Spiny goddess of the sea

 

Wine-plume Dorid (Acanthodoris nanaimoensis)

This nudibranch was photographed on Bodega Head on 7 July 2012.  Note the white/gray background color, the yellow-tipped papillae, and the red (wine-colored) rhinophores and margins of the gill plume.

Here's a view head-on where you can also see the narrow yellow margin.

 

The rhinophores are chemosensory organs (rhinophore means "bearing a nose").  To increase the surface area for smelling, the rhinophores often have additional folds or lamellae (see close-up below).

 

This species has been reported eating bryozoans and compound ascidians (tunicates).  In the first photo above, there are bryozoans on the rock to the right of the nudibranch (they look a bit like lace), but I don't know if the nudibranch was eating them.

The genus, Acanthodoris, means "spiny goddess of the sea", and refers to the spiny-looking papillae covering the body surface (see below).

Keep your eyes open for this beauty when tidepooling along the rocky outer coast!

Eye colors

Can you guess whose eye this is?

 

Northern Clingfish (Gobiesox maeandricus)

  

Clingfish have an adhesive disc between their pelvic fins that allows them to cling tightly to the undersides of rocks.

 

I could get lost in the colors of these fish eyes.  

(Two different individuals shown below.)

 

 

The first sculpin was in a shallow pool in the low intertidal zone.

 

We encountered the second sculpin in a small crevice waiting for the tide to return.

 

Here's the "fish out of crevice."  [We removed it from the crevice, photographed it, and released it into the water below.]  Amazing how well it blends in with the rock and coralline algae.

 

I'm looking for some help with identifying these sculpins.  If you're familiar with them, I'd love to learn what species they are.

Hola, Heermann's!

 

Heermann's Gull (Larus heermanni) on Salmon Creek Beach, 5 July 2012

Of the 14 gull species documented on Bodega Head, Heermann's Gull is one of the most distinctive.  This is an adult.  Note the all white head contrasting with the gray body, and the two-toned bill (red with black tip).

Most of the world's Heermann's Gulls (90-95%) nest on one island in the Gulf of California (Isla Raza).  After nesting, they migrate north along the Pacific Coast, generally arriving in our area around mid-late June.  Most will depart for Mexico in mid-late fall.

Several more views of this striking gull:

 

Extratubular

 

While tidepooling today on Bodega Head, Eric called me over to look at something unusual.  Can you see the small greenish-colored animal near the center of the photo above?  (It was ~5 mm across.)  In the field we thought it might be a sea anemone, but it looked odd and if it was an anemone, we weren't familiar with the species.  We decided to bring it back for a closer look.

Here's what it looked like under a microscope:

 

Surprising!  Now we could see that the tentacles were very long and feathery (with side branches).  And what looked like the column or body of anemone in the field was actually a round donut-shaped gelatinous mass containing lots of white embryos!

The structure of the tentacles made it clear that this was a feather-duster worm.  But the egg mass was puzzling.  Neither of us had seen a worm that brooded its embryos like this.  

Here's a close-up of the beautiful tentacles, called radioles.  (The side branches are called pinnules.)  The tentacles are used to capture food from the water and in respiration.

 

And here's a view of the white embryos embedded in the clear, gelatinous ring.

 

We started searching the Internet for a possible identity and it turns out that this type of brooding is rare in feather-duster worms.  We very quickly narrowed the choices.  And after reviewing basic characters, habitat, and life history, we think this might be Parasabella media (formerly called Sabella media and Demonax medius).

Remarkably, this species attaches an extratubular ("outside-of-the-tube") egg mass to the outer lip of the tube it lives in.  [Most sabellid worms either broadcast spawn or brood within the tube.]  The worm protects and cleans the egg mass with its arching tentacular crown.  

The worm can withdraw into its tube.  We were fortunate to capture this on film.  The first photo below shows most of the worm pulled in, with just the tips of the tentacles showing in the center.  The following photo shows the worm deep within the center of the egg mass.

 

 

We don't know if this species has been documented on Bodega Head yet.  We're looking into one possible record, but it might be a first!

In a paper about sabellid worms in the northeast Pacific, Banse (1979) describes this species:

"...specimens were found with eggs deposited in a ring of jelly around the opening of the tube; the opening was flush with the surrounding encrusting organism. With the tentacular crown spread-out, the animals appeared to the naked eye as small Anthozoa." [Anthozoa includes anemones and corals.]

It seems we weren't the first to puzzle over whether this extratubular brooding worm might be an anemone!

'Tis the season

 

 Summer fog on Bodega Head, 1 July 2012

Purple pelagic cyprids

Early summer is a good time of year to look for pelagic gooseneck barnacles, Lepas anatifera, washed up on beaches.  They're often attached to driftwood, seaweed, or plastic debris.

The adult barnacles may look familiar, but it's also worth examining specimens closely for a view of the larvae.  On 1 July 2012, I encountered them attached to a few different species of seaweeds (e.g., Sea Palm, Feather Boa Kelp, Bull Kelp, Chain Bladder Kelp, and Sea Sacs).

Here's a newly settled larva (next photo).  This stage is called a cyprid.  You can see how the larva attached to the substrate (in this case, the stipe of a floating Sea Palm) head-first with its antennules.

 

The cyprids often settle gregariously (see below).  Some had very obvious "gold bodies", or oil droplets that serve as lipid reserves in this non-feeding stage.

 

 

Once attached to the substrate, the cyprid undergoes a dramatic metamorphosis to become a juvenile barnacle.  In the photo below, note that the shed cyprid carapace is still visible at the base (and just above) the newly transformed juvenile.  It has the same shape of the cyprid, but is transparent.

 

Hoeg et al. videotaped this process and published some helpful photos illustrating the stages of metamorphosis.

 

Modified from Hoeg et al.  2012.  Metamorphosis in balanomorphan, pedunculated, and
parasitic barnacles: A video-based analysis.  Integrative and Comparative Biology.  doi:10.1093/icb/ics053

Once transformed, the barnacle is now a filter-feeder, sweeping the water for food.  Here's a close-up of the expanded feeding appendages, also known as a cirral net.

 

P.S.  When researching the development of these barnacles, I came across a paper with an entertaining title.  Being pelagic, but needing to attach to something, Lepas sp. are found on a variety of floating objects:

Barnes, D.K.A. et al.  2004.  Polar pedunculate barnacles piggy-back on pycnogona, penguins, pinniped seals, and plastic.  Marine Ecology Progress Series 284: 305-310.

These researchers in Antarctica found pelagic gooseneck barnacles attached to a sea spider (pycnogonid), Macaroni Penguins, Antarctic Fur Seals, plastic debris, as well as the leg band of a Wandering Albatross!

Sky sailors

A friend of mine kept a list of "ballpark birds" and other species he observed at sporting venues.  I can't help thinking that he would have been impressed with White-throated Swift (Aeronautes saxatilis).

 

These aren't very good photos, but it seemed worth posting them since White-throated Swifts are so awe-inspiring.  And perhaps it will encourage other people to keep an eye out for them if attending a SF Giants game at AT&T Park.  Photos were taken there on 29 June 2012.  (Has anyone seen them at the Oakland Coliseum or Candlestick Park?)

 

Note the long wings and relatively long tail.  The tail has a shallow notch (see next photo).  Unfortunately, their striking black-and-white plumage is not visible in these images.

 

The genus, Aeronautes, means "sky sailor."  It describes how they take advantage of air currents and updrafts, as well as their amazing speed and agility in flight.  These birds were foraging within and just above the upper deck of the park.  But I read that White-throated Swifts were once observed at an air mass convergence zone at 2,500 meters (or 8,202 feet, or 1.5 miles!).

 

Here are a few other shots taken from the ferry on the way to the park (below).  Both are looking west — one with the Golden Gate Bridge and fog in the background, the other with a silhouette of Alcatraz Island.

 

 

P.S.  I've also seen some nice dragonflies at AT&T Park — probably the best so far is a Black Saddlebags (Tramea lacerata).