. The Canadian field-naturalist. 1981 LowRY AND Frost: Biology of Arctic Cod 189 old Arctic Cod were of similar length in both areas. Third, in the northeastern Chukchi and Beaufort seas small fishes (< cm) were proportionately more abundant in waters 100 m or less deep (Table 2). The size distribution of Arctic Cod from that area (Figure 2) is therefore influenced by the depth distribution of tows. Twenty-four of 33 tows were made in water 100 m or less in depth. Tows in northern Bering Sea spanned a much smaller depth range (29-80 m) and no relationship between fish size and water dep
. The Canadian field-naturalist. 1981 LowRY AND Frost: Biology of Arctic Cod 189 old Arctic Cod were of similar length in both areas. Third, in the northeastern Chukchi and Beaufort seas small fishes (< cm) were proportionately more abundant in waters 100 m or less deep (Table 2). The size distribution of Arctic Cod from that area (Figure 2) is therefore influenced by the depth distribution of tows. Twenty-four of 33 tows were made in water 100 m or less in depth. Tows in northern Bering Sea spanned a much smaller depth range (29-80 m) and no relationship between fish size and water depth was evident. Growth rates of Arctic Cod appear to be quite variable, especially during the first 2 yr of life (Figure 3). The transition from larvae to juvenile is reported to occur in August at a length of 3-5 cm (Rass 1968). Should we assume a mean length at transition of cm, Arctic Cod we examined from northern Ber- ing Sea had grown cm in 10 mo while those from the Chukchi and Beaufort seas grew only cm in 12 mo. First-year growth rates reported for Arctic Cod in the Barents Sea (Hognestad 1968; Gjosaeter 1973) fall between those values. Our data for the Ber- ing Sea and that reported by Gjosaeter for the Barents Sea show the expected sequential decrease in annual length increment with age. However, in the Chukchi and Beaufort seas and in the samples from the Barents Sea examined by Hognestad, growth in length was greater in the second year of life than during the first. Hognestad found differences in postlarval growth during the first summer of life both between areas in the same year and between years at the same area. Interestingly, he found the greatest annual growth increment in the second year of life even when data for 10 sampling years was combined (Figure 3). This strongly suggests that greatest growth in length during the 2nd year of life may be common or characteristic in Arctic Cod. Reported sizes attained at the end of the 1st year of adult life
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