Peeking out

  

A beautiful view of the tentacles of an Orange Sea Cucumber (Cucumaria miniata).  You can also see a few of the cucumber's tubefeet closer to the rock.  Photo from Del Norte County in California on 4 April 2026.

With thanks to Eric for a great photo! 

September star

  

Nice view of a Forbes' Sea Star (Asterias forbesi) in a shallow tidepool in Scituate, Massachusetts, on 20 September 2025.

Eric was able to zoom in for an amazing closeup, too:

 

 

Visible above are short white calcareous spines, the orange madreporite (sometimes called a sieve plate, which is an opening to the water vascular system), and the transparent papulae (finger-like projections involved in gas exchange).  

Thanks for the great photos, Eric!
 

Blue background

  

Last week I came across an Ochre Sea Star (Pisaster ochraceus) that was noticeably blue.  It's a little hard to tell from the photo above, but hopefully you can see the blueish background coloration among the clusters of white spines.

We've been monitoring Pisaster for over a decade and have observed thousands of individuals during that time, but I can't recall seeing a blue adult sea star until now.  The most common colors are orange, brown, and purple, but this blue individual seemed unusual, so I took a quick photo for the record.

That said, we often see juveniles with blueish coloration — see photos below from this past winter:

 

 

 

I've often wondered if the blue juveniles gradually turn purple, and perhaps some do, but the blue adult in the first photo shows that sometimes the adults can be blue, too! 

Little one

  

A tiny Six-armed Sea Star (Leptasterias sp.) photographed in Mendocino County on 31 May 2025.  This juvenile sea star was only ~3-4 mm across from arm tip to arm tip.  

If you look carefully, you can see some of its tube feet extending away from its arms.  And the small red eye spots at the tips of the three arms in the foreground are also visible. 

Rather than releasing eggs into the water column, Leptasterias broods its embryos and the young sea stars crawl away from the adult.  Back in 2012, I shared photos of an adult Leptasterias with its brood of embryos and an image of an adult with many juveniles in the surrounding area (it's likely the juveniles recently crawled away from the adult).  To review those photos, check out the post called "Four brooders in one" on 29 February 2012.

P.S.  Thanks for the great photo, Eric! 

Upcoming

  

For all of the marine invertebrate enthusiasts out there — I wanted to mention that Eric will be presenting a webinar for Bay Nature magazine this week on Wednesday, Feb. 5, from 12-1 p.m. PST.  He'll be discussing the local diversity of marine invertebrates and some new discoveries, accompanied by lots of great photos and videos!

If you're interested in checking it out, you can register to join the talk online here.

P.S.  This is a Dwarf Brittle Star (Amphipholis squamata) photographed on Bodega Head last week.

Glass-spined

  

Glass-spined Brittle Star (Ophiothrix spiculata) photographed in Bodega Bay on 27 January 2025.

Twinkle, twinkle

  

Juvenile Short-spined Sea Star (Pisaster brevispinus) photographed in late December 2024.  This individual was only ~20 mm across (arm tip to arm tip).

Time for owls

  

Some of you might remember that I sometimes see owls in pieces of sea urchin test.  Here's one perched on a branch of coralline algae.  :)  From 8 June 2024.  Do you see an owl, too?

P.S.  For more "urchin owls," see the post called "Duetting" on 11 March 2013.

New Year's Eve ball drop?

  

Very young Red Sea Urchin (Mesocentrotus franciscanus), about 8 mm across, on 31 December 2024.  Best wishes for 2025!

Winter star

  

Juvenile Ochre Sea Star (Pisaster ochraceus), about 6 mm across, on 30 December 2024

A hint of orange

  

An interesting find today (27 June 2024) -- Pachythyone rubra, a more southern sea cucumber that's more common south of Monterey.  It's been documented in Bodega Bay previously, but only a couple of times.  Note that hints of orange color at either end of the cucumber, and the tubefeet that are scattered across the body rather than in regular rows.

To learn more about Pachythyone rubra, check out the previous post called "Goodbye, Rubra Tuesday" on 5 March 2018.

P.S.  If you happen to come across this species in Sonoma County or farther north, I'd love to hear about it.

18!

  

Okay, how many arms on the Six-armed Sea Star above? 

And how many arms on this greenish Six-armed Sea Star? 

And how many arms on this Six-armed Sea Star that's having a tube foot party?

Add then all together -- how many arms total on all three of these Six-armed Sea Stars?

Yes!  18!  (Okay, most of you know I'm a Boston sports fan...and I can't help but post a big congratulations to the Boston Celtics for winning the 2024 Championship and their 18th Championship Banner!  That was an amazing season, Celtics!  Woohoo!)

Role model?

  

Two Henricia pumila sea stars in a shallow pool in the low intertidal zone.  The one on the left is likely older than the one on the right, but growth rates in juvenile sea stars are highly variable, so it's hard to say for sure without knowing more about these individuals.  Photographed in Mendocino County on 9 June 2024.

Pool of light

  

 Morning light in a tidepool with sea urchins (purple) and sea anemones (green).

Lots of loli!

  

We saw at least 10 species of loli, or sea cucumbers, while snorkeling in Hawai'i.  Eric made this great mosaic before we saw the 10th, so above you can compare 9 different species!  [You can click on the image for a larger version.]

Top left: loli, or White-spotted Sea Cucumber (Actinopyga varians)
Top center: loli, or Teated Sea Cucumber (Holothuria whitmaei)
Top right: kohe lelewa, or Sand Sea Cucumber (Holothuria arenicola)

Middle left:  loli, or Difficult Sea Cucumber (Holothuria difficilis)
Middle center: loli okuhi kuhi, or Black Sea Cucumber (Holothuria atra)
Middle right: loli koko, or Impatient Sea Cucumber (Holothuria impatiens)

Bottom left: weli, or Conspicuous Sea Cucumber (Opheodesoma spectabilis)
Bottom center: weli, or Tahitian Sea Cucumber (Euapta tahitiensis)
Bottom right: loli, or Light-spotted Sea Cucumber (Holothuria hilla)

And the 10th (not pictured) was a loli ka'e, or Stubborn Sea Cucumber (Holothuria pervicax).

Fun to see so many different species of loli!

ha`uku`uku`ula`ula and unauna

Two fun invertebrates found snorkeling in Poipu today (3 April 2024).  

Above, meet ha`uku`uku`ula`ula, or Red Slate Pencil Urchin (Heterocentrotus mamillatus).

Below, check out this tiger-striped crab — a Cone Shell Hermit Crab (Ciliopagurus strigatus).  (The general Hawaiian name for hermit crab is unauna.)

Fun fact — Eric learned that this crab’s flattened body and legs allow it to live within the shells of cone snails (Conus spp.), which are rarely used by other hermit crab species.

We have been feeling very lucky to spend a little time learning about these amazing animals.

Mahalo to Eric for the great photos!

Pinky

  

Okay, this isn't a recent photo, but I've been busy working on a presentation about sea stars...so here you go!  A young Short-spined Sea Star (Pisaster brevispinus), photographed on 23 May 2015.

Mine!

 

 

We've been busy with sea star surveys this week, but I couldn't help taking a quick photo of these two Western Gulls (Larus occidentalis) fighting over an Ochre Sea Star (Pisaster ochraceus).  

 

The gull on the left was trying to swallow the sea star when gull on the right flew in and started pulling on one of the sea star's rays.  (If you're wondering, the second gull was eventually successful at pulling the sea star away from the first.)

A profound change

  

For Eric’s class this summer, he raised the early life stages (larvae) of the Bat Star (Patiria miniata).  Eggs and sperm from spawning can be mixed in the laboratory to produce fertilized embryos.  Like many marine invertebrates, the fertilized embryos of sea stars develop into a swimming larval stage that looks very different from the adult form.  The photo above shows the larval stage (called a brachiolaria) of the Bat Star about 25 days after fertilization.  This stage uses cilia to swim through the water as it feeds on phytoplankton. 

By about 45 days after fertilization, the juvenile sea star is starting to form at the base of the larval body.  In the photo below, the golden-white dome-like section is the developing juvenile body (called the juvenile rudiment), which is already forming its skeleton (made of shiny calcareous plates called ossicles) and its tube feet (that it will use to crawl on the bottom).  

 

At this point, the larva is ready to make its way back to the rocky shore where it will attach and metamorphose into a juvenile sea star!  Metamorphosis requires profound changes, as the larval arms and larval body (transparent structures in image above) are completely reabsorbed into the juvenile body.

Now for the best part.  Eric was able to capture some microscope video of the bat stars over the course of their development!  In the video below you will see the larvae swimming about at ~25 days (where the pink structure is their stomach), and at ~45 days (with the developing juvenile body clearly visible).  In the final video clips from about 50 days, you will see the metamorphosed juveniles walking along the bottom using their first tube feet.  These new juveniles are very tiny (< 0.5 mm across)!

[If you can't see the video player in your e-mail, click on the title of the post above to watch the video on the NHBH website.]

You can read more about this amazing process of development in Bat Stars in some previous posts, "A new star(t)" on 12 August 2013 and "First steps" on 8 August 2017.

P.S.  Many thanks to Ellie and Christina for spawning the Bat Stars, and to Eric for the great video!

Mottled

  

Whew, we've had a busy week of field work during early morning low tides.  At the end of our surveys today in Mendocino County, Eric photographed this wonderful Six-armed Sea Star (Leptasterias sp.).  Thanks, Eric!