We are seeing seastars again along the shores of the Salish Sea!
Not in the same density as before the Seastar Wasting Syndrome (SSWS) epidemic killed upwards 90% of the seastars along the Pacific coastline two summers ago, but a definite recovery. I’ve been surveying my local shorelines since this started and what I’m seeing now at the start of summer 2016 is good news. Summer 2014 was a disaster, with thousands of dead and dissolving seastars, every site affected. Summer 2015 was a season with very few seastars, but those few were mostly healthy. I posted a report a year ago detailing my observations at that time (www.dailykos.com/...). This year so far I’ve seen about a third of the pre-SSWS population at two of my regular sites, and very few at two more sites. A few days ago I went out on a kayaking survey of two headlands, and being disappointed at finding none on one, I was delighted to see many seastars on the other: about half the pre-SSWS numbers.
The Daily Bucket is a regular feature of the Backyard Science group. It is a place to note any observations you have made of the world around you. Rain, sun, wind...insects, birds, flowers...meteorites, rocks...seasonal changes...all are worthy additions to the bucket. Please let us know what is going on around you in a comment. Include, as close as is comfortable for you, where you are located. Each note is a record that we can refer to in the future as we try to understand the patterns that are quietly unwinding around us.
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I can only observe from spring to fall since the rough water and high daytime tides makes it impossible during winter. The water was flat calm this day which helps seeing underwater where most seastars live.
Actually the Friendly Seal was just checking us out and saying hello. She hangs out around one of the headlands we surveyed this day and the bays on both sides of it but I don’t see her at the other headland. We paddled across the bay, she went back to fishing.
At the Sinibaldi/Olsen headland we saw 2 orange Pisaster ochraceus, both adults, and 18 purple Pisaster.
We also saw a Mottled Star, another of the species most devastated by the epidemic.
Of course I like seeing any and all wildlife when I’m out in the kayak. Slight detours in the survey....
Besides flat water and a reasonably bright sky, a moderately low tide is necessary for observing seastars. If the tide is very high, the seastars will be too deep to see. A super-low tide is no good though because down there all surfaces are covered with seaweed, with the seastars hiding underneath or even further down on bare rock. Seastars are Echinoderms — they can’t survive long out of the water. They climb up as far as they can to feed on barnacles and mussels but would rather stay safely immersed. Extreme high tides drop fast. A seastar waiting out a low tide in the dry intertidal will seek out a shady spot — hard to see.
We had a medium tide this day, as you can see by the mix of rock and seaweed on this shore.
Along with my usual camera I brought a GoPro to see if I could get any underwater pictures. Here’s a comparison. Seen from above, the three baby Purple Seastars are just below the waterline, so we get a pretty good view of them,
while the same 3 seastars seen from below are less bright. Even a foot or so of water reduces visibility markedly. Note how in just the few minutes it took me to switch from one camera to the other how the seastars have moved. You can’t see them moving but they travel faster than you’d think. The photo at the top of the Bucket was taken ten minutes before these...the bluer baby seastar has traveled a foot in that time.
This spot was a goldmine of baby Purple Stars. Besides the three here, there were 5 others a bit deeper, and 3 more just around the corner. They were all approximately 3” in diameter, which means they were born, I estimate, about 2 years ago. Last year’s seastars would be more like 1-1.5” now. This means some individuals survived the worst of the epidemic and reproduced; these 11 are of that cohort. There are more I know, beyond my sight. This is a very hopeful sign!
Other sea life I was able to peek at using the underwater camera:
Seastar Wasting Syndrome has hit seastars hard along the west coast. We know the pathogen that sickens them, a densovirus, and that some environmental factors have been linked to its spread, like higher water temperatures than usual in some locations. But the outbreak is not as simple as that. Scientists at Oregon State University have been monitoring seastars along the coast for years and report:
“Something triggered that virulence and it happened on a coast-wide basis,” said Menge, a distinguished professor in the Department of Integrative Biology in OSU’s College of Science. “We don’t think it was a result of warming because conditions were different in Oregon than they were, for example, in Washington and likely other parts of the West Coast. Ocean acidification is one possibility and we’re looking at that now. Ultimately, the cause seems likely to be multi-faceted.”
However they are measuring a recovery in Oregon, and the UC Santa Cruz SSWS monitoring program reports the same. There have been relatively few reports of diseased seastars compared to the last two summers. My own observations are consistent with these region-wide data, and Ron K up north in Bellingham Bay is seeing quite a few too. I’ll continue surveying seastars over the summer, and report what I find at the Bucket.
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The Daily Bucket is now open for your nature observations. Tell us what you’re seeing in your own natural neighborhood these days. Seen any wild animals around where you live?
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