The effect of methallibure and a constant 12 hours light : 12 hours dark photoperiod on the gonadal maturation of pink salmon (Oncorphynchus gorbuscha) ...

• Main Author: Flynn, Michael Bernard
• Format: Text
• Language: English
• Published: University of British Columbia 2011
• Subjects: Pink salmon
• Online Access: https://dx.doi.org/10.14288/1.0101204; https://doi.library.ubc.ca/10.14288/1.0101204

This study was undertaken to try to delay gonadal maturation of pink salmon for one year beyond their normal two year life cycle. This would allow these fish to spawn in years of low or nonexistent escapement and possibly increase these "poor" year populations. Three experiments were conducted to investigate the efficacy of the antigonadotropic drug, methallibure, in inhibiting gonadal maturation in pink salmon. Gonadosomatic index, oocyte diameter, and stages of cell maturation in the testis and oocyte maturation in the ovary were measured. The first or pilot experiment involved a range of doses of methallibure (0.10 mg., 0.32 mg., and 1.0 mg./gm./2wks.) to determine the optimal dose for subsequent experiments. All doses had only a slight slowing effect on maturation. This result and possible undesirable effects of higher doses prompted the decision to use the 0.10 mg./gm. dose for subsequent experiments. The second or long-term experiment investigated the effects of methallibure and a constant 12 hours ...