages at

Port Blair, A & N  Islands

 

At Port Blair, A&N Islands, fattening of Panulirus versicolor was attempted using suspended cages. The lobsters fed with clam meat showed higher growth rate (0.39 g/d) as compared to lobsters fed with mussel (0.33 g/day), trash fish (0.34 g/day) and chicken waste (0.21 g/day).

 

During the fattening of mud crab (Scylla serrata) using bamboo cages, the crabs fed with mussel meat attained maximum growth of 0.58 g/day as compared to the crabs fed with trash fish and chicken waste.

 

Spawning of lobster and rearing of phyllosoma larvae:

Over 3.4 million phyllosoma hatched out from 17 successful spawning in the hatchery in spite of a long post spawning and resting period. Unilateral and bilateral studies conducted in lobster showed the possibility of production of phyllosoma by the way of induction of gonadal maturation. The larvae were reared up to 85 days for the first time in India reaching the 5th stage. A number of experiments in relation to nutrition (especially live feeds such as Artemia, mussel gonad and artificial feeds like microencapsulated and flake type feeds, hatchery made micro-particulate diets, etc.), water quality and microbial control for obtaining better growth of phyllosoma were also conducted. Further studies are progressing to rear them up to puerulus / juvenile stage.

 

Water quality, disease diagnostics and preventive measures:

During the experiment on the influence of water exchange rate on growth performance of lobsters, it was observed that the lobsters provided with 50% water – exchange rate showed high growth rate as compared to lobsters provided with 25%, 75% and 95% water exchange rate. Experiment on the influence of stocking density on the growth performance of lobsters indicated that 7 animals / sq. m. would be more ideal as compared to 9, 12 and 14 animals / sq. m.

 

The hydrobiological parameters like salinity, pH, temperature, dissolved oxygen, nitrite, nitrate and ammonia were also studied in relation to fattening studies. Microbiological aspects like total heterotrophic bacteria, vibrio and ecto-protozoa were monitored regularly during fattening experiments, which indicated that these parameters were well within the optimum range.

 

Biochemical studies in relation to fattening and breeding:

To elucidate various biochemical processes involved in the growth and reproduction of Panulirus homarus, a comprehensive analytical approach was adopted in relation to nutritional and hormonal requirements of juvenile lobsters. Biochemical analysis conducted on various live feeds (mussels, clams and squids) revealed the acceleration of moulting in mussel fed animals as compared to clam and squid fed lobsters due to relatively high level of lipid, total free sugars and free amino acids in the mussel meat. The changes in the level of total protein, free amino acids, total free sugars, protein bound sugar, glucose, glycogen, total lipids and cholesterol were also studied in relation to different stages of moulting in the juvenile lobster. The changes in the level of moulting hormone, 20 - hydroxyecdysone, were also studied in inter-moult, pre-moult and post-moult lobsters. Unilaterally and bilaterally eyestalk ablated lobsters showed a significant increase in the level of 20 - hydroxyecdysone as compared to eyestalk un-ablated lobsters. The unilaterally and bilaterally ablated lobsters were also noticed with a significant change in the level of estradiol - 17b in the haemolymph. The ovary of ablated animals was filled with pre and post vitellogenic oocytes as compared to un-ablated ovary, which contained only immature oocytes.

 

Further, role of other gonadal steroids progesterone and testosterone in relation to gonadal maturation isalso being elucidated. Serotonergic control of reproduction and growth is also being examined by following the procedures of HPLC - EC and immuno-cytochemistry in the eyestalk, brain and thoracic ganglia of lobsters. More interestingly, the occurrence of corticosteroid - like molecules in the haemolymph and hepatopancreas observed in the spiny lobster is reported for the first time in an invertebrate system.

 

In an attempt to identify moult related protein, native and SDS polyacrylamide gel electrophoretic studies carried out did not reveal any change in the protein pattern of haemolymph collected during different stages of moulting. Therefore, further work was undertaken in this line to observe the changes more closely during pre-moult stage alone after dividing into 4 different substages. In case of muscle, an additional protein band in the muscle was observed as compared to inter-moult animals.

 

 

Transfer of technology to island and coastal communities:

A protocol for fattening technology has been developed by NIOT and two entrepreneurs have already been identified for undertaking the technology developed by NIOT at the field level. A training programme on lobster fattening using live feeds is being organised for the island and coastal communities. A workshop in order to explain the various important issues related to the enhancement of lobster resources in India is also being organised.