Dan Young, Carol Ann Woody, and Joseph Margraf

Introduction

Recent declines in the annual sockeye salmon (Oncorhynchus nerka) return to the Kvichak River, including the Lake Clark watershed, concern subsistence users and managers regarding the health of the sockeye salmon populations. Historic studies provide estimates of the return time to the Newhalen River and estimated peak spawning times in select tributary spawning populations. However, information regarding habitat use by spawning adults is limited to the clear portions of the glacially influenced watershed. Our study will further understanding of spawning habitat use and migration patterns of sockeye salmon as a species and provide park managers with the tools to “protect the watershed necessary for the perpetuation of the red [sockeye] fishery in Bristol Bay” (ANILCA, 1980).

Study Area

Objectives

• Identify and map the spatial and temporal distribution of major spawning aggregations.
• Determine in-lake migratory routes and run time for Lake Clark sockeye salmon.
• Assess the role of environmental variables on run time, migration, and spawn time.

Methods

Adult sockeye were captured with a seine (A) as they entered Lake Clark and radio-tagged (B) with an esophageal tag (n=20 in 1999, n=175 in 2000, n=157 in 2001). Six tags were deployed per day in 2000. Five tags were deployed per day in 2001; during migration peaks the number of fish tagged was doubled.

Tracked salmon movements throughout the lake system every 5-7 days by boat (C) or airplane (D) to their final spawning location. Recorded time, date, signal strength, and GPS location for each fish relocated.

Monitored fish passage and movements at select remote stations (E) 24 hours/day.  Verified spawning and estimated spawn time by visual observation or seining.  Deployed remote temperature sensing units at 10 sites to monitor inter-gravel incubation temperatures (F). Note: These data are currently being collected.

Preliminary Results

Identified 30 different spawning areas through radio telemetry (n=7 in 1999, n=23 in 2000, and n=26 in 2001). Documented 10 previously unknown spawning habitats (Regnart 1998, traditional local knowledge).

Preliminary Map of Beach and Tributary Spawning Areas Identified by Radio Telemetry

Relocation data will be analyzed for all radio-tagged fish to determine possible migration patterns and run time through the system.

Results

Dynamic in-lake migration patterns observed for homing sockeye salmon (pdf 762k) - poster given at the American Fisheries Society Annual Meeting in Anchorage, Alaska on September 12-15, 2005

Preliminary Conclusion

This study has documented at least 10 previously unidentified spawning areas. Spawning locations, identified by radio telemetry, suggest that glacially influenced beach and riverine spawning are more important than historic aerial escapement counts indicate. However, because of the relatively low number of adult sockeye salmon returning to Lake Clark during the study, it is likely that other unidentified spawning areas exist.

Literature Cited

Alaska National Interest Lands Conservation Act (ANILCA). 1980. 16 U.S.C. 3101 et seq (1988), Dec. 2 1980, Stat. 2371, Pub. L. 96-487.

Regnart, J. R. 1998. Kvichak River sockeye salmon spawning ground surveys, 1955-1998. Alaska Dept. of Fish and Game, Regional Information Report 2A98-38.

Acknowledgements

This research is funded by the Federal Office of Subsistence and the National Park Service - Natural Resources Parks and Preservation Program.  I would like to thank Doug Palmer, Randy Brown, and the numerous field personnel who have helped make this project happen.