Monday, April 22, 2013

Elwha River Fine Sediment Sampling

Late last summer, the U.S. Fish and Wildlife Service (FWS), NOAA Fisheries, Lower Elwha Klallam Tribe, U.S. Geological Survey, and National Park Service participated in a multi-agency effort to measure fine sediment concentrations in salmon spawning areas of the Elwha River. This sampling was the first to occur following the initiation of dam removal on the Elwha River; baseline data had previously been collected for 2 years prior to dam removal.

Sampling area within the 'shield' showing
sediment conditions prior to dam removal (2010)

The removal of Elwha and Glines Canyon Dams is expected to release 7-8 million cubic meters of sediment. About half of this is fine sediment (silt and clay), which should be transported quickly by the Elwha River into the Strait of Juan de Fuca. However, this material could alter spawning habitat downstream of the dams. Monitoring fine sediments in locations where salmon are likely to spawn will help determine whether any impacts occur and, if so, how long they persist.

We sampled both mainstem and floodplain channel habitat, collecting 30 samples from just below Glines Canyon Dam to near the mouth of the river. A plywood shield blocked water flow during sampling, providing a calm water area where the sample of the river bed material could be collected. We removed the surface layer of the sediment and placed it into a sample bag for later processing to determine sediment size distribution. We also collected a 'before-and-after' water sample to determine the amount of fine sediment that was suspended in the water column during sampling.

Measuring pre-sampling water depths within the shield.
This is done to determine the depth of the sediment sample and
the water volume behind the shield. This volume is used to
calculate the overall weight of fine sediment suspended
in the water column during sampling.
Preliminary results suggest that there is more fine sediment in the spawning areas today than before dam removal began; however, the level was lower than expected. There was also a change from large cobble to gravel substrate in some areas, which will greatly improve salmon spawning habitat. We expect larger changes this year following the complete removal of Glines Canyon Dam, which holds back the majority of the sediment in this river system.


Thursday, April 11, 2013

Transporting Coho - The Journey from Quilcene NFH to Quilcene Bay Net Pen

U.S. Fish and Wildlife Service (USFWS) Pathways student technician Michael Farnum and I had the opportunity to participate in transferring young coho salmon to a net pen in Hood Canal last month. During this once-a-year event, approximately 200,000 coho smolts from Quilcene National Fish Hatchery (NFH) are moved to a net pen in Quilcene Bay. This partnership between USFWS, Washington State Department of Fish and Wildlife (WDFW), Northwest Indian Fisheries Commission, and the Skokomish Tribe is helping to rebuild Hood Canal’s salmon population for tribal and sport fisheries.

The transfer of coho from Quilcene NFH to the net pen is a multiple-step process. The first step happened at the hatchery, where the coho smolts are moved from the raceways into the WDFW fish transport truck using a pump and tubing. During this process, I helped crowd the fish to one end of each raceway; this makes the transfer to the fish transport truck a lot easier. Once loaded, the WDFW fish transport truck headed to the harbor to meet the boat. At the harbor, we transferred the coho from the truck into a 1,000-gallon tank on the boat. Once the fish and technicians were safely aboard the boat, we set out on the final leg of our journey to Quilcene Bay.

On the way to Quilcene Bay net pen
These coho salmon will spend the next couple of months in the net pen acclimating to saltwater and growing a lot. The net pens will also protect the fish from predators that are looking to dine on a tasty and naive young fish just entering the marine food web.

Transferring coho from the boat to the net pen
My experience participating in this event was a positive one. I was able to gain valuable experience and, as usual, working at Quilcene NFH was an interesting and educational experience.

--Tim Grun, Biological Science Technician