Population Characteristics of the Tuna Baitfish spratelloides delicatulus (Clupeidae) from Lakshadweep, India

摘要

The blue sprat, Spratelloides delicatulus is the dominant species of bait used in the pole-and-line tuna fishery ofudLakshadweep. Length-frequency data were collected on a monthly basis during 1988-89 and 1989-90 fishing seasonsudfrom Minicoy and Agatti. Analyses were performed using the compleat ELEFAN suite of programmes. The resultsudindicate that L, is between 65 and 66 mm and K values range from 4.9 to 5.0 per year. Total mortality estimates with L,udas 66 and K = 5 varied widely in the three methods employed and between sites. Natural mortality at the sites was similarudwhile fishing mortality and exploitation rate was maximum at Bangaram. Recruitment patterns showed high percentageudduring August and December at Bangaram while at Perumal Par it showed a delayed pulsing with maximum mode inudJanuary. The exploitation rate (E) values obtained for the bait fishery suggests fishing to be near optimum with marginaludincrease especially at Bangaram. Therefore, the bait fishery at Agatti require close monitoring and further expansion inudeffort must be viewed with extreme caution.