Tidepooling at 66° North

During our first few days in Iceland, we were fortunate to find some excellent tidepooling locations.  We've been taking lots of photographs, but it's hard to find time at the end of the day to write a complete post , so I'm sharing a few fun highlights for now.

 

 

Silver-spotted Anemone (Aulactinia stella)

 

 

 

 

Northern Red Chiton (Boreochiton ruber) 

 

 

 

  

A small staurozoan (Haliclystis sp.).  This stalked jellyfish was very active so the image is a little blurry, but we were excited to find a couple of them! 

 

 

 

  

A striking Daisy Brittle Star (Ophiopholis aculeata).  We found quite a few individuals all with different color patterns.

 

We've been impressed with the diversity of marine invertebrates in the tidepools in Iceland and feel fortunate to be exploring and learning more about them.  We hope you enjoy meeting them, too!

Blue-rayed

A beautiful limpet…from Iceland!  Meet the Blue-rayed Limpet (Patella pellucida).  We’ve done some tidepooling around Reykjavik during the last couple of days and this is a species I hoped to see.  Lots of other amazing marine invertebrates to share, so stay tuned!

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). 

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!

Plume de mer?

  

Close-up of the gill plume of the nudibranch sometimes known as a Sea Lemon (Peltodoris nobilis).  Note the extensive branching to increase surface area for respiration.

Evidence suggests that nudibranchs evolved from gastropod ancestors that lost their coiled shell and original internal gills.  Dorid nudibranchs like this one secondarily evolved an external gill plume for respiration.
 

Hidden talent

  

Eric was doing some field work tonight (17 January 2026), but on the side he ended up with several great shots of an intriguing Red Octopus (Octopus rubescens).  

Above, note how well the octopus blends in with the background, matching the surrounding colors and textures. 

Below, a closer view from the side next to the sea anemone:

 

 

 

And a zoomed in view, highlighting that beautiful eye:

 

 

 

 

When the octopus changed position, it changed color and texture, this time matching some of the surrounding seaweeds and nearby animals.  And check out how it matched the color of the sponge in the upper right corner of the photo — the suckers are the same deep orange color as the sponge!

 

 

 

P.S.  With thanks to the octopus and to Eric for the great photos! 

Shuttle service

 

 

We were working along the Bodega Harbor shoreline a couple of days ago when I noticed some movement out of the corner of my eye.  

Octopus!  

It was very high above the waterline, so Eric decided to pick it up and help it get closer to the water.

Two more views, including a close-up of the eye: 

 

I know most of 2026 is the Year of the Horse, but wouldn't it be fun if there was a Year of the Octopus?

 

Tripping the light fantastic

  

During a walk at Dillon Beach on 27 December 2025, we came across several large masses of egg capsules.

Here's a photo in Eric's hand for scale: 

 

 

These are egg capsules of the Opalescent Inshore Squid (Doryteuthis opalescens).  When you look at the capsules up close, if the embryos are far enough along in their development, you can see tiny squid inside.  Look especially for the two large eyes.  Each compartment holds one squid (so an individual egg capsule can hold 50 or more developing embryos):

 

 

 

Development time is dependent on water temperature, but it can take 6-10 weeks for the little squid to hatch out in cooler temperatures. 

 

One of the egg capsules (above) appeared to have mature squid larvae that looked like they'd be ready to hatch soon.  We put the capsule into a large ziploc bag with seawater and what do you know, about an hour later, tiny (~3 mm long) squid larvae had emerged from the capsule and were swimming around.

 

Eric was able to capture some amazing video of the squid larvae and their beautiful chromatophores under a microscope (see below).  [If you can't see the video player in your e-mail, click on the title of this post above to go directly to the NHBH website to watch the video.]  It's fascinating to see the pulsing chromatophores in action.

 

We thought you might enjoy a little light show to ring in the New Year!

 

Best wishes for 2026! 

 

P.S.  For more information about how chromatophores work in squid and octopus, check out this "Hide and seek" video that Eric made in 2021.

 

Curiosity

  

Eye of an octopus 

Are you interested in the diversity of local marine invertebrates?  

If so, Eric is going to be giving a talk in the Science Uncorked series on Wednesday, October 1.

Come hear about "Spineless wonders: Exploring the tidepool animals of Bodega Bay" at Gourmet Au Bay in Bodega Bay at 6 p.m.

More info is available here.

Layers

   

Close-up of a Red Abalone (Haliotus rufescens) shell, 9 September 2025

ADDENDUM (12 September 2025): There were a couple of requests to show more of the abalone shell.  In this case, the original photo was just a section of the rim of a shell, but here's the photo without any cropping:

 

  

P.S.  Note that I've found that the lighting matters a lot when photographing abalone iridescence.  Overcast days bring out the colors the most. 

A clam like no other

 

 

I looked down to see this distinctive shell washed up at Point Reyes this past weekend (23 August 2025).  Note the elongate shape and the fine ridges radiating from the hinge (the hinge is at the bottom of the photo).

 

I posted briefly about this species back in 2015 (See "File this away" on 28 June 2015), but it's rare to observe Hemphill's File Clam (Limaria hemphilli) in our region, so I thought it would be worth sharing another record.  Limaria hemphilli has a more southern distribution, with most records south of Point Conception (and only a few records north of Monterey).

 

I also remembered that Sam documented a file clam in Bodega Harbor in 2024.  He was lucky to find a live individual and he captured the beautiful and intriguing tentacles.  Check it out!

 

 

 

 

Here's an even closer view of those amazing tentacles:

 

 

 

The tentacles are extensible -- they can stretch out far away from the shell.  And interestingly, there are reports of predators being distracted by tentacles that have been dropped, so at times the tentacles might be used to deter predation (somewhat similar to a lizard's tail).

 

With many thanks to Eric for the photo of the shell and to Sam Briggs for the spectacular photo of the live file clam. 

Breathe in, breathe out

  

An unexpected surprise this morning (11 July 2025), a beautiful octopus in the low intertidal zone.  I only had a minute or two before it continued on, but it was a magical minute!

I managed a short video clip (see below, or click on the title of the post above to go to the NHBH web page to see the video player).  The octopus is drawing water into its mantle cavity (where it will then pass over the gills) and expelling water through its siphon.

Many thanks to Eric for editing the video clip!

Flecktones?

  

A nice little chiton for you — a juvenile Lepidozona radians.

Photographed in the low intertidal zone on 29 June 2025.
 

Special find

  

Summer classes started at the Bodega Marine Laboratory this week, and with all of those keen eyes around, special things are bound to be found!  

Above, a small Red Octopus (Octopus rubescens) discovered this morning.

Thanks to James for spotting the octopus, which was observed for a short time in the field and then released. 

A hat trick?

  

We were focused on other species while doing surveys along the coast in Mendocino County last weekend, but along the way Eric spotted several nice chitons.  Above, meet Tripoplax regularis.  (Also refer to the post called "The original sequins" on 26 February 2017.)

Below, this looks like a species of Mopalia, but we're not sure which one.  We wondered about Mopalia imporcata, a species we're not familiar with.  If anyone has thoughts about the identity of this chiton, we'd be interested!

 

 

 

And, one that was fun for us —  a juvenile Katharina tunicata.  This individual was only ~1.5-2 cm long.  Katharina has become less common in the Bodega Bay area, so it's encouraging to see a young one starting out:

 

 

 

A wonderful trio, Eric!

The color purple

  

Eric spotted this beautiful Striped Dogwhelk (Nucella ostrina) yesterday (2 May 2025).  This is a common snail in the rocky intertidal zone in northern California, but we can't recall seeing purple variants of Nucella ostrina, so here's a photo for the record.

More often, Striped Dogwhelks are versions of black, brown, gray, or white.  Here are some individuals feeding on barnacles:

 

 

 

Occasionally you'll spot an orange Nucella ostrina —they really stand out! 

 

 

Breeding experiments suggest that color variation in Nucella ostrina likely has a genetic basis (Palmer 1984).

Just in time for Easter -- lots of eggs!

  

We went out to the rocky shore early this morning to start some surveys.  Right away Eric noticed that the tidepools looked unusual.  All of them appeared cloudy or milky.  We were aware recent ocean conditions might trigger spawning in some marine invertebrates, and sure enough, this was a massive spawning event of California Mussels (Mytilus californianus), probably the largest we've encountered.

In the photo above, the orange coloration is eggs released by female mussels.  Here's another example, with clusters of eggs concentrated along the edge of a pool:

 

 

In other pools, the color was white or gray, clouded by vast quantities of sperm released by male mussels:

 

 

Nearly every tidepool we observed on Bodega Head appeared to have mussels spawning, so the extent of this synchronous mass spawning event was truly remarkable.  Even the largest pools were visibly cloudy:

 

 

 

The ocean temperature went up from 11°C (52°F) to 13°C (55°F) yesterday, and there was a phytoplankton bloom nearshore — both environmental cues that are thought to trigger spawning in some invertebrates.

Amazing!  Let us know (and send photos) if you notice local marine invertebrates spawning, too!

Gold stripes and gold flecks

  

Beautiful gold-flecked hermit crab in a Three-colored Top Snail (Calliostoma tricolor) shell.  Photographed on 28 January 2025.

On the move

  

 

Eric photographed this beautiful Opalescent Nudibranch (Hermissenda opalescens) wandering through a world of pastel colors on 29 January 2025. 

 

In the background: the pale pink is a crustose coralline algae, the bright pink is a Derby Hat Bryozoan (Integripelta bilabiata), and the peach is another species of bryozoan (unidentified species).

Dusky?

  

Dusky Tegula (Tegula pulligo), a beautiful snail in the low intertidal zone, photographed on 29 January 2025.

P.S.  In this case, I'm not sure about the name "dusky" -- how about pearlescent lavender?  :)