Wadge Bank trawl fishery studies. Pt. 1. The effect of the 1928 to 1935 commercial trawling on the demersal stock

The demersal fish stock of Wadge Bank is one of the important fish resources for both Sri Lanka and India. Sivalingam and Medcof (1957) have given an account of its history, general features and relative productivity. According to records the total fishing effort on the bank had been fluctuating and very recently the number of boats operating on the bank has suddenly increased, and there is a possibility that still more will begin operating on the bank in the near future (Mendis, 1965). The increased fishing effort with the possibility of still further increase calls for proper management practices by those concerned, in order to obtain the maximum sustained yield from the demersal stock. For this purpose a detailed study of the past performance of the fishery is essential. With this in view all records of commercial operations up to 1960 are being analysed by the present author and are to be published in a series. This is the first paper in the series and gives a detailed analysis of the first commercial trawling operations from 1928 to 1935. Since there had been a major break of about 10 years between this and the present fishery this data is being analysed separately.

Pt. 2. The effect of trawling on the catch per hour from 1945 to 1960. Bulletin of the Fisheries Research Station, Ceylon, 19(1-2), pp. 19-26. - Pt. 3. Nature and composition of the resident population. Bulletin of the Fisheries Research Station, Ceylon, 20(1), pp. 27-38. - Pt. 4. An analysis of the length frequency measurements of the sea bream (Lethrinus nebulosus) made in 1949 and 1953 to 1958. Bulletin of the Fisheries Research Station, Ceylon, 20(1), pp. 39-50. - Pt. 5. Rational exploitation of the resident demersal stock. Bulletin of the Fisheries Research Station, Ceylon, 20(1), pp. 51-64. - Department of Fisheries, Fisheries Research Station, Ceylon now incorporated in: National Aquatic Resources Research and Development Agency, Sri Lanka