Five years after a mysterious disease began killing millions of
starfish and turning their tissues to mush, the decimated
population has yet to recover. Meanwhile, researchers continue to
struggle to identify a cause for the disease, which appears to have
uncertain ties to viruses and possibly environmental
conditions.
In Puget Sound, it’s not as easy as it once was to find a
diseased sea star, which seems to be a promising sign until you
consider how many have died. As I learned last week during an
outing to Lofall in North Kitsap, the total number of starfish
remains low compared to four years ago, and recovery has been
minimal, if at all.
Under the Lofall dock,
volunteers have observed that the number of sea stars is still low,
but sick ones are no longer common.
Photo: Christopher Dunagan
Local volunteers have been observing sea stars at Lofall since
the beginning of 2014. I first visited the site the following
summer with three retired women who lead the monitoring effort
there. (See
Water Ways , June 17, 2014.) They are still making regular
trips at low tide, counting and measuring the starfish and looking
for signs of disease.
“The numbers are way down,” noted volunteer Barb Erickson as we
stood beneath the Lofall dock last Friday, “but we haven’t seen
many sick ones. We also aren’t seeing the little ones.”
It was a dark and stormy night — but that didn’t deter the Three
Starfish Musketeers from going out at low tide on Saturday to check
on the condition of sea stars clinging to the Lofall pier.
Researcher Melissa Miner
examines sea stars on the Lofall pier while volunteer Peg Tillery
watches. // Photo by Christopher
Dunagan
If you recall, I introduced these three retired-age ladies in a
story last summer, when they first reported a scene of devastation
on the North Kitsap pier and nearby beach, where a multitude of sea
stars lay sick and dying. Many sea stars were afflicted with a
mysterious disease called sea star wasting disease, which had
already affected hundreds of locations from Alaska to Mexico.
The three women — Barb Erickson, Linda Martin and Peg Tillery —
have been serving as amateur researchers, monitoring the Lofall
beach, like hundreds of other volunteers at various locations along
the West Coast. When they started monitoring the beach in February
2014, they observed dozens of healthy sea stars — but conditions
changed dramatically by June.
Barb tells the story with photographs in her blog,
Ladybug’s Lair, and I’ve included a summary of her observations
at the bottom of this page.
I was not sure what to expect when I accompanied the three women
to the Lofall pier on Saturday, the night before the Seahawks NFC
championship game. Joining us on this dark, rainy night were
researcher Melissa Miner of the University of California at Santa
Cruz, who has been working with volunteers up and down the coast.
Also with us was Jeff Adams of Washington Sea Grant, who has been
coordinating local efforts.
What we saw Saturday was a great many more young sea stars than
last year, along with adults that seemed to be healthy. None of the
starfish showed signs of disease.
“That’s good news, and there are some big ones in here,” Melissa
commented, as she examined the pilings where the monitoring is
taking place.
“It feels better this time when we’re out here,” Jeff said,
adding that last fall he saw far more sea stars turning to mush and
disintegrating. “All we saw were body parts strewn all over.”
Melissa said researchers are seeing much greater numbers of
juveniles at many of the sites along the coast and inner waterways.
That could mean that the population is rebounding, but there is
still great uncertainty, she said. Some evidence points to
temperature as playing a role in the disease.
“It seems like around here temperature is a pretty big factor,”
she said. “When summer comes around, we’ll be able to see how
things change.”
In November, a group of scientists identified a virus, known as
densovirus,
that is clearly associated with diseased sea stars. Further work is
needed to determine how the virus affects the animals and what
other factors are in play. See
Proceedings of the National Academy of Sciences and my Nov. 22
blog post in
Water Ways.
If we are indeed in a period of recovery at Lofall — and
hopefully many other sites — it will be interesting to see how the
ecosystem rebounds and how long it takes for the sea star
population to return.
Jeff Adams told me in November that he hopes to maintain the
volunteer monitoring program for years to come — not just to track
the sea star disease but to understand more about the cycles of
marine life.
Barb Erickson summarized the findings of the group before
Saturday’s outing:
“For our data collection, all of our observations take place in
a specific area centered on three concrete piers under a dock at
Lofall. In the beginning, a great number of ochre/purple sea stars
and a few mottled stars congregated on each of the piers. That
number has steadily declined over the past year and, although we
are aware that these animals come and go with the tides, we feel
their decline is directly related to the disease.
“We began our observations in February 2014, when we counted 56
sea stars, adults and juveniles. Many small juveniles were tucked
away in corners and under cables on the piers. Of those 56, only 4
appeared to be in the early stages of disease. In April we counted
100, all of which appeared healthy. In May, of the 53 we found, 33
were in various stages of illness. By June, the majority of the sea
stars were dead or dying. Of the 12 living stars we found, 11 were
in the early stages of disease.
“Throughout the rest of the summer and early Fall, the area was
littered with dead stars and the number of living ones, including
juveniles, continued to decrease. By October, we found a total of
only 7 living adult stars and no juveniles; 5 were diseased. In
January 2015, we found 56 (20 adults and 36 juveniles); all
appeared healthy.”
The count from Saturday’s outing was 48 sea stars (21 adults and
27 juveniles), and all appeared healthy.
