Pacific oysters thrive in Hawaii’s climate


By COLIN M. STEWART

Tribune-Herald staff writer

Native to the Pacific coast of Asia, Pacific oysters, aka Crassostrea gigas, were introduced to North America and are currently the most cultured variety of oyster in the world.

They also happen to grow in Hawaii like gangbusters, according to researchers with the University of Hawaii at Hilo’s Pacific Aquaculture and Coastal Resources Center.

While Hawaiian waters currently can only be used to raise hatchling oysters to be sent to growers on the mainland, their potential is huge, said Maria Haws, the center’s new director.

“We’ve done some trials in Hawaiian fish ponds that can produce market size (between 3 and 4 inches) Pacific oysters in five to six months,” she said.

That’s a pretty amazing feat, when you consider that the same species takes two to three years to mature in waters in the Pacific Northwest, she said.

The difference is mainly due to the year-round warmer weather, which produces a constant supply of algae for the oysters to filter out of the water and eat. Meanwhile, Hawaiian waters have so far shown themselves to be less susceptible to the acidification process that has plagued oyster hatcheries along the West Coast in the last decade.

The Pacific Oyster is a filter feeder, Haws explained, sucking in nutrients from the water to feed itself and expelling clean water. In fact, she said, if enough oysters were grown in Hilo Bay, they could clarify the water, which is darkened by algal blooms brought on by water tainted by nutrients in agricultural runoff.

Currently, students and faculty with the aquaculture center are looking at using ancient Hawaiian fishponds as cultivation areas, because their walls provide protection from predators and rough waters.

“There are thousands of acres of fishponds available, and you don’t have the same permitting issues you might have elsewhere,” Haws said.

So what do you get when you combine Hawaii’s warm waters with just the right pH balance and plenty of sunlight-fed algae?

Carbohydrate-rich specimens of Pacific Oysters, with firm, white flesh. They’re referred to as “fat oysters” to those in the know, Haws said.

“They’re like wines. Every place you go will have a slightly different tasting oyster,” she said. “The oysters we grow here are great quality. They have a very sweet start and a salty finish — what is considered a superior oyster.”

Email Colin M. Stewart at cstewart@hawaiitribune-herald.com.

 

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