Eelgrass Survey Overview
Eelgrass, a marine plant that grows in the nearshore photic zone, provides critically important habitat for salmon, invertebrates and other marine life. Juvenile salmon and many small marine organisms rely on eelgrass beds as places to hide from predators. Pacific Herring lay their eggs directly on the plant's leaves. Herring, in turn, are one of three Puget Sound forage fish that are staples of the salmon's diet.
For more than a decade, we have engaged volunteers and private contractors to gather data on the distribution and health of eelgrass beds along our county's nearshore.
In 2007 we began our most ambitious eelgrass project to date. We partnered with WSU Beach Watchers, now Sound Water Stewards, to equip a highly-skilled volunteer team to gather eelgrass data from a private boat and a light aircraft while simultaneously conducting boots-in-the-muck studies. This team is collaborating with the Washington Department of Natural Resources (DNR) and are following the agency's scientific protocols while also working with top eelgrass experts at the University of Washington's Friday Harbor Laboratories.
The boat survey was conducted annually by volunteers from 2009-2019. Volunteers used a boat equipped with portable videography and data-collection gear including a towfish laser camera, trolling motor, computer and GIS navigation. The survey team recorded underwater video of all the eelgrass growing along DNR-specified transects that run at right angles to the shoreline. Members of the team then reviewed the video data to document the presence or absence of eelgrass habitat along the entire length of each transect.
For a broader view, volunteer Gregg Ridder flies over the county's shoreline in a private aircraft equipped with a wing-mounted camera. He does this on summer, low-tide days. All images are stamped with GIS coordinates and stitched into a continuous record that gives a big-picture view of eelgrass and other intertidal vegetation over a large area.