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Timing of the maturation transition in haddock Melanogrammus aeglefinus
Author(s) -
Tobin D.,
Wright P. J.,
O'Sullivan M.
Publication year - 2010
Publication title -
journal of fish biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.672
H-Index - 115
eISSN - 1095-8649
pISSN - 0022-1112
DOI - 10.1111/j.1095-8649.2010.02739.x
Subject(s) - haddock , biology , oocyte , vitellogenesis , spawn (biology) , development of the gonads , seasonal breeder , follicle , andrology , zoology , fishery , medicine , embryo , endocrinology , fish <actinopterygii>
The timing of maturation in haddock Melanogrammus aeglefinus was examined using changes in gonad development, follicle stimulating hormone β (FSH‐β) transcript expression profile, growth and condition of 1 year old females held under a common environment between the summer and winter solstices. The circumnuclear ring, cortical alveolus and vitellogenic oocyte stages were first observed in August, October and November, respectively. FSH‐β transcript levels did not change significantly until September but increased markedly thereafter in maturing fish. A combined analysis of the mean oocyte diameter of the leading cohort, histological staging and FSH‐β transcript profile provided evidence of a commitment to maturation by October or November. Contrary to that previously proposed for gadoid species, histological analysis of field‐caught immature M. aeglefinus during the spawning season indicated that cortical alveolar, rather than circumnuclear ring, stage oocytes provided definitive evidence of maturation. A decrease in relative liver size following the summer solstice suggested a possible link between energy status and maturation.