Fishery scientists from Alaska and Canada met in Juneau, Alaska, 23-25 November 2009 as part of the Pacific Salmon Commission (PSC) Transboundary Technical Committee to review and discuss research and management activities on the Taku, Stikine, and Alsek Rivers during 2009. Catch and management summaries by species and system were presented for Chinook, sockeye and coho salmon.
The activities include smolt estimation through mark recapture and coded-wire tagging, adult weir counts, foot and aerial surveys, collection of genetic samples for baseline GSI work, and harvest data relevant to overage/underage treaty agreements. In addition, committee chairs presented an update on the funding process for the PSC Northern Fund in 2010.
Funds from this source went directly to pre-approved continuing NOAA/ABL projects for Northern Boundary Sockeye, Southeast Coastal Monitoring, and a small allotment to support UAF/ABL work at Auke Creek.
On the final day, a detailed presentation was made by Blair Holtby from Canada on improving the escapement goals and population modeling of Taku River coho salmon. He utilized a variety of data sources including the NOAA/Alaska Department of Fish and Game (ADF&G) Auke Creek time series on coho salmon to provide an analysis of the Taku River population. This provided the foundation for lively discussions of plans to improve the estimation of smolt numbers and stock population characteristics in order to ultimately improve marine survival and escapement goal evaluations.
Concurrent to the management summary, the enhancement subcommittee reviewed and summarized sockeye enhancement activity on the Taku and Stikine Rivers. Enhancement of sockeye salmon, now with formalized plans for each river has been technically challenging and controversial. The plans tie enhancement directly to harvest sharing agreements, so there is a large investment in planning and monitoring enhancement activity.
This review included information about the egg and fry survival rates of gametes taken from Tatsamenie (Taku) and Tahltan (Stikene) Lakes where the bulk of enhanced production is on either river. Gametes are brought to Snettisham Hatchery in the United States, otolith-marked during incubation, reared for a very short period, then planted back into their respective lakes.
Technical issues arose with the methodology for brood stock collections, holding of adults for egg takes, and use of virus-free water for onsite extended rearing to minimize losses to infectious hematopoietic necrosis virus (IHNV).
Additional enhancement work focused on smaller systems on the Taku River to help fill production gaps created by poor returns to the Tatsamenie. On the Stikine River, a Tuya Lake migration barrier which has been an impediment to further enhancement was at least partially breached with a successfully engineered blasting effort in 2009.
