Steelhead Archival and Acoustic Tag Project

Objective 3

Collect and compare marine habitat data from returning tagged steelhead to identify utilization of important oceanic features and routes of migration.

The 2002 acoustic data have been collected and is currently being analyzed.  Preliminary results will be posted in the near future.

Fifteen VR2 monitors were recovered and the data collected by the VR2 monitors was downloaded in the field using a magnetic probe and PC interface designed for use with the VR2 monitor.  After the data is collected, the mooring and monitor can be redeployed.  The monitors that were not affixed to an acoustic release were retrieved by pulling the mooring from a boat. The data collected by the acoustic receivers has been used to determine the migration timing and pathways of fish leaving the stream and moving along the coast and we will relate time tagged fish spend near the mouth of the stream with tidal activity.

Both acoustic and archival tags will be collected from post spawn tagged fish out-migrating during subsequent spawning migrations.  The tags will be removed surgically resulting in a non-lethal  method for collecting tags.  Data from archival tags will be plotted to determine temperature, depth, and geolocation over time and movement patterns will be compared among streams.  The plots will also be compared to those presented by Walker et al. (2000. Fisheries Oceanography. 9:171-186) to confirm that diel variations in temperature correspond to vertical migration.  Methods and results will be compared to studies in California and British Columbia to determine effectiveness of each study and provide guidance concerning application of acoustic and archival tags to the CoML.

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