OOCYTE DEVELOPMENT IN SUMMER FLOUNDER: SEASONAL CHANGES AND STEROID CORRELATES

R.R. Merson, C.S.Casey, C. Martinez, B. Soffientino, M. Chandlee, J.L. Specker-2000

Journal of Fish Biology, 57(1): 182-196

Abstract:

Seven ovarian stages are described in summer flounder Paralichthys dentatus. In the prespawning season plasma oestradiol levels increased in maturing fish with lipidogenic oocytes and gonadosomatic index increased in fish undergoing vitellogenesis. Atretic oocytes present in the postspawning season indicated which individuals may have spawned. The pattern of oocyte development is similar to that of other flatfishes and some teleosts. The summer flounder was unusual in having a long lipid uptake phase (oocyte diameter up to 301 µm) prior to any indication of vitellogenin (yolk protein) uptake. This information will be useful in the construction of an updated maturity schedule for the wild population.

(Graduate School of Oceanography, University of Rhode Island, 218 South Ferry Road, Narragansett, Rhode Island, 02882, U.S.A., Tel.: (401) 874-6858; fax: (401) 874-6887; E-mail:jspecker@gso.uri.edu)

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