Ocean acidification poses threat to shellfish industry (video)

A US oceans expert has been working with New Zealand to help combat the threat posed by ocean acidification to our multimillion-dollar shellfish industry. In the US acidification proved disastrous for hatcheries in Oregon and Washington state, as the coastal waters were transformed into a dead zone. Dr Todd Capson of the Global Ocean Health Programme says acidification is a consequence of burning fossil fuels and deforestation.

“Carbon dioxide enters the ocean, and when it enters the ocean it reacts with water, which forms a weak acid,” he said on Firstline this morning. “Acid releases hydrogen atoms… which look for something to react with, and that something that they react with is carbonate. The problem with that is it removes carbonate that would otherwise be available for organisms that make shells.”

Dr Capson says from 2007, shellfish hatcheries in the US northwest have been hard hit. “When the levels of carbonate are too low, they can’t make a shell. A larval shellfish has about two days to make its shell, otherwise it doesn’t survive.” Oyster hatcheries in the area lost 80 percent of their production, which had consequences down the line for shellfish farms, putting 3000 jobs at risk in an industry worth $300 million.

But is it happening in New Zealand? Dr Capson says he hasn’t seen any signs of it yet, but the acidity of the ocean is changing worldwide, so it could be a matter of time. “The oceans are now about 30 percent more acidic than they were at the beginning of the Industrial Revolution. But it’s like any complex environmental issue – it shows up in different places at different times.”He says New Zealand shouldn’t be complacent, and should look to future-proof the shellfish industry here before it does happen.

Dan Satherley, 3NEWS, 02 July 2014. Article & video.

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