Join me in the cold, dark, life-sustaining NE Pacific Ocean to discover the great beauty, mystery and fragility hidden there.

Posts from the ‘MARINE INVERTEBRATES’ category

Beware of taxi-crabs and “Cling like hell to your rock”

Oh how did I get to be today-years-old without knowing of this Robert Service poem that is so timely and speaks for a limpet?

His poem “Security” includes:

So if of the limpet breed ye be,
Beware life’s brutal shock;
Don’t take the chance of the changing sea,
But – cling like hell to your rock.

Yes!

Full poem is below which includes life lessons about taxi-crabs 🦀

Keyhole Limpet which I photographed near Port Hardy. Diodora aspera builds a shell up to 7.6 cm across.


 

Security
Robert Service

There once was a limpet puffed with pride
Who said to the ribald sea:
“It isn’t I who cling to the rock,
It’s the rock that clings to me;
It’s the silly old rock who hugs me tight,
Because he loves me so;
And though I struggle with all my might,
He will not let me go.”

Then said the sea, who hates the rock
That defies him night and day:
“You want to be free – well, leave it to me,
I’ll help you get away.
I know such a beautiful silver beach,
Where blissfully you may bide;
Shove off to-night when the moon is bright,
And I’ll swig you thee on my tide.”

“I’d like to go,” said the limpet low,
“But what’s a silver beach?”
“It’s sand,” said the sea, “bright baby rock,
And you shall be lord of each.”
“Righto!” said the limpet; “Life allures,
And a rover I would be.”
So greatly bold she slacked her hold
And launched on the laughing sea.

But when she got to the gelid deep
Where the waters swish and swing,
She began to know with a sense of woe
That a limpet’s lot is to cling.
but she couldn’t cling to a jelly fish,
Or clutch at a wastrel weed,
So she raised a cry as the waves went by,
but the waves refused to heed.

Then when she came to the glaucous deep
Where the congers coil and leer,
The flesh in her shell began to creep,
And she shrank in utter fear.
It was good to reach that silver beach,
That gleamed in the morning light,
Where a shining band of the silver sand
Looked up with with a welcome bright.

Looked up with a smile that was full of guile,
Called up through the crystal blue:
“Each one of us is a baby rock,
And we want to cling to you.”
Then the heart of the limpet leaped with joy,
For she hated the waters wide;
So down she sank to the sandy bank
That clung to her under-side.

That clung so close she couldn’t breath,
So fierce she fought to be free;
But the silver sand couldn’t understand,
While above her laughed the sea.
Then to each wave that wimpled past
She cried in her woe and pain:
“Oh take me back, let me rivet fast
To my steadfast rock again.”

She cried till she roused a taxi-crab
Who gladly gave her a ride;
But I grieve to say in his crabby way
He insisted she sit inside. . . .
So if of the limpet breed ye be,
Beware life’s brutal shock;
Don’t take the chance of the changing sea,
But – cling like hell to your rock.

 


I ensured this is indeed Robert Service in all his glory by ensuring it was in the “The Complete Works of Robert Service” (1945) but could not find further detail on when he wrote it.


My additional posts featuring limpets:

 

Who You Calling “Unstable”?

Don’t you hate when people use a provocative “hook” to get you to read their material? Yes, that’s what I’ve done but I promise you, it is worth it.

While I think all of us are a little unstable right now, this blog is not about me. It’s about the astounding adaptations of a little limpet assigned the name of “Unstable Limpet” (Lottia instabilis). 

 

Unstable? This species just limpetted along on its own evolutionary path!

Most other limpet species are shaped so they can suck down securely on a FLAT surface for protection This works well because these most often graze on algae encrusted rocks. But the Unstable Limpet can secure to a ROUNDED surface.

Which rounded surface? Oh I will never forget the first time I noticed this species and realized the marvel of the adaptation. Unstable Limpets are shaped to be able to hunker down on the cylindrical stipes (stem-like structures) and holdfasts of the kelp species upon which they also feed!

Screen grab from “Invertebrates of the Salish Sea”. Caption: “The uneven edges of the shell of Lottia instabilis can easily be seen in this end and side view. The shell is shaped to fit snugly around a round stipe instead of a flat surface.”

 

I suspect that, like their flat-shelled brethren, Unstable Limpets have a specific spot to which they “home” and where their shell fits perfectly.

As is supported by others’ observations, I have found Unstable Limpets living / feeding on Stalked Kelp (Pterygophora californica) and Split Kelp (Laminaria species).

Underside of an Unstable Limpet on the stipe of kelp.

 

An individual with a lot of coralline algae growing on its shell.

I hope that this little limpet leads to you reflect anew on the wonder of the natural world around us and . . . about how being “unstable” just might mean being better adapted to the conditions you are in. It may even be of benefit in having a unique place and perspective in the world. 🙂

Below are further details about the species and an explosion of my photos documenting them.


Size: To 3.5 cm across

Known range: Northern Alaska (Kodiak) to Southern California (San Diego) from the intertidal to 73 metres depth.

Variation: Greg Jensen reports that: “Some members of this species settle on rocks, where they develop a more conventional limpet sharp and are difficult to distinguish from other limpets. This rock form was previously known as Lottia ochracea.” (Source: Jensen)

Behaviour: If touched by predatory sea star species, the Unstable Limpet “vigorously” runs away. Predatory sea star species referenced in the study are Six-Rayed Stars( Leptasterias hexactis), Sunflower Stars (Pycnopodia helianthoides), and Ochre Stars (Pisaster ochraceus ). It was unclear to me from reading a summary of the research (and being unable to find the original paper) if this response behaviour is different if the Unstable Limpet is on its “feeding scar” (a bit of an indentation in the surface of the kelp). It may be that it responds then like the Seaweed Limpet (Discurria insessa) whichusually responds to contact by elevating its shell (“mushrooming”) and rocking from side-to-side, but rarely moving away from the scar.” (Source: Snail’s Odyssey).


 

Little limpet. Long stipe of kelp.

 

This individual may have had another limpet species feeding on the algae on its shell.

I believe you can see the scars here of where the limpet has been feeding on the kelp.

 

The following photos offer additional perspectives on two of the individuals shown in photos above.

I believe you can see where this individual has been feeding and yes, thats a lovely hat of algae that is growing on the shell.

 


Sources:

  • Jensen, Gregory C, Daniel W. Gotshall, and Miller R. E. Flores. Beneath Pacific Tides: Subtidal Invertebrates of the West Coast. , 2018. Print.
  • Lamb, Andrew, Sheila C. Byers, Bernard P. Hanby, Bernard P. Hanby, and Michael W. Hawkes. Marine Life of the Pacific Northwest: A Photographic Encyclopedia of Invertebrates, Seaweeds and Selected Fishes. Madeira Park, BC: Harbour Publ, 2009. Print.
  • Homna, L. 1995. DISTRIBUTION, ABUNDANCE, AND REPRODUCTION OF THE ALGAL SPECIFIC LIMPET, LOTTIA INSTABILISMaster’s Thesis. Moss Landing Marine Laboratories, San Francisco State University. 77pp.
  • Snail’s Odyssey; Limpets & relatives – Predators & Defenses: Escape-crawling from Seastars
  • Walla Walla University. Invetebrates of the Salish Sea – Lottia instabillis

Crabs Making Bad Choices

[Update: Species corrected thanks to Greg Jensen. I initially posted that the crab in the first 3 photos was a Moss Crab].

How do crabs make bad choices?

Let me show you via my photos and a “conversation” with the crab in the next three photos.

 

Oh hello mature male Sharpnose Crab. I almost didn’t see you there!

Please may I take a photo of how you have fabulously decorated yourself to camouflage against predators, using bits of algae, sponges, tunicates and hydroids?

It’s fascinating how your species, and others who decorate themselves, have little hooks (setae) on your exoskeleton to which attach life from around you AND that you change outfits when your change backgrounds. Do you sometimes also use the camouflage as easy-to-reach snacks?

 

Oh, oh! Wait!

You don’t know you are walking onto the head of a Red Irish Lord, an ambush hunter who is extraordinarily camouflaged too.

 

 

Careful! You are on the menu for this fish species.

The Red Irish Lord will try to grab you, ideally from the back of your shell. That’s what happened to the crab in the next two photos.

 

Indeed, that’s the same species of fish. Red Irish Lords have incredible diversity in colour to blend in so that you, and I, have great difficulty detecting them.

When the fish does not have the advantage of a sneak attack, you can defend yourself by spreading out your claws really wide. Like what you see below.

Then, it’s difficult for the Red Irish Lord to fit you into his / her mouth.

 

Yes, I too imagine the crab in the above two photos saying, “You want a piece of me?!”

It’s said of your species that you “put little effort into decoration”. Such judgement!

In another species, the Moss Crab, a correlation has been found between size and how much decoration there is. Once big, especially with claws spread wide, mature male Moss Crabs cannot easily be gulped up whereby there is less need for camouflage. But mature male Moss Crabs are huge! Up to 12.3 cm just across their carapace. Your species, the Sharpnose Crab (Scyra acutifrons) is only up to 4.5 cm across the carapace. Mature males of your kind have a far greater reach with their claws than mature females.

By the way what’s with the posturing with mature males of your kind when they do what is shown in the photo below?

Yours is NOT the only crab species that can be gulped up. I think it might be a Graceful Kelp Crab who has been engulfed by the Red Irish Lord below.

 

Below is another crab in danger of making a fatal choice as it advances down the face of the Red Irish Lord. See how precarious this is? The fish will remain motionless, waiting, waiting till you are in the ideal position to ambushed from behind. Then your claws are of little use to you.

 


There you go dear human readers.

I do not know the fate of either of the crabs on the heads of the Red Irish Lords. I had to return to the world where we humans can also make really bad choices.

Why no, my referencing human bad choices on November 4th 2020 is purely coincidental. Insert innocent eye batting here. What choices could I POSSIBLY be referencing? ☺️

Be kind. Be colourful. Be careful. Be truthful. Be safe.  💙

Regarding the photo above, see the Red Irish Lord and the two crabs with outstretched claws?


Related TMD Blogs:


Sources: 

Drake, Catherine Anne, “Decorating Behavior and Decoration Preference in the Masking Crab, Loxorhynchus Crispatus” (2016). Capstone Projects and Master’s Theses. 74.

Jensen, Gregory. (2014). Crabs and Shrimps of the Pacific Coast: A guide to shallow-water decapods from southeastern Alaska to the Mexican border.

Wicksten, M. (1978). Attachment of Decorating Materials in Loxorhynchus crispatus (Brachyura: Majidae)Transactions of the American Microscopical Society, 97(2), 217-220. doi:10.2307/3225595

 

Who Goes There? Scrape marks on rocks.

Update: 4 pm PDF October 26
Looks very likely that these tracks have been made by a limpet species. Further information under UPDATES below.


Here’s an unsolved mystery, that led to another unsolved mystery, and I suspect there will be more related mysteries to come. 🙂

It began with the photo shown below with an ID request by Marcie Callewart John and Stephen Lindsay. Stephen had taken the photo of the underside of this rock in Stewardson Inlet in Clayoquot Sound, SW Vancouver Island, British Columbia. 

They wrote: “We were wondering about your thoughts on these markings. . . . Limpet or chiton feeding marks? Or egg attachment marks?”


I knew that the markings were from the radula of a grazing marine mollusc but not WHICH mollusc.

Marine and terrestrial snails and slugs (including nudibranchs), limpets and chitons all have incredibly strong “rasping tongues” covered with teeth-like structures called radula. In moon snails and some species of whelk, the radula are strong enough to drill holes into shells so that they can feed on whatever mollusc relative lives inside the shell.

In the grazing molluscs, it is the tongue studded with radula that enables them to scrape algae off rocks.

ICT scan of limpet radula from The Scientist Magazine.

I thought the radular scraping were more likely from a marine snail than a limpet or chiton BUT needed expertise bigger than my own to solve this “who done it”. Thankfully, I could reach out to Rick Harbo, author of Whelks to Whales.

Rick confirmed these were radular markings but did not recognize which marine snail made them. He had a mystery of his own. See below.

 

 

This led to input from Dr. Douglas Eernisse, professor of Biology at the University fo California, Santa Cruz.  He did not recognize the specific tracks in Stephen’s or Rick’s photos. He shared the image below showing OTHER radular tracks but with a big difference. His photo showed the marine snail species making the tracks. See the Black Turban snails having dinner? To give you an idea of scale, maximum size of Black Turbans is 4.5 cm.

 

So out into the world this blog goes in the hopes of engagement and interest and maybe even that someone has documented similar tracks as those in Stephen’s and Rick’s photos with the grazers caught in the act.

I hope it makes you smile too to reflect on how we humans still have so many mysteries to solve. Just peering under a rock or any algae covered surface could lead to another mystery, leaving you wondering “Who goes there?!”

Schematic to give a sense of how the radula are positioned in gastropods (represented by the black zigzag line). I am emphasizing here that both marine and terrestrial snail and slug-like animals have radula. Source of image: Wikipedia. 


UPDATES

Information shared by Jason Knight points solidly  toward a limpet species being who made these tracks.

  1. The screen grabs below are from Dale Fort’s blog with the same image also being found on the website of the Field Studies Council in the United Kingdom for the Common Limpet (Patella vulgata). We do not have this species in British Columbia but the similarity in the pattern certainly supports that a species of limpet made the tracks in Stephens’ image.

Limpet radula marks on the rock

2) The following screen grab is from Smithsonian Ocean, photo by Helen Scales. The species of limpet is not specified.


 

Extra:  A fascinating study from 2015 found that limpets (generally) are the “bulldozers of the seashore”. The study found that their “teeth” (radula) are made of the strongest biological material ever tested (and these teeth are less than a millimetre long)! The strength is the equivalent of one string of spaghetti holding up 1,500 kgs. From Professor Steven Hawkins, of the University of Southampton. “The reason limpet teeth are so hard is that when they’re feeding, they actually excavate rock. In fact, if you look at their faecal pellets they actually look like little concrete blocks – because by the time it’s gone through their gut it’s hardened.” (Barber et al).


Related TMD blog:


Sources:


More tracks made by gastropods

Terrestrial: 

Tracks made by a species of garden slug, Richmond British Columbia. Photo: George Holm.

 

Tracks made by a Banded Garden Snail, Cepaea nemoralis in Queensborough, New Westminster, British Columbia Photo: George Holm.

A Smack of Jellies

The last little while there have been hundreds, and hundreds, and hundreds of Moon Jellies = a “smack” of them. That truly is the collective noun for jellyfish.

It should also be the collective noun for the number of jellyfish photos I am delivering in this blog.

 

May these photos from my last dives north of Port Hardy offer you a bit of escape. I tried to capture trees in photos of jellies and the reflection of the jellies against the surface of the water. I hope the images communicate interconnectedness of land, sea and sky. May  they also contribute to understanding and connection to our neighbours in the sea.

Moon Jellies are easy to discern from other jelly species by having the clover shape which is 4 gonads / sex organs (Aurelia labiata to 40 cm across). 


Most jellies in the class to which Moon Jellies belong (the Scyphozoan) release eggs and sperm into the water column. But in Moon Jellies, when the male releases sperm, the pulsing action of the female Moon Jelly brings the sperm in contact with the eggs under her arms and the are brooded there. The following three photos show females with eggs. The eggs are the less translucent white structures. 

 

 


And as if this was not all amazing enough there was also a ” blizzard* of babies . . . just LOOK at how many juvenile Widow Rockfish there are!

It was so extraordinary to see them nipping at the bells of the Moon Jellies, darting about everywhere. There was another phenomenal explosion of young like this in 2016 and, with site fidelity being so strong, those fish may well be the bigger ones we saw at these sites too.

 

 

The following facts about Widow Rockfish are from Dr. Milton Love’s brilliant “The Rockfish of the NE Pacific”: The mothers produce one brood of about 95,000 to 1,113,000 eggs/year which hatch as larva from their mothers (rockfish are viviparous). They stay in the plankton for about 5 months feeding on copepods and krill and can grow up to 0.61 mm/day. Then they settle out to be in nearshore areas like you see here and feed on salps and jellies, small fishes, crabs, amphipods and krill.

Why are they named “Widow” Rockfish ? “. From Dr. Love’s book too: Julius Phillips, a great observer of the rockfish fisheries of California during the mid-twentieth century, believed the term widow can about because the “black peritoneum an small effeminate mouth give the impression of lonesomeness to occasional specimens that appear amount the more common bocaccios, chilipepper and yellowtail rock cods” (Phillips, 1939).

Maximum  life expectancy for Widow Rockfish (Sebastes entomelas) is 69 years. Maximum length 60 cm. Females typically bigger than males.

The bounty of babies has been reported by myself and others to those monitoring rockfish health. To my knowledge, nobody knows why there have been these two explosions of young of this species (2016 and 2020).

 


And to conclude, I had hoped that I might also photograph a Lions Mane Jelly with land in the background. On the last dive of nine, the light and life lined up to allow me to take this photograph.

 

The Lion’s Many Jelly is one of two of the biggest jelly species commonly found off our coast = Cyanea capillata (the other is the Egg Yolk Jelly). Maximum size of Lion’s Mane Jellies is to 2.5 m across with 8 clusters of 70 to 150 tentacles which can be . . . 36 m long! This is the largest jelly species in the world. Know that the larger ones tend to be further offshore and that they can retract their tentacles. These two species are also the only two common jelly species in our waters that can create a sting that irritates human skin, even when the jellies are dead or you get a severed tentacle drifting by your face.

A Lion’s Mane Jelly is the murderer in a Sherlock Holmes short story entitled “Adventure of the Lion’s Mane” (I kid you not), BUT the “victim” had a preexisting heart condition. The solution to the irritation is vinegar (acid), meat tenderizer (enzyme) and I know that many fishers swear by Pacific canned milk. Research at this link puts forward that vinegar is the only real solution. Clearly I’ve never been stung badly enough to deter trying to photograph them.


Photo below is of planktonic me after a full dive trying to capture jellies and trees in the same image. Photo by dive buddy Janice Crook.

Aristotle’s Lantern

What is so thought-provoking that it warrants the name “Aristotle’s Lantern”? It’s what the mouth-parts of urchins are called.

Today while I was submerging, there was a dead Green Urchin floating at the surface, spines rotted off but mouth still intact.

This allowed me to photograph the jaw parts outside the urchin’s shell (test).

Close-up on the dead Green Urchin’s underside with the mouthparts.

 

This is something I would not normally be able to photograph because I would have to lift an urchin to do so and I do not want displace the life I see. Also, because most dead urchins I find floating about have been “otterized”. An otterized urchin is where a predator has broken through the bottom of the urchin. Mammalian predators of urchins include River Otters, Sea Otters, Mink and humans. Wolf-Eels and Sunflower Stars are also predators. Another reason the mouth parts are difficult to photograph is because they can retract into the urchin when alive.

The photos included below of the full mouth structure are from another dead urchin whose “Lantern” I preserved. See how complex it is? There are 5 jaws made from plates of calcium, which are held together by muscle. When wanting to chew away at seaweed / algae, the structure is pushed out whereby the mouth opens and the urchin can chew by moving the structure side-to-side. You can imagine that chewing would wear down the calcium but no worries – the Lantern grows from the tip, reportedly at 1 to 2 mm / week.


Why are an urchin’s mouthparts called “Aristotle’s Lantern”? Because Aristotle is believe to have described them as “lantern-like” in Historia Animalium (The History of Animals) more than 2,340 years ago.

Indeed, the “horn lanterns” used in Aristotle’s time looked like the mouthparts; having 5 panes covered with cow horn that had been boiled and shaped. BUT there are biologists who disagree, believing that there were “historical ambiguities with the original translation” and that Aristotle was referencing the WHOLE urchin’s shell as being lantern-like, rather than just the mouthparts.

Oops – if that be true, Aristotle would not be happy that the mouthparts of urchins’ near relatives, sand dollars, are also referenced as “Aristotle’s Lanterns”.

There don’t you feel better now knowing all of this? I am here striving to lighten and enlighten . . . lanterns and all. 💙☺️💙

Here’s a “Shape of Life” video of urchins feeding, narrated to be oh so dramatic:

 


About regeneration, aging and life expectancy in sea urchins

Like sea stars and other  echinoderms, urchins can regenerate body parts e.g. their spines and tube feet. Research by Bodnar and Coffman (2016) found that this ability to regenerate lost or damaged tissues does not decrease with age in 3 local urchins species: the Variegated Urchin (Lytechinus variegatus), Purple Urchin (Strongylocentrotus purpuratus) and Red Urchin (Mesocentrotus franciscanus).

This is of particular interest since the life expectancy of these three urchin species is very different; respectively 4 years, 50+ years, and 100+ years. Yet, “the fact that all species showed the same consistent ability to regenerate tissue despite age and life expectancy undermines the current evolutionary theories of ageing. It was previously expected that species with shorter lifespans would invest fewer resources in maintenance and repair, perhaps to invest greater energy in reproduction. So this study has shed light on a new, unexpected factor that contradicts the current theory.” Source: Biosphere.

Regarding the life expectancy of Green Urchins (Strongylocentrotus droebachiensis) from Fisheries and Oceans Canada: “Aging techniques for B.C. Green Urchins are currently being developed by the Pacific Biological Station, but Green Urchins on the Atlantic Coast have been known to live from 20 to 25 years of age.”

 


See below for images of urchins feeding and of “urchin barrens” . Urchins are an important part of the marine ecosystem but when we killed off Sea Otters who eat urchins, this led to too much kelp being eaten. The resulting “urchin barrens” are a loss of habitat and food for other organisms and result is less carbon buffering and oxygen production by kelp.

Sea Star Wasting Disease, and specifically the devastation to Sunflower Stars (Pycnopodia helianthoides), has also led to urchin barrens because Sunflower Stars too are predators of urchins. For more information, see my blog “Wasted. What is happening to the sea stars of the NE Pacific Ocean?


Below are images of urchin barrens.

Sources: 

Red and White

Some red and white for you on Canada Day.

 

May we celebrate all that is wild, good and free.

May we truly know the privilege of it all.

May we be the neighbours and stewards who are as open-eyed and open-hearted as this land is large.


Photo: Two Rose Anemones touching, different colours, same species.
Aka Fish-Eating Anemone, Urticina piscivora to 30 cm across.

A Lone Giant

[If you are coming here from Instagram, please see this link for background on Sea Star Wasting and where to report sightings.]


Endangered? I gasped when I saw this adult Sunflower Star on my last dive and hung nearby for a little while. I found myself thinking in a way that could be interpreted as prayer.

Did you realize Sunflower Stars are now so rare – these giants that should be abundant on the coast from Alaska to Mexico?

 

Endangered? Many of us who have been monitoring Sea Star Wasting Disease since 2013 certainly think so and there is a campaign in Washington State to have them recognized as such.

There has been such misunderstanding and “ocean blindness” about what has been going on. Even reputable news outlets have put into the world information about the Disease that speaks of sea stars as if they were one species and hence, if some sea stars are sighted, well then everything is fine.

It’s not fine. At least 20 species of sea star have been impacted by Sea Star Wasting Disease. Some are recovering well but . . . this the world’s largest sea star species, the Sunflower Star, Pycnopodia helianthoides, is NOT.

We sometimes see waves of juveniles, maybe resulting from more adults being at depth who are close together enough that when they broadcast spawn,  fertilization results (broadcast spawning is when males and females release their sex cells into the water on cue). But, ultimately these juveniles disappear.

Sea Star Wasting Disease (SSWD) is the largest wildlife die off in recorded history. That be truth. But because it is happening below the surface there is less engagement, funding, and knowledge.

Does it matter? Yes, it matters a lot, ecologically and with regard to what the Disease may teach us.

Sunflower Stars have a similar ecological niche to Sea Otters re. grazing on urchins and maintaining kelp forests (see video below). You know that if Sea Otters were dying en masse we would certainly be engaged, invest in research, and want knowledge.

A close-up of the same individual.

What is the cause? Specifically for Sunflower Stars, it is known that there is a virus that has been around for more than 70 years that, since 2013, is having an unprecedented impact .

Why would a virus that is not new be able to have a greater impact? Due to stressors and yes, these are believed to be related to climate change.

To those wonderfully engaged humans who have read all of this, please know this is not an additional problem that requires novel solutions. You are the last people who I wish to burden, you who care as you do. The plight of Sunflower Stars is a symptom of what is the same set of problems re. short term economies, absence of precaution, fossil fuel use, and consumerism.

Reporting sightings? I have reported the sighting of this lone, adult Sunflower Star to add to the knowledge of the impacts of SSWD. Citizen science is so important to understanding. Further information on the Disease and where to report sightings of sea stars can be in my blog at this link. 

And to you dear Sunflower Star,
May you find another of your kind for the sake of biodiversity, ecology, human learning and understanding, and so that your species will not disappear from children’s drawings of life on our coast.

May it not be that we continue on a path where Sunflower Stars slip away from our memories, or that we end up talking to children about “There used to be these giant, colourful sea stars . . .”

💙

 

Sighting was made on June 15th, near Port McNeill.

Video below re. Sea Star Wasting Disease and ecological impacts.

 

Rose Star – No Two Alike

One species. So many colours.

That’s beauty. That’s biology.

 

Rose Stars have such diversity in colour and pattern, that the species is also known as the “Snowflake Star”; a name suggesting that no two are alike.

Am I trying to make some sort of point as it applies much more broadly? Why, whatever would make you think that? 😉

Surely we humans rejoice in the beauty of diversity?

 

Notice that above this Rose Star, there is another local, marine ambassador for diversity of colour within a species.See the Blue-Line Chiton (Tonicella undocaerulea)?

Please see additional photos (and slideshow) below to get a further sense of the diversity, the beauty, and the perfection.

Species information:

  • Crossaster papposus to 34 cm but in British Columbia the maximum size is believed to be 17 cm.
  • They can live to at least age 20. Species is slow growing. Maximum size is reached around age 10.
  • Even the number of arms varies. Most Rose Stars have 11 arms but number ranges from 8 to 16. From personal communication with zoologist Neil McDaniel: ” I did counts of 63 images I had on file [all from British  Columbia’ and nearly 90% (87%) had 11 arms, about 10% had 10 and 3% had 12.”
  • They are SPEEDY! Zoologist Neil McDaniel clocked them at 50 cm/min. Larger individuals were documented to travel over 5 meters in 12 hours. They are speedy because they are serious predators.
  • Diet is known to include sea pens, nudibranchs, bryozoans, bivalves (e.g. clams), juvenile urchins and tunicates. Their diet is likely broader than this as they are not picky eaters. I often see them in rocky habitats covered by coralline algae species (see photo below) and believe that is, at least in part, because the prey there include Orange Social Tunicates. They are one of the few species of sea star known to feed on nudibranchs.
  • How they feed: When they feel their prey, and are hungry, they retract their sensory tube feet (tube feet at the tips of their arms), and then stretch up on their tippy toes (extending their terminal tube feet) to be higher and able to “pounce” on their prey when on the ocean bottom. Smaller prey are swallowed whole. Larger prey are held with the tube feet and, as is the case with other sea star species too, they evert their stomach OUT OF THEIR BODIES and into or over their prey.
  • Research supports that Rose Stars can sense potential prey and other sea stars by smell (distance chemoreception).
  • In the photos below you will also see the intricacy of the surface of sea stars. You will see:
    • Spines
    • Pedicellaria = amazing little structures that can nip off the tube feet of other species of sea star e.g. the predatory Morning Sun Star (Solaster dawsoni).
    • The tufts are “papulae”. They are the gills / respiratory organs of the sea star. They can retract into the surface of the sea star’s body.
  • Range: Bering Sea to Puget Sound; Arctic Ocean, North Atlantic Ocean, North Sea, western Baltic Sea.
  • Depth: Found from the shallows of the intertidal to ~1,200 m. Believed to more often be in low current areas.
  • I saw little impact on this species from Sea Star Wasting Disease around NE Vancouver Island BUT Rose Stars were hit very badly in 2014 in other areas e.g. Sechelt Inlet, British Columbia (McDaniel, pers. comm.). See photo at the end of the blog. The species seems to be rebounding, unlikely Sunflower Stars which remain devastated across their range. [Note: this information has been updated from a previous version of this blog.]

 

 

 

Rose Star and retracted Orange Zoanthids. Some are likely being snacked upon.

 

 

 

 

 

 

Very typical habitat for where I find Rose Stars. I believe their prey on these coralline algae covered rocks include the small orange animals you see = Orange Social Tunicates. Notice too that there is another Blue-Line Chiton. 

The next 3 images are of the same individual.

 

Slideshow:

Sources: 

One of many Rose Star ravaged by Sea Star Wasting Disease near Sechelt, British Columbia.
Photo ©Neil McDaniel.
See Neil’s information about SSWD at this link.

 

In a Galaxy Far, Far Away . . .

 

 

In a galaxy far, far away . . .

Oh wait no, this was yesterday, diving in a soup of Red Eye-Medusa.

Imagine the water thick with plankton to the extent that it actually feels soupy, and throughout, these jellies are suspended . . . like little, living fairy lights in the dark.

When the visibility is poor like this, it of course limits what else can be seen. But, when you’re in the dark, that’s where you are and that’s where there is still much learning to be done and beauty to be seen.

Yep = life metaphor.


Polyorchis penicillatus are up to 10 cm in size and they are “sink fishing” when hanging like this (detail below).

Look at the bottom of the bell for the red “eyes” (eyespots / ocelli). These can sense light intensity, helping the jelly know which way is up.

The stomach is in the middle and the gonads are the elongate organs surrounding that. Species has up to ~160 tentacles (more often around 100). This jelly species makes “hopping” motions. In part, this is believed to help when feeding near the seafloor by stirring up prey (true story).


More detail on feeding from the University of Oregon:
They feed in both the water column and on the bottom, using different methods for each (Mills et al. 2007). On the bottom, they perch on their tentacles and eat benthic organisms by touching the sediment with their manubrium [stomach with mouth at tip]. Sometimes, they will hop on the sediment, likely to stir up possible prey or move to a new location (Mills 1981, 2001). In the water column, they use “sink fishing” to find their prey. During sink fishing, the medusae extend their tentacles out from their bell and let the distal ends sink downward. They either maintain their position in the water column or sink slowly and catch prey with their tentacles. When a prey item touches a tentacle, the medusa will use that tentacle to bring the prey to the manubrium, though large prey sometimes require more tentacles; this process causes cessation in swimming and crumpling (Arkett 1984).”


#YouAreWhereYouAre

Another Red-Eye Medusa at the same site in Port Hardy.
Species of sea star on the anchor chain is a Leather Star.


Source of annotated diagram below and ALL you wish to know about the species:

Polyorchis penicillatus, A publication of the University of Oregon Libraries and the Oregon Institute of Marine Biology Individual species.