Friday, July 8, 2016

Pycnopodia Watch! Cautious Optimism about Sunflower Stars!

The Starfish Wasting Disease was first documented on the west coast of North America in 2009 and began to hit really hard in 2013 as I blogged about here and it became suddenly noticeable by MANY scientists on the west coast from Canada to California.  Due to a massive population explosion there followed a catastrophic die off in British Columbia which I documented here, with pictures courtesy of Jonathan Martin. 

In the intervening years, the Starfish Wasting Disease "event" had taken on a HUGE stage. UC Santa Cruz now monitors the health of west coast asteroids on their website (here). 

The first Sea Star Wasting Symposium was held earlier this year in Seattle. A meeting which I attended and reported on here

Perhaps one of the most significant losses following the massive starfish wasting disease epidemic that hit the west coast of North America (and possibly parts of the east coast) was the apocalyptic loss of the iconic sunflower sea star, Pycnopodia helianthoides.
When I was growing up on the west coast, there were sunflower stars that were HUGE!!  Tall tales would  report them reaching two and a half, then THREE feet across! But most were a good dinner plate size.

These animals were voracious predators and for starfish, moved quickly across the intertidal and subtidal...

Sunflower Stars are an ecologically important species. 

Unfortunately, populations of this species were DEVASTATED by the starfish wasting disease epidemic. More so than almost any of the other species, the sunflower stars were more often than not, completely removed from local areas along the coast.

Ecologically this has had VERY significant ramifications. Recent ecological studies, such as this 2016 paper in PeerJ by Schultz et al   have indicated that green sea urchin abundance in British Columbia has increased FOUR FOLD!

This has agreed somewhat with anecdotal observations by naturalists on Twitter observing sea urchin abundance in California...
The exact reason is not clear. Possibly because the sunflower stars are not around? and the animals have just come out of hiding? Or have the stars been controlling the population structure of the urchins?  But it DOES seem to be related to the absence of the once abundant and mighty sunflower stars.

But Sunflower stars are also an ICONIC species..
In addition to be an ecologically important part of the intertidal and subtidal ecosystem, there's a lot to be said for how they really represented the North Pacific. Pycnopodia is an endemic, found nowhere else in the world.. and was often used as an example of the special and diverse fauna on the west coast of North America..

Some of the individuals which had been on display in public aquaria died within days. Some of these individuals had been around for over 20 years. Suddenly? Gone.

Those of us who are most familiar with the West coast fauna.. divers, naturalists, scientists, citizen scientists, beach goers, students, fishermen, anyone with an intertidal or subtidal ID guide was suddenly NOT seeing this species. It was and still is a significant and sad loss.

And so.. observations of THIS species have had a SPECIAL significance..

BUT today, a colleague of mine, Ms. Brenna Green observed THIS. A juvenile Pycnopodia helianthoides in Northern California!! According to her, one of the first she's seen in a good long while!!
A small individual. Only a few inches across. But still...

I was directed to iNaturalist which has been monitoring observations of ALL asteroids on the west coast.. There were only 60 observations of Pycnopodia since 2014!!- so only about 20 per year that are reported  Note also-some of those observations were from areas that are distant from the primary Sea Star Wasting Disease areas (such as Alaska).

Make no mistake, that's a very low number... but surprising considering that they were considered completely gone from some areas..

But they ARE still out there. And are still popping up..

An anecdotal skim of Flickr and Twitter shows that small sunflower stars have been popping up over the last year or so...
From Titlow, Tacoma, Washington from February 29, 2016
Sunflower Sea Star
Weir's Beach, British Columbia by Laura Verhegge (taken April 21, 2015)
Pycnopodia helianthoides

Recent accounts (such as this one) have documented a resurgence in populations of sea stars hit by starfish wasting disease (based on this paper).

But I would like to think that is SOME good news, even if this doesn't mean a full and immediate recovery..

Another significant issue? SIZE of the observed individuals
Here's one of the most critical parts of these observations: Most are consistently SMALL. Many of the "adult" individuals we were used to encountering were easily dinner plate size or larger have not really been encountered.. or if so, not regularly. 

Are the small sized ones a sign that they simply grow very slowly?  Or more ominously,  do they die as they reach a certain size??

On the upside, I have heard SOME anecdotal observations of adult (~40 cm) sized individuals being seen in Washington and in other localites...

Stay tuned! Research continues. 

In the meantime, for further news check out:


Vadim K said...

Hi Cristopher,

Thanks so much for your fascinating articles and images on echinoderms!
I'm working on a kelp forest community model which includes Pycnopodia (hopefully they'll bounce back, though as a side note their non-consumptive effects on grazers are quite strong, so they can still limit grazing in sites where they're rare). Any ideas on how long they typically live? I suspect "dinner plate-sized" is 3-5 years, but I'm not sure and don't know how common bigger ones are (used to be)?


ChrisM said...

There is some uncertainty in Pycnopodia where size/age relationships are concerned. And I'm not sure all of your questions have good answers.

Pycnopodia in captivity were, in some cases, approaching or even slightly exceeding 2 feet across. Some of those, such as the one at the Seattle Aquarium had been there for 20 or 30 years (since the 80s or 90s). There were reports of animals that big in the wild but I'm not sure if those accounts have ever been entered into the literature or properly documented. I would not be surprised if "dinner plate sized" was anywhere from 3 to 10 years but there is some indication that many of these stars are capable of growing at a surprisingly fast rate. Again, anecdotal accounts. I suspect that places like Monterey Bay Aquarium might still have some alive, and there might be some record of how big they were during the time they were collected.

sorry I don't have better info. You might also try some anecdotal accounts in Boolootian's 1966 which had a few paragraphs on age in sea stars.

Unknown said...

Hi Chris, Here is another data point. A buddy of mine just posted a picture of a 6" sunflower in the Monterey area on Facebook.

Note: Lauren is a mechanical engineer and not prone to wild exaggeration. She probably dove without a ruler, so I'd put a 20% error bar on the 6" measurement. But it's way bigger than the 1" juveniles I've seen and provides encouraging evidence that at least some of the juveniles are surviving.

Do you know how size correlates to age? Is the age of a 6" specimen measured in months or years?

Ralph Wolf said...

"Unknown" above was from Ralph Wolf, if anyone cares...

ChrisM said...

Thank you Ralph! A 6 inch sized individual is significant but I'm unsure if we have a good understanding of how size translates to age. I will ask around.

ChrisM said...

if possible, if you can send me the image another way with a stable link or perhaps log it on iNaturalist? so that I can share it? thank you.

Erin McKittrick - Ground Truth Trekking said...

Hi Chris,

What would be most useful to know/record right when the disease hits? Either about the stars, or about the other species that could be affected by their loss? I live in an area of Alaska that is just getting hit by wasting disease right now. Pycnopodia were common, large and healthy earlier this summer. My son was counting legs and got leg # data on 47 different stars this summer. I took a photo of a huge one in July. At this latest low tide cycle in August, I couldn't find a single live one, and there's piles of goo all over one of the bays where they used to be common. Some species and places are hit, and others (including the pisaster) not yet.

I'm an ex-molecular biologist who enjoys citizen science projects and loves low tide critters (I'm also on iNaturalist), so if there's any useful data I could gather, I'd love to.

Erin McKittrick

ChrisM said...

Hi Erin,
WOW! thank you for your efforts. I think that keeping your observations on a site such as INaturalist is the best you can do, short of actually publishing a paper or a note documenting observations. Either that or contacting someone at the Starfish wasting website at UCSC (above). Starfish wasting has given us a new appreciation of citizen scientist data given the huge amount of information that has come from your and many other observations!

At the moment I'm not sure there's more you can do other than to observe and notify me or someone involved of anything particularly unusual.

Thank you!

Erin McKittrick - Ground Truth Trekking said...

Oh, my son's data is just a 7-year-old's pet project, nothing fancy I need to be thanked for. It was just striking because he was super interested in the sunflower stars right before they happened to die off.

I'll go through all my sea star photos from the summer (getting good photos of all the intertidal critters and a list of all the species I find on each beach was my summer's pet project, so I have a lot), and upload more to iNaturalist. I'll try to log things on the UCSC site too.

I don't think I have anything particularly unusual to observe. Pisaster ocracheous isn't really affected yet, so I'm curious to see how long it takes for those to succumb, or if the leather stars remain immune, as they seem to be so far (that was also observed elsewhere, I know).