Size at Maturity for Northwest Atlantic Redfishes (Sebastes)

Abstract

Morphological differences in Northwest Atlantic redfishes (Sebastes) are recognized but their biology is relatively unknown, due to the confusion associated with redfish systematics in past decades. For a redfish reproductive biology study we utilized historical sex and maturity data collected between 1957 and 1969. We applied the logistic model to estimate the size at maturity from 4501 S. marinus and 43 988 beaked redfishes (S. mentella and S. fasciatus combined) covering the whole Northwest Atlantic. The sizes at maturity for female redfishes were significantly larger than that of males for both S. marinus and beaked redfishes. The size at maturity in female S. marinus was significantly larger than that of beaked redfishes whereas in males there was no significant difference between groups. A geographic cline in size at maturity was noted in beaked redfishes, with a decreasing trend for S. mentella from Baffin Bay southward to the Gulf of St. Lawrence, and for S. fasciatus from the Grand Bank to the Nova Scotian Shelf.

Approaches to Improving Groundfish Survey Abundance Estimates by Controlling the Variability of Survey Gear Geometry and Performance

“…The species composition of adult redfish, and hence also of their larvae,in the Gulf of St. Lawrence is less clear. Meristic (Ni, 1982), maturation (Ni and Sandeman, 1984;Ni and Templeman, 1985) and electrophoretic (P. J. Rubec, Maurice Lamontag ne Institute, Mont-Jol i, Quebec, pers. comm.)…”

Available Information for Estimating Reproductive Potential of Northwest Atlantic Groundfish Stocks

“…In most of the stocks, males mature at a smaller size and younger age than females, and often the lifespan of males is shorter than that of females. Differences in the length and age at 50% maturation are especially pronounced in the flatfish stocks (Bowering and Brodie, 1991;Burnett et al, 1992;O'Brien et al, 1993;Morgan and Colbourne, 1999;Walsh and Morgan, 1999), but also occur in many gadoid stocks (Templeman et al, 1978;Beacham, 1983a,b,c;O'Brien et al, 1993, Trippel et al, 1997, grenadier stocks (Atkinson, 1995;Murua and Motos, 2000) and redfish stocks (Ni and Sandeman, 1984;Mayo et al, 1990). Earlier maturation in males than in females and potentially higher male mortality affect the composition of the spawning stock by sex and age (Jakobsen and Ajiad, 1999).…”

Evaluation de l exploitation du sebaste atlantique (sebastes mentella) par la peche sportive hivernale sur le Saguenay saison 1990-91

“…Cette stratification persiste durant la période de mai à novembre (Côté, 1977) alors que pour les mois d'hiver, malgré un rapprochement de la température entre les zones, la salinité demeure relativement faible à la surface durant cette période de Tannée (Chassé, 1988 (Kenchington, 1984;Scott et Scott, 1988;Templeman, 1959). De plus, les sébastes effectuent très peu de migration horizontale (Hamon, 1972;Ni et Sandeman, 1984;Scott et Scott, 1988;Templeman, 1959). Des expériences de marquage réalisées à Eastport (Maine), sur le sébaste marinus, ont permis de capturer à cinq reprises les mêmes poissons exactement sur les mêmes lieux (Hamon, 1972).…”

“…Cette période peut s'étirer selon les secteurs, dépendant des conditions du milieu. Dès la fin de la reproduction, il y séparation des sexes et formation de bancs unisexués (Ni et Sandeman, 1984).…”

“…(Ni et Sandeman, 1984). La maturité sexuelle suivrait un gradient Nord-Sud avec une maturité retardée dans les régions plus nordiques (Ni et Sandeman, 1984). Le caractère arctique des eaux de fond du Saguenay (Drainville, 1968) (Sylvain, 1988).…”