In addition to leaving a void in a finely tuned ecosystem, the
loss of sea stars would also disrupt a seeming iconic shoreline organism.
The current outbreak
of sea star wasting syndrome was first reported in June 2013 along the coast of Washington by researchers from Olympic National Park.
Hewson speculates that the virus may have mutated as it wiped out various
species of sea stars, allowing it to infect others.
Underwater footage recently taken in the East Antarctic by the Australian Antarctic Division shows thriving
communities of sea stars, sponges, and other colourful creatures.
The
outbreak of sea star wasting disease caused significant changes to the ecosystem as sea stars are a keystone species that plays an important role in controlling the numbers of other creatures.
In one trial, the research team selectively removed the largest species of coral guard - crab, T. flavopunctata, from corals in the path of the
army of sea stars and observed the effects.
In fact, the Oregon Department of Fish and Wildlife put submersible vehicles off Oregon's coast during a hypoxic event that went anoxic (oxygenless) in 2006, he says, monitoring conditions and recording numerous
carcasses of sea stars, sea cucumbers, marine worms and fish.
Then white lesions appear on the
surface of the sea star's body that turn into holes; those lesions are typically followed by the disintegration of skin around the lesion and the loss of a limb or several limbs, and in extreme cases the animal's entire body is affected by the syndrome.
When that's the case, as it was last August just north of Vancouver, British Columbia, the chances for recovery are high since the plankton, or floating forms,
of the sea stars from healthy, nearby populations can recolonize those areas that were hit.
The die - off also occurred about two years before recent
incidents of sea star wasting syndrome were observed along the West Coast.
Two cling gobies spend their entire lives among the tentacles of a sea lily, a close
relative of sea stars that extends its tentacles to capture plankton in the water.
An example would be the indirect
effects of sea stars on vegetation in the rocky intertidal zone caused by changes in mussel density via predation.
Monica Moritsch from the University of California, Santa Cruz, with «Intertidal community
consequences of sea star wasting syndrome.»
She and her students have been studying an earlier densovirus outbreak on the east coast;
populations of sea stars in Rhode Island's Narragansett Bay abounded before a crash in 2011.
Looking for some historical perspective, Hewson tested museum
samples of sea stars collected between 1923 and 2010 along the U.S. west coast.
A likely situation, Hewson and his colleagues say, is that an
overabundance of sea stars increased the transmission of the virus, especially if they were stressed by competition for food, which could make them more vulnerable to infection.
C. Melissa Miner and colleagues analyzed nearly two decades of data to better understand the
impact of the sea star wasting disease on sea star populations along the Pacific coast of North America.
In 2013 to 2014, scientists witnessed the largest die -
off of sea stars ever recorded along the Pacific Coast.
Sea Stars in the San Juan Islands — Predatory Jewels of the Intertidal Zone The colorful
beauty of sea stars belies their true nature as the top tidepool predator.
Some
species of sea star (known commonly but erroneously as «starfish») use asexual reproduction via fragmentation as their main reproductive mode.
Underwater footage recently taken in the East Antarctic by the Australian Antarctic Division shows thriving
communities of sea stars, sponges, and other colorful creatures.
Although there have been minor outbreaks in previous decades, this one is much more widespread, and more than 20 species
of sea stars have been afflicted; other kinds of echinoderms, the animal group to which sea stars and sea urchins belong, have not.