The Indian mackerel; V Population

Pradhan (1956) examining the mackerel landings at Karwar from 1948-49 to 1952-53 concluded that the sex composition of the commercial catches during the fishing season was roughly as 45% male and 55% female. Similar qualitative statements regarding sex distribution of commercial landings at various specific centres are available in the annual reports of the Central Marine Fisheries Research Institute. In 1965-66, the sex ratio studies at Cannanore indicated that the proportion of males was slightly higher than females (53.18:46.32) in the adult population. The predominance of males was also seen in Juveniles (modal size 135 mm). In the medium sized fish (modal size 205 mm) which contributed to the bulk of the catch, the sex-ratio was in the reverse order (40.7M;59.3F). In the same year, at Cochin females dominated the catches except for April and September (Central Marine Fisheries Research Institute Annual Report 1966). In 1966-67 season, the sex ratio during the fishing season was found to vary though in some centres was almost equal (Cenrtal Marine Fisheries Research Institute Annual Report 1967). In the first half of 1967-68 season, the sex-ratio of a sample analysed at Karwar showed that females were more numerous. At Mangalore, males were more numerous in the aggregate. Sexes were almost equally represented at Cochin and Cannanore. At Vizhinjam males were predominant in March. In the second half of the year, at Cannanore the females increased to more than twice that of males (Central Marine Fisheries Research Institute, Annual Report 1968). The above excerpts will show that there is no uniformity in the sex distribution in the commercial catches either among various centres or between various fishing seasons. In the absence of