M.A. HYE
Manager, Trawler Fleet, BFDC
INTRODUCTION
Bangladesh having 66440 km2 shelf area in the Bay of Bengal provides potential resources of fish & shrimps. About 37000 km2 is within 50m depth zone which is considered as good fishing area. The coast line extends about 480 km long. Based on different surveys and research works in the Bay of Bengal, it is estimated that the standing stock of fish is around 2,64,000 to 3,73,000 M.T. and that of shrimps around 9,000 M.T. The marine fisheries catch is about 28% of the total catch of the country (1989–90) and approximately 13.21% (1994) of the total national requirement of fish. The marine fisheries catch was about 95,000 M.T. in 1975–76 which has increased to about 2,60,000 M.T. in 1992–93. This shows an increase of 273% in 17 years period. The major contribution (95%) of this catch is of the small and artisanal fisheries sector. The contribution of industrial fishing with trawlers is although not significant interms of quantum (5%) remarkably shares the export earning.
* Manager, Trawler Fleet, BFDC, Fish Harbour, Chittagong. The paper was presented to the Seminar on Sustainable Development of Marine Fisheries Resources in Bangladesh, MFTS, FRI, Cox's Bazar, August 29–30, 1994.
2. RESEARCH
Since 1958, several surveys & studies were made to evaluate the abundance of fish and to promote the marine fishery. Japanese survey vessel Chosui Maru Pioneered the investigation. Kagawa Maru, (1960), Kinki Maru, (1961–62), Jalwa (1962-66), Sagar Sandhani & Meen Sandhani (1968–71), Lesnoy (1969–70), Tamango & SRTM (1972), Santamonica & Orion (1976–77), Fishery Research Vessel II (1979), Dr. Fridtj of Nansen (1979–80) and Anusandhani (1981–84) followed the survey and made assessment of the stock. The results of the surveys have provided potentiality, abundance and economical viability of commercial fishing in the Bay of Bengal. The Research vessel Anusandhani is assigned to carry out continuous studies to outline guidance for a judicious exploitation of the resource.
3. POTENTIALITY
Results are available from survey reports and review papers. Al surveys have identified “SOUTH PATCHES” in the east part of the area near Cox's Bazar and Elephant Point as good fishing ground. The other two potential fishing grounds are “CENTRAL ZONE OR MIDDLING” and “SWATCH OF NO GROUND”.
West (1973) calculated demersal fish on the basis of data collected during 1968–71 and recommended a potential yield of 175000 M.T. FAO (1972) estimated the same amount of potential yield.
Khan et al (1983) estimated demersal fish stock on the basis of R.V. ANUSANDHANI Trawling cruise at 1,50,000 M.T.
Lamboef (1987) indicated the estimate as 150,000 to 1,60,000 M.T. of demersal fish in 10–100 m depth stratum and 25,600 tons as pelagic fish and concluded the overall estimates as 188,000 M.T. in Bangladesh EEZ deeper than 10 m.
Hussain (1970) reported 475 species of fish belonging to 133 families among them 42 species are of economic importance.
The study made by R.V. Anusandhani from Sept, 84 to June, 86 tabulated the percent composition of commercially important fishes and narrated that the main groups of species are jewfishes 12.8%; catfishes 11.6%; threadfin breams 4.4%. Other species of good commercial value are present in lesser quantities.
4. FISHING GROUNDS
The surveys and researches so far carried out in the Bay of Bengal give a fair idea of distribution of fish/shrimp in different depth strata. The distribution of commercially important, demersal species by depth strata is 38.5% in 10–20 m, 26.7% in 20–50 m, 13– 3% in 50–80 m and 21.5% in 80–100 m. The distribution of shrimp by depth strata is 45.2% in 10–20 m, 31.2% at 20–50 m., 12.7% in 50–80 m and 10.9% in 80–100 m. Thus it is evident that approximately 65% and 75% of fish and shrimps respectively are available within 50 m of the surface.
The Marine Fisheries Ordinance 1983 provides “Area for fishing with trawlers are earmarked for operation beyond 40 meters of marine waters at its highest tide”. The distribution of fish/shrimp and the jurisdiction of fishing area has created controversy and indicates under exploitation of demersal fish/shrimp within 50m depth stratus. The area upto 40m depth was kept reserved under the preview of the ordinance for the benefit of small scale fisheries. But the actual situation calls for reviewing and making to date the jurisdiction for different types of fishing.
5. STATUS OF MARINE FISHERIES TECHNOLOGY
The small scale fishing sector with about 6,000 mechanised boats and over 12,000 indigenous boats contribute 95% of marine catch. There are about 55 trawlers, at present operating in the Bay of Bengal catching shrimp and fin fish. The small scale fisheries use drift gill nets, set bag nets, bottom set long line, seine nets, drag nets, cast nets etc. The trawlers use bottom trawl nets mainly for catching demersal shrimp and fin fish. It is helpful to emphasize the following improvements to harvest the fish resources of Bay of Bengal effectively.
5.1 PELAGIC FISHERY
Extensive efforts for ascertaining pelagic and semipelagic fishery resources was hardly carried out in the Bay of Bengal. Surveys conducted in the past on national and regional basis in the Bay of Bengal undertook test gill netting and long lining for Tuna, Mackerels, Sharks and other pelagic fishes expeditiously. Successful test result would lead to development of a fleet of mechanised boats for pelagic fishing in the distant waters.
5.2 UTILIZATION OF BY CATCH FROM SHRIMP TRAWLERS
It is reported that, about 35 to 40 thousand metric tons of trash fish are annually discarded and thrown in to sea by the shrimp trawlers (White and Khan 1985). This situation prevails more or less throughout the whole world. Only about two thirds of the world's catch is eaten directly by humans. It is estimated that about 20% of the global catch from fishing vessels each year is discarded. It is also said that “Modern methods destroy up to 5 kg. of fish to obtain 1 kg of shrimp”.
Bangladesh has a shortage of fish production and cannot afford to allow the wastage. The industrial shrimp trawlers should be induced to save the low priced by-catch of the shrimp trawler by offering them an incentive price for the by-catch. Steps should be taken to process the trash-fish items into nutritious and high priced human food. Measures should be taken to exploit the shark populations for vitamin rich oil and exportable fins.
6. IMPROVEMENT OF TECHNOLOGY
Introduction of diversified and more effective fishing gears and equipping selected types of boats with appropriate engines, would receive priority so as to enable the small scale sector to more effectively exploit the fish and shrimp. Regional experience in this respect should be utilised.
The world fisheries has already made tremendous improvements in technology. It is essential to draw on their experience and improve technologies suitable to the country's situation.
Fish Aggregating Devices (FAD) have already been developed in marine fishing. The fisheries training section of the South Pacific Commission (SPC) has developed the production of resource materials to provide a logical follow up to FAD developments. A training kit consist of eight modules covering areas such as safety at sea, fish handling and quality, small fishing business management and of course the fishing technique is available with the SPC.
In the Philippines fishermen using super light, an attractant using halogen or metal halide bulbs with ultraviolet gas to lure and congregate fish. Luring lamps are in wide use to improve the efficiency of squid catching unit.
Daily forecasts to boost catches are also in practice in many developed fishing countries. Fish forecasting services to provide fishermen with reliable data on water temperature, water current directions, vessel position and fish catches are monitored to improve catch per unit (CPU) effort by developing catch prediction modules.
Marine computing guide, the most comprehensive international classified directory of computer software systems and services for the maritime industry is being used by the developed fishing nations.
Selective fishing gear and practices are yet to be developed by us which recognises the need to protect biodiversity, waste of catch of target species and also to minimise the incidental catch of non-target species and resources.
Steps should be taken for the development of ecologically friendly fishing gear and technologies to promote the sustainable harvest of under exploited fish species. Introduction of new fishing gears/methods reducing reliance of current destructive gears would save frequent damage.
Reduction of the by catch in shrimp trawling has already been taken into consideration by fisheries institutions. In Australia it is proved that larger square mesh in the codends reduces the amount of fish by-catch by 33% on average, compared to diamond mesh. Thus, square mesh in codend has great potential for reducing fish by-catch in shrimp trawls.
7. RECOMMENDATIONS
On the basis of the foregoing discussions the following recommendations are made to augment the fish catch, to utilize the resource judiciously and to improve the technological level as developed by fishing nations of the world.
Continued research and survey should be conducted to ascertain the MSY, fishing grounds, home range of migratory fish/shrimp, routes of migration etc.
Research and extension should be co-ordinated to facilitate effective fishing.
Institutional facilities should be provided to improve pragmatic fisheries technology and to train manpower practically.
Fisheries regulatory and monitoring functions should be strengthen to effectively co-ordinate the Govt. and field efforts.
REFERENCES
Anonymous, 1994. Fishing Technology Digest for Asia Pacific. Infofish, Issue No. 7. Kuala Lumpur, June, 1994.
Anonymous, 1994, News item Matshya-Pashu Sampad Barta, No. 3, July, 1994.
Hussain, M.M. 1970. Marine and Estuarine Fishes of the North East part of Bay of Bengal. Scientific Researches. East Regional Laboratories. Pakistan, Vol. VII, No. 1.
Hye, M.A. 1991. Fish Resources in Bangladesh. The Bangladesh Observers, 24th December, 1991.
Khan G.M. Bongoposhagorer Matshya Sampad O. Tar Arthonaitik, Guruthya, Matshya-pashu Sampad Barta No. 6, 1993.
Lamboe-uf, M. 1967. Demersal Fish Resources of the continental shelf, F.I.DP/BGD/80/025. FAO, Rome.
West, KQB. 1973. Fishery resources of the upper Bay of Bengal. Indian Ocean Programme, Indian Ocean Fisheries Commission, Rome, FAO JOFC/DEV/73/28.
White, T.F. 1985a. Marine Fisheries Resources survey, Demersal Trawling survey cruise report 1984, BGD/80/0 25/CR4.
