Native Olympia Oysters Cope With Acidification Through "Brooding", Non-native Pacific In Reproductive Collapse

Native Olympia oyster (l)

Pacific oyster (r)

More than oysters need calcifying agents

An article The World reports how native Olympia oysters are able to cope with the increasing acidification of the ocean's waters while the non-native Pacific oysters are in a state of reproductive collapse. This crisis has resulted in taxpayers having to provide millions of dollars to support an industry fixated on an oyster native to Japan, attempting to grow them in the waters of Puget Sound and Drakes Estero where the Olympia oyster is the only native oyster. It has additional costs.

Canary in a coal mine

or a Chihuahua in the Arctic?

Better parenting results in better adjusted children
According to George Waldbusser, PhD in Biological Oceanography and a member of the "Blue Ribbon Panel" on ocean acidification, native Olympia oyster hold their eggs internally for several weeks after fertilization. The non-native Pacific oysters "broadcast" their spawn into the waters currently experiencing a drop in pH levels, where problems with shell formation occur due to a drop in the levels of carbonate ions needed for calcification (read more in this 9mb file on OA).

The result is the successful spawning and setting of native Olympia oysters in the waters of Coos Bay, Willapa Bay and Puget Sound, all waters experiencing a drop in pH levels. In the case of the non-native Pacific oysters, hatcheries have either closed or resorted to extreme monitoring and/or buffering of waters to create an artificial environment in which the "brood" is able to survive. Once "fostered" to a certain age these oysters are then placed into the waters where they grow at a rapid rate, reaching maturity in 1 to 2 years, as opposed to 3 to 4 for the native Olympia oysters.

Rapid growth = rapid use of ions and nutrients needed by all native species
A secondary outcome of this artificial support for a non-native species is the stress created on other species who also need those same carbonate ions and nutrients used by the non-native shellfish being grown commercially. As was pointed out in a recent piece by a professor in Marin County, Joe Mueller, Drakes Bay Oyster Company's growing of 20 million non-native Pacific oysters in Drakes Estero, and their harvest, uses and removes those same ions and other nutrients needed by all species native to the waters of Drakes Estero.

When we come along and funnel many of those nutrients into [20 million] oysters for tourists then the system is not able to provide adequately for all the other components of the system (marine invertebrates, fish, birds, marine mammals etc.). This may be somewhat sustainable from a human-use point of view, but it clearly short-changes the non-human aspects of the system.

Suggested reading
Suggested reading includes a paper by Dr. Waldbusser in which he points out how the removal of the shells from the ecosystem also removes their ability to help buffer the waters, returning some of the calcifying agents to the waters they were removed from. In the case of Drakes Estero, it is one of the points made by Professor Mueller and seemingly lost on Dr. Goodman in his response piece. A second paper reinforces the sensitivity of non-native Pacific oysters in the larval stage to the changing water chemistry within which all species will be impacted. 20 million non-native Pacific oysters in Drakes Estero do have an impact in a changing world, and the world is changing.

Non-native Pacific oysters survive only with life support to get the brood through "infancy". Once an "adolescent" and placed into the waters, their rapid growth uses large amounts of the diminishing carbonate ions, critical to huge numbers of native species. Its reproductive collapse may not be a "canary in a coal mine." It may be the equivalent of trying to raise a Chihuahua in the arctic.