In the drift line

  

I didn't expect to find a Purple Sea Snail (Janthina umbilicata) tonight (2 March 2026), but I also thought there was potential.  Ocean temperatures have been warm this winter and there was a lot of debris washed up on the beach tonight, so I kept the color purple in my search image and I happened to spot one individual.

The last time I recall Janthina being in our area was during the winter of 2024 (see post called "It's been a while" on 21 February 2024.)

It looks like there were several Janthina sightings in San Mateo County and Santa Cruz County in late February, so it's a good time to keep your eyes open for these beautiful pelagic snails.  If you come across one, I'd love to hear about it!

On the windward side

  

While in Hawai'i, we walked some east-facing beaches to look for pelagic invertebrates washed ashore.

Above, a small Portuguese Man O' War (Physalia physalis) on Kaua'i on 4 April 2024.

Below, a Purple Sea Snail (Janthina umbilicata).  (Interestingly, the Janthina we found on Kaua'i were quite a bit smaller than the Janthina we observed in California back in March.)

 

 

 

One of the beaches where these species were found:

 

 

 

Up close and purple

  

I've been surveying for Purple Sea Snails (Janthina umbilicata) and encountered some washed up this morning (5 March 2024).  Janthina is rare in our area, and these snails were still alive, so I took a few photos for the record.

Remember that these snails float upside down at the surface of the ocean, hanging from their own bubble raft!  So these photos show the snails suspended below the surface of the water.

Above, note the bifurcate or forked tentacles, with one long and one shorter branch (highlighted with black pigment).

Next -- look for the large, rounded, black foot.  Janthina reaches up to collect a pocket of air and then surrounds it with mucous to create a bubble to add to its raft:

 

 

They also use their foot to smooth the bubble raft:

 

 

Janthina is a predator, feeding on By-the-wind Sailors (Velella velella) and Portuguese Man O' War (Physalia physalis) when available.  They have a tubular proboscis to reach out and grab prey, and a rasp-like tongue (radula) at the end of the proboscis: 

 

 

 

 

 

P.S.  If you happen to see Purple Sea Snails washed up on the beach this spring, I'd love to hear about your observations!

Cloudy with a chance of sailors

  

Eric and I did a quick beach survey at the end of the day today as the storm was letting up.  There were thousands of By-the-wind Sailors (Velella velella) washed up.  Some were up to ~3-4 cm long, but the vast majority were under 1 cm long and the most abundant size was only ~1-2 mm long (second photo below with millimeter ruler):

 

 

 

 

We also found one Purple Sea Snail (Janthina umbilicata), hundreds of swimming bells of the siphonophore Diphyes dispar, one pyrosome (I thought there might be more today), and pieces of driftwood with pelagic barnacles (Lepas sp.).

 

The view as rain showers were clearing:

 

 

 

It's been a while

  

It's been a while (about 6 years!) since we've seen Purple Sea Snails (Janthina umbilicata) in Bodega Bay, but some have appeared on local beaches this week.  

The last time we observed large numbers of this species was during the 2014-2016 marine heatwaves (which included a significant El Niño).  Smaller numbers also appeared in 2017 and 2018. 

Although there is a significant El Niño this winter, we haven't observed too many biological signs of it in Northern California — i.e., in terms of marine invertebrate occurrences — at least not yet.

I don't know if these Janthina observations will be isolated or if we will continue to see them during the next several months.

The post I shared back in 2016 is a good introduction to Purple Sea Snails, so if you're interested in learning more about them you can check that out here.

These snails are pelagic — usually found offshore.  They're fragile — they don't live in an environment where they need a thick shell (they float upside down with a bubble raft at the surface of the ocean).  And they're small — most of the individuals I saw this morning were ~5 mm long (with some smaller, some larger).  The purple color is eye-catching!  I'd love to hear if you come across any in Northern California.  Watch for them washed up in the wrack line, especially perhaps on south-facing beaches, and after strong southerly or westerly winds.

 

 

P.S.  Quite a few pyrosomes have also washed up this week, along with Diphyes (a siphonophore).  I'll post some more photos soon.

 

Blue and purple

Just a quick note about a couple of recent observations:

 

There were thousands of By-the-wind Sailors (Velella velella) washed up on Salmon Creek Beach on 16 March 2018.  Most were between 10-20 mm long (those are millimeter marks on the ruler in the photo), but many were smaller than that.  With a storm coming mid-week, there might be more Velella washed ashore.

We also spotted a few Purple Sea Snails (Janthina umbilicata) on 16 March 2018:

 

Although we haven't seen many Purple Sea Snails during 2017-2018, we remain curious about what oceanographic conditions are driving these pelagic snails onshore two years after an El Niño event (with which their appearances here are more often associated).

 

Visitors from offshore

 

Remember these snails?  This is a Purple Sea Snail (Janthina umbilicata).  I wasn't expecting to see them right now, but I found a few while doing a survey on Salmon Creek Beach tonight (25 January 2018). [Those are millimeter marks on the ruler, so the snail was ~10 mm across.]

During the 2015-2016 El Nino, many Purple Sea Snails washed ashore in Bodega Bay.  I wrote a post introducing this species on 20 January 2016 — click here to review that summary (including a nice video!).

Purple Sea Snails are often associated with By-the-wind Sailors (Velella velella).  Sure enough, there was a handful of Velella washed up today.  Here's one:

 

I'd be very interested in hearing about any other Purple Sea Snail sightings.  So if you see one, take a picture, and let me know!

 

A long tail?

Remember all of the Purple Sea Snails (Janthina umbilicata) we found last year?  For example, review the posts from 20 January 2016 and 6 March 2016 (or scroll down to the bottom of this page and enter "janthina" in the search field to see all of the previous posts).

You might also recall that we found six Janthina on 24 January 2017.

And I haven't mentioned it on the blog, but I also found one individual on 13 March 2017.

We're continuing our surveys to document the "tail" of the distribution of observations associated with the 2015-2016 El Niño.  That is, how long do species likely associated with the El Niño continue to appear in northern California, even after El Niño conditions have ended?

Well, we found one Purple Sea Snail today (25 April 2017)...so the tail continues to lengthen:

 

Let me know if you encounter any of these little purple pelagic snails.  We'd love to hear about any other sightings this year.

So cool!

 

Well, it finally happened — we found our first live Pelagic Red Crabs (Pleuroncodes planipes) in Bodega Bay!

Although we have found parts of these southern crabs a few times prior to this (in October 2015, February 2016, and earlier in January 2017), we found 19 live crabs on Salmon Creek Beach tonight.

Most of them were ~9-10 cm long (with the tail tucked underneath):

 

Here's a view from above:

 

And one in my hand (Note: they can pinch!):

 

It was very exciting to see them alive.  It appeared that they were just washing in this evening, having just been left behind by the receding waves.

Let me know if you see any on beaches near you!

For the record, we also found a half a dozen Purple Sea Snails (Janthina umbilicata) today:

 

This was somewhat unexpected.  The water has cooled down this year, and we haven't seen any Janthina in Bodega Bay since last spring.  [Interestingly, the our first sighting of Janthina last year was on 19 January 2016.  To review information about Janthina, click here.]  We have a lot to learn about the movements of these tropical species to northern waters.  

The weight of the whorled?

For the record, this is the fifth month in which we've found Purple Sea Snails (Janthina umbilicata) in Bodega Bay.  Although most were found in March and April, we also spotted them in January, February, and May.

Here's one of four individuals that I encountered on 11 May 2016:

 

Did you notice the small pelagic barnacles (Lepas sp.) attached to the outer whorl of this snail?  We had heard that Lepas sometimes attaches to Janthina, but we didn't see this ourselves until April-May.

Here's a view of a snail shell floating at the surface, with the attached barnacles hanging below (their feeding appendages are extended like fans):

 

Although they start out small, these pelagic barnacles can grow to a size much larger than the snail.  Do the barnacles eventually weigh down the snail?  Does a snail have to add more bubbles to its raft to counteract the barnacles?  (For a picture of a bubble raft, review the post from 20 January 2016.)

Big foot captured on video

Remember the Purple Sea Snail (Janthina umbilicata) I've shown several times during the past couple of months?

During certain conditions from late January-present, we've been finding quite a few of them washed up on the beach.  On 12 March 2016, we were walking along the beach counting them, when we noticed one snail that looked similar but slightly different.

 

It was larger, paler, more compressed (flattened from top-to-bottom), with a shorter spire (the first few whorls), and it had a more substantial float.  The striations (or lines) on the shell were also different — rounded all the way around, rather than angled.

Here's the same snail from below.  Although it's completely covered with sand grains, look for the float emerging from the shell:

 

It has been interesting enough to see one species of Janthina this year...and here was a second!  Although we need to confirm the identification with an expert, my best guess right now is that this is Janthina janthina. 

We didn't know if the snail was alive, and because this species is so rare in this area, we decided to bring it back to the lab for documentation.

The snail floated in sea water, so we left it in a tank overnight.  When I arrived the next day, this is what I saw:

 

  

The snail was alive and in about 12 hours it had created an impressive float made of very large bubbles. 

Here's a view from the side in a small aquarium:

 

The online record is incomplete, but in a quick search we could only find one entry for Janthina janthina in Northern California — from 1935!  Its occurrence here this year is likely related to the current El Niño event.  We took some additional documentary photographs and video (see below).

One thing we noticed right away was how different the tentacles are between the two species.  Although they both have forked tentacles, Janthina janthina's tentacles are much more rounded.  They made us think of velvety deer antlers, or mittens (with thumbs)!

The next photo shows a close-up of the snail, emerging from its shell, with its broad foot gliding over its bubble raft.  Look for the tentacles on either side of the proboscis (left side of the photo — they almost look like lobster claws). 

 

Eric was very fortunate to capture some nice footage of Janthina janthina working on its float.  In the video clip below, watch for:

— The front of the foot expanding (tremendously!), then breaking the surface to grab a bubble of air and wrap it in mucus secreted by the foot.  (If you watch closely, you can even see the bubble below the foot as the snail attaches it to the float.)  

— The snail's large black foot gliding over the float (applying another layer of mucus?)

— A glimpse of the extended proboscis with sharp radular teeth exposed at the tip.

janthina_janthina_sanford from Jackie Sones on Vimeo.

Amazing, right?  Not many people get to see these pelagic snails in action, so we hope this helps you visualize and wonder about their lives at sea.

P.S.  If you want to review the photos and video of the first species, Janthina umbilicata, click here.

 

Epic!

Well, we couldn't resist...the conditions were just right for interesting things washing up on the beach — a storm during El Niño conditions with large waves (~14 feet) and strong southwest winds (20-30 knots).

So we went for a short walk at Salmon Creek Beach, and we weren't disappointed.  

There were By-the-wind Sailors (Velella velella), pyrosomes (Pyrosoma), gelatinous pseudoconchs of Corolla spectabilis, three species of siphonophores (Chelophyes, Diphyes, Physophora), and two species of pelagic barnacles (Lepas and Dosima).  

And we can now say that 2016 is an "epic" year for Purple Sea Snails (Janthina umbilicata) in Bodega Bay.  There were hundreds of them washing ashore today.

I know I've posted about Purple Sea Snails several times during the past six weeks, but it seems important to document their appearance in Northern California this year (and they're fascinating animals, so there's a lot to learn about them!).

Below are two examples, each with three snails.  Can you find them among the Velella?

 

 

Now that you've had some practice, how many Purple Sea Snails can you find in the picture below?

 

It takes a bit of searching for that distinctive purple color.  And learning that they're lighter on one side (the spire side that floats downward) and darker on the other (the large whorl that floats upward).

Here's the same picture with the snails circled in yellow:

 

If you missed the snail in the upper right corner, don't worry!  You'd eventually find it with practice.

I think you can tell from these pictures that many Velella washed ashore today — we estimated millions.  Although a good number of Velella were ~1 cm long (see photos above), many were only 1-2 mm long (see next photo, with one Purple Sea Snail surrounded by uncountable masses of juvenile Velella):

 

Stormy conditions are expected to continue this week.  If you're at the beach, be safe around the large waves.  If you spot any Purple Sea Snails, I'd love to hear about it.

 

Purple pelagic predators

Remember the Purple Sea Snail (Janthina umbilicata) that I introduced in January (see post from 20 January 2016)?  I mentioned how this pelagic snail makes a bubble float and drifts at the surface of the ocean (see below):

 

Eventually we also observed some feeding behavior.  First, here's an orientation to their basic anatomy.  Remember that you're looking at the snail from above as it drifts upside down.  Prominent in this photo is the extensible proboscis that the snail uses to reach for nearby prey.  Note that the tip of the radula is also visible.  (The radula is like a rasping tongue.)  Many predatory marine snails use their radula teeth to tear the flesh of their prey:

 

You might be wondering what a Purple Sea Snail eats.  Various types of prey are mentioned in different accounts, e.g., By-the-wind Sailor (Velella velella), Blue Button (Porpita porpita), and Portuguese Man O' War (Physalia physalis).

When we encountered these Purple Sea Snails, there were many juvenile By-the-wind Sailors in the wrack line, and some of them came in with the snails.  So, of course we were curious — would the snails eat the Velella? 

Here's a hint: 

 

Above, you can see the snail's proboscis and radula approaching a tiny juvenile Velella.  The radula of a Purple Sea Snail consists of two bundles of sharp, slender teeth that grasp the prey.

And then the snail inhaled the Velella!

 

Because some of the snails weren't alive, this was a rare opportunity to see their radula teeth up close.  Eric took this picture under high magnification (100x).  Note the slender teeth, with a slight hook at the tip.  And they're abundant!

 

If you're curious, Eric was exceptionally fortunate to film one of the snails probing with its proboscis and revealing a hint of the radula teeth.  In this video, watch for a few different things: an introductory image, the snail using its large black foot to maintain its bubble raft, and then the proboscis with the arching, glistening radula teeth.

janthina radula sanford from Jackie Sones on Vimeo.

It was amazing to see these purple pelagic predators in action!

Little swimmers

Remember the Purple Sea Snail (Janthina umbilicata) egg capsules?

 

When I took this picture, the embryos were still developing inside the capsules.  A few days later, some of the larvae emerged from the capsules as active swimming veligers.

These Janthina larvae are extremely small, and are good swimmers.  Here are two still shots (the best I could manage), but at the end of this post there's a short video clip that's much better.

View from the side:

 

View from above:

 

Mostly what you're seeing is the reddish shell and the ciliated velar lobes.  In the video, watch for the long cilia beating along the edges of the velar lobes — the motion is useful for both swimming and feeding.

Note that this video was made under a microscope — it's magnified 200x!

By the way, from what we can gather, not many people have filmed Janthina larvae, so although this is a short video, you're probably one of the few people in the world to watch a swimming Purple Sea Snail veliger! 

[If you're receiving this via e-mail, click on the title of the video below to watch the clip.] 

 

janthina_veliger_sanford from Jackie Sones on Vimeo.

Little red caps

About a week ago, I wrote about Purple Sea Snails (Janthina umbilicata).  We found those snails on 20 January.  A few days later, on 23 January, I found a few more and one of them had eggs!

Janthina lays egg capsules and attaches them to the underside of its float.  In the photo below, it's easy to see the bubbles making up the float on the left, and the egg capsules (filled with embryos!) on the right:

 

A close-up reveals the small white embryos inside the clear capsules.  One book estimated that Janthina umbilicata has about 80 embryos per capsule.  What do you think?

 

We kept this snail in the lab, and here's what the embryos looked like today (4 days later):

 

They've grown quickly!  Their cap-shaped shells are an intriguing shade of brownish-red:

 

The embryos are still very small (the egg capsules themselves are only ~2 mm long).  This is the best view I could get:

 

Eventually, the larvae will emerge from the capsules as free-swimming veligers.  But I haven't been able to find information on development time within the egg capsules, or the duration of the larval stage once free of the capsule.  For example, how long does it take until the swimming larvae metamorphose into floating snails and start living at the surface of the ocean?  When do they create their first float?  (How many bubbles are in their first float?  When do the shells become purple?  Does the color change happen when they start eating Velella?)