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Sea Stars Wasting Away


July 2014

No Net Loss

Sea Stars Wasting Away

by James Wells

James Wells develops systems that support energy efficiency incentive programs. He spends his spare time encouraging people to actively participate in the decision about the Gateway Pacific coal terminal.

To No Net Loss Readers: This month I am taking a break, but I am thrilled that James Wells has agreed to write this month’s column on an issue that touches us close to home. Star fish wasting disease has hit Larabee State Park. It is part of a greater pattern of biodiversity loss, and mass extinction of species. When other species are not doing well, it does not bode well for our own species, which is dependent on the ecological services that keep our planet healthy. There are no easy answers and no easy cures, but continuing in the direction we are heading is not a option. Until next month, Wendy Harris

A family trip to the seashore revealed to us yet another instance of what feels like the natural world unraveling before our eyes.

We had been on the lookout for Sea Star Wasting Disease this spring. Just two weeks before, my daughter and I were looking at the purple sea stars around Boulevard Park and Taylor Dock - they all looked good.

On this day, my wife and I took our junior scientist out to Larrabee State Park to check out the epic low tide, usually the best time to see the critters of the intertidal, especially the iconic form of sea life at Larrabee – the sea stars. Kids of all ages come to see them.

Now, many of the sea stars were dead or dying. They had white lesions over their bodies, and they had lost the small white spiny points that mark a healthy sea star. Some had twisted themselves on themselves, instead of the classic pose of five legs radiating out from the body center. Others were entirely missing one or more legs.At the end stage, the sea star sometimes falls completely apart, the legs literally tearing themselves off the main body. In addition to many dead sea stars, we saw legs scattered around the intertidal.The population appeared to be much lower than we had seen at previous very low tides. Previously, it was normal to see clusters of a dozen of more sea stars in any given crevice in the mid to lower intertidal.It was a somber trip home. In any trip to a natural place, I try to show my daughter something about the world around us, the systems which are at the same time wondrous and fragile, and how we need to protect them. Today felt like a whole lot more education than I had planned on or hoped for.

According to a site on the disease maintained by University of California Santa Cruz:

“As yet the cause of the syndrome is unidentified, and it’s not clear whether it’s a due to an environmental change, disease or something else. Similar die-offs have occurred before in the 1970s, 80s, and the 90s, but never before at this magnitude and over such a wide geographic area.”

The currently recorded extent is basically the entire US west coast, from southern California to Alaska.

The implications for the marine ecosystems are clear:

“Ecologists consider both sunflower and ochre stars to be keystone species because they have a disproportionately large influence on other species in their ecosystem. In fact Pisaster ochraceus was the basis of the Keystone species concept because of its potential to dramatically alter the rocky intertidal community in which it occurs.”

So, the species of sea star that we saw dying (Pisaster ochraceus) is not only a Keystone species, it is the animal that inspired the whole idea of keystone species.

It’s natural to consider the potential human-caused impacts that may be making things worse. Some investigators have pointed to the overall warming of ocean waters as a likely cause or aggravating factor.

But caution is in order. This outbreak has continued to spread through last winter, a time when water temperatures were relatively cold. So if warming of the ocean has played some role, something else must also be at work.

One scenario is that a new and more virulent strain of an existing pathogen is spreading. Another possibility is that sea stars have been weakened by some set of environmental stressors, making them more susceptible during this outbreak.

Researcher Melissa Miner of UC Santa Cruz emphasizes that research may be only just beginning. On the topic of identifying a pathogen responsible for the syndrome, she says “You can prove a given microbe is present in affected sea stars, but it is much more difficult to prove that it’s the cause of the syndrome.”

And what about the prognosis? Is extinction a real threat for one or more species? Miner observes, “This is one of the largest marine die-off events in the record. It’s very concerning. The good news is that typically some percent of the population in a given area survives the syndrome. Hopefully the affected species can recover, although it may take a long time. ”

A big decline in a key population still matters. “You’re likely see notable effects in certain areas, but less in others,” Miner says. “In areas having Bay Mussels, such as around Bellingham Bay, mussel populations could initially go up because the sea stars are their main predator.” That increase could have other effects in turn, which can’t be predicted with any kind of certainty.

A critical part of studying sea star wasting syndrome has been to collect observations about where and when the syndrome is seen. Fortunately, a monitoring network has been in place for several years, collecting data along the entire west coast and storing the data in a systematic manner. When the wasting syndrome arrived, the network allowed researchers to document the spread of the syndrome much more quickly than they otherwise could have.

This is still an essential need. Anyone can play an important role by submitting observations to the University of Santa Cruz site. Simply go to the web site, enter key information including the date and lat/long of your observations, and record what you see. You can also upload pictures to the site.

For people who want to become more involved and are willing to commit to making regular observations over a period of time, training is available by arrangement with several local organizations, including Re Sources in Bellingham and the Padilla Bay National Estuarine Research Reserve in Skagit County.

Whatever the specific cause of the widespread sea star die-off, we find ourselves in a world where these occurrences have become all too common.

The book “Extinction,” by Paul and Anne Ehrlich, introduced the rivet popper analogy  to describe the unraveling of our natural world:

As you walk from the terminal toward your airliner, you notice a man on a ladder busily prying rivets out of its wing. Somewhat concerned, you saunter over to the rivet popper and ask him just what the hell he’s doing.

“I work for the airline — Growthmania Intercontinental,” the man informs you, “and the airline has discovered that it can sell these rivets for two dollars apiece.”

“But how do you know you won’t fatally weaken the wing doing that?” you inquire.

“Don’t worry,” he assures you. “I’m certain the manufacturer made this plane much stronger than it needs to be, so no harm’s done. Besides, I’ve taken

lots of rivets from this wing and it hasn’t fallen off yet.”

In each individual case, it’s not always possible to definitely prove that pollution, climate change, or other human impacts caused the die-off, or made it worse. Still, the pattern seems clear.

How many rivets will it take until the entire wing comes off?

Notes

Thanks to Melissa Miner from UC Santa Cruz for a very informative phone interview.

The UC Santa Cruz web site is www.seastarwasting.org


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