Age validation and growth of Greenland halibut (Reinhardtius hippoglossoides (Walhaum)):: A comparison of populations in the Northwest and Northeast Atlantic

Age validation exercises clearly established the expected modal size of 0-group Greenland halibut specific to the study area and time of sampling. Subsequently, the modal sizes of at least ages 1-3 (and sometimes 4) were determined and indicated that at these ages Greenland halibut will grow on average about 6-8 cm per year. It is emphasized, however, that validation work is specific for the years and areas in which the data are collected. Female Greenland halibut have a longer lifespan than males. It is shown that the difference between the maximum age of males and females differ by as much as 8 years in the Northwest Atlantic but the difference declined in recent years. In most instances for both the northwest and northeast Atlantic growth rates for females are slightly higher than for males after about age 5-6. For the northwest Atlantic data the apparent differences are greater in earlier years but show little difference since mid 1980s. Greenland halibut in the northeast Atlantic are generally larger at age up to about age 8 compared to those of the northwest Atlantic. By 1996, the overall patterns appear more similar. The results suggest that the growth patterns between the two regions may be converging to a similar pattern in recent years.