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Sunday, September 24, 2017

Neighborhood kites

Lots of chores today, so not much time for pictures.  But here are a couple of kite photos from the past week.

Circling overhead on the way to the roost site:

Gathering in one of the tallest trees on our streetHow many kites can you find?  (Hint: Some are on the far side of the tree.)  Click on the photo for a larger version:

I'm sure about 8 kites, and there might be 9 (see below):

Saturday, September 23, 2017

One cell at at time

Several days ago, Peter was showing me some algae that he had collected on the tidal flats in Bodega Harbor.  When he picked it up, a small nudibranch-like animal was left behind in the tray.  I was intrigued because it didn't look familiar to me.  

When we looked at the animal under the scope, we realized that it wasn't a nudibranch, but a sacoglossana group that is sometimes known as "sap-sucking sea slugs."  From the name, perhaps you can guess that sacoglossans eat algae.

Here's one of the first views we had.  Note the small, black eyes and the large, rolled rhinophores above the eyes:

There are many projections called cerata on the backcylindrical, greenish, with scattered gray flecks and white tips:

On the underside, you can see a smooth muscular foot with irregular black splotches (creating a marbled pattern):

Meet Aplysiopsis enteromorphae!

While we watched, the most striking thing about this species was its feeding behavior.

Aplysiopsis enteromorphae is known to feed on only a few species of seaweeds.  (This individual was feeding on Chaetomorpha.)  The feeding behavior was described originally by Gonor (1961).  The slug grasps the algal filament with the front of its foot and a pair of oral lobes (see diagram below).  It slices open an algal cell with a single row of teeth on its radula, sucks out the contents, and then repeats this process along the filament.  After the filament passes by the mouth, it's easy to see the now-empty algal cells! 

Modified from Gonor, J.J.  1961.  Observations on the biology of Hermaeina smithi, a sacoglossan opisthobranch from the West Coast of North America.  Veliger 4: 85-98.

 This is exactly what we saw:

Here's an even closer view.  Look for the solid green algal strand in front of the mouth (at the bottom of the photo), and the nearly-clear algal strand after it leaves the mouth and passes along the foot.  The eaten portion of the strand is a little hard to see because it's almost transparent, but there are a few green cells left:

We were curious about whether you could see the slits in the algal cells.  We couldn't with our eyes alone, so we put a strand under a compound microscope (200x magnification), and voilà!  Below, the arrows are pointing to two of the slits:

Eric was able to capture a few seconds of feeding behavior on video.  Watch carefully as the slug moves along the single strand of Chaetomorpha — grasping, slitting, and sucking out the contents.

Thursday, September 21, 2017

Crescent before the fall

Crescent moon photographed near moonset on 21 September 2017

 (just before the autumn equinox on 22 September 2017)

Happy Fall !

Wednesday, September 20, 2017

7:18 p.m.

Sunset from Cotati, 20 September 2017 

Tuesday, September 19, 2017


Spiny Lobster (Panulirus interruptus) molt, washed up on Bodega Head, 19 September 2017

Although we had wondered if we'd ever find a Spiny Lobster in Bodega Bay, we were surprised to look down and see this on the beach tonight.

Spiny Lobster are a southern species they are primarily found south of Point Conception, and they're most abundant off the central coast of Baja California, Mexico.  During El Niño years, they may be observed north to Monterey.  Since about 2011, molts have been discovered occasionally in San Francisco (Crissy Field) and Bolinas (Agate Beach).

There is a 2001 record for a post-larval stage Spiny Lobster in Bodega Harbor, but to our knowledge, this is the first record of an adult Spiny Lobster molt in Bodega Bay, and therefore the northernmost record for a Spiny Lobster molt on the West Coast!

Spiny Lobsters can reach a carapace length of ~44 mm in 2 years.  The molt we found was missing the carapace, but we can still come up with an estimate — see photo with ruler below:

Here's some rough, but interesting guesswork.  The carapace on this individual might have been ~50 mm long...which is a potential match for a 3-year old lobster...which is a potential match for a lobster that settled in northern California during the warm-water anomaly ("The Blob") in 2014.  We have some research to do on these measurements, but it's interesting to think about when the lobsters might have arrived on our coast.

We'd be very interested in any other sightings of Spiny Lobster molts from Point Reyes north, so let us know if you spot any washed up on the beach (and please take a photo)!

P.S.  I was curious about the scientific name.  The specific epithet "interruptus" comes from the interrupted groove on each abdominal segment.  Below, note the gap (white arrow) separating the grooves that run through the middle of each abdominal segment:

Monday, September 18, 2017

Mid-September reflections

Red-necked Phalarope (Phalaropus lobatus), feeding in a salt marsh pool along the edge of Bodega Harbor on 18 September 2017.

Sunday, September 17, 2017

Kites at sunset

Not much time tonight, but here are a few more pictures of White-tailed Kites just before heading to a roost site for the night on 17 September 2017.  (Click on the images for larger versions.)

A beautiful immature bird, with rusty coloration on the breast, white-edged feathers behind the "black shoulder", and gray at the back of the head.  (The eyes are also darker than those of an adult.)

Below, the immature kite turns to watch another individual trying to land nearby This is a good look at the underwing pattern (and the tail feathers being molted note the different lengths of the feathers).

A kite soaring overhead with just a hint of the setting sun: