The waters of the Gulf of Maine are warming faster than oceans almost anywhere on Earth. And as the level of carbon dioxide rises in the atmosphere, it's absorbed by the oceans, causing pH levels to fall. Ocean acidification makes it difficult for shellfish to thicken their shells—their primary defense against predators.
source https://phys.org/news/2020-10-declines-shellfish-species-rocky-seashores.html
