Plasma steroid hormone concentrations in relation to the reproductive cycle of the sweep Scorpis lineolatus (Kyphosidae) caught from the wild

Dedual, M. . Leigh Marine Lab.; Pankhurst, N.W.

Plasma steroid hormone concentrations in relation to the reproductive cycle of the sweep Scorpis lineolatus (Kyphosidae) caught from the wild

1992

Dedual, M. (Auckland Univ. (New Zealand). Leigh Marine Lab.) | Pankhurst, N.W. (New Zealand Dept. of Conservation, Turangi)

Changes in gonadosomatic index (GSI), hepatosomatic index (HSI), oocyte development and plasma levels of steroid hormones were studied during the reproductive cycle of the sweep. GSI values for both sexes were maximal in March and April. During this period the size distribution of oocytes showed a predominance of advanced stages of vitellogenesis, whereas males were completing spermatogenesis. However, staging data suggest that spawning may not begin until April. HSI was maximal 2 months prior to the beginning of gametogenesis in both sexes. Changes in oestradiol-17 beta and testosterone in association with vitellogenesis in females are consistent with those reported for other teleosts, whereas changes in 17,20 beta P, testosterone and 11-ketotestosterone in males are different from those previously reported.

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