Fig. 1.

Gonads promote the growth of tilapia. (A) Photographs of male tilapia at 50 d after sham operation, gonadectomy, or ectopic transplantation. (Scale bar: 2 cm.) (B) Comparison of body weight among the experimental groups. At 40 d (initial, before surgery), the average body weight was no different among groups. At 90 d (50 d after surgery), gonadectomized fish of both sexes (GA) exhibited growth retardation compared with sham-operated fish (SO). Fish that received the ectopic gonad transplant (ET) did not differ in weight compared with SO fish. Results are mean ± SEM calculated for each group. Values with different letters are significantly different (P < 0.05; n ≥14).