History

Primordial
••Success
Stone Age
Greeks
Romans
Middle Ages
Renaissance
••Exploration
18. & 19. Cent.
••USA
••Gold Rush
••Willapa Bay
••Equipment
••Boats
••France
••Coste
••England
Belle Epoque
20. Century
••1. Half
••2. Half
••France
••Chesapeake
••Willapa Bay
21. Century


Evolutionary Success Story
John McCabe

A closer look at today's oysters reveals at least a couple of the ingredients of the evolutionary oyster recipe for success: Adaptability and lots of babies!
One of the most striking survivalists among today's oysters is the Pacific Oyster (Crassostrea gigas). Crassostrea gigas could be called the docile counterpart of Tyrannosaurus rex in the oyster world. Fully grown, it is a huge oyster weighing many pounds. It is a voracious plankton feeder and grows faster than most other oysters. C.gigas excells in adaptability. It lives in deep waters of about 40 meters. It also does very well in shallow coastal waters, even when "high and dry" for several hours every day during low tide. It tolerates the high salinity of the ocean as well as the low salinity of brackish coastal waters. Unlike many of its predators, it doesn't even mind drastic salinity changes on a seasonal basis or even a daily basis. Although it doesn't particularly care for baking in the sun or freezing temperatures for very long, it more often than not will survive even these occasional extremes. It can live in these varied places, "happy as a clam" if you will, for more than 20 years. It's also considered very disease resistant.

But that's only the "half shell" of it. When the coastal waters reach a certain temperature during the summer months, the Pacific Oysters start romancing each other rather indiscriminately on a almost unbelievable scale. One female can produce 100 million eggs and catapult them out into the water. A male will do the same with a far greater number of sperm. Somewhere the sperm meets the eggs and countless oyster larvae develop. Although the majority will end up being "lunch" for a vast number of natural enemies, many will survive and settle on some rock or shell to become "oyster babys" (so called "spat"). There's also never a shortage of males or females, as oysters are hermaphrodites to boot. Living comfortably in its mother of pearl palace inside, it's thick insulating shell casing presents a formidable fortress to just about anything that creeps, crawls, walks, swims or even flies. Native to Asian ocean waters, this species is likely to have been around for more years than can be displayed on many pocket calculators. It comes as no surprise that the Pacific Oyster is the darling of countless oyster growers in many parts of the world. That Pacific Oyster on our plate carries a Japanese, Chinese, American, French, Canadian, Irish... - even a German passport by now. As humble and simple this oyster overtly appears, Crassostrea gigas is nonetheless a first class evolutionary success story and a respected world citizen by now. Internationally, no other marine animal species is cultivated on a grander scale. In 1996, the Food and Agriculture Organization of the United Nations (FAO) rated the Pacific Oyster as #2 worldwide in terms cultured aquatic production (surprisingly, kelp is #1). Mankind, qualifying itself of course as a far greater evolutionary success story and unquestionably the most powerful predator ever to roam this planet, thins the ranks of the Pacific Oyster to the tune of just about 3.000.000 tons per year.

Other oysters had different evolutionary "ideas." Take the noble European Oyster (Ostrea edulis) for example:
Although a female can "only" come up with about 500,000 to 1 million eggs, it will allow them to be fertilized by the sperm within the safe environment of her shell. Here the larvae will be allowed to grow for a while before they also get kicked out into the vast plankton fabric of the ocean to make their own way. Once it was the premier oyster in the western world. It has, however, since proven to be no match for the onslaught of mankind, has suffered greatly from a number of diseases and, today, contributes only a small fraction one percent to the world wide oyster market volume.

Species of another oyster family (called Spondylidae) evolved into fortresses bristling with spears, certain to turn off a great number of natural oyster predators.

Unlike many other bivalves (like clams and scallops for example) "running away" was, oddly enough, never part of the evolutionary survival recipe of the oysters. They are the classic "home bodies of the ocean." They actually have no choice but to stand their ground when danger nears. From childhood on they're stuck right where they are in plain sight on the ocean floor for as long as they live. Barring storms (and mankind nowadays of course) that may move some of them involuntarily, they'd surely be a postmaster's dream: Never a "change of address."

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