Coastal Aquaculture and Mariculture

Unit 8- Deep sea fisheries

8.2.3. Conservation of exploited fisheries resources
The following main action points need to be considered for the sustainable utilization and conservation of exploited fisheries resources.
Reduce losses
Discards at sea constitute up to 30%. Other post harvest losses are up to 15% and on account of non-food uses up to 9.73%. In other words, up to 55% of the fish which is actually caught at sea could be better utilized for human food purpose through appropriate intervention to reduce losses.
Harvesting immature / undersized fish
Use of undersized fishing nets result in capture of undersized / immature fish. This results in great loss to the fishery resources. Strict adherence to the recommended cod end mesh size of 35 mm will allow the juveniles to escape and grow to commercial size, thus contributing to the total weight (quantity) of fish caught from the seas.
Banning destructive fishing
Fisheries use several destructive methods of fishing such as blasting, poisoning, trawling in reefs, sea grass bed. Appropriate action should be taken by the Government to prevent such destruction. Ghost fishing must be reduced.
Implemetation of closed seasons
The committee apponted by the Government of India has recommended a closed season for 47 days from 15th April to 31st May along the east coast and 15th June to 31st along the west coast. All maritime State Government should be directed to strictly enforce the monsoonal ban as per the recommendations.
Diversification of fishing
The pressure on the nearshore fish stock should be reduced by opting for diversification of fishing to multi-day fishing, deep seafishing. This will increase yields substantially.
Optimising fishing fleet size
The non-mechanized sector contributes to 13% of the yield. This sector has an overcapacity of 81 %. The motorized sector contributes to 20% of the yield. This sector has an excess capacity of 60%. In contrast to these, the mechanized sector which contributes to 67% of the yield has an excess capacity of 55%. It is this sector where the excess capacity has to be gradually reduced to optimum levels. Even a reduction of 10% of trawlers can increase the fish yield by 50 lakh tonnes annually,
Sea ranching
One of the methods to enchance coastal productivity is through sea ranching of juveniles of hatchery produced fish and shellfish. This has to be massive and continuous at various locations to achieve a noticeable impact. Government sponsored schemes are to be implemented for sea ranching of shrimps, high value species such as lobsters, crabs, sea cucumbers and demersal fishes on a long term basis for visible increase in production.
Reducing biological overfishing of stock
The overall exploitation rate (E) is 0.59 for Southeast Asia while the optimum should be between 0.3 and 0.5. Therefore, reduction in exploitation rate is an ideal way to increase the yield.
Degradation of critical habitats
Substantial loss of critical habitats such as mangroves, seagrass beds, estuaries, coral reefs occurs due to coastal pollution, fishing, industrialization, urbanization, global warming etc. Government action is needed to put in to place coordinated action plan to restore degraded critical habitats.
Mariculture
Production of fish from sea also could be enhanced through growing fish in sea by using pens, cages. Shellfishes like mussels, oysters, clams, scallops, seaweeds could be grown on rafts by using ropes, nets etc. The production of mussels through mariculture has reached the present level of 6,000 tonnes/year and oysters 1,000 tonnes/year. However, it must be realized that production of fish and shellfishes through mariculture has its limitations and it would never compensate adequately the gap in capture fisheries, although value-wise the increase could be remarkable. Further, it would add to coastal livelihood, employment and nutritional security.
Artificial Reefs and FADs
These man-made structures will attract fish to these areas, thus allowing local fishers to undertake concerted fishing to capture fish easily. There is need to install FADs in certain sensitive and distressed areas to promote local livelihoods, but this should not be taken up as a massive activity across the coastal regions as it has also adverse impacts on the fish resources.
Responsible fisheries
By following the code of conduct for responsible fisheires both in letter and spirit, it will be possible to increase marine fish yields systematically over the next few years. It must be reckoned that interventions in the capture process will result in an initial decrease which should be viewed without any panic. The situation will show improvement slowly as it takes time for the resources to respond. In a year or two, the anticipated results will be achieved. Governmental initiative in this direction is urgently called for.