Figure 1

Expression (Q-RT-PCR) of luteinising hormone subunit (LHβ) in the pituitary and the gonadosomatic index (GSI) in male and female eels. Eels were sampled at the start, after three months rest, after three months of SW-swimming and three months after a single GnRHa injection (Gonazon For Fish, Intervet). In females, regression occurs during the experimental period, an effect which is more pronounced in the resting group than those stimulated by SW-swimming and GnRHa. In males however, SW-swimming and GnRHa activate maturation (student t-tests with * = P < 0.05; ** = P < 0.01; 3 m rest vs. start, 3 m swimming or 3 m GnRHa vs. 3 m rest).