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Tuesday, February 21, 2017

"Soft belly"

Here's a quick introduction to the Furry Crab (Hapalogaster cavicauda).  [The best part is the video at the end!]

This species reaches its northern range limit at Cape Mendocino.  We haven't encountered it very often in northern California, but we photographed two individuals on 12 February 2017.

In all of these photos, look for the short, dense setae (hair-like bristles) covering the carapace and claws that give this crab its common name.  In the photo above, note the very broad abdomen curled under the body.  Although you can't tell from these pictures, the abdomen on Furry Crabs is very soft.  It's quite noticeable when you hold these crabs.  Fun fact: Their scientific name "Hapalogaster" — means "soft belly."

Here's a good view of the dense setae on the claws:

Here's a juvenile (and a slightly better view of the abdomen, curled under the body between the last pair of walking legs):

Eric put together a great video clip of Hapalogaster.  Watch for a few different things views of the dense setae; a close-up of the eyes; and some bryozoan "friends" living on one of its claws!  [If you can't see the video below, click on the title of this post to go to the web page.]


Monday, February 20, 2017

Off the top

A few wave images from 20 February 2017.  Swell heights were ~12 feet.  Winds were from the south at ~15-20 knots, creating good conditions for spindrift blowing back off the tops of the waves.  [Click on the images for larger versions.]

Sunday, February 19, 2017

Foamy photos

A few foamy photos from yesterday (18 February 2017).  It was windy enough that large pieces of foam were becoming airborne:

Can you find the "foam elephant" in the photo below?  :) 

As you can probably tell, many of these pieces were much larger than snowflakes:

Sometimes the foam was lifted high into the sky who knows how far it traveled? 

P.S.  One of the dangers of trying to take pictures of flying foam is that sometimes your camera (or your face) is in the direct line of flight!  It's a funny experience because it's a bit scary to realize that a large flying object is headed towards you, but then you remember it's just foam, and you feel a gentle but noticeable "thwap"and then the clump of bubbles breaks apart upon contact.

Saturday, February 18, 2017

Northwest winds

If felt like spring today, with strong 20-25 knot northwest winds.

I'm guessing the swell was ~12-14 feet when I took this picture ~mid-day today (18 February 2017).

Thursday, February 16, 2017

Pelagic Red Crab zoea!

Okay, here we go the answer to last night's mystery photo.  As a reminder, here's the image:

We received several correct guesses.  This is the zoea (free-swimming larval stage) of a Pelagic Red Crab (Pleuroncodes planipes)!  The photo below shows the entire zoea:

We haven't been able to find many pictures of Pelagic Red Crab larvae, so we thought it would be fun to share a few.  Eric also recorded some video (see below)!

Here's the basic sequence of events:

After finding live Pelagic Red Crabs on 24 January 2017, I was measuring them and counting the number of males and females.  I discovered that several of the females were carrying eggs.  Similar to lobsters, they brood their eggs attached to the underside of the abdomen (see below):

We wondered if the embryos would develop in Northern California waters.  Based on a previous study that found they did well at 12°C, it seemed like they should develop and hatch in ~22 days.

Right on schedule, the embryos hatched today (after a minimum of 22 days)!  This is what we saw when we came into the lab this morning — an adult female surrounded by hundreds of larvae, each ~2 mm long:

And here's a close-up of some of the larvae in the jar:

Carl Boyd described the larval stages of Pelagic Red Crabs in 1960.  This drawing shows the first zoea:
Modified from Boyd, C.M.  1960.  The larval stages of Pleuroncodes planipes Stimpson (Crustacea, Decapoda, Galatheidae).  Biological Bulletin 118: 17-30.

And here's a close-up of a zoea in a similar position (shown in dorsal view, from above):

As mentioned, Eric took advantage of a rare opportunity to film some live Pelagic Red Crab larvae.  You'll see the very active newly-hatched zoeae zipping around.  (Among the swimming sequences and close-ups, watch for the rapidly beating heart.)  Note: If you receive this via e-mail and can't see the video file below, click on the title of the post above to go directly to the web site.

I can't help showing a couple more pictures — two extreme close-ups.  Check out the beautiful telson (last abdominal segment or "tail")...

...and the wonderful second antenna (the outermost antenna, adjacent to the eye):


We feel very fortunate to have observed and photographed these fascinating larvae.  We hope you enjoy them, too!

Wednesday, February 15, 2017

Guess who?

Time for a close-up mystery photo!  

Do you have ideas about what type of organism this is?  

[I'll reveal the answer tomorrow night.]

Tuesday, February 14, 2017

Sunrise in the western sky

The moon in the western sky at sunrise, as seen from Cotati on 14 February 2017.