Spatial diversity of Pacific herring (Clupea pallasi) spawning areas

Hay, D. E., McCarter, P. B., Daniel, K. S., and Schweigert, J. F. 2009. Spatial diversity of Pacific herring (Clupea pallasi) spawning areas. – ICES Journal of Marine Science, 66: 1662–1666.Eastern Pacific herring spawn in intertidal and shallow subtidal areas. Spawning sites are conspicuous: milt turns coastal waters white, sometimes for distances of many kilometres. This attribute has enabled biologists to document spawning distributions for more than 70 years throughout the 29 500 km coastline of western Canada. Spawning distributions and spatial diversity have varied over time. When aggregated over 70 years (1938–2007), spawning occurred along 5574 km or ∼20% of the total coastline. Cumulative annual spawn length ranges from 131 (in 1966) to 770 km (in 1992). We examined annual changes in spawn distribution using spatial units of variable size, ranging in area from a maximum of >1000 km2 to a minimum of