SOURCE: Seattle Times
DATE: January 30, 2019
SNIP: Once a common delight of every beachcomber, sunflower starfish — the large, multi-armed starfish sometimes seen underwater at the near shore — are imperiled by disease and ocean warming along the West Coast.
The devastation occurred over just a few years and even affected starfish in deeper water, according to research co-led by the University of California, Davis, and Cornell University published in the journal Science Advances.
At one time plentiful, the sea suns, or sunflower starfish, right now cannot be found off the California coast and are rare northward into Alaska, said Drew Harvell, the paper’s co-author and Cornell professor of ecology and evolutionary biology. The starfish have become so rare over the past three years the scientists consider them endangered in the southern part of their range.
Sea star wasting disease beginning in 2013 caused a massive die-off of starfish of multiple species, from Mexico to Alaska. Hideous to behold, the disease causes starfish to fall apart, with pieces of their arms walking away, or their bodies disintegrating on pilings, beaches, rocks and the seafloor.
The sunflower star continues to decline, even in the deepest ocean, and is not recovering like some other species, such as the ochre star.
Global warming is likely a major cause of the disease, causing a heat wave in the oceans. Warmer temperatures exacerbate sea star wasting disease, allowing it to kill faster and have a bigger impact.
Starfish matter in the ocean — and not only because they are every kid’s first friend on the beach. Sunflower stars in particular prey voraciously on sea urchins — which keeps urchin grazing on kelp forests in check. As sunflower stars crash, urchins surge — and mow down kelp forests. That reduces the waving, green underwater nurseries that young fish need to thrive.
“The cascading effect has a really big impact,” said Joe Gaydos, an author on the paper and science director at the SeaDoc Society.