Solving The Starfish Death Mystery

By James Donahue

We have known them as starfish but scientists now say the creatures should be called sea stars because they are not fish. They are sea creatures that are shaped like stars that are usually found in abundance in the oceans of the world.

But something has been killing the sea stars by the millions this year and marine researchers have been working overtime trying to find out what it is. They have described it as a kind of "wasting disease" that literally causes the lovely sea stars to turn into goo and fall apart.

The attack has been mostly noticed on the Pacific Coast of the United States and Canada, but sea stars also have begun dying along the Atlantic coast as well. The disease is striking at least seven different varieties of these creatures. Some researchers have rated the sea star problem as the largest marine crisis of its kind ever recorded.

Now, after months of study, marine biologists say they have identified a mutated variety of a common virus, or densovirus that suddenly began attacking its hosts. Now the problem is learning why the virus is behaving like this.

This particular virus has been cohabitating with sea stars for centuries. To suddenly mutate and begin killing its host is not normal behavior for this virus. Once the host dies the virus perishes with it.

Is the problem related to global warming? Probably not, the researchers say. They note that sea stars in warmer waters have been attacked by viral infections in the past, but nothing as vast as has been happening this year. Not only are the sea stars dying in the warm waters, but they are also perishing in the cooler waters of the north. Water temperatures do not appear to be a factor.

The research team has noted that the sea stars appeared to be getting overpopulated along the Pacific Coast in recent years. Are they experiencing a natural die-off of the species? Is the problem linked to the Fukishima disaster?

Will there be an environmental impact? Researchers say they don’t know. Sea stars feed on mussels, thus controlling that population. Without an abundance of sea stars, the mussels may proliferate and ruin undersea kelp forests that help hide the small fish from predators. They also help protect coastal areas from sea surge and flooding from storms.

Thus an extreme kill-off of sea stars could cause an upset in a natural balance of the natural order of things just off the western U.S. coast.

"These kinds of events are sentinels of change," said Drew Harvell, professor of ecology and evolutionary biology at Cornell University. "When you get an event like this, I think everybody will say it’s an extreme event and it’s pretty important to figure out what’s going on."

He said an event affecting multiple species of sea stars, stretching from Southern California north to British Columbia has been virtually unheard of. Also troublesome is that sea stars along the Atlantic coast also are under attack. It is not known if the same virus is involved in the Atlantic die-off.