Growth-maturation interactions of Acadian redfish (Sebastes fasciatus Storer) in the Gulf of Maine-Georges Bank region of the Northwest Atlantic
Growth and maturation rates were derived for redfish ( Sebastes fasciatus Storer) from data collected on bottom trawl surveys conducted in the Gulf of Maine-Georges Bank region between 1975 and 1980. Estimates of L x ranged from 32 to 35 cm for males and 37 to 41 cm for females, depending on season...
| Published in: | ICES Journal of Marine Science |
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| Main Authors: | , , , |
| Format: | Text |
| Language: | English |
| Published: |
Oxford University Press
1990
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| Subjects: | |
| Online Access: | http://icesjms.oxfordjournals.org/cgi/content/short/46/3/287 https://doi.org/10.1093/icesjms/46.3.287 |
| Summary: | Growth and maturation rates were derived for redfish ( Sebastes fasciatus Storer) from data collected on bottom trawl surveys conducted in the Gulf of Maine-Georges Bank region between 1975 and 1980. Estimates of L x ranged from 32 to 35 cm for males and 37 to 41 cm for females, depending on season and location. Growth coefficients (K) were higher for males (0.158 to 0.175) than for females (0.144 to 0.148), but were consistently lower for both sexes in shallower inshore regions of the western Gulf of Maine. Instantaneous growth rates were also lower for younger fish of both sexes inshore. Differences in linearized growth rates between males and females were highly significant (p<0.01), while seasonal effects were generally not significant (p>0.05). Distinct differences in spatial and temporal distribution patterns of redfish larvae were noted between the eastern and central regions of the Gulf of Maine; it is suggested that larval transport may influence juvenile growth. The maturation process commenced as early as age 3 for some individuals and was essentially complete by age 10 for both sexes. The overall median size at maturity was slightly lower for males (20.9 cm) than for females (22.3), although the median age at maturity (5.5 years) was similar for both sexes. However, estimates of both median age and size at maturity were considerably lower in the shallower inshore area than in the offshore region, suggesting a linkage between accelerated maturation and reduced growth rates of immature rednsh in the inshore region. Interactions between early growth and maturation were investigated using a two-factor logistic model incorporating size and age. Both factors accounted for a significant amount of the variation in the proportion mature for males and females in the offshore Gulf of Maine and for females inshore. For inshore males, however, maturation appeared to be almost exclusively age-driven. The two-factor model, which provides a visual representation of the maturation surface, can provide an ... |
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