© 2003 by ICES/CIEM International Council for the Exploration of the Sea/Conseil International pour l'Exploration de la Mer
Time scale of ovarian maturation in Greenland halibut (Reinhardtius hippoglossoides, Walbaum)
a Commission Européenne, Direction Générale de Pêche Joseph II 99, 1040 Bruxelles, Belgium
b Instituto Español de Oceanografía Apdo, 1552 Vigo, Spain
c Department of Fisheries and Oceans PO Box 5667, St. John's, NL A1C 5X1 Canada
*Correspondence to S. Junquera; tel: +32-2-2984727; fax: +32-2-2955700. e-mail: susana.junquera{at}cec.eu.int.
Evidence for a prolonged ovarian development phase in Greenland halibut is presented. The reproductive cycle in this species was originally described based on the assumption that this phase should last about one year. The results of the present study, which involves data series covering a long time period and different geographic areas, show instead that there is more than one year between the mean age of the females that are at the onset of ovarian development and the mean age of the females that are actually spawning. There are two possible interpretations for this observation. One is that the ovarian development phase (vitellogenesis) could last more than one year and thus as a consequence, individual spawning would not necessarily occur on an annual basis. The other would be the existence of a high proportion of non-spawning females every year for other reasons not related with the natural rhythm of oocyte development.
Keywords: Greenland halibut, adolescent phase, vitellogenesis, spawning
Received 20 January 2002; accepted 17 March 2003.