sea star

Sunflower sea stars — vividly colored creatures with up to 24 arms, and which can weigh as much as a small dog — once thrived along the Pacific Coast between Alaska and Baja California.

For example, they’ve witnessed people wading into the water in the tidepools, a sensitive habitat that’s home to a variety of sea life, including octopus, urchins, sea stars, crustaceans and small fish.

While sunflower stars have not recovered, adult ochre sea stars on rocky shores are growing in size and number to what was measured before the disease epidemic.

When the disease first broke out in the Caribbean, “we were scratching our heads,” says Ian Hewson, an oceanographer at Cornell University who has studied diseases in sea stars and other marine animals.

The pandemic led to an estimated 90% decline in sunflower sea stars, which are now listed as critically endangered.