نویسندگان
1 گروه شیلات، دانشکده کشاورزی و منابع طبیعی، دانشگاه آزاد اسلامی واحد علوم و تحقیقات تهران، صندوق پستی: 14515-775
2 موسسه تحقیقات علوم شیلاتی کشور، تهران، صندوق پستی: 6116- 14155
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسندگان [English]
In this study, the effects of photoperiod alternation on the maturational progress of the white spotted rabbit fish (Siganus sutor) were investigated. A hundred adult fish (total length: 306.4 ± 2.12 mm; body weight 401.5 ± 8.45 g) were caught from Lavan Island. They were divided in 300 l tanks (n = 5) and exposed to tree different day length including 8, 12 and 16 h combined with constant 2000 lux light intensity with three replicates during prespawning season. After 60 days, the GSI mean values were 2.03± 0.34%, 5.83± 0% and 10.39± 0.80%, respectively, for females and 8.15± 0.43%, 13.91± 1.52% and 14.56± 0.41%, respectively, for males according to photoperiods. These results showed significant differences between fishes were reared under 8 h and 16 h photoperiods (P<0/05). In the case of gonad histology, the maturity stages of ovaries along with photoperiod increasing were 3, 4 and 5; whereas testes of males reared in all treatments reached to stage 5. These results clear that increasing of light duration from 8 h to 16 h in combination with 2000 lux light intensity have positive relation with the gonadal progress of white spotted rabbit fish in both sexes. Thus, rearing of fish fewer than 16 h day length obtains the highest level of sexual maturity.
کلیدواژهها [English]
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