FISHERIES RESEARCH INSTITUTE,MOA,TAIWAN

The black croaker (Atrobucca nibe) is one of the important commercial species for trawl fisheries in southwestern Taiwan. Monthly samples of specimens taken from the trawl landings at Tongkang fishing port from July 2012 to July 2013 added up to a total of 871 specimens (348 females and 523 males). The total length (TL) and body weight (BW) of the collected fish ranged from 158 to 480 mm and from 43 to 1247 g, respectively. For females, the relationship between TL and BW was estimated as BW=2.0 × 10 -5 TL2.925 (R2=0.974, n = 348). Based on the macroscopic appearance, histological examination of ovaries, and gonadosomatic index, the spawning season for the black croaker in the coastal waters off southwestern Taiwan likely lasts from January to May and peaks from March to May. The mean fecundity and mean batch fecundity of this species were estimated as 247,426 ± 227,408 and 57,576 ± 37,205, respectively. The sex ratio (female/total) was 0.40, but females outnumbered males at TL ≥ 300 mm. The size (in TL) at 50% maturity (L50) was estimated to be 310 mm. Logistic curves describing the relationship between the proportion of maturity at each length interval and TL were estimated as P = 1/(1+e6.29 -0.02TL).