Pelagic fishery resources of Sri Lanka and its present level of exploitation with special reference to off-shore and deep-sea waters

Pelagic resources around Sri Lanka may be categorized into three major groups: (1) the small pelagic varieties such as the sprats, halmessa, sardines (salaya, soodaya), and herrings (hurulla). (2) the medium size pelagic species such as the mackerel (kumbala and bolla), barracuda (jeela), seer Spanish mackerel (thora), frigate mackeral (alagoduwa), mackerel tuna (atawalla) and the skipjack (balaya). (3) the large size fishes such as yellow fin tuna (kelawalla), big eye tuna, marlins (koppora and gappara), sail fish (thalapath), sharks (mora) and rays (maduwa). Production levels of exploited resources are noted, and seasonal patterns and annual in their abundance are considered. On the basis of observations and estimations of the existing fisheries, and the results of experimental fishing, figures are presented of the potential yield of those species already exploited. The development of that potential depends on the development of modern techniques of pole and line fishing, application of tuna longline and shark longline, increasing the number of units of drift nets and the introduction of a bait fishery for the longline and pole line fishery. Some features upon which the successes of any venture to exploit such resources are noted, particularly those which relate to the nature of the fishing vessels used.

Operatives for off-shore and deep-sea fishing vessels

The need for operatives for the offshore and deep-sea fishing vessels is currently very great, and the importance of fisheries training has long been recognized by the Department of Fisheries. In 1974 the Sri Lanka Fisheries Training Institute was established with Japanese aid. The author discusses the purpose and functions of the institute, the first batch of trainees from which finished their training in June 1977. Annexes describe the courses offered, diplomas and certificates, admission requirements, and the conditions required for candidates sitting second-hand fishing vessel examination of the Mercantile Marine Department, Bombay District.

Infrastructure facilities for deep-sea and off-shore fishing

The author presents a brief account of the infrastructure facilities required for the fishing industry. He describes those facilities presently available in Sri Lanka, and those that are under construction, and gives a few suggestions indicating the nature of infrastructure facilities that are vital to the local situation at its present stage of development. The principal facilities discussed are (1) fish landing places; (2) unloading handling facilities; (3) vessel servicing facilities; and (4) navigation aids.

Private sector to invest in off-shore fishing and to encourage the financial incentives to be introduced for deep-sea fishing in Sri Lanka

The author discusses the financial aspects of private sector investment in off-shore fishing, with particular attention to tax incentives, such as those offered to tourist hotels, which are considered applicable to the current case of fishing vessel purchase, and the operation of the vessels themselves, hiring, publicity and profitability. Tax incentives which were introduced to encourage investment in the tourist industry should be introduced to encourage investment in the fishing industry on the lines presented. It is essential that wide publicity be given for the incentives introduced so as to achieve the desired results.

The storage of red snapper (Lutjanus spp.) in ice, chilled sea water and chilled fresh water

The results are given of trials conducted to determine the effect on quality of holding fish (Lutjanus species) in chilled freshwater and also to compare the quality loss of fish stored in chilled seawater and chilled freshwater and in ice. No adverse effects were observed when storing in chilled freshwater apart from loss of external appearance after 6 days storage; taste panel tests showed acceptable conditions up to 15 days. Chilled seawater is unsuitable for storage as it spoils the intake of salt from the medium, making the flesh unpalatable.

An illustrated key to the Malacostraca (Crustacea) of the northern Arabian Sea. Part 3: Euphausiacea

The key includes twenty-one species of euphausiids belonging to two families and six genera. The key was prepared following Brinton (1975). Since several authors attributed a fundamental importance to thelycum in systematics of euphausiids therefore the available figures of thelycum are also included.

Studies on isolation of salmonella from sea foods 1. Comparison of enrichment and selective media for recovery of salmonellae from fish

Three enrichment broths and six plating media were compared for efficiency of detection Salmonella in the presence of numbers of Coliforms (10super(5)/ml) and proteus (10super(3)/ml) from artificially inoculated fish samples. Recovery experiments Salmonella anatum, S. typhimurium and S. enteritidis indicated that the two enrichment broths Dulcitol Selinite (DSE) and Selinite Cystine (SC) were equally efficient. Further, the viability of Salmonella, inoculated into fish muscle and kept at 4°C for 48 hours, was found to be not affected by the low temperature storage. Selective plating media like Xylose Lysine Deoxycholate agar (XLD), Brilliant Green Sulphadiazine agar (BGS) and Brilliant Green agar (BG) were found to be superior in performance to Salmonella-Shigella agar: (SS) and Bismuth Sui phite agar (BiS).

Modification to the bilge and sea water pumps fitted in 17.5 metre Jingha type trawlers

This paper brings out the difficulties encountered with the Bilge and sea water circulating pumps which are fitted and drawn in series along with a fresh water pump in the 17.5 m fishing trawlers.

Design of refrigerated sea water plant for preservation of fish

To study the feasibility of employing refrigerated sea water on board fishing vessels for the preservation of fish, a pilot model has been designed, the details of which are presented in this paper.

Problems associated with the over protection of fishing trawlers against sea water corrosion and fouling

Some presently used anti-fouling materials contain metals and other compounds, which are toxic in the environment. Coating products are not always stable, and there is a resulting pollution hazard. In particular if surfaces are poorly prepared and manufactures' instructions are not closely followed the application of anti-fouling substances becomes pointless and dangerous. In addition the salinity, constant biological activity and suspended particles make seawater a highly corrosive material in its own right.

Studies on preservation of fish in refrigerated sea-water

Storage characteristics of oil sardine (Sardinella longiceps), mackerel (Rastrelliger kanagurta) and seer (Scomberomorus guttatus) in refrigerated sea-water (RSW) were studied in comparison with their storage in crushed ice. Oil sardine stored in RSW was found to be comparable to iced ones only during the initial stages (up to 2 days) of storage and on further storage the former was found to be inferior to the latter. RSW can be advantageously employed for preservation of mackerel and seer. Mackerel and seer could be stored in RSW in acceptable condition for 4 to 6 days and 12 to 14 days respectively.

An analytical study of the sea water slime with reference to bacterial flora

A detailed study of the primary film of slime with reference to the bacterial flora, its quality and quantity, as observed on different material surfaces exposed to sea water is carried out. A correlation has been established between bacteria and slime deposited on different surfaces.

Economic analysis of 22m and 23m deep sea trawlers

The cost-benefit analysis of 23m and 22m trawlers operated from Visakhapatnam base is presented. The study indicated that the deep sea fishing in Indian waters is a profitable venture. The profit over capital investment for a 23m trawler worked out to about 18% whereas the same was about 10% for a 22m trawler. Catch per trawling operation, cost of production, productivity per man year, energy yield etc. establish the economic superiority of 23m vessel.

Incubation temperature for total bacterial count of frozen sea foods

Effect of incubation temperatures of 37°C ambient and 5-10°C on total plate count of commercial frozen prawns, squids, cuttle fish and froglegs were studied. Results indicate that incubation at ambient temperature gives the best results.

Effect of chilled sea water storage of oil sardine (Sardinella longiceps) on quality changes during frozen storage

The shelf-life of frozen oil sardine (Sardinella longiceps) can be improved by preserving the fish immediately after catch in chilled sea water before freezing. Delayed icing caused considerable deterioration in quality and reduced frozen shelf-life. Oil sardine preserved in chilled sea water were found to be suitable for freezing up to 5 days whereas iced samples could be frozen only up to 2 days.