OBSERVATIONS ON THE FISHERIES OF THREADFIN BREAMS (NEMIPTERIDAE) AND ON THE BIOLOGY OF NEMIPTERUS lAPONICUS (BLOCK) FROM KAKINADA

Abstract

Of the four species of threadfin breamf occurring, N. japonicus is the most
dominant at Kakinada. Peak landings are obtained during first and last quarters.
There is significant difference in length-weight relationship of males and females.
Peak values of Relative condition factor are associated with accumulation of fat.
This species is a fractional spawner releasing the ripe ova in two batches during
a protracted spawning season: August-April. The length at first maturity is esti-
, mated as 125 mm in females. The estimated fecundity ranges from 23049 to
139160 in fishes of 134-199 mm length; in this length range, there is linear relationship
between length and fecundity and between weight and fecundity. Generally
males outnumber females and attain larger length. N. japonicus attains 185 mm,
255 oun and 285 mm at the completion of the first, second and third years, respectively,
at Kakinada. The various growth parameters are estimated as:
L a " 314 mm, K « 0.75142 and t,, = -0.17309 years