Feasibility of Estimating Aggregate Coho Salmon Escapement to the Lower Fraser Management Unit

The absence of reliable escapement estimates for Coho Salmon in the Lower Fraser River (LFC) MU and its three component Conservation Units (Lillooet, Lower Fraser A, and Lower Fraser B collectively discussed as LFC in this proposal) represents a critical information gap for Southern Boundary Coho Salmon Management.

This proposal addresses this concern by proposing an approach that eliminates the need to access hard-to-reach watersheds, reduces the need for visual escapement surveys from several to only the Nicomen Slough and Upper Lillooet River, and leverages existing infrastructure (hatcheries), processes (Coded Wire Tagging (CWT) and otolith tagging) and projects (monitoring of recreational and Food, Social and Ceremonial harvests, Lillooet sonar imaging (ARIS), and Nicomen Coho CWT, Chilliwack hatchery juvenile rearing and adult counts) with advanced technologies (PIT, radio tags, GSI) and a test fishery.

We propose to estimate total LFC escapement through the expansion of stock composition ratio data gathered at a test fishery. A new test fishery will sample the Fraser Coho migration, and a random, representative sample of Coho will have DNA, CWT and otolith samples taken to estimate stock composition ratios.