With a pearly luster

  

A quick shot of a fun sea squirt, Cnemidocarpa finmarkiensis.  One description says this species has a "pearly luster," which seemed right to me.  

Photograph from the South Jetty in Bodega Harbor on 24 July 2024.  Good spotting, Eric!

Bound together

 

 

Yellow social tunicate (Perophora annectens) photographed in the low intertidal zone on 29 May 2021.  Although it's hard to tell, all of these zooids (each yellow blob) is connected via a stolon or runner that extends across the substrate.  The smallest zooids in this photo are new buds that arise from the stolon. 

A clam, a sea squirt, and a snail

Well, I didn't get a chance to take any photos today, so I browsed through photos from the last month or so (from various locations) and picked a few that caught my eye.  I hope they brighten your day!

 

Juvenile Pacific Razor Clam (Siliqua patula)

 

A golden colonial tunicate (sea squirt), Pycnoclavella stanleyi 

 

Red Turban Snail (Pomaulax gibberosus) with coralline algae

P.S.  What did the clam say when the sea squirt and the snail walked into the bar?  "Sorry, I'm just about to close up for the night."  :)

Tickling the tunicates

 

I was working on a backlog of photo organization tonight, so here's an image from August 2019.  The striped peanut worm (Phascolosoma agassizii) has extended its introvert and is searching for food particles with its short tentacles.  The yellowish-green animals are tunicates or sea squirts (Perophora annectens).

Dense little clubs

 

Pycnoclavella is one of my favorite tunicates (sea squirts).  This photo gives you a feel for how it grows in dense colonies.  (But remember, each one is only a few millimeters high!)

I first introduced this species ~6 years ago, so for more information, see the post called "The tiny tunicate, Pycnoclavella" on 17 February 2012.

P.S.   I think Pycnoclavella means "dense little clubs."  It's an appropriate name!

 

Spot-on

I was sorting through some pictures from last spring when I encountered this one:

 

I said to myself, "Huh...do Two-spotted Keyhole Limpets (Fissurellidea bimaculata, formerly Megatebennus bimaculatus) eat sponges?"  It certainly looks like the limpet (relatively small, dark brown shell surrounded by a bright yellow mantle) had been eating the green sponge (Halichondria sp.).  

So I read the species account in Intertidal Invertebrates of California which said this:

"This species often occurs on compound ascidians where the color pattern provides good camouflage.  In the laboratory, Megatebennus has been observed feeding on compound ascidians, and sponge spicules have been found in the gut of specimens collected in the field."

And then I laughed, because the next photo I found was this one:

 

The Two-spotted Keyhole Limpet above is in the center — with a dark brownish shell (barely visible) surrounded by a pale yellow mantle.  It's flanked by several compound ascidians, and you can see how well camouflaged it is.

The description in the species account by Don Abbott and Gene Haderlie was spot-on!

Purple pools and purple waves

Eric and I did some early morning field work today.  When we first got there, we noticed a purplish hue at the high tide line.  When we got closer to the tidepools we saw this:

 

The pools were filled with doliolids!

Here's a close-up showing how dense they were:

 

And another shot, with some of the doliolids floating at the surface.  You can see their barrel-shape, with prominent muscle bands:

 

I don't recall seeing abundances and concentrations of doliolids in the intertidal zone like this before.  For the record, here are a few more examples:

Draped over Feather Boa Kelp (Egregia menziesii)

 

Undigestible portions being spit out by Aggregating Anemones (Anthopleura elegantissima) — the large pinkish blobs emerging from the anemones' mouths:

 

There were so many doliolids, they were painting the waves purple!

 

I introduced doliolids last year, so to learn more about them, read the post from 15 June 2015.

P.S.  I heard that doliolids were also seen at Doran Beach today.  If you come across them, let me know — it would be fun to know where else they're showing up.

 

Roll out the Barrel

Last night I showed a picture of doliolids washed up on Salmon Creek Beach:

 

 

I thought it would be valuable to document this event, and to illustrate what the doliolids looked like en masse on the sand because you might encounter them that way.  However, I felt badly that the picture didn't provide a proper introduction to doliolids.

So here you go!

 

These animals were ~1 cm long.  Doliolids are barrel-shaped with prominent muscle bands.  (In doliolids the muscle bands completely encircle the animal, whereas in salps the muscle bands are incomplete.)  They have openings at both ends — water is drawn in through the oral siphon and expelled through the atrial siphon (see diagram below).  The muscle bands are used for swimming, and for opening and closing the siphons.

 

Modified from Biology of the Invertebrates, 6th Edition by Pechenik (2009)

 

Doliolids are active filter-feeders, using a mucous net to capture small particles in the water.

Cilia on the pharynx generate a water current.  As the water passes through the pharyngeal cavity, food is trapped on a mucous sheet (secreted by the endostyle) and then is rolled into a string and transferred to the mouth.  The pharynx is also a site for gas exchange.

Here's another individual in which you can still see the pharynx (at the bottom of the picture):

 

I was intrigued by the structure of the pharynx, so I've included an even closer view where you can see the gill slits (the long, narrow openings in the pharynx):

 

Although many doliolids are tropical or semi-tropical, Dolioletta gegenbauri is a relatively cold-tolerant species.  This species is found in northern California, but it's uncommon to see them near shore.  They're open ocean animals, so finding them on the beach is rare (and fascinating!).

Purple slime

A quick walk at Salmon Creek Beach on 14 June 2015 yielded some interesting sightings.

 

There were quite a few (perhaps 25?) Blue Buoy Barnacles (Dosima fascicularis).  Many individuals were attached to By-the-wind Sailors (Velella velella), but some had their own floats, as above.

There was a lot of foam, and many bubbles, and you know I can't resist photographing colorful bubbles.  

I couldn't choose a favorite bubble picture, so I've included a few (below).  Which one do you like?  (Some of these bubbles were attached to Velella, which created a vivid blue backdrop.)

 

 

 

 

One of the most interesting things we saw wasn't easily photographed.  Here's a picture:

 

I know it doesn't look like much, but I'm guessing you can tell that it looks gelatinous, and purple!

There were probably millions of doliolids washing up on the beach tonight.  Doliolids are planktonic animals related to salps and pyrosomes.  We first noticed doliolids in the surf zone about ten days ago.  This is the first time we've observed large numbers stranding on Salmon Creek Beach.  Although we didn't identify them for sure, it's likely to be Dolioletta gegenbauri.  You can see a nice picture of an individual doliolid at the JelliesZone web site.  (They also include a description of doliolids.)

Unfortunately, the doliolids didn't retain their shape when washed up on the sand, so they just looked like patches of purple slime.  If I get a better picture in the days ahead, I'll post one.  Meanwhile, if you're walking local beaches and see something similar to the picture above, perhaps you'll recognize it as an interesting pelagic animal!

 

P.S.  Eric also noticed an unusual, strong sulfur smell while walking the beach — perhaps emitted by phytoplankton?

 

Puzzling pigment and points

 

With so many Velella washing ashore recently, I have been wondering why other pelagic animals haven't appeared also.  I was thinking about it again tonight, when I looked down to see this animal near my feet. 

Do you remember it?  Doug found one that was similar last fall — see the post from 20 November 2014.  At that time I mentioned that I'd never seen this stage of this species, so needless to say, I was very intrigued to encounter it tonight.

Here's a picture with a ruler for scale:

 

This is the solitary stage of a salp (or pelagic tunicate) called Thetys vagina.  You can read more about salps in previous posts (e.g., see the link above).

Tonight I'm going to show two close-ups, because this is what caught my attention while observing the animal:

 

There is a pair of pigmented posterior projections.  I know they look like "horns" at first, but keep in mind that these are trailing off the posterior end.  I looked very hard to find a description and explanation for these projections, but I came up empty.  Why do they have them?  Why are they green (and blue)?  It appears as though a portion of the salp's body extends into the middle of these projections — what is that and what is its function?  Do the projections have something to do with streamlining while swimming?  Are they involved in camouflage/distraction?  What do you think?  Do you have any ideas?

 

And here's another close-up, this time of the middle portion of the salp's body:

 

Did you notice all of the small gelatinous spines?  Why do they have these raised points?  Do they deter predators?  They're so small.  I found one paper that suggested a texture like this, rather than a smooth surface, might cut down on reflections, making it more difficult for predators to see the animals.  Let me know if you have other ideas!

(I've always wondered about the role of surface texture in Corolla spectabilis, too — see pictures from August 2012 and November 2012.) 

Crab trap surprise!

What fun to open my e-mail, to see a request for help with identifying a local animal, and then to see this photo:

 

This animal came up in Doug Wilgis's crab trap!  He was in Bodega Bay, off the Estero de San Antonio, on November 12th.  The trap had been set at about 25 fathoms (150 feet).  This curious animal was about 4 inches (10 cm) long.  Do you recognize it?

I've mentioned this type of animal on the blog before (a couple of years ago), but I haven't shown this stage — because I've never seen it!

This is the solitary stage of a salp (or pelagic tunicate) called Thetys vagina.  Note the two fascinating amber-colored projections — they're on the back end.  And I'm sure you can also see the banding in the mid-section.  These are muscle bands that the salp uses for swimming and pumping water for filter-feeding.

A salp spends its entire life in the open ocean.  Its life cycle includes two stages — a solitary stage and an aggregate stage.  [For comparison, on 30 July 2012, I showed a picture of a Thetys from the aggregate stage.]

The solitary stage shown in Doug's picture is asexual and produces chains of aggregates (shown in my July 2012 picture, and see below).  The aggregate stage is sexual and produces the solitary stage.

In late October, I found some small aggregate stage Thetys washed up on the beach, which made me wonder if there were some actively reproducing solitary stage individuals around.  Doug's observation confirms that there are!

Here are the small aggregate stage individuals that I encountered in October (see below).  They don't look like much after being washed up on the sand, but I thought it would be useful to document these smaller individuals.

You can see that the first is ~8 cm (3 inches) long, and the second is only ~4 cm (1.5 inches) long.

 

I'm very thankful to Doug for sharing his picture.  Not many people get to see these offshore animals, so it's fun to pass along this story to you!

Diamonds in the drift

Last night, on 25 August 2014, I was waiting for someone and decided to pick up some trash on the beach.  I glanced along the water line and noticed something that reminded me of the few times I've seen hail being concentrated in driftlines by the incoming waves:

 

I bent down for a closer look:

 

Salps!  Although I've seen other species of salps washing ashore on Bodega Head, I believe this is the first time I've seen Thalia democratica stranding on local beaches.

Here's an image with a ruler for scale (below).  When they're in this chain-like stage, they remind me of diamond bracelets (but note if you try to pick them up, the individuals in the chains separate very easily):

 

Thalia democratica has a somewhat complicated life cycle.  There are two stages: an aggregate stage (as above) and a solitary stage.  The aggregate stage is sexual — each individual in the chain produces one embryo that will develop into a solitary individual.  The solitary individual is asexual — each solitary individual will bud off a chain of aggregates.  This life cycle is illustrated below:

 

 Example of a salp life cycle modified from Alldredge, A.L. and L.P. Madin. 1982.  Pelagic tunicates: Unique herbivores in the marine plankton.  Bioscience 32: 655-663.

Since observing Thalia democratica on Bodega Head has been rare, I brought a few salps in for documentation.

This is a picture of an aggregate individual under the microscope.  The purplish oval spot at the bottom is called a nucleus and the structure just to the right of the nucleus is a developing embryo (it will become a solitary individual).

 

The next image shows the posterior end of a full-grown solitary individual.  Note the two long projections (pointing backwards).  There is a developing chain of aggregates wrapped around the gut.

 

While looking through the specimens, I noticed one that looked different and had me puzzled for a moment.  Most of the individuals were easy to sort into either aggregate forms (rounded or tear-drop shaped) or solitary forms (with two long projections).  Here was a small salp that  looked like it had two little "fists" and two "triangular bumps" at the back end:

 

When I looked very closely at those little "fists," I realized what I was probably looking at:

 

I'm not sure what the structure is, but there's something in the little fist that looks funnel-shaped (a bit like Shrek's ears)!  When I saw that, I remembered seeing the same thing in the full-grown solitary individual: 

 

Above, you can see the "Shrek-like" funnel structures at the base of the two long posterior projections.  Also note the two curved spikes, closer to the top of the picture.  I believe the mystery animal I observed is a very small, juvenile solitary individual, and that eventually the "fists" will become long posterior projections and the triangular bumps will become curved spikes.  Although I've seen Thalia democratica before, I've never encountered such a small solitary individual.

One more note: I checked the seawater temperature after finding these salps.  It was approximately 17.5°C.  I'm wondering if their presence this summer has something to do with the warm water?  I'd love to hear about any other sightings of Thalia democratica.

March Madness

Over the last few years, I've come to realize that March (and April) are good months to look for interesting pelagic invertebrates washing ashore on local beaches.  I'm guessing it has to do with the beginning of upwelling season, strong winds, and big waves.

So although some people call this time "March Madness" for other reasons, I've also come to know it by that name.  Partly because the intense weather during this month can feel somewhat "mad."  And partly because I'm "mad" about these fascinating animals that we don't get to see very often.

For example, if you look back at the blog during previous Marches and Aprils, we've documented a hyperiid amphipod living in a salp, sea angels, siphonophores, and salps.

A few days ago we came upon another species of salp.  It didn't look like much at first — mostly clear and elongate, with a large orange/reddish spot at one end.  This individual was ~5 cm long.

 

 

However, when we brought it in to identify it under the microscope, it was a different story!  Many of its organs were visible through the transparent body wall.  (Note that because the salp had washed up on the beach, there are scattered sand grains in the background.)

 

To make this easier, here's a diagram with some of the organs labeled: 

 

Modified from The Biology of Pelagic Tunicates (Bone 1998)

A salp has a similar body plan to its close relative the sea squirt (an ascidian), except that the salp's incurrent and excurrent siphons are on opposite ends of the body.  Water enters at one end and passes through a mucous net that is produced by an organ called the endostyle.  The mucous net is suspended between the endostyle and the gill bar and traps fine particles of food.  Periodically the food-laden net is rolled up and moved into the stomach to be digested.  The muscle bands contract to force water through the net and the excurrent stream of water also moves the salp via jet propulsion.

And now I'll go back and identify these same organs in the picture I showed above: 

 

 

Below is an even closer view of the heart and a portion of the gill bar and endostyle.  The tubular heart is intriguing because it periodically reverses its direction of pumping which drives the clear blood through the circulatory system in the opposite direction! 

 

I think this is Salpa fusiformis.  Although this species is known to occur along the West Coast, this is the first time I've documented it washing ashore in the Bodega Bay area.

For more general information about salps, you can review the post from 29 March 2013.

And here's a photo of March Madness weather when we found these salps:

 

Wide mouth and ribbon-like muscles

Sometimes when you discover gelatinous bits washed up on the beach, it's hard to tell what animals they came from.  But other times, if you take a closer look at those mysterious bits of transparent "jelly," you might find structures that provide more clues.

Here are a few photos of a gelatinous animal we found washed up on Salmon Creek Beach on 23 March 2013.  It was roughly cylindrical and ~3 cm long. 

 

Under the microscope the dramatic ribbon-like muscle bands encircling the animal were quite prominent.

In the photo above, note the wide mouth near the top of the photo (see close-up below).

 

And the small reddish spot at the bottom of the "V" below the mouth.  I'm not 100% certain, but I think this is the brain/eye of this animal (again, see close-up in next image).

 

At the posterior or tail end, there was a pointed projection and a pale mass which is probably the gut.  Here are two slightly different views.

 

 

This is a type of pelagic tunicate called a salp.  Salps are much more common offshore.  They don't often wash up on beaches unless there are strong onshore winds.

Many of them are very strong swimmers, hence the well developed muscle bands.  The large slit-like mouth is the equivalent of a siphon.  It takes in water which, after passing through the body, is released out the back end.  This water current is used for jet propulsion, gas exchange, and feeding.  As the water flows through the barrel-shaped body, food is captured in sheets of mucous and ingested.

I don't have a lot of experience identifying local salps, but I think this could be Iasis zonaria.  I'll be sending out the photos for confirmation.

If you are having trouble envisioning the animal with all of these parts, here's a basic illustration with labels:

 

Modified from The Biology of Pelagic Tunicates (Bone 1998)

 

Reproduction in salps is somewhat complicated.  They alternate between a solitary form and an aggregate (or chain) form, and one form produces the other.  The solitary form reproduces asexually and releases a long chain of aggregates.  The aggregate form reproduces sexually; each aggregate form produces one (or a few) solitary individuals.

Earlier in March we found a solitary individual that was producing a chain.  I'm not sure if this is the same species as the one pictured above.  It's possible, but either way, it's still worth showing you what a salp chain looks like.  I hope you can make out that there are lots of tiny individuals all lined up next to each other.  If this salp hadn't washed up on the beach, eventually the chain would have been released and would have been free swimming in the ocean.

 

This seems to be a good time of year to find gelatinous animals on local beaches.  I'll feature a few more during the next few days.