Studies on the fishery and growth rate of oceanic Skipjack Katsuwonus pelamis (Linnaeus) at Minicoy island from 1966 to 1969

Abstract

Although the skipjack fishery att Minicoy extends aP through the year the peak fishery is during Novernbe~April. The size in the wmmercia~ catches mnps batween 350 and 695 mm. The total catches fluotuate appreciably from year to year. The catch cornpasition end the catuh ~raste in difiment months are preented. hploying the probability-plot meithod (Hrurding 1949, and Cssvie 1954) 4 yealr olasses have k e n recognissd, and it is fwnd that the fish attains 402.2, 494.0, 562.6 and 620.5 mm mpectively whejn it is 1-year, 2-year, 3-year and Cyear old. By lengthdfrequency study 5 year cl!pses were traced, hsvjng the size of 410, 500, 570, 630 and 680 mm ~re~pectivelyfa r the I-, 2-, 3-, 4- lad 5-year classes. Van Bentalanffy's growth equation was fitted to the observed values and the growth parametars were wtirnakd both graphiodly alnd a r i h & i 4 y which gave identical results. The calculated values of the parameters were L a = 843 ' mm, to = 11.45 yeaa and K = 0.22314. The length mt age, a11nucd inarement an$ @he average molnithly growth rate obta~ilned i~n these differenlt methods were almost identiall.