Journal of the Marine Biological Association of India

Volume 15 Issue 2

A Survey of the fishery resources in the northeastern part of the Arabian Sea.

S. Zupanovic and S.Q. Mohiuddin

In this paper the authors present a rough stock assessment for demersal fish and shrimps off the coast of West Pakistan. They note that local fishing appears very intense and that the local stocks are probably fully exploited. This applies only to depths upto about 30 m and perhaps to the area close to Karachi. Landings of demersal fish at Karachi, presumably come mostly from the heavily fished area, is equivalent to a yield of a little under 30 kg/ha. Assuming that this could be increased somewhat by better management, the potential might be as much as 40 kg/ha.

In the offshore waters, between 30 - 100 m the demersal species may form the bulk of th9 potential fish resources. Beyond 100 m catches tend to decrease.

Study of shrimp populations by the analysis of commercial catches indicates that over its range of exploitation, the shrimp exhibits a pronounced decreasing gradient of abundance. Maximum stock density, during 1966-69, occurs off the mouth of the Indus River, near the Indian border. Continuous decline in catch of large specimens may be connected with an apparent higher fishing mortality rate of adult individuals.

In studying the problem of yield in relation to lunar phases, there is reason to believe that shrimp fishing increases in brighter phase of the moon. The difference between the two series is not suggestively, and statistically significant (P = 0.10-0.05). The catch related to the time of day indicates that the catches per unit effort (kg/hr) were higher during the day time.

This study is the first attempt to assess the potential catches for commercial bottom trawling and to obtain the basic biological information necessary to establish more effective and efficient fishing methods to harvest the existing fisheries resources off West Pakistan. Investigations of the environmental factors, such as physical and chemical characteristics of the water masses and their seasonal changes have also been discussed.

Date : 31-12-1973