| Abstract/Description or Keywords |
This is the fifth report in a series on Pacific salmon resources by the Pacific Fisheries Resource Conservation Council (PFRCC) describing the current state and the ability to assess and understand the status of salmon resources in British Columbia, the Yukon and Arctic. This report examines the wild salmon in Canadian portions of northern BC and Yukon transboundary rivers and focuses on the: (a) Stikine River, (b) Taku River, (c) Alsek / Tatshenshini River, and (d) Upper Yukon / Porcupine rivers. Each of these watersheds comprises a portion of estuary and lower river within Alaska U.S. territorial boundaries with headwaters located in Canada. The Unuk, Whiting and Chilkat rivers are also briefly discussed in this report, but have limited Canadian based salmon resources and few ongoing monitoring and assessment programs in Canada. Information presented in this report is derived from Fisheries and Oceans Canada (DFO) and Alaska Department of Fish and Game (ADF&G) salmon spawning, catch and stock assessment records, reports from the Transboundary Technical Committee (TCTR) of the Pacific Salmon Commission (PSC), the U.S. and Canada Yukon River Joint Technical Committee (JTC), the Pacific Scientific Advice Review Committee (PSARC), the Canadian Science Advisory Secretariat (CSAS), and published technical references and literature and online published sources. Cross border mark-recapture estimates, catch and spawning counts are used to examine Canadian based salmon population status and trends in abundance. Most of the data are reported as numbers of salmon spawning in Canadian river and streams and are based on mark recapture assessments, weir and fence counts and visual survey estimates where available. Unlike many other regions of BC, estimates of salmon catch and escapement for the upper Yukon, Alsek, Taku and Stikine river systems are based on very consistent methods with long time series records for specific index sites (i.e., fence or weir locations). Assessment and monitoring programs have been maintained through agreement based on the Pacific Salmon Treaty (PST) between the governments and Canada and the U.S (Gov. Canada, Gov. U.S. 2006) and the Yukon River Joint Technical Committee (JTC). Single annual visual or aerial surveys are often used to index spawning salmon. In these instances, the accuracy of these estimates of escapement is often unknown between sites and years. Efforts have been made to use estimates in this report which have been reported and published and are comparable between survey methods and years, but variations in salmon numbers presented may be accounted for by several sources over time and space including: salmon returns, spawner abundance, fishing harvest effort, climate and local and regional effects in freshwater and coastal habitats or site conditions, and changes in annual assessment and survey methods used to determine catch and spawner abundance. The estimates used in this analysis are limited to local and regional watershed trends in wild salmon resources in Canadian waters and are not intended to represent changes in salmon stock specific production related to survival and mortality trends among various life history stages of salmon (e.g. egg to fry survival, marine survival of adult salmon, migration survival to spawning adult salmon). In many instances, few estimates are available for both harvest and escapement to examine trends in all or even specific salmon populations and stream systems in the entire watershed. In recent years, cooperative management between the Alaska Department of Fish and Game (ADF&G) and Fisheries and Oceans Canada (DFO) through the Pacific Salmon Treaty Pacific Salmon Resources In Northern BC and Yukon Transboundary Rivers January 2012 Pacific Fisheries Resource Conservation Council (PST), have created abundance based assessment programs intended to derive species specific whole watershed catch and escapement estimates which can form the basis to predict salmon production. Public interest and discussion on wild salmon is often focused on conditions and situations that are considered detrimental to the survival and success of salmon species. Many populations of salmon face declines in their numbers or survival rates through pressures from water and land development, population growth, habitat disturbance and destruction, and more wide ranging issues including climate variation and change. As a species, salmon continue to represent an irreplaceable link to human culture and society on the west coast of Canada and the Pacific Rim, and still remain resilient and diverse. This report is a compilation of information to document the long-term status and current trends of wild Pacific salmon in northern BC and Yukon transboundary watersheds. |
