Authors: KyungMi Jung Sukyung Kang Suam Kim Arthur W Kendall
Publish Date: 2006/12/01
Volume: 62, Issue: 6, Pages: 859-871
Abstract
Walleye pollock Theragra chalcogramma is an ecologically and economically important groundfish in the eastern Bering Sea Its population size fluctuates widely driving and being driven by changes in other components of the ecosystem It is becoming apparent that dramatic shifts in climate occur on a decadal scale and these “regime shifts” strongly affect the biota This paper examines quantitative collections of planktonic eggs and larvae of pollock from the southeastern Bering Sea during 1976–1979 Mortality advection and growth rates were estimated and compared among the years encompassing the 1970s’ regime shift These data indicate that pollock spawning starts in late February over the basin north of Bogoslof Island Over the shelf most spawning occurs north of Unimak Island near the 100 m isobath in early or mid April Pollock eggs are advected to the northwest from the main spawning area at 5–10 cm/sec Larvae are found over the basin north of Bogoslof Island in April and over the shelf between Unimak Island and the Priblof Islands in May Compared to 1977 the spawning period appeared to be later in 1976 a cold year and earlier in 1978 a warm year in the study area At the lower temperatures in 1976 egg duration would be longer and thus egg mortality would operate over a longer period than in the other years Mean larval growth appeared to be lower in 1976 than in 1977 and 1979 Estimated egg mortality rate in 1977 was 06 in April and 03 in early May
Keywords: