Comparison of Sockeye Salmon (Oncorhynchus nerka) Monitoring in the Fraser River Basin, British Columbia, Canada and Bristol Bay, Alaska, USA

摘要

We assess the quantity and quality of sockeye salmon {Oncorhynchus nerka) monitoring in two regions in North America (Fraser River, British Columbia and Bristol Bay, Alaska). We classify monitoring into two discrete types: that of a "parent" metapopulation (Tier 2), and individual populations (Tier 3). Effort within the Fraser River is focused more intensively at Tier 3, and consists of methods that provide relatively accurate counts of spawners. The monitoring in Bristol Bay is comprehensive and robust at Tier 2. While Tier 3 monitoring occurs throughout Bristol Bay, it is mostly in the form of aerial surveys, which provide less accurate estimates of spawner abundance. A rich set of data exists from visual ground surveys at Tier 3 in the Wood River, Alaska, drainage, but these data have not been analyzed to address population persistence, and there is a clear gap in reliable data on individual populations inhabiting the other major drainages in Bristol Bay. The overall level of monitoring efforts in the Fraser River basin, standardized to the amount of salmon spawning habitat, is conservatively four times higher than that currently expended in Bristol Bay. We encourage investments in continued monitoring and assessments of individual populations in the Wood River drainage, and recommend expanding efforts to include population scale monitoring in other drainages within the Bristol Bay region.