Friday, April 29, 2011

Wild Salmon Production at the Northwest Corner of the United States

This year we began monitoring wild salmon and steelhead in the Tsoo-Yess River, located at the northwest tip of the Olympic Peninsula near Neah Bay, Washington.  The goal of the project is to determine how many wild salmon and steelhead juveniles are produced each year in the part of the Tsoo-Yess River upstream of Makah National Fish Hatchery (NFH).  Results from this study will tell us about the ability of the Tsoo-Yess River to support wild salmon and help the USFWS and Makah Tribe determine how to best manage Makah NFH operations while supporting wild fish populations. 

USFWS student intern Ben Leonard checks 
the screw trap for fish
This week we installed a screw trap just a few hundred meters upriver of the hatchery.  A screw trap (see picture) has a rotating cone that captures fish moving downstream.  Fish are held in a live box at the back of the trap where they wait to be removed, identified, and measured by a biologist.  Although it might look a little scary, these traps are actually very gentle on the fish.  On the first 2 days, we captured 18 coho salmon and 3 steelhead smolts, as well as a few coho fry, some juvenile cutthroat trout and rainbow trout/steelhead, 2 sculpins, and 1 lamprey.

Of course, these traps can’t catch every fish migrating downstream, so we have to test how efficient the trap is at catching fish.  To do this, we release marked fish a few hundred meters upriver to see what percentage we catch in the trap.  We put the marked fish in buckets (with aerators) and took them by canoe upriver to the release site (picture below).  Not a bad job on a sunny day!

Ben releases marked fish to check trap efficiency