Zygoparity and sex steroid hormone profiles in bluemouth Helicolenus dactylopterus

Sequeira, V.; Couto, Elsa; Neves, A.; Vieira, A. R.; Paiva, R. B.; Canario, A.V.M.; Gordo, L. S.

http://hdl.handle.net/10400.1/13141

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Abstract(s)

Two hundred and seven individuals (103 females and 104 males) of bluemouth Helicolenus dactylopterus (Scorpaeniformes, Sebastidae), a commercially important deep-water species with an unusual reproductive strategy, from the eastern Atlantic Ocean ranging from 13<bold></bold>9 to 37<bold></bold>5 cm total length (L-T) were analysed from September 2011 to October 2012. The analysis included gonad maturity phases and blood-plasma levels of oestradiol-17 (E-2), 11-ketotestosterone (11-KT) and 17,20-dihydroxypregn-4-en-3-one (17,20-P). Results confirmed the existence of an annual reproductive cycle with asynchrony between females and males and a spawning season from January to May. A pronounced peak in 17,20-P in October for both sexes was associated with possible mating behaviour and recent copula. Levels of E-2 increased preceding the elevation of the gonado-somatic index during ovarian growth and were lower during regression and regeneration. The frequency distribution of oocyte-embryonic stages and variation of hormone levels suggest the existence of daily rhythms. Fertilization was detected between 2000-0000 and 0800-1200 h and spawning took place throughout the day peaking between 2000 and 0000 h. The cyclic pattern of sex steroids and ovarian recruitment provides a new insight into the reproductive strategy of this species.