Even on a double island with 50 miles of wonderful beaches, Quartermaster Harbor stands out as special.

The glaciers graciously oriented it north-south, open toward the winter sunshine, and incidentally protected it from the prevailing southwest winds by mounding up south Vashon as a windscreen. Because of its relatively narrow width, there is no long stretch of water where big waves can build up. So Quartermaster Harbor is mostly protected from violent surf that on exposed beaches scours away three inches of sand or more in some winters. Little-necks, manila clams, and other critters that occupy the upper beach layer can survive winters in Quartermaster. With longer life expectancies, biological communities can develop more complexity, more species and larger individuals. It is because of its key roles in nurturing healthy area-wide biological food webs that Quartermaster and Maury were named an Aquatic Reserve by Washington state.

The bay is relatively shallow and many beaches slope gradually, rather than steeply. Gradual beaches have a broad band within the elevation range preferred by most clams. It has been an ideal habitat for people for a very long time.

When Dr. Julie Stein from the University of Washington directed a dig at Jensen Point a few years ago, she found evidence that native peoples had lived here for 7,000 to 9,000 years and consumed great quantities of shellfish and herring.

The 1927 testimony of Lucy Gerand, native S’Homamish born in the 1840s in inner Quartermaster, relates that her people also hunted waterfowl by stretching nets at Portage to snag the birds as they flew between Quartermaster and Tramp Harbor on foggy mornings.

We have no counts of the shellfish, the herring runs or the numbers of waterbirds from 1854. We do have data on herring from the 1977-1995 stock assessments conducted by the state. They show that although herring numbers crashed in the north Sound in the 1980s, they held fairly steady in Vashon. The Quartermaster run was then the third largest in Puget Sound.

Surf smelt and

sand lance also

spawn the bay. These forage fish are a significant part of the local marine food web, used by salmon, grebes and other animals.

The forage fish are one reason Quartermaster hosts many waterfowl. National Audubon designated Quartermaster as an Important Bird Area in 2001 because it sustained 35 species of wintering aquatic birds, including nearly 10 percent of the state’s western grebes. Dan Willsie had counted 1,775 western grebes in Quartermaster in 1989, 1,500 in 1991, and 1,805 in 2000. Their numbers have fallen considerably in recent years, however, according to the Christmas Bird Counts: 366 in December 2007, 17 in 2008, and 120 in 2009.

Shellfish are apparently still abundant, but harvesting is usually closed because of high fecal coliform counts. A newer concern is that areas of depleted oxygen may be developing on the floor of Quartermaster. In dead zones lacking oxygen, even aquatic creatures suffocate. The cycle starts when large algae blooms are triggered by an excessive influx of nutrients like nitrogen and phosphorus. Later the algae dies, sinks to the bottom, and the process of decay uses up oxygen.

Thanks in part to a 2009 EPA grant, detailed studies of Quartermaster started last summer, and are beginning to provide data to help scientists better understand the bay’s problems and possible solutions. Two sources of the excess nutrients appear to be failing septic systems and runoff of fertilizers and livestock manure carried into the harbor by streams. Both failing septic systems along the shoreline and others all over the watershed could be involved.

But hopeful efforts are also unfolding. Newly approved on-site septic systems are beginning to reach the marketplace — systems that might work on some of the small, steep lots around Quartermaster.

Other innovative approaches are also in the works, such as a new and promising experiment with the role of shellfish in Quartermaster. The nonprofit Puget Sound Restoration Fund, which has planted native Olympia oysters in Raab’s Lagoon, plans to install a raft holding columns of blue mussels to see whether they can improve water quality. As filter feeders, they are known to take up excess nutrients. What if this species of shellfish could play a major role in cleaning up the harbor for other species of shellfish?

Quartermaster Harbor is something special, a living geographic marvel that is admirably situated relative to the earth’s rotation and the paths of glaciers.

Can we cultivate its health and vitality so that it can once again flower into an exceptionally rich marine ecosystem? Can we and the Puyallup people enjoy harvesting its delicious bounty in sustainable balance, while we enjoy observing its many forms of marine plants and animals?

— Rayna Holtz is a beach naturalist and a librarian at Vashon Library.

The health of Quartermaster Harbor will be explored during the fifth annual Vashon-Maury Island Low-Tide Festival at Point Robinson from 10 a.m. to 3. p.m. on Saturday, May 15.

At 10:30 a.m., Larry Stockton, King County’s Groundwater Protection Program Manager, will give an overview of the preliminary findings from the EPA-funded study of Quartermaster.

Bill Tobin, head of the Vashon-Maury Island Community Council’s Septic Solutions Committee, will speak at 11 a.m., about new on-site septic systems and the shellfish rights guaranteed to Vashon’s first people, the S’Homamish/Puyallups, in the Treaty of 1854.

Brian Allen of the Puget Sound Restoration Fund will speak at 2 p.m. about the group’s effort to experiment with mussels.

The low-tide festival will include other events, including guided beach walks, bird walks, a native plant walk and tours of the historic Point Robinson lighthouse. See next week’s Beachcomber for more information.