End of a long odyssey

For Eric’s summer class, we used a small plankton net to collect some plankton near the mouth of Bodega Harbor during a flooding tide last week.  The students sorted through the plankton sample in lab to see what larval forms they could find.  One of the students (Zack) spotted an amazing larval form.

This is a brachiolaria, a late-stage larva of a seastar, that appears to be the Ochre Seastar (Pisaster ochraceus).  The photo above was taken under the microscope, but the specimen is quite large for a planktonic larval stage, close to 2 mm long and visible with the naked eye. This larval form is beautiful and alien in appearance and doesn't look much like an adult seastar!   

A surprising feature of the brachiolaria larva is that the juvenile seastar begins developing within the transparent larval body.  In the photo above, the juvenile body is visible near the bottom of the larva and is shiny white in color.  With a closer view, you can see that the developing juvenile body already includes the start of calcareous ossicles that will become the internal skeleton of the juvenile and adult seastar!  In the photo below, the developing ossicles look like intricate snowflakes (white arrow).

 

This brachiolaria appeared to be nearing the completion of its planktonic larval phase, which can be a long odyssey in seastars.  Under laboratory conditions, the planktonic phase has been reported to last from ~40 to 228 days in Pisaster ochraceus, depending on temperature and food.  Pisaster spawns in the spring in California, so this larva likely spent at least several months at sea before entering Bodega Harbor.

When the brachiolaria returns to a rocky shore and finds suitable habitat, it will initially attach to the rock with a short stalk.  Remarkably, the transparent larval body is reabsorbed into the juvenile body during a dramatic metamorphosis. Soon after settlement, the juvenile sea star breaks off its stalk and crawls away as a tiny sea star. 

The larval phases of a sea star.  Illustrations compiled and modified from various sources.

Eric was able to capture some video under the microscope of this beautiful sea star larva.  In the video, notice the long ciliated larval arms used for swimming and gathering food from the plankton. You will also see a close-up of the developing juvenile body (white in color) and the snowflake-like ossicles.  (If you can't see the video player below in the e-mail message, click here to go directly to the video.)

With many thanks to Zack for spotting this planktonic wanderer!  And to Eric for his microscope camera skills and the helpful diagram.

P.S.  For more information about development in sea stars, see earlier posts on the larvae of the Bat Star (Patiria miniata) — "A new star(t)" in 2013 and "A profound change" in 2023.

P.P.S.  As a reminder, when juvenile Pisaster are first visible to human eyes in rocky shore areas, it's about 4-6 months after metamorphosis.  Here's an example of one that's about 4.5 mm across (between ¹/₈ inch and ³/₁₆ inch), photographed in November 2014.

 

Morning sky

  

Such interesting clouds yesterday!  

Morning view from Cotati on 22 July 2026.

Sea star art

  

Close-up of the upper surface of a Bat Star (Patiria miniata).  Those are papulae (in purple) among clusters of spines (in pink).  (Papulae are finger-like projections for gas exchange). 

Red sky at night...

 

 

...sailor's delight.  

 

A saying that certainly held true last night and today! 

 

Sunset from Cotati on 11 July 2026. 

 

Anchovies and a rock

  

I was at the Spud Point Marina docks briefly this afternoon and noticed lots of schools of what look to be young Northern Anchovies (Engraulis mordax).  [Feel free to correct me if I'm wrong!]

Also came across a nice juvenile rockfish (Sebastes sp.).  It was only ~4 cm (1.5 inches) long:

 

 

Seeing lavender

 

Sea Lavender (Limonium californicum) flowers, 7 July 2026

A festive fourth

  

Red Sea Urchin (Mesocentrotus franciscanus) from Mendocino County in late May 2026.

 Happy Fourth of July! 

Cape Cod reflections

  

I was at a family wedding on Cape Cod recently (Congratulations, Katie & Aiden!), so here are a few quick shots from Massachusetts.

Above, Butterfly Weed (Asclepias tuberosa).

Next, sandbars and sky: 

 

 

And a sunrise, too:

 

 

 

New to the north?

  

Abby wrote to let us know she had observed an unusual flatworm on 17 June 2026.  Amazingly, we encountered what looks like the same species in a different location on 20 June 2026.  Both were found along the rocky shore in the low intertidal zone.

We think this is Stylochus franciscanus, although it's a new species for us, so we're open to feedback.

There are two flatworm species that apparently look similar but differ in subtle ways.  For example, Stylochus franciscanus has marginal eyes that only extend ~1/4 of the way along the perimeter of the body, while Stylochus californicus has marginal eyes that extend along the entire perimeter.  And the tentacles of Stylochus franciscanus are closer to the anterior margin vs. farther from the margin in Stylochus californicus.  See illustrations below (modified from Libbie Hyman's 1953 account of flatworms in California -- see a photo of Libbie in this post):

 

 

 

Because both of these flatworms are unusual in northern California, we documented this individual with a microscope video (below).

 

In the video clip, watch for several features: 

- an overall pattern of lighter and darker brown spots

- at 18-20 seconds, you can see the marginal eyes (tiny black dots) along the margins, but only at the anterior/head end

- at ~30 seconds, note the pair of transparent nuchal tentacles that are relatively close to the anterior margin

- at ~38-40 seconds, a head-on view shows the clusters of cerebral eyes (black dots) *within* the nuchal tentacles (!)

 

 

Stylochus franciscanus records primarily come from San Francisco Bay and the central and southern California coasts.  From what we can tell so far, these are the first records north of San Francisco (although we need to do additional research to confirm the distribution records).  

 

With many thanks to Abby for alerting us to the presence of this species in Marin County and to Eric for capturing and editing the video footage. 

P.S.  If you can't see the video player in the e-mail message, click on the title of the blog post to go to the NHBH website to see the video.

P.P.S.  Fun fact -- "franciscanus" in the species name likely refers to San Francisco Bay, as the first specimens used to describe the species were collected from locations within the Bay.

P.P.P.S.  If you happen to see this flatworm north of Bodega Bay, we'd love to hear about it/see photos!

P.P.P.P.S.  Happy summer!  :) 

Reading the shells?

  

While in Monterey last weekend, we were thinking about southern species that might become more common farther north if a major El Niño event arrives this fall/winter.  For fun, while walking the beach we gathered some shells and ended up with 11 of these species.  We used all of them to spell out El Niño in the photo above.

Three barnacles: Megabalanus tintinnabulum, Paraconcavus pacificus, Tetraclita rubescens

Six snails: Acanthinucella punctulata, Californiconus californicus, Hespererato vitellina, Atrimitra (formerly Mitra) idae, Pseudomelatoma torosa, Pseudopusula (formerly Trivia) californiana

Two limpets: Fissurella volcano, Lottia gigantea

You can click on the image above for a larger version, and here's an example with labels, a close-up of the "E":

 

 

 

P.S.  If you're interested, you can follow NOAA's El Niño predictions at this link (updated monthly). 

Love for the oceans

  

Seemed like this photo could be appropriate for World Oceans Day (8 June 2026).  

A heart from and for the ocean!

Here's the entire animal:

 

The heart shape surprised us, as the central opening on the underside of a sand dollar is usually circular.  But this skeleton broke in just the right way to create a perfect heart.  Pacific Sand Dollar (Dendraster excentricus) photographed in Marin County on 22 May 2026.

Sharing our thanks and love for all of the Earth's oceans. 

The colors of the sky...

  

...in a shell!  

Two close-ups of the inside of an abalone shell.  

I thought the first one (above) looked like an aurora, while the second (below) was more like a sunset.

[You can click on them for larger versions.] 

 

 

 

 Photographed in Monterey County on 6 June 2026.   

Flotilla

  

We were in Monterey yesterday (5 June 2026) for a concert, but we drove down early to spend a little time along the coast.  Here's a nice seascape including a flotilla of sea otters in the kelp offshore from Pacific Grove.  [You can click on the photo for a larger version.]

Yellow-bellied

  

A quick look at a Western Yellow-bellied Racer (Coluber constrictor mormon) this afternoon (3 June 2026)

With its head raised, the nice yellow color on the underside was easy to see:

 

 

Golden-edged and fine-lined

  

It's hard to believe that this striking flatworm remains undescribed.  Abby noticed it in the low intertidal zone last week and Eric was able to get some video for documentation (see video clip below).

This flatworm is listed in the Intertidal Invertebrates of California (Morris, Abbott, and Haderlie 1980) as Eurylepta sp.  They didn't include an actual photo, but instead represented this species with a painting.  The colors are a little different, but I think you'll see the resemblance:

 

Modified slightly from Morris, Abbott, and Haderlie (1980) 

 

There have been more recent discussions regarding whether this flatworm is in the genus Prostheceraeous, but at this time we can't locate a reference to cite for that, so we'll just say that it's in the Euryleptidae family.

 

There are only a few records of this species in Marin County, and none that we know of north of there.  Most observations are in the Monterey area and farther south. 

 

If you happen to see one, we'd love to see photos and to hear about other records. 

 

And now for the video!  Eric put together a few clips so you can appreciate the color pattern and the flowing movements of this flatworm.  [If you're reading this in an e-mail, click on the title of the post above to go directly to the NHBH website to see the video player.]

 

 

 

With many thanks to Abby for sharing her observation and to Eric for creating the video!

Rock star?

  

Whew, we were busy with field work during the low tides this past week, but we managed to take a few photos on the side.  

Here's one that Eric took in Mendocino County today (23 May 2026) -- a beautiful Daisy Brittlestar (Ophiopholis kennerlyi) on the underside of a rock with clusters of small tubeworms. 

Sky blue

  

Walking over to the farmers market this morning, I caught a glimpse of a dragonfly exploring the sun-exposed branches of a willow tree.  It disappeared, but when I turned the corner I started scanning up high, looking for potential sites where it could have landed.  I was about to give up, when my eyes caught the blue of the darner's eyes.

Blue-eyed Darner (Rhionaeschna multicolor) in Sebastopol on 17 May 2026. 

Beauty and the beast?

  

Coastal Bluff Morning-glory (Calystegia purpurata ssp. saxicola) and Poison Oak (Toxicodendron diversilobum), 14 May 2026 

Ocean art

  

 Early morning sand patterns in the swash zone, 6 May 2026

  

Blue on blue

  

Eric and I have been busy with lots of early morning field work recently.  As we were walking on a beach in Marin County this morning, I looked down to see a Blue Buoy Barnacle (Dosima fascicularis) attached to a By-the-wind Sailor (Velella velella).

Blue Buoy Barnacles are pelagic (offshore) barnacles that float at the surface of the ocean.  They are unusual in northern California and can be indicators of warm-water conditions, or water that's normally farther offshore coming closer to the coast.  I'll have to check my notes, but I think the last time we saw one in our area was ~10 years ago (back in 2016).

With the high numbers of Velella washing ashore at this time, the chances of finding Dosima are greater as this barnacle often attaches to Velella floats. 

We're interested in other observations of Blue Buoy Barnacles in northern California, so keep your eyes open and if you happen to come across one, I'd love to hear about it! 

P.S.  For an introduction to Blue Buoy Barnacles, see the post called "Blue buoys!" on 31 August 2014.  And more information (and a great video!) can be found in the post called "Driftin' blues" on 23 September 2014. 

On the move

  

A beautiful White Wagtail (Motacilla alba) was found near Gaffney Point in Bodega Harbor yesterday.  I took a short break from work and felt lucky to snap a few quick photos.  The wagtail was feeding along the shoreline, actively chasing after insects.

White Wagtails are accidental vagrants here.  It sounds like this is only the second record for Sonoma County, but feel free to correct me if I'm wrong about that.  

To learn more about White Wagtail records in California, you can check out the Rare Birds of California species account here. 

Color in the clouds

  

The rainbows continued today (22 April 2026).  Here's one that appeared high in the clouds over Sonoma Mountain at the end of the day.

Earth Day

  

Passing showers during the early morning of 21 April 2026 brought views of several rainbows.  Here's a quick shot to help celebrate Earth Day.

Remember to go outside today and send out thanks to the Earth.  As David Byrne says, "She's the only one we have."

Shiny and new

  

The beautiful wings of a California Darner (Rionaeschna californica).  Note how shiny and new they look.  [You can click on the image for a larger version.]  I could see this darner's wings glittering in the sun as it flew across a grassland.  When it landed nearby, I leaned in for a closer view.  Because the wings are so fresh, it's likely this individual metamorphosed recently.  Once a dragonfly has been flying for a while, the wings lose their shine and can show nicks and other impacts.

Colorful fans

  

Wow!  Eric took some striking photos of featherduster worms last weekend.  This is Serpula columbiana, a marine worm that lives in a white calcareous tube and uses its broad fan to filter food from the surrounding water.

The round, trumpet-like structure is an opercular plug.  When the fan is withdrawn into the tube, the plug seals the opening to protect the worm within.

I'm a big fan of these beautiful tubeworms, and Serpula columbiana comes in lots of different color forms, so here are two more examples:

 

 

 

 

 

Photographed in a large, fairly deep tidepool in the intertidal zone in Oregon.  Nicely done, Eric!

Sunset rainbow

  

After off and on rain showers for most of the day (12 April 2026), Eric spotted a brilliant rainbow to the southeast of Cotati at sunset. 

A dip in the creek?

  

We spent some time watching an American Dipper (Cinclus mexicanus) in a creek along the Oregon Coast today (5 April 2026).  I had trouble deciding which photos to share, so here are a few different views.  Enjoy!