Counting fish to determine a stream’s health

How are fish doing in the Olympic Experimental State Forest (OESF)? Stream surveys led by Washington Department of Natural Resources (DNR) fish biologist Kyle Martens hope to help answer that question. Martens is monitoring how forest practices — road building, timber harvesting and other activities in the woods — affect the fish that live in streams running through the 270,000 acre state forest on the western Olympic Peninsula.

DNR steam monitoring crew member
A DNR steam monitoring crew member measures fish gathered from a forest stream.

Martens and his crews use the electrofishing method to monitor stream health — a crew member wearing a backpack containing a battery powered generator sends a small electric current through a wand into the water. The current causes fish to emerge from their hiding places so that crew members can carefully collect them in nets and place them into buckets to record their length, weight and species. Once measured, the fish are released back into the stream habitat. Crew members also note other factors that can indicate the stream’s health, such as the presence of frogs or other amphibians.

backpack-mounted electrofishing equipment
A trained operator using backpack-mounted electrofishing equipment.

This project was initiated in 2015 with sampling efforts to help determine the best methodologies for the multi-year monitoring project. In 2017, which will be the first full year of the project, 35 of the 50 streams in the OESF will be surveyed. These population surveys are done to ensure that the approach to forest practices outlined in DNR’s 1997 Habitat Conservation Plan are effective. DNR developed the plan in response to the federal listing of certain threatened and endangered fish and other species that live on forestland the agency manages in western Washington.

These studies will provide a better understanding of how DNR forest management practices affect salmon and riparian habitat on lands it manages. The OESF is a designated area for research and monitoring where information can be gathered that represents other forests in Washington. The OESF maintains research partnerships with universities, colleges, federal agencies and other organizations.

You can find more information on the OESF here.