Growth pattern of the big eye grunt Brachydeuterus auritus (Valenciennes, 1832) off Lagos, Nigeria

Abstract

The growth pattern of the big eye grunt Brachydeuterus auritus (Valenciennes, 1832) off Lagos coast, Nigeria was investigated by determining the length frequency distribution, length-weight relationship and condition factor. Four hundred and fifty specimens were used for this study having body lengths in the range 11.7 - 19.3 cm total length and 9.6 - 16.3 cm standard length. The body weight ranged from 12.4 to 110.5 g. The length frequency distribution showed a unimodal pattern and and the modal size group was 15.0 - 15.9 cm which formed 26.7% of the specimens examined. The length- weight relationship was determined using the regression equation Log W = -1.3351 + 2.6829 Log L (n = 450, r2 = 0.5327, p < 0.05). B. auritus had a negative allometric growth (b = 2.6829) which indicated that proportionate growth was more in body length than body weight. There was a positive correlation between body length and body weight of B. auritus (r = 0.7299). The condition factor for combined sexes was 1.97 ± 0.02. The condition factor was 1.98 ± 0.03 for males and 1.91 ± 0.03 for females. The males had higher condition factor than the females. However, there was no significant difference (p > 0.05) between the condition factor of males and females. The study is significant for estimation of growth parameters of B. auritus, which is essential for management of the fishery.