Posted on Seafood Business Magazine: 01 Jun 2014 — By Bruce Steele
A decade ago, Japanese researchers showed that seawater soured by carbon pollution would hamper sea urchins’ reproductive capabilities. I read their report and saw trouble on the horizon. As a commercial urchin diver in California, I hoped this trouble would stay far away. Now it’s here.
Christina Frieder at UC-Davis has demonstrated that waters acidified to pH 7.8 — a level already detected along the West Coast — can reduce fertilization success by 20 percent in red sea urchins, which are harvested from California to Alaska. Frieder states that 60 percent reductions in fertilization success may occur in the decades ahead as pollution pushes seawater pH down to 7.5. This means that red sea urchins will have a harder time recruiting into the fishery, and they will be less abundant. Surface waters had an average pH of 8.2 in pre-Industrial times; acid from carbon emissions has reduced that to about 8.1 in today’s ocean, and it’s heading south fast.
Now ocean acidification is my problem. If you work in seafood, it’s yours too.
Red king crab suffers 100 percent mortality of larvae after 90 days in seawater at a pH of 7.5. Oysters, mussels, clams, abalone and some scallops are vulnerable, which shellfish farmers are learning the hard way. Corals that shelter vulnerable fish populations in much of the world are at risk. Shells of pteropods, common zooplankton that are a key food source for salmon, are already dissolving in Pacific Northwest waters. Two recent studies found that modest levels of acidification can impair growth in American lobsters. Direct impacts on fish are also becoming clear: Some fish lose their ability to smell and evade predators or distinguish them from their own prey. The catalog of harm includes damage to organ tissues, neurological functions, growth and reproduction.
For the seafood industry, some consequences are now inevitable. But there is no place to hide, so we had better defend ourselves. Both the causes and the consequences of acidification can be reduced.
How to curb the causes?
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