Fishery and biology of the oil sardine at Karwar

The oil sardine fishery at Karwar showed erratic fluctuations during the years of study, from an annual landing figure of 4.41 tonnes in 1964-65 to 250.06 tonnes in 1967-68. The average, based on the earlier 14 years' catch worked out to 91.21 tonnes. The three length frequency modes at 135-140, 160-165 and 185-190 mm have been interpreted to correspond to I, II and III age groups. The fish attains maturity at about 140 mm and the spawning season lasts from July-August to November-December. This is also supported by the trend of change in 'K' values. A good fishery season seems related to the temperature range of 27-29.5°C, lower salinity and a low phosphate content in the water