Environmental conditions spur growth spurt for Alaska oysters

Numbers are on the rise for Alaska’s shellfish growers: They sold more than 1.8 million oysters in 2017 for a 27 percent increase over 2016 and a 70 percent increase over the 10-year average. At the going rate of $19 per pound, revenues for the growers tallies up to more than $2.8 million.

Increased sales of the oysters to the retail market link back to favorable conditions in the growing pens. A continuous challenge for the growers involves raising baby oysters from the size of a pinhead to the market-ready size of 3 inches long. A key component in an oyster growing operation rides on producing their food, algae, which arrives in tiny glass tubes from the Lower 48 and has to be grown to tons of edible fodder for the oysters within months.

“We start growing the algae in January,” said Suzanne Torian, one of the growers at Kachemak Shellfish Growers Co-op, in Homer. Torian says the company sets 3 million oysters each year, and they consume thousands of liters of algae in days.

At the same time, water conditions must remain favorable for at least three years in flupsies (floating nurseries that include upwelling systems) to move nutrients and algae to the oyster babies.

Myriad environmental factors need to align to ensure survival and allow the oysters to mature. In Alaska, volcanic eruptions and other natural calamities can alter oceanic conditions that reduce survival rates. Fluctuations in sea surface temperatures also take their toll.

Lately, however, conditions have been favorable, with survival rates running at around 95 percent.

“We’ve had such good luck with our seed,” says Torian. “It seems the oysters are growing bigger, faster.”

When the oysters reach 15 millimeters in length, they are delivered to local oyster farmers who grow them to “petite” in 2 to 3 years, medium in 3 to 4 years, and 4 to 5 years or more for large oysters.

About the author

Charlie Ess is the North Pacific Bureau Chief for National Fisherman.

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