Contaminants in larval, juvenile, and adult Pacific lamprey (Entosphenus tridentatus), Oregon, 2017-2021

This data release contains analytical results of organohalogenated compounds and mercury in lamprey and sediment that were collected from rivers in Oregon and along the Pacific northwest coast from 2017 to 2021. In 2017, 20 lamprey were collected off the Washington and Oregon coasts by the National Oceanic and Atmospheric Administration. These ocean-caught juvenile lamprey were parasitizing targeted fish and were bycatch. In 2019, larval lamprey were collected by the Confederated Tribes of Warm Springs of Oregon from 8 sites on the Warm Springs Reservation. Larval lamprey were collected by electroshocking depositional sediment areas. Collocated depositional sediment samples also were collected along with the larval lamprey. In 2021, returning adult lamprey were collected at Sherars Falls along the Deschutes River by the Confederated Tribes of Warm Springs. Returning adults were collected from the fish ladder at night as they migrated upstream. All lamprey tissues (larval, ocean-caught juvenile, and adult) were analyzed for 56 organohalogenated compounds by the US Geological Survey National Water Quality Laboratory in Denver, Colorado. Larval lamprey and corresponding sediment samples also were analyzed for total mercury and methylmercury (tissue only) by the USGS Forest and Rangeland Ecosystem Science Center in Corvallis, Oregon. Sediment samples were analyzed for total organic carbon and percent moisture by RTI Laboratories in Livonia, Michigan.