Predation and food limitation as causes of mortality in larval herring at a spawning ground in British Columbia

Abstract

The published version of this article is copyrighted by Inter-Research and can be found here: ud http://www.int-res.com/journals/meps/meps-home/We quantified both in situ predation on Pacific herring (Clupea haregus pallasi ) larvae by soft-bodied zooplankton, and microzooplankton prey of herring larvae in Kulleet Bay, Vancouver Island, British Columbia. Samples were collected at 0 to 5 m depth daily at peak larval hatching from 14 to 21 April 1985. The hydromedusa Aequorea victoria was the only soft-bodied zooplankter that ate herring larvae. Densities of A. victoria reached as much as 17 m⁻³, and averaged 1 to 5 m⁻³. Predation on the herring larvae was severe, averaging 57 ± 29% d⁻¹ of larvae during each sampling period. Microzooplankton prey of post-yolksac herring larvae were mainly copepod nauplii and eggs, shelled protozoans, and bivalve veligers, and averaged 40.8 ± 21.51⁻¹ in the environment