Studies on length frequency of the Oil Sardine,Sardinella longiceps, Cuv. & Val., and on certain factors influencing their appearance on the calicut Coast of Madras Presidency

Abstract

(1) The studies on the length frequencies, size groups and age groups of the Oil Sardines of Malabar Coast for the period 1936–37 to 1942–43 have been made and the year classes which contributed to the Oil Sardine fishery in the different years are indicated. (2) The movements of the Oil Sardines and the spawning and survival of the young Oil Sardine on the Malabar Coast seem to indicate a correlation with the surface temperature and specific gravity of sea water and the availability of food. The effect of the surface temperature on the movements of adult sardines month by month and year by year has been indicated. (3) The variations in the surface temperature in the in-shore regions and off-shore regions and on the coasts are discussed in relation to the appearance of Oil Sardine. It is suggested that further investigations on the age of the Oil Sardine and the occurrence of the fish in the off-shore regions, beyond the present fishing limits, in different months may further aid in appraising the causes for the fluctuations of the Oil Sardine fishery.