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Climate change making oysters smaller

A new study focused on Sydney rock oysters has found that the oysters are getting smaller due to coastal acidification.

A Natural Environment Research Council (NERC) study carried out by Scottish and Australian scientists at two commercial oyster farms in Wallis Lake and Post Stephens, both in the mid-north coast of New South Wales, confirmed that the oysters’ diminishing size and falling population is due to acidification from land and sea sources.

While the Sydney rock oyster research project focused on Australian aquaculture, lead author Dr Susan Fitzer warns that seafood lovers around the globe could begin to find smaller and smaller oysters on their plates because of the increasing acidity of seawater.

“The first thing consumers may notice is smaller oysters, mussels and other molluscs on their plates, but if ocean acidification and coastal acidification are exacerbated by future climate change and sea level rise, this could have a huge impact on commercial aquaculture around the world,” said Fitrzer, a NERC Independent Research Fellow at the University of Stirling in Scotland.

Increasing amounts of carbon dioxide (CO2) in the atmosphere from fossil fuel combustion, land-use change and other human activities result in increased CO2 being absorbed by the ocean.  That combination of CO2 with seawater makes the water more acidic, said another study, The US West Coast Shellfish Industry’s Perception of and Response to Ocean Acidification.