Translocating Adult Pacific Lamprey within the Columbia River Basin: State of the Science

摘要

The Pacific lamprey (Entosphenus tridentatus) is in decline in the Columbia River Basin, and translocating adult lamprey to bypass difficult migration corridors has been implemented since 2000. We describe and report results from two current translocation programs, provide context for use of translocation, and discuss potential benefits, risks, and uncertainties. Both translocation programs appear to have increased the number of spawning adults and the presence of larvae and juveniles; however, any subsequent increase in naturally spawning adults will require at least one, and likely more, generations to be realized. It was seen that the number of adults entering the Umatilla River increased beginning four years after the first translocations. Potential benefits of translocation programs are increasedpheromone production by ammocoetes to attract adults, increased lamprey distribution and abundance in target areas, increased marine-derived nutrients, and promotion of tribal culture. Potential risksinclude disruption of population structure and associated genetic adaptations, disease transmission, and depletion of donor stocks.