Acid and the Dungeness Crab

In 2009, after some sincere lobbying by school children across the US state of Oregon, the Dungeness Crab was honoured with the title of ‘state crustacean’.

This status gives extra protection for the Dungeness crab, and allows sustainability practices to be further supported by law.

Unfortunately this level of protection seems to have had limited effects on protecting the crab’s environment.

On the 2nd of January 2021, 29 tonnes of crab caught by the Quinault tribe were voluntarily recalled after high levels of the marine toxin, domoic acid were found in them. If eaten, domoic acid causes nausea, vomiting, cramps and diarrhea. Urgh!

Domoic acid is released by high concentrations of algae and sometimes causes erratic behaviour in larger animals - with a suspected domoic acid outbreak being the inspiration behind Alfred Hitchcock’s ‘The Birds'.

A 2017 study by the National Academy of Sciences USA has suggested that excessive algae growth is linked to climate-scale warming of the oceans. Which in this case has the knock-on effect of toxifying marine organisms.

This is because of a process called biomagnification, which is where toxins in food chains build up and increase.

Substances like domoic acid are difficult to break down, and so it stays in the organisms that eat it, in this case the Dungeness crab. The concentrations of the toxin are then magnified in whatever predator might eat the crab, in Alfred Hitchcock's case, a whole load of birds! 

Biological processes can be confusing, but don't worry, we'll be coming back to 'biomagnification' soon! 

For now, if you happen to be in Oregon, DON'T EAT THE CRABS!