Study on the gill structure and the respiratory area of Chu's croaker Nibea coibor

The gill ultrastructure of Chu's croaker Nibea coibor with different body weight (4.75~35.51 g) was studied, as well as the relationship between individual size, life habit and the respiratory area. The results obtained were as follows: the average value of relative respiratory area of the N.coibor was 4.011.62 cm2g-1. The total number of unilateral gill filament (N) was more closely correlated with body weight (W) (N=28.81+158.45lnW, R2=0.9670，P0.01) than with body length (L) (N=17.31L1.4542, R2=0.8241, P0.01). The number of secondary gill lamella (N) per millimeter significantly declined by N=49.971W-0.3909 (P0.01). The single secondary gill lamella area (a) significantly increased by a=0.3199W0.2528 (P0.01), with the increasing of body weight (W). Total respiratory area (A) was significantly positively correlated with body weight (A=11.559W0.7109, P0.01), while relative respiratory area (RA) was significantly negatively correlated with body weight (RA=11.561W-0.2904, P0.01).