Resources of the Wadge and Pedro Banks

Sri Lanka's interest in trawler fishing dates back to 1902 when a Colombo merchant attempted to operate a trawler off Sri Lanka's waters. The next attempt was made in 1907. These attempts did not proceed any further. Between 1920 and 1923 a very comprehensive survey of the littoral waters around the island was carried out. One of the principal aims of the survey was to investigate the possibility of trawler fishing in the seas around. Malpas (1926) and Pearson and Malpas (1926) reporting the results of the survey indicated that the Wadge and Pedro banks were the only areas available for commercial trawler operations and indicated that the fish resources in the two banks could be profitably exploited. Commercial exploitation of the Wadge bank commenced in 1928 and a fishery is now firmly established in the bank. The Marine Biologist and the Director of fisheries in their administration reports and Sivalingam and Medcof (1957) and the author (1965) have reported on the progress of the Wadge bank fishery. Some of the trends indicated by an analysis of the records of the commercial trawling operations are further discussed in this paper.

Results of a stratified random bottom trawl survey for scad and mackerel in Mozambican waters, from May to June 1984

The total abundance of small pelagic species in Mozambican waters was estimated to be 100 (plus or minus 45) thousand tonnes of which scad and mackerel constituted 57 (plus or minus 39) thousand tonnes. These abundance estimates must be considered as minimum estimates of biomass as the efficiency of the trawl was assumed to be equal to 1.0.

Assessment of impact of ten days fishing ban in the major spawning grounds of hilsa (Tenualosa ilisha, Fisher and Bianchi, 1984)

A study was undertaken to find out the impact of ten days fishing ban in the major spawning grounds of hilsa during October to December. The study revealed a positive impact of fishing ban during spawning season on reproduction success of hilsa. Proportionate distribution of male and female hilsa also showed a significant level of distribution in and around the spawning grounds where the ratio was 35:65. Percent of oozing hilsa during fishing ban period in the spawning grounds was observed 1.61%. About 5% spent hilsa was observed in the fish landing centers and was compared with the data of Global Environment Facility (GEF) and Bangladesh Fisheries Research Institute (BFRI) studies and was found about 2.80-3.57 times higher than that of the findings of 2002 and 2003. Estimated egg production value showed about 46,800 Kg of eggs could have been produced that indicating a positive impact of 10 days fishing ban in spawning season. Abundance of higher percentages of gravid hilsa was found which were not available in the same quantity and condition in the non-fishing ban period. During the present investigation, fairly higher amount of spent hilsa and juveniles were also observed in the spawning grounds. Along with the jatka fry, spawn and fries of other fishes were also found in higher quantity than the previous years and thus it is assumed that fishing ban also might have positive impact on the successful breeding of other fishes. Overall, the fishing ban was found effective for successful breeding of hilsa.