Pacific lamprey (Entosphenus tridentata) are native to rivers along the West Coast of North America, but their populations have declined dramatically in recent years for reasons that are unclear. There is a massive effort currently underway to help restore lamprey populations by understanding their habitat needs and fixing apparent bottlenecks, such as passage at mainstem dams and entrapement of larval lamprey by water withdrawals. This effort was started by Columbia River Indian tribes (see www.youtube.com/watch?v=RIsRfSoCvXA), with support from US Fish and Wildlife Service, several states, and fish conservation groups.
While this effort has greatly increased our understanding of lamprey while they are in freshwater, Pacific lamprey are anadromous (reproduce in freshwater but spend part of their life in the ocean) and very little is known about their marine existence. Major questions to be resolved include: where they go in the ocean, how long they stay in marine waters, what species they parasitize, how quickly they grow, and whether some aspects of their marine ecology have contributed to their decline. Ocean surveys run by NOAA Fisheries’ Northwest and Alaska Fisheries Science Centers and fishery observers on commercial vessels collected over 300 Pacific lamprey from marine waters in 2017. This collection represents an untapped gold mine of information on the marine ecology of Pacific lamprey.
The goal of this internship is twofold: first, to process the lamprey (which are frozen) and second, to do initial analysis on the generated data. Processing the fish includes: recording collection information; take lengths and weights, measure and preserve stomach contents (for genetic analysis of diets), collect fin clips (for genetics), and remove heads for statolith analysis (structures similar to otoliths [fish ear bones] from which freshwater origin and age can be determined). Analysis will include: develop a length-weight and length-oral disk diameter relationship for ocean-caught lamprey; map the latitudes and longitudes of collected fish and use spatial statistics to examine distributional patterns; estimate growth rates and age of lamprey based on changes in size over time and size distributions.
Opportunities to experience other projects at HMSC (including going to sea) is encouraged as part of the internship.