Pacific salmon and Pacific herring mortalities in the Fraser River plume caused by river lamprey (Lampetra ayresi)
Dates
Publication Date
1995
Citation
R.J. Bearnish and C.M. Neville. 1995. Pacific salmon and Pacific herring mortalities in the Fraser River plume caused by river lamprey (Lampetra ayresi), Can. J. Fish. Aquat. Sci. 52: 644-450.
Summary
Abstract: River lamprey (Lampetra ayresi) enter the Strait of Georgia from the Fraser River and feed almost exclusively on Pacific herring (Ckupea harenglas) and salmon (Oncsrhyncheas spp.). Although the major prey of river lamprey is Pacific herring, the greater effect of lamprey predation was on the populations sf chinook (0. tshawyfscha) and coho (0. kisutch) salmon. In 1990 and 1991, river lamprey killed a minimum of 20 million and 18 million chinook salmon, respectively, and a minimum of 2 million and 10 million coho salmon in the same years. In 1991, river lamprey in the Fraser River plume killed an equivalent of approximately 65 and 25% sf the total Canadian hatchery and wild production of coho and chinook salmon, respectively. [...]
Summary
Abstract: River lamprey (Lampetra ayresi) enter the Strait of Georgia from the Fraser River and
feed almost exclusively on Pacific herring (Ckupea harenglas) and salmon (Oncsrhyncheas spp.).
Although the major prey of river lamprey is Pacific herring, the greater effect of lamprey
predation was on the populations sf chinook (0. tshawyfscha) and coho (0. kisutch) salmon. In
1990 and 1991, river lamprey killed a minimum of 20 million and 18 million chinook salmon,
respectively, and a minimum of 2 million and 10 million coho salmon in the same years. In 1991,
river lamprey in the Fraser River plume killed an equivalent of approximately 65 and 25% sf the
total Canadian hatchery and wild production of coho and chinook salmon, respectively. These
estimates are probably low because river lamprey also feed in other areas and the abundance
estimates are conservative. These high mortality rates indicate that river lamprey predation must
be considered as a major source of natural mortality of chinook and coho salmon in the Strait of
Georgia.
