Reproductive performance of yellowtail rockfish,Sebastes flavidus

Abstract

SynopsisField and laboratory studies were conducted for 3 years on the yellowtail rockfish, Sebastes flavidus, from Cordell Bank, California, in order to characterize the reproduction of this species whose northern stocks have declined. Research findings included reversal of the sex ratios and male-female ages and sizes at age throughout the annual cycle, heavier and longer females at age than males after sexual maturation, maturation of females at 6 and males at 8 years, long reproductive lifespans, distinct male and female gonadosomatic index patterns over the annual cycle, age-and size-specific fecundity, no difference between potential and realized fecundity and the seasonal changes associated with gonadogenesis. The reproductive profile of the Cordell Bank yellowtail rockfish provided a base for comparison with northern populations that appeared to differ, especially in age and size.

Energetics of early development in the viviparous yellowtail rockfish

“…The sizes and ages of this group of females [means .. (ranges) for L S , somatic mass (total mass-ovary mass) and age were: 36·6 3·4 (28·5-46·0) cm, 1261 320 (673-2083) g and 15·6 6·5 (6-33) years, respectively] were representative of the general population of adult yellowtail rockfish at Cordell Bank which had been sampled and studied since 1985 (Eldridge et al, 1991).…”

“…Tel. : +1 831 420 3936; fax: 831 420 3977; email: Beth.Norton@noaa.gov cycle and variability in reproductive effort of the yellowtail rockfish have recently been established (Eldridge et al, 1991;Eldridge & Jarvis, 1995). Nutritional dynamics and their relationship to reproduction were described and analysed by Norton & MacFarlane (1995) and MacFarlane et al (1993).…”

Female reproductive biology of the bluemouth Helicolenus dactylopterus dactylopterus: spawning and fecundity

“…The absence of more captures at this stage is probably related to the behaviour associated with reproduction. Since spawners (large specimens) are mainly caught by longliners, if they stop feeding [as happens in related species such as Sebastes flavidus (Ayres) (Eldridge et al , 1991)] it becomes difficult to capture them. Another explanation could be related to the bathymetric distribution of the species, where the largest specimens of H. d. dactylopterus are found in progressively deeper waters (Massutí et al , 2000), together with the so‐called Mediterranean reproductive fish refuge paradigm (Caddy, 1993).…”

Metabolic costs of viviparity in yellowtail rockfish,Sebastes flavidus

“…Male rockfish were anesthetized and similarly handled without catheterization. Since males were sexually inactive at this time in their annual reproductive cycle, having matured and copulated during the August and October period (Eldridge et al 1991), they were tested to represent metabolism in non-reproducing adults.…”