Once in a...

  

...blue supermoon (Caerulea grandeluna)  ;)

Photographed from Cotati on 30 August 2023.

Staying close with your sibling

Okay, last night I mentioned there was more to the River Otter story.  A couple of days after I had noticed the mother with an injury, I was doing an unrelated survey and spotted one of the pups.  I was curious about whether the mom was alright, so I decided to watch for a little while to see if she showed up.

I stayed out of sight, and didn't know it at the time, but it was time for the otter pup to take a "gravel bath" and then a nap.  I've seen this behavior before (but not very often) and it's fun to watch — lots of rolling around and sliding through a patch of sand and gravel:

 

 

 

Afterwards the pup found a sheltered spot and curled up for a nap.  A little bit later, out of the corner of my eye I noticed the second pup approaching from a distance.  Here's a photo when it got closer to the first pup:

 

 

 

 

Over the years I've learned that young River Otters like to be close to each other, and the next scene made me laugh.  The second otter didn't lie down right next the first, it walked up on top of its sibling and sat down.  Ooof!

 

 

 

Later it shifted slightly and did some grooming:

 

 

 

Well, I'm sure you're wondering if mom showed up.  I didn't see her during this initial observation, but I swung by one more time later in the day and briefly spotted her in the distance.  And then about a week or so later I heard about another sighting of her and the two pups.  So far it seems like she is doing okay and raising healthy pups despite her injury.

Ouch

  

This is a follow-up to my last post on River Otters...and a bit of a puzzle.  I had to sort through some photos, but when I was looking at some of them I realized the mother otter had a fairly serious injury.  In the photo above, you can see several oblong lacerations in a row, and I think there was at least 1-2 more of those on her rump and near the base of the tail.  You can also see another larger laceration closer to her mid-section (in front of her hind leg).  

I'm not sure what caused these injuries, but my first thought was wondering whether it could have been a shark.  Researchers at UC Santa Cruz have documented an increase in sea otters with shark wounds (and years ago I found one sea otter on a local beach that had been bitten by a shark), but I haven't heard about shark bites and River Otters.  Have you?  Or can you think of other possible causes for this type of injury?  I'd be interested in any feedback.

If you are concerned about the otter, I'll note that she appeared to be active — swimming and catching fish (for herself and her pups) despite the injury.  And I also saw her the next day (more parts of this story to come!).

Washing up

 

 

With ocean temperatures quite warm recently (in the 17-18°C or 62-64°F range) and with El Niño conditions present in the Pacific Ocean, we're keeping an eye out for more southern/warm-water species.

 

Above is a piece of a Purple-striped Jelly (Chrysaora colorata) that we encountered at Limantour Beach on 26 August 2023.  (To see an entire individual, see the post called "Southern drifter?" on 27 July 2014.

We also came across this wooden pallet covered with pelagic gooseneck barnacles (Lepas sp.).  These barnacles aren't necessarily associated with warm water, but they are typically found offshore, so seeing them on the beach indicates that offshore species are appearing closer to the coast.

 

 

 

 

 

Soaking up the Reyes?

 

 

I was admiring the nice scales and color pattern on this Western Fence Lizard (Scleropus occidentalis) today while it was basking at Point Reyes, so now I'm passing along a close-up to you!  Photographed on 26 August 2023.

A bigger anchor

 

 

I was leading a walk about seaweeds today and we encountered a few of these Bull Kelp (Nereocystis luetkeana) holdfasts attached to small rocks.  The rocks likely served as anchors when the kelp was small, but once they grew larger these rocks just weren't heavy enough to keep the kelp in place.

 

 

 

Fun to see the little kelp "feet," but maybe next time the microscopic stage of the kelp will find a larger rock.  You know the famous quote, "You're gonna need a bigger boat anchor."  ;)

Blondie

  

During a field trip to Tomales Bay on 17 August 2023, Melissa spotted this small yellowish-green sea hare crawling on some eelgrass (Zostera marina).  At first I wasn't sure about the identity of this sea hare, but after looking more closely I believe it's a Hedgpeth's Sea Hare (Elysia hedgpethi).  (Those small bright blue spots helped with the i.d.)

I've mostly encountered this species on rocky shores where they are a deep green color (see "Not a flatworm!" on 25 June 2013 and "Magic cape" on 17 August 2022).  So the paler "blonde" color was confusing until I read that this species can be yellowish or brownish, too.  Is the color driven by what they are eating?  Or related to the condition of the chloroplasts they ingest?

Eric was able to get a few nice video clips, too, so check out the video below.  Watch for the rolled rhinophores, the two dark eye spots behind the rhinophores, the wide flaps held upright on either side of the body, and the scattered blue spots.  [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.]

Many thanks to Melissa for spotting this sea hare and to Eric for putting together the video!

Outer bands?

 

 

Interesting clouds to the east of Cotati last night (21 August 2023) at sunset.  I think these might have been some of the outer bands of tropical storm Hilary (or at least storm-influenced).

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!

Summer nap

 

 

Mom and pup River Otters (Lontra canadensis) resting in the intertidal zone on 19 August 2023.  You could tell mom was tired — she kept nodding off while the pup was fishing and returning to check in with her.  And then the pup curled up for a nap (that's mom's tail that the pup is resting its chin on).

 

Into the night

  

I know I showed a White-lined Sphinx Moth (Hyles lineata) photo not too long ago (see "Lined up" on 13 August 2023), but that one had washed up on the beach and tonight we had a beautiful moth fly into our house.  Eric caught it and when we went to release it outside it sat on his fingers for a couple of minutes.

I haven't worked with sphinx moths up close, so it was interesting to see their antennae.  Above you can see that the antennae taper towards the outer tips and then are hooked at the very end.  And in the photo below you can see that the antennae are lamellate on the ventral side, with lots of fine divisions:

 

 

This one flew off into the night, but now I want to see another one up close!  Photographed in Cotati on 18 August 2023.

Nectaring at the coast

 

 

Air temperatures reached ~65°F (~18°C) on Bodega Head today.  There was lots of insect activity, including quite a few Painted Lady butterflies (Vanessa cardui) — some nectaring on Coyote Brush (Baccharis pilularis) as in the photo above, others on Seaside Daisy (Erigeron glaucus).

Before the split

  

Always fun to see juvenile Bull Kelp (Nereocystis luetkeana).  This one was photographed a few days ago on 12 August 2023.  The blades haven't quite split apart yet, but you can see where that will happen.

Nestled among the branchlets

 

 

We looked down to see this interesting seaweed on the beach today — Cumagloia andersonii.  It usually doesn't have little white specks on it, so we took a closer look.  Below you can see a hint of what's attached to it:

 

 

These are juvenile pelagic gooseneck barnacles (Lepas sp.).  That means it's likely the seaweed has been drifting offshore for a while (long enough for planktonic barnacles to find it, settle, and start to grow).  Although we often see Lepas attached to drift kelp, I couldn't recall seeing Lepas on Cumagloia before, so took a few documentary photos.  

 

Here's an even closer photo where you can see the barnacles nestled among the branchlets of the seaweed:

 

 

P.S.  Ocean temperatures off Bodega Head have been quite warm this week — up to ~16°C or >60°F.  It'll be interesting to keep an eye on these temperatures during the next couple of months.

Lined up

  

I'm guessing some of you have been seeing these moths recently, perhaps visiting flowers in your yard?  This is a White-lined Sphinx Moth (Hyles lineata).

I've received several reports and questions about them, and yesterday I noticed this one washed up in the wrack line on the beach.  (Sometimes that happens to insects — my guess is that they're dispersing but then end up too far out to sea and wash up with the drift.)

This moth was still alive — here it is crawling on my hand:

 

 

You can see that this is a medium-sized moth — with a wingspan of ~3.5" (~9 cm) across.  That's smaller than the larger silk moths, but larger than many other moth species.  Because White-lined Sphinx Moths hover at flowers for nectar, they can be mistaken for hummingbirds from a distance.  [Anna's Hummingbirds have a wingspan of ~4.5" (~10 cm).]

Here's another quick photo for scale: