Reproductive biology of Sardinella longiceps along Ratnagiri coast off Maharashtra

Indian oil sardine Sardinella longiceps is a highly migratory fish with large scale shoaling along the coast of Ratnagiri. Length weight relationship equations analysed for males were W = 0.0350 L 2.4918 females were W = 0.0536 L 2.3410 , indeterminants were W = 0.0200 L 2.7021 and for combined sexes were W = 0.0321 L 2.5225 indicating no significant difference between the sexes of S. longiceps . Average GSI values of females were 1.4998 with maximum GSI value 5.4962 in the month of September and minimum (0.4299) GSI value in the month of October. In males the maximum GSI value 4.4962 were observed in the month of September and minimum GSI value 0.2992 were observed in the month of October. Observations reveal that spawning in S. longiceps generally takes place only once in a year. Females were always more in number with an average ratio of 1 male:1.1549 females with highest ratio in the month of January. Size at maturity varied from 16 to 20 cm, with occurrence of well developed mature gonads in the months of August-September and spent ones in the months of November to February. Number of mature eggs in the ovaries of the gravid females with the total weight of fish ranging from 50-60 kg varied from 45,000-75,000.