Growth-maturation interactions of Acadian redfish (Sebastes fasciatus Storer) in the Gulf of Maine-Georges Bank region of the Northwest Atlantic

Growth and Maturation of Acadian Redfish in the Gulf of Maine

“…Also during this period, the Gulf of Maine experienced climate change, as well as changes in community structure, including significant declines in populations of Atlantic Cod, a predator of Acadian Redfish (Link and Garrison 2002). Despite these changes and in contrast to the past findings of other groundfish species mentioned previously, the estimates of ages and lengths at maturity for female Acadian Redfish found in the current study (L 50 = 21.7 cm, A 50 = 6.6 years) were very similar to those using samples collected from 1975 to 1980 (L 50 = 22.3, A 50 = 5.5 years : Mayo 1990;O'Brien et al 1993). The difference in the A 50 found between these studies may in part reflect different techniques used to age the fish or assess reproductive states, but both studies found all fish were mature by 10 years of age or larger than 26 cm.…”

“…Previous studies have demonstrated that juvenile Acadian Redfish tend to concentrate in relatively shallow inshore locations in the Gulf of Maine (Mayo et al 1990), although finescale movements and seasonal migration patterns of this species are not well understood. Growth differences have been noted between fish sampled from inshore and offshore locations (Mayo et al 1990), and depth-related differences have been attributed to changes in the age at which the fish become sexually mature (Sandeman 1969). In the current study, greater 46 numbers of small (≤19 cm), immature fish were sampled from inshore waters, and this may reflect the larger mesh size used during offshore sampling.…”

“…Understanding the life history characteristics of commercially important species is essential to maintain healthy populations and formulate sustainable fisheries management plans (Gabriel et al 1989). However, some of the life history characteristics of Acadian Redfish, such as age structure and growth, are based on data collected in the 1970s and 1980s (Mayo et al 1990). Since that time, there have been major changes in fishing pressure, population biomass, and ecosystem structure that may have impacted Acadian Redfish growth and maturation.…”

“…The estimated starting parameters were then optimized using the SOLVER routine of Microsoft Excel software for nonlinear least-squares regression analysis. Ovary processing.-The maturity of male Acadian Redfish could not be determined with confidence due to a lack of samples collected during peak copulatory months in the autumn when male Acadian Redfish maturity stages are least likely to be misidentified (Mayo et al 1990). As female reproductive stages can be assessed throughout the year, however, female maturity estimates were assessed from the three sampling periods.…”

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).…”