Willapa Bay nestles in a sparsely-populated coastal county of southwestern Washington. It once drained the Columbia River, which changed course and now exits just to the south. The Columbia still leaves its mark on Willapa Bay, however, because sandy sediments carried by the river have been deposited in the long sand spit that marks the western border of the bay, the Long Beach Peninsula (named North Beach on nautical charts). When storm winds blow from the south, the river plume travels close to shore and can enter the bay as the tide moves in, reversing the standard estuarine salinity gradient – the bay can be freshest at its mouth.

The bay’s denizens of 10,000 years ago linger as subfossil shells in uplifted sediments near Bay Center on the east side. At eye level, tumbled together in broad strata, are many shells of native oysters, some clams and whelks, and an occasional piece of wood. These shells are visible because of tectonic activity along the coast. Local earthquakes have caused parts of the bay to rise or fall several meters in a geologic instant, and the resultant tsunamis are known to have leveled trees all along the Long Beach Peninsula. The last major tsunami occurred three or four hundred years ago.

The history of Willapa Bay since the arrival of European explorers comes to life in the first-hand accounts of James Swan, who spent three years living on the bay beginning in 1851 (“Three Years on Shoalwater Bay”). This memoir includes natural history – flowers blooming from February to December, salmon so thick that hundreds could be caught in a day, enormous sturgeon stranded in high pools on the mudflats as the tide receded – and cultural history – supernatural beliefs, songs, sobering news of smallpox epidemics in the Tribes. Willard R. Espy fills out the history of oystering in his book “Oysterville,” based on family stories and documents about his grandfather, one of the first people to exploit native oysters commercially, also in the early 1850s.

Exploitation of the native oyster Ostreola conchaphila resulted in the removal of literally billions of individuals over about four decades. Few descriptions or pictures of Willapa Bay tideflats exist from more than a hundred years ago, but as far as we can tell, native oysters grew in large accumulations of shell at and below low tide, often lining channels of the bay. Such habitats are now essentially nonexistent. Native oysters were harvested with long-handled tongs, placed on flat bateaux, sailed on plungers to small towns springing up around the bay, and then loaded on schooners bound for urban centers such as San Francisco and Portland. The native oyster was commercially extinct before the turn of the century, despite last-minute attempts to set up Oyster Reserves that would serve as sources of small oysters (spat). Subsequently, several non-native species of oysters were introduced to revive the failing industry. In the late 1800s, Eastern oysters Crassostrea virginica traveled across the continent by rail as spat and were transplanted to Willapa Bay. Repeated imports over many years maintained a small industry until about 1920, when local mortalities and reduced availability of spat closed the fishery. In 1928, Pacific oysters Crassostrea gigas began to be transplanted to Willapa Bay, usually after long ocean voyages as spat from Japan. Japanese spat continued to be outplanted until the mid-1970s, when reliable hatchery production of larvae replaced these imports. Early on, Pacific oysters naturalized in the bay, recruiting throughout its southern end, but not reliably at high enough densities to maintain the industry. Still, State records of oyster recruitment stretching back seven decades attest to the importance of “natural spatfall,” as well as providing an unparalleled ecological time series.

This short and idiosyncratic history of Willapa Bay would be incomplete without mention of Trevor Kincaid, one of the University of Washington’s first scientists, who spent many summers on the coast collaborating with oyster growers and State shellfish biologists. His books and pamphlets brim with ecological information and a host of unanswered questions, many of which still command attention today: What has prevented the recovery of native oysters? Why don’t oysters grow as fast as they used to? What causes oyster beds to differ in productivity? Kincaid self-published his final book on Willapa Bay at the age of 95, by typing the pages, photographing each page, and gluing the photos into a bound notebook. He acknowledges “the many kindnesses” shown by oyster growers in facilitating his work and life, a tradition that, in our experience, continues today.

Willapa Bay is locally proclaimed a pristine estuary. This claim undoubtedly stems in part from relatively low development of its shores – only about a third of the high marsh has been lost to diking and filling. Few chemical pollutants enter the bay, which has no major industrial ports. The “pristine” moniker fails, however, when it comes to introduced species. About 40 new species of algae and invertebrates inhabit the bay, some of which were purposely introduced, but most entered accidentally with shellfish or ships. In fact, these species include several that have wholly transformed the biological habitat of the bay: Pacific oysters, which can form large reefs of hard substrate in the midst of vast mudflats; smooth cordgrass, which has extended the salt marsh down a vertical meter or so; and Japanese eelgrass, a small eelgrass species that has vegetated mudflats below the cordgrass. Willapa Bay is clean, certainly, but also biologically transformed. For us as scientists, these invasions represent excellent opportunities to study food web perturbations, which have had both beneficial and harmful consequences for people living and working on the bay.