Comment:

The ISRP encourages the proponents to investigate (1) solutions to the problem of longholding times that increase prespawn mortality and (2) ways to minimize the impact of American shad at Lower Granite Dam.

1. Objectives, Significance to Regional Programs, and Technical Background

This project continues to make valuable contributions to the region. This proposal requests support to continue operating the Lower Granite Dam adult trap to provide information to managers on age class structure, wild/hatchery proportions, predator and harvest wounds and other data that are useful to manage restoration programs. Operating the adult trap also provides access to returning adult fall Chinook, coho, and sockeye to obtain adults for hatchery and recovery program needs. Data collected are used by several agencies and tribes. Data that benefit other projects are uploaded several times a day and available in near-real time.

The technical background describing how adults are diverted into the trap holding area is adequately explained. Improvements to the data collection system are briefly described in the proposal.

2. Results and Adaptive Management

Scales from returning PIT-tagged fall Chinook salmon are collected to better understand their life history diversity. These data indicate that a large percentage of returning adults each year are yearling or reservoir type migrants. These results have led to the design of other research projects such as transport studies, overwintering telemetry studies, and otolith microchemistry studies.

3. Methods: Project Relationships, Work Types, and Deliverables

Project relationships involving broodstock collection, transport studies, and run reconstruction are mentioned. The proposal mentions that the Lower Granite Dam is the best location for examining the physical effects on adults resulting from passage through the downstream hydropower system. No mention is made of how these data are used. Similarly, adult passage times through the ladder are monitored for the effects of the trapping facility on passage, but it is not clear what is done with this information. More details are needed in future proposals.

The importance of the facility continues to increase with the focus on improved monitoring to better understand the impact of hydrosystem operations, or actions that impact fish, while also taking account of mainstem habitat research and the effects of climate change.