Lake Washington Sockeye Smolt Collection: 2017 and 2018 Report

This report describes the 2017 and 2018 collection of sockeye (Oncorhynchus nerka) smolt in lakes Union and Washington as they began their migration to the sea. Since 2004, the goal of this collection is to assess the relative survival of hatchery and natural origin sockeye salmon after one to two years of rearing in Lake Washington as fry to smolt. Sockeye smolt are sampled with a purse seine once per week in late April through May. Hatchery origin sockeye have been marked with unique otolith thermal bands so they can be differentiated from natural origin fish. Other information collected as part of the sampling effort includes smolt length, pathology evaluations, catch rate, and species composition. These data offer insight into annual rearing conditions for sockeye in Lake Washington.