Variability of the Characteristics of the First Scale Annulus and Length of Year-Old Fish in the Bering Sea Walleye Pollock Theragra chalcogramma

Abstract

Geographic and interannual variability of the number of annuli and the radius of the first scale annulus, as well as the retrospective length of year-old walleye pollock from the western, northern, and eastern parts of the Bering Sea, was examined using data for the years 1995, 1996, 1998, and 1999. The characteristics of the first scale annulus were varying. By these parameters, walleye pollock from the western Bering Sea significantly differs statistically from walleye pollock of the eastern Bering Sea. With respect to number of annuli, the radius of the first ring, and the retrospective length of year-old specimens, the walleye pollock from the Navarinskii region occupies an intermediate position between fish from the western and eastern parts of the Bering Sea. Interannual variability of the three parameters was found for walleye pollock from the Navarinskii region.