Warming Temperatures Are Killing Millions of Starfish

Image: Natureworldnews.com

Warming Temperatures Are Killing Millions of Starfish

Three years ago the West Coast of the United States was swept by the single largest, most geographically widespread marine disease ever recorded. This disease targeted millions of starfish along the coast causing the sea stars to decompose, as if they were melting. Millions of starfish were killed by this virus with some regions losing up to 95 percent of its starfish population. And a recent study has found that the rising water temperatures caused by climate change only exacerbated what was already a species crippling epidemic.

Starfish are what is called a “keystone species.” A keystone species is a plant or animal that plays a unique and crucial role in how an ecosystem functions. Without keystone species such as the starfish, their ecosystem would either be drastically altered or cease to exist altogether. In the ecosystem along the west coast, the starfish ensure the biodiversity of the region by preying upon the mussel populations. Without the starfish to keep the mussels in check we are already seeing a rise in the mussel population that threatens to push out other marine species in the area.

Marine biologists have been aware of the disease that decimated the starfish since 1942 when infected starfish were first discovered. It was only recently discovered however how great an affect water temperature had upon the virus.

“Warmer water temperatures might not have been the catalyst for the disease, but our findings show that if the water hadn’t been so hot that year, the impact would most likely have been less,” says Drew Harvell, a member of the study and a professor of ecology and evolutionary biology at Cornell University.

In the study, researchers watched the ochre sea star, the most prevalent species of starfish on the West Coast. The team analyzed water temperatures before, during, and after the epidemic struck the starfish at locations around the San Juan Islands and Puget Sound in Washington. What they discovered was that as water temperatures rose, so did the risk of infection for sea stars. Sites with the highest water temperatures were also the sites where starfish had the highest risk of infection.

To confirm their findings, researchers also placed starfish in aquarium tanks with temperatures between 54 degrees to 66 degrees Fahrenheit. The hotter the tank, the faster the starfish fell to the illness.

Marine biologists are hopeful that the starfish will be able to rebuild their population after this event. However the long term effects that this will have on the region’s marine life can only be speculated at.

The research team that led the study wasn’t ready yet to speculate on what climate change would mean for the species, but they did tell us where to look next.

“Alaska is where the action is now,” Harvell said. “They’re experiencing incredible warm temperature anomalies in the northernmost range, and that’s the next region to see how sea stars react there.”