The consumption of euphausiids by the pelagic fish community off southwestern Vancouver Island, British Columbia

The consumption of adult euphausiids was estimated for the seven most abund ant fish species found on the continental shelf off southwestern Vancouver Island, British Columbia, Canada. Empirical data on fish feeding rates, die ts and biomass were used to estimate euphausiid consumption in August for e ach year from 1985 to 1997. The fish community in August was estimated to c onsume an average 297 kt of euphausiids (124 t km(-2)). Pacific hake (Merlu ccius productus) and Pacific herring (Clupea harengus) accounted for 60% an d 30%, respectively, of the total euphausiids consumed by fish. The total e stimated consumption of euphausiids per tonne of fish averaged 0.93, and th ere was no significant trend in the time series. In addition, there was no significant relationship between the total fish community consumption or eu phausiids consumed per tonne of fish and euphausiid biomass, and there was no change in the fraction of euphausiids in the diet of small or large Paci fic hake. Thus, it appears that predation pressure from the pelagic fish co mmunity was relatively constant and not responsible for the apparent fivefo ld decline in adult euphausiid biomass observed in the 1990s.