Where the eelgrass is greener

Beach seiners sample island’s array of nearshore habitats.

It’s a partly sunny afternoon at Fay Bainbridge State Park, and the beach seining team has waded into a well-watered garden.

Just offshore is a meadow of eelgrass – not technically seaweed, but a submerged flowering perennial, and a staple of the Puget Sound ecosystem.

With a steady pull, the seiners drag the ends of the 100-foot net across the plants’ slender leaves to encircle the subjects of the day’s study, gently herding them into a pocket of fine mesh at the center.

Racing against the receding tide that threatens to strand the captured marine life on the sand, they sort through an impressive haul of crabs, gunnels, pile perch, juvenile salmon, and a sea of shiners – the crew stops counting at 869.

For the city’s Beach Seining Project, now entering its third year of sampling nearshore marine life, it is a typical find along an eelgrass-colonized shore.

“One of the things that is obvious to seining volunteers is the difference between the island’s different habitats,” said project coordinator Peter Best. “At low tide, in eelgrass, we can see over a dozen species.

“Kelp is the old-growth forest of the waters; eelgrass is something like the second growth.”

Eelgrass meadows are one of a number of distinct coastal environments – from the banks and bluffs of Rolling Bay to the sand spit at Battle Point – that the seining study regularly visits.

At each stop, the team not only catalogs marine life, but records a host of other observations, including temperature, salinity, and turbidity, or clarity, of the water – a technique in which a disk colored with white and black wedges, called a secchi disk, is lowered to the depth at which it just disappears from view.

“Bainbridge has lots of different habitats – very unusual for a city,” Best said. In the recently finalized “best available science” portion of the city’s Nearshore Assessment, consulting scientists concluded that “virtually all coastal and estuarine habitat types described for Washington State are found on or adjacent to Bainbridge Island.”

While Best emphasizes the seining project was not designed to be a comprehensive scientific study, it is a first step toward understanding the contribution different habitats make to local marine life.

“While we can’t draw direct conclusions, we can use the presence of certain fish species and plants as indicators,” he said.

Data from the Bainbridge study has already had applications beyond the island. In addition to helping the Suquamish tribe track dispersal of its hatchery fish, the survey of local species is being used by the state Department of Ecology to assess the impact of last December’s oil spill at the Port Madison Indian Reservation near Indianola.

On Bainbridge, where conclusions about nearshore habitat can have controversial implications – evidenced last year by the firestorm generated by proposed changes to the Shoreline Management Master Program – Best views the seining project as a step toward “adaptive management,” a practice that emphasizes ongoing monitoring over enforcement of fixed regulations.

“All nearshore environment isn’t necessarily created equal,” he said. “The better information we have about it, the better management decisions we can make.

“We need this kind of monitoring to have good discussions and to make good decisions.”

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