Comparison of Some Life History Characteristics of Pacific Herring (Clupea pallasi) from the Canadian Pacific Ocean and Beaufort Sea

Abstract

We compared several growth and reproductive characteristics of Pacific herring (Clupea pallasi) from the Canadian Pacific Ocean and Beaufort Sea using data for 2310 fish gillnetted in the northern Strait of Georgia or near Tuktoyaktuk, N.W.T., over the 1985 spawning season. Weight-at-age was similar but Beaufort Sea fish were longer-at-age. Total weight-at-length was significantly greater for Strait of Georgia herring because their size-specific ripe ovary weights were 2.1 times greater. We attributed differences in growth and surplus energy allocation to adult instantaneous mortality rates being 1.8 times higher for Strait of Georgia herring. Size-specific ripe egg weight was 30% smaller in Beaufort Sea herring presumably because warmer sea temperatures over the larval period resulted in a higher mortality rate. Weight-specific fecundity was 1.5 times greater in Strait of Georgia fish. Ovarian growth rates near spawning were lower in Beaufort Sea herring because they mature in colder water.