Effect of combining different photoperiod regimes on the sexual maturation of male sea bass (Dicentrarchus labrax L.) during the first two years of life

This study assesses the effect of combining different photoperiod regimes on the sexual maturation and growth of male sea bass during the first two years of life. In two different trials, regimes of continuous light (LL) lasting 24 consecutive months (Trial 1) or shorter periods within the summer-early autumn months during the first and second annual cycles (Trial 2) were compared to control groups under a natural photoperiod (NP). In a third trial (Trial 3), fish kept under either NP or LL conditions during the first year were subsequently assigned a treatment involving exposure to NP or a constant long photoperiod (LP) throughout the second year. The rates of spermiating males, gonadal size (GSI) and growth under all these photoperiod regimes were analyzed. Exposure to LL reduced the rates of precocity in all trials (
The authors wish to thank C. Marín and X. Simó for their technical assistance in rearing and sampling the fish. The work of the authors in this article was supported by UE projects Q5RS-2002-01801 (PUBERTIMING) and Grants AGL2006-04672 (PUBERCONTROL) and CSD2007-00002 (AQUAGENOMICS) from the Spanish Ministry of Science and Innovation (MICINN) and PROMETEO/2010/003 (Generalitat Valenciana). RR was supported by a FPI fellowship from the MICINN (Spain).