Tuesday, February 2, 2016

What's New in Sea Star Wasting Disease?

image by Jonathan Martin
So, my apologies for the delay between my last post and this one. Between traveling from the west coast, the blizzard and my laptop experiencing..."difficulty" I've missed one or two posts... But! here's what I have been up to...

So about two weeks ago I was in Seattle at the Sea Star Wasting Summit, hosted by the Seattle Aquarium!

This was an informal gathering of about 35-40 people who work on the west coast of North America, ranging from Alaska to Southern California to report on various aspects of Sea Star Wasting Disease (aka Starfish Wasting Disease aka Starfish/Seastar Wasting Syndrome).
The meeting brought together folks from a broad range of occupations that all have had some experience or contribution to our knowledge of the Starfish Wasting Disease phenomena: pathologists, veterinarians, ecologists, citizen scientists, aquarists, taxonomists, educators, and etc..
So, while I can't repeat everything that was discussed (some of it was still unpublished) here are some further insights...

What do we know?
1. Who? The disease seems to affect sea stars in the family Asteriidae most acutely. This includes Pycnopodia helianthoides (aka sunflower star), Pisaster spp (esp. P. ochraceus-the Ochre star), Evasterias troscheli (mottled stars) and Orthasterias koehleri (rainbow stars). Pycnopodia helianthoides, the sunflower star seems to have been one of the hardest hit...
Image by Jonathan Martin
140101_scuba_017

but ultimately the disease seems to affect nearly every shallow-water seastar species on the Pacific west coast. So that includes leather stars (Dermasterias), Bat stars (Patiria), sun stars (Solaster) and so on...

There were a few species which showed much lower incidence of being infected but its unclear if that's simply an artefact (i.e. they aren't seen that often to begin with), less vulnerable, but there is really no further data...
Image from this article in Vice: http://www.vice.com/read/the-wasting-0000650-v22n5
2. Where? The disease, as part of the larger event starting in 2008 is now known from southern Alaska, British Columbia, Washington, and Oregon down to Southern California (and apparently Baja California).
map from http://data.piscoweb.org/marine1/seastardisease.html
At the moment, almost all of our observations are from intertidal/subtidal observations. Nothing really substantial from "deeper" water...

There is another "die off" event on the east coast but it has not been as thoroughly evaluated, so not sure.  This 2012/2013 blog by Elena Suglia documents some of this phenomena 

3. What? Symptoms of the disease of course are widely known and have been outlined in detail here at the UCSC Seastar Wasting page. The disease begins with white lesions and tissue necrosis (as shown below) and leads to "wasting" or "melting" of the body into an ugly pool of tissue and ossicles... But there's MUCH more to be seen at Seastarwasting.org in terms of characterization, etc. 

There's a whole bunch of observations of these symptoms all over the internet Both from my prior blogs: Pycnopodia die off, and a further account here..  and many, MANY accounts of starfish wasting disease from Allison Gong's blog.

But, one important new clue: The Gonads! One of the interesting details which Ian Hewson reported at the SSW Symposium (link here) which was further reported in the news was this bit: the gonads in infected sea stars are often inflamed with tissues sometimes extruding from the gonopores (the openings through which the gametes are emitted). Note the white blobby bit between the arms of the purple Evasterias troscheli (mottled star) in the picture below...
image by Allison Gong
A further important consideration is that gonads and reproduction are tied to activity during certain times of the year as temperature fluctuates. This might also be an important consideration.

This is will likely be important in piecing together the actual cause of how the disease actually kills the sea stars, which remains poorly understood.

Challenges: figuring out what causes the disease is difficult and remains elusive.
So, by now many people have likely seen Ian Hewson et al.'s (2015) article showing identification of the Sea Star associated Densovirus (SSaDV) with the disease. Popularly reported here and in other news outlets..

This was an important first step. But its important to realize that we still do NOT KNOW that this is the actual CAUSE of the disease. 
Sea star with (likely) wasting syndrome
Probably one of the most important lessons I  picked up from the meeting was how careful the work of disease pathologists needs to be. 

Correlation is NOT Causation! 
Powerful genetic tools have allowed us to characterize the SSaDV virus and experiments show that it is ASSOCIATED with the disease. But we have yet to identify exactly HOW Starfish Wasting Disease actually works. In other words, what actually happens to the animal to initiate death?

Just because we have this "disease associate" does not actually mean that it causes the disease.. it could simply be present with the disease as part of the suite of entities (e.g., bacteria, protists, etc.) taking advantage of the sick animals. Or it could be something already present that has become fouled or modified by some other factor.

My take away message was that MULTIPLE lines of evidence (genetics, tissue analysis, external observations, etc.)  should all converge on the same conclusion. In other cases, pathologists are able to actually observe the agent (virus, bacteria, etc.) perform whatever action it takes to create the disease and thus the symptoms..

At this point, we are still working on what actually causes the "wasting symptoms" to occur. This is not to say we are clueless about it..but a definitive cause has not been shown.

One of the biggest issues we have right now? Understanding starfish biology.
     A LOT of the study of invertebrate physiology went "out of style" in the 1960s along with a bunch of natural history research. There are many instances when we just don't understand what "normal" is for sea stars (or their relatives for that matter).

And so..the other powerful tool at play? Careful critical thinking..

(and yes.. what this means in the real world is that NO zombie or science fiction disease movie is likely EVER going to be solved in two hours!!)

What Tools are being used?
   So now that I just got done saying a whole bunch of stuff about care and critical thinking, that is NOT to say that scientists are not throwing a whole arsenal of scientific tools at this problem to try and obtain as many different types of data as they can!

Dr. Felicia Nutter and student Eric Littman at Cornell University for example utilized sophisticated imaging techniques ranging from traditional X-rays to CT scans in order to look at the endoskeleton in afflicted sea stars, which it was thought, might be showing decreased skeletal density.
Image from http://phys.org/news/2016-01-imaging-technology-combat-disease-endangers.html
Other tools include the Illumina technology sequencer which was used to investigate the phylogenomics of the virus and other microbes present in diseased individuals. Long story short: Tissue are taken from infected animals, recover DNA (or RNA) is extracted and purified, these machines sequence it (i.e., analyze it), and this permits identification of the organisms present. This was how the SSaDV (the sea star virus) was identified and characterized...along with the many other bacteria and other ambient forms living in/on the sampled sea stars..

These are among the many types of tools being applied..but there are certainly many more that fall into the more traditional roles: taking tissue samples, aquaria and freezers for living animals and tissue specimens

But as mentioned above, all roads should lead to Rome.. and with any luck, the results from these studies should all be consistent with one another...

Are there/Will there be Ecological Effects??
So, although a LOT of the attention both public and scientific is on the disease itself, many folks often forget that the after effects of the disease will also be very significant!

Sea stars such as Pisaster ochraceus and Pycnopodia helianthoides occupy very important roles in marine ecosystems. Called keystone species, their presence and/or absence as predators is thought to have a HUGE effect on the organisms around them.. (I wrote up a little of this on Pisaster here)

So what happens when those predators are suddenly gone??

sea star shortage
There were no rigorous and statistical cases showing a clear "cause-effect" loss-of-predator-leads-to-increased-prey data presented. But in many cases there were anecdotal observations that "trophic cascades" might be starting... This one for example, allege that there has definitely been a shift in abundance of prey species..such as sea urchins as mussels.

That basically means that the loss of a predator triggers an increase in prey (here was an earlier blog post about urchin barrens).  
Purple Urchins

which then results in some other ecological effects in the ecosystem.. say, a decrease in kelp coverage (resulting from urchin overfeeding) which in turn results in the loss of kelp-inhabiting species and so forth and so on....

Some scientific observations suggest that we might be seeing some of this.. but not necessarily everywhere.  Environments across the coast vary.... so what you see in some parts of California might NOT be the same situation in some protected cover in Oregon....

Time, further data and experiments will tell..

Other Miscellaneous Questions! 

1. Are all the starfish on the coast extinct?   Is my favorite species (e.g., Pycnopida, Pisaster, etc.) extinct?? 
In NO instance is ANY of the species surveyed thought to be completely extinct. Some individuals and news agencies have either misreported or exaggerated the the impact of the disease. MANY populations have been decimated. Localized populations have been wiped out...but there STILL are healthy populations of all afflicted sea stars species.

So, some species are "locally extinct" which means that you might not see any at your favorite local rock pool or pier but there's no evidence for complete and total extinction.

2. What about the juveniles we are seeing? 
There are many reports (such as this one in Nat Geo and this one in the OregonLive) of smaller individuals of various species, Pisaster, Pycnopodia, etc. being seen widely along the west coast where adult starfishes have been wiped out by SSWD.

There were MANY reports of these out in the intertidal zones along the coast. The significance of the juveniles is unclear at this point.   Possible reasons and questions as to why we are seeing them:
  • They are now more obvious because the adults are gone (and we are looking)
  • They have become more bold because the adults are gone.
  • Are there more of them present now because of absent adults? 
  • How fast do they grow? Will they enter in the former adults ecological setting?
Sadly, there HAVE been reports that small individuals can contract the disease. But they don't all seem to have it. So what's going on?? This whole dynamic involving juvenile species remains poorly understood.

If you see any, you can report them to the Seastar Wasting Website here.

You can download a nifty GUIDE to identifying tiny juvenile sea stars HERE.

3. Is the worst over?   
Yes. It seems to be, but mainly because most of the adults which carried the disease are themselves all gone. Its unclear what factors are at play insofar as why some populations have been more heavily hit than others.

4. Do Any of the standard aquarium antibiotics work? 
Many of the standard aquarium drugs (antibiotics, etc.) seem to be most effective against the secondary bacterial infections which attack the animals after becoming sick. But unfortunately, they don't seem to curtail the actual disease much if at all.

5. Is Climate Change/Temperature a factor? 
I would say yes. And others would agree with me (here). There have been several informal experiments and observations of seasonality which suggest that higher water temperature is, at least, significant and worth investigating as a factor. But, at the time of this writing, a clear paper has not been published which establishes a rigorous link.

6. Is the wasting disease caused by Fukushima/Republicans/Democrats/Cthulhu/Extraterrestrials/ Atlantis/Inner dimensional beings from the 7th Parallel? 
Nope. Not even a little.

My thanks to Lesanna Lahner, Ian Hewson, Melissa Miner and the other participants at the Sea Star Wasting Symposium!

Standard caveat: i've done my best to represent a LOT of information. Any mistakes are my own.

Further Resources:
The Sea Star Wasting Site at UCSC:
http://www.eeb.ucsc.edu/pacificrockyintertidal/data-products/sea-star-wasting/

Ian Hewson's blog about SeaStar Microbial Ecology: https://seastarwastingdisease.wordpress.com/

iNaturalist: Tracking Sea Star Wasting Disease:
http://www.inaturalist.org/projects/pisaster-disaster-tracking-starfish-wasting-disease

A useful summary page from Sanctuary Integrated Monitoring Network (SIMoN)
http://sanctuarysimon.org/projects/project_info.php?projectID=100401

Wednesday, January 13, 2016

LyrocteisThe Imperial Harp Shaped Comb Jelly!

Picture by Robert F. Bolland from the Okinawa Slug site
Happy 2016! And a fine one it has been so far! I'm on my annual holiday travel to San Francisco visiting friends, family and my colleagues at the California Academy of Sciences..

During this visit, Curator Bart Shepherd, a colleague of many years from our days at Steinhart Aquarium indulged me in showing off this recent collection from the Academy's scientific expedition to the Philippines: the benthic ctenophore Lyrocteis! Possibly Lyrocteis imperatoris..
These are inspiring animals. They're not only big (about four to 6 inches tall) but they are also WEIRD things that nobody (other than scientists) ever gets to see, but now? thanks to social media and some excellent aquarium science.... these mysterious animals may actually get some time in the sun!  This aquarium in Japan has actually be able to breed them

But WHAT ARE THEY??
I have described and mentioned benthic or "bottom" ctenophores (= comb jellies) before (and recently! see here).

Long story short: Most comb jellies are midwater (=pelagic) swimming gelatinous animals... but SOME of them are unusual in that they have adapted to living on the sea bottom.. Some live on sea stars, while others on coral. 

Today I thought I'd just focus on this one genus: Lyrocteis the only member of the family Lyrocteidae. Lyrocteis includes two species, one from the Antarctic and one from the tropical Pacific.
The name apparently refers to its resemblance to a Lyre. (think of the root word of "lyric" which means "of or for the lyre") Neat, eh?  and "cteis" which refers to the comb rows present in all "comb jellies"
1004182

There's not a lot known about them. They feed (see below) in a manner similar to the swimming species using long tentacles to capture food. When described in 1941 (here), they were labelled as "sessile" but the Antarctic species was described as being able to move 1 to 2 meters per day (here to see)

Here's an individual identified as the Antarctic species: Lyrocteis flavopallidus
                    Ctenóforo
2.... and the other one?
and there's a second species known from throughout the tropical Pacific called Lyrocteis imperatoris, described in 1941 by Professor Taku Komai at Kyoto Imperial University to honor Emperor Showa of Japan. The original specimen was apparently collected from Sagami Bay by the Biological Laboratory of the Imperial Palace. He described it as a "strange marine animal.."

This species is described mainly from the tropical Pacific. Possibly the Indian Ocean I suppose (based on the ones below) but none are known from the Atlantic.  Most of these live in relatively deep-water, at the lower edge of SCUBA depth to significant depths in the deep-sea (>500 m).

Its name in Japanese: 
kotokurage コトクラゲ

Here's the species we saw in the Hawaiian Islands during the Okeanos Explorer cruises in September. In theory.. there are only two species.. the Antarctic one and the tropical Pacific species.
So, this is possibly Lyrocteis imperatoris.. but exact details remain elusive.  A great MANY different color variations have been observed in observed specimens of Lyrocteis.. This makes biologists wonder if they are seeing multiple species??? Or perhaps one species with a lot of color variation??Dr. Komai, the scientist who described this species noted a great variation in color when originally collected.

Its possible (and even likely) that there is more diversity (i.e., more species) but the animals don't make it easy to study them.

Why? Because they aren't seen frequently and when they do, collecting is difficult. The individuals
aren't easy to sample and for whatever reasons, the body of these animals is extremely difficult to preserve..so intact specimens aren't generally available to study...

Here were some spectacular red ones from Okinawa..
Bart Shepherd & the California Academy of Sciences Expedition to the Philippines encountered THREE color forms... the speckled one above and two others: a purple/red one and a yellow one...

and here's a South African species in the Indian Ocean. Another color and puffier..

Feeding! 
One of the nice things about our modern age is that video and image observations have become easy and of high quality

If you have Facebook, here's a feeding video of the Lyrocteis collected by Steinhart Aquarium from the Philippines..

Here's one of the purple south African species observed via video with its feeding tentacles extended...


Here's a nice one of a Japanese species with tentacles extended... from SHINKAYABLOG which translates to "deepsea" blog  This is basically similar to the way that swimming comb jellies feed...
This also explains the kawaii (cartoon mascot) for Lyrocteis imperatoris!   Note the feeding tetnacles catching the fish!!
from @deepsealife https://twitter.com/deepsealife/status/605369053209755648

Amazingly, someone is SO fond of these that they have made tiny magnets out of them!
3. The Story About its original discovery!!?
Dr. Komai, in his 1941 description of this species recounts an interesting story about "when" this species was discovered. Because apparently, although he described it in 1941.. he was NOT the first one to have encountered it!!
What makes the story of the discovery of this remarkable ctenophore more interesting is the fact that another specimen of evidently this form had been obtained previously from the same Sagami Bay and recorded by a Japanese zoologist, but without any idea of its real nature....
...in August, 1896, we find a short note in Japanese by T. N. (obviously Tokichi Nishikawa, the inventor of the famous cultured pearl) entitled " A curious animal" with rather good illustrations, one of which is reproduced in Fig. 3. The accounts and figures clearly show that the 'curious animal' was no other than a specimen of the present platyctenid.
Nobody who saw it at that time could tell what it was. The real nature of this form thus remained enigmatic only to be made clear forty-five years later."
..and don't worry, I haven't given up echinoderms! But travelling makes you appreciate opportunistic topics!! 

Wednesday, December 30, 2015

An Eventful Echinoblog in 2015! #Recap!

So, I don't normally do these "end of the year" recaps, but man, 2015 was BUSY.  I travelled to three continents, described a NEW FAMILY of starfish in addition to all the other stuff.. Here are highlights....


1. JAPAN part TWO! 
Starting at the end of January I returned to study at Japan's world famous National Museum of Nature and Science in Tsukuba, Japan (outside Tokyo). Among the many cool adventures:



One such interesting starfish was Trophodiscus! The starfish which broods babies on the disk surface! 
2. Someone made one of my starfish into a TOY! 

A video of the set is here.. My contribution is at the end..

3. I described a NEW FAMILY, genus and two new species of sea stars! The first hydrothermal starfish Paulasterias


Named for deep-sea biologist Paul Tyler, the type species is the first to be found living in association with hydrothermal vent habitats.
The second species, occurs in the North Pacific and is named for my colleague Dr. Craig McClain at Deep-Sea News and was collected during an expedition which I was present on due to Craig's invitation! Scientific collaboration in action! 


4. I visited and have studied at the Iziko Museum in Cape Town South Africa!

One of my most memorable trips was from April-May when I visited the Iziko Museum in Cape Town, South Africa!! Thanks to a collaboration with Dr. Lara Atkinson from their marine environmental organization, SAEON (the South African Environmental Observation Network) I was able to visit their marine invertebrates collection and study the collections.

This was a VERY frutiful visit. I identified nearly 700 specimens, and discovered several rarely seen species as well as working with the the citizen science community to ID species seen by divers and naturalists.


Here were some images from the trip... one of the South African Museum's specimen catalogs and Candice one of the curatorial techs holding a specimen of Hymenaster! A specimen of a deep-sea slime star which had been sitting undiscovered for some 40 years! 


My thanks to Lara and the staff at the Iziko Museum including curator Wayne Florence and collections personnel Liz and Candice for a GREAT visit! 

5. Described new Deep-sea starfish which feed on corals
So, I described several new species this year..but for some reason a bunch of them feed on deep-sea corals.. Here's a post where I talk about a new paper describing new Hawaiian species.. Some of which I saw later on when Okeanos investigated the Hawaiian Islands!
                            

6. I provided my usual narrative and information to Okeanos Explorer in Puerto Rico and Hawaii! 
For the last few years I've participated as part of the "shoreside" talent pool which Okeanos calls upon to assist with identifications and questions about sea stars and echinoderms. 

I also take screengrabs of the live feed and post highlights. This year, Okeanos travelled from the tropical Atlantic, working off Puerto Rico, travelling across the canal to the North Pacific where they worked in the Hawaiian Islands!!

Perhaps one of my proudest moments from the Puerto Rican expedition was being able to identify this rarely seen solasterid starfish, Laetmaster spectabilis from the abyss of the tropical Atlantic!

This species had been collected once in the 19th Century and not been seen again until the Okeanos Oceano Profundo expedition! Here's a recap post from that week. 

When Okeanos Explorer reached the Hawaiian Islands we saw some species that I described back in 2006. This for example, was Circeaster arandae, which was known originally from Madagascar and New Caledonia. Now we know it lives in the Hawaiian Islands! 

Its a weird feeling to have described something like this from preserved specimens and then to seem them alive like this..
and we saw some weird critters like this, which were probably new but remained a mystery...

We also saw a LOT of glass sponges.(go here)

Stalked crinoids, benthic ctenophores and enormous sponges! (go here)


7. Took a little break for the first INTERNATIONAL POLYCHAETE DAY! on July 1st! 
In honor of Dr. Kristian Fauchald, curator of polychaete worms at the Smithsonian's NMNH, who passed away on April 5, 2015. This year we celebrated the very first International Polychaete Day on Kristian's birthday. 
Polychaete worm
Here is the Storify if you missed it! 

8. Then I helped launch SEA SLUG DAY!! 
This event was similar to International Polychaete Day except that it celebrated the very much alive, Dr. Terry Gosliner at the California Academy of Sciences. The world's foremost authority on nudibranchs and their kin.  Sea Slug Day was appropriately enough held on October 29th, his brithday the Friday before Halloween! 
Goniobranchus roboi
Here is the Storify if you missed it! 

9. Studied Deep-sea Starfish at the Paris Museum in November! 
I've been visiting Paris for several years now and so, the trip has become almost routine. I'm usually there for about a month working on new species from exotic Pacific and Indian Ocean locales collected by French museum scientists.

I even worked some Cretaceous (fossil) starfish into the visit this time around. Hopefully by next year you will be seeing some of the new species published and publicized here!

10. And last but not least.. I topped 3000 Twitter followers! My thanks to all of you!!
My ongoing efforts at education and outreach would not be possible without YOU!!! 
Its good to know that what I produce is read and of interest. Twitter has given me a more regular way to share..but the blog remains appropriate for "long form" stories...

Thanks to everyone who follows! 

For those who are interested, I actually try to keep track of my new species on this post. It shows images of each! (its a little behind at the moment..but soon!)

Thursday, December 24, 2015

Happy Holidays! Protoreaster lincki! A festively colored tropical Indian Ocean starfish for your winter solstice!

Image taken by Jan Mees. From the World Registry of Marine Species
This week, a photoessay and odd little facts about this very strikingly colored/decorated oreasterid starfish, Protoreaster lincki!  You can check this past post on how to tell Protoreaster species from the similar Pentaceraster species..

This is a shallow-water tropical species known primarily from the western Indian Ocean, especially on the east African coast. The species descriptor "lincki" is named for the German naturalist Johann Heinrich Linck, the author of a noted monograph on sea stars, De stellis marinis liber singularis published in 1733. Johann Linck is also the namesake of the familiar starfish genus Linckia. Many years ago I wrote a little bit about where funky starfish names come from before, especially Nardoa and Luidia.
We really don't know much about the primary biology of this species. Its thought that they feed primarily on microalgal film so presumably they are dependent on the "goo" on sea grass, sea bottoms, etc.  

This species is fairly easy to recognize due to its striking red on white coloration, but also the very distinctive pattern of spines and etc... There is some variation however. Spines in some individuals are more conical versus others which are more blunt...
Image taken by Adrian Pingstone 2005 at Bristol Zoo Aquarium, Bristol, England via Wikipedia

red starfish
Close up of Starfish (Protoreaster linckii), Kenya.
red-knobbed starfish (Protoreaster linckii)
Red, yellow, and grey starfish
Zanzibar Starfish
The spines on this species and other oreasterid starfish likely serve against larger predators. Its unclear if they are effective against smaller specialized echinoderm predators such as these harlequin shrimp

Variation! The skeletal patterns on these sea stars are broadly consistent and distinctive for this species. But in the same way that people can have different hair and skin color, different facial features, etc. starfish show variation in spination, pattern and even color... 

Here are some examples. Its unclear if the differences are simply random or if they correspond to some kind of environmental factor such as food, etc.

Mozambique
Red-knobbed star

Tanzania, African coast.
DSCN3193
Tanzania, African coast.
Red-knobbed Starfish
Tanzania, African coast
Tanzania March 2009 261
Zanzibar, African coast
Zanzibar 2005 192 (Large)
and the occasional 6 armed variant..
Red star on the beach

As with the Indo-Pacific species, P. nodosus, this species is fished for the tourist trade. Data about its reproductive abilities and "carrying capacity" for a fishery aren't well documented.
StarfishStarfish flashers

ART! For some odd reason, this species has also served as the inspiration for many distinct types of art. This postage stamp...for Mozambique in 1982 and the more recent rendition below it, including the pastel and of course TATTOOS! 
via the World Registry of Marine Species


Starfish by CreativeCurseKina on DeviantArt

starfish tattoo by SunofKyuss on DeviantArt

Happy Holidays from the Echinoblog!