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Monday, September 22, 2014

Summertime blues


Since about mid-July, whenever we walk the local beaches, we've been seeing bluethis has been an extraordinary year for By-the-wind Sailors (Velella velella).  Then on 30 August, we encountered Blue Buoy Barnacles (Dosima fascicularis).  And now, on 21 September, we found these.

The extreme close-up above might be a little puzzling at first.  I'll zoom out a little more, and then I'll show some pictures of the entire animal.


Okay, here we go, the next two photos will give it away.



This is Fiona pinnata, a pelagic nudibranch.  I first wrote about Fiona on 19 October 2012, but in that case those individuals were brown.  Fiona's color depends on its food.  When eating barnacles, they're brown, but when eating By-the-wind Sailors, they're intensely blue!  This is the first time we've seen the blue form of Fiona pinnata.

Eric's sharp eyes first spotted Fiona's egg capsules on Velella sails washed up on the beach.  Then I found one Velella with both eggs and a nudibranch!  We started looking for others, and counted at least 20 Velella sails with Fiona egg cases and at least 12 blue nudibranchs!

Below are two examples of what they looked like on the beach (the off-white blobs are the egg masses):



We weren't sure what kind of condition they'd be in after a journey through the surf zone, but to document their occurrence in Bodega Bay this year, we brought a few back to the lab for photographs.  The next image was taken in a small aquarium:  


The whorled egg masses are packed with developing embryos: 


When the nudibranchs turned on their sides, you could see what looked like developing eggs inside:


If you're wondering about the blue color...well, so am I.  I watched Fiona actively feeding on VelellaFiona's digestive tract extends into its cerata (the structures on its back).  So the reason you're seeing blue is because you're seeing fragments of ingested Velella.  Benjamin Kropp wrote about this after an experiment in 1931.  When he starved or fed blue Fiona different food, they lost their blue coloration within 2-3 days.  When he fed them Velella again, they regained their blue coloration within 2-4 hours!  [See Kropp, B.  1931.  The pigment of Velella spirans and Fiona marina.  Biol. Bull. 60: 120-123.]


It's officially fall now (when I'm writing this), but I can't help wonder if another blue animal will be discovered before the water turns cold again?

Sunday, September 21, 2014

Offshore neighbors

During late summer and fall, I try to get out on at least one or two pelagic trips to Bodega Canyon and Cordell Bank.  I went out on September 19th with Shearwater Journeys aboard the New Sea Angler.  Here are a few trip highlights:


Guadalupe Murrelet (Synthliboramphus hypoleucus) — (in 2012, Xantus's Murrelet was split into two different species, Scripps's Murrelet and Guadalupe Murrelet).  Guadalupe Murrelet is one of the southernmost breeding alcids (a group that includes auks, auklets, guillemots, murres, murrelets, and puffins).  They nest on islands off the west coast of Baja California and then disperse northward after the breeding season. However, it's rare to see them in central/northern California.  

Note the amount of white on the face and how it arches up and over the eye.  Also look for the white wing linings in the last picture (below).





We also had great looks at an adult Tufted Puffin (in non-breeding plumage): 


And although challenging to photograph, there was a good number of Arctic Terns (Sterna paradisaea), ~180 during the entire trip.


The mammal highlight was a lone male Orca (Orcinus orca) — a different individual than the Orcas we observed on 7 September:


This Orca wasn't rising very far above the surface, but here's another image in case it's useful for identification purposes: 


Every trip out to sea is different, and I'm thankful for every opportunity to become more aware of our "offshore neighbors."  Spending time on a boat changes how I look at the ocean from land.  When I scan the western horizon from Bodega Head, I visualize these amazing animals and wonder about their lives in the open ocean.  It's helpful and inspiring to know who lives out there!

Saturday, September 20, 2014

Mystery moth (and migrating thrushes!)

Not much time tonight, but here's a nice moth, photographed in Bodega Bay on 20 September 2014.


P.S.  While I was taking pictures of this moth, I heard migrating thrushes calling overhead.  It's worth listening for them on calm nights!

Thursday, September 18, 2014

0.12


0.12 inches — of rain, that is!  I'm guessing this Pacific Treefrog (Pseudacris regilla) was happy about the rainfall last night and this morning.

Here's a close-up of its wonderful toe pads:


CORRIGENDUM (21 September 2014): Originally this post was called "0.4" and I said that 0.4 inches of rain had fallen.  Jim pointed out that much less rain fell in Bodega Bay.  I'm not sure what happened, as I thought I had checked the measurement data, but somehow something got mixed up.  I want the record to be right, so I edited the post to read the correct amount of 0.12 inches of rain.

Wednesday, September 17, 2014

Dolphins in the surf

For a few years now, I kept missing out on sightings of Bottlenose Dolphins (Tursiops truncatus) in the Bodega Bay area — until tonight!  Thanks to Lewis, we watched a small group of them off Salmon Creek Beach in the early evening.


There were at least 6, possibly 7 or more, individuals.  It was hard to count as different animals dove and surfaced.

Note the relatively large size, slate gray coloration, tall and falcate (sickle-shaped) dorsal fin, and in a few photos, a glimpse of the beak.


We were excited to see at least one calf.  In the next image, compare the larger fin of the adult with the smaller fin of the calf.


These dolphins were fairly distant, so I was taking pictures and just hoping that some of them would come out.  Although I didn't know it at the time, I caught the calf with its head out of the water:


(Calves nurse for 18-20 months, but then stay with their mothers for another 3-6 years.)


Much of the time, the dolphins were swimming parallel to the waves.  Sometimes they would stop and mill around, perhaps to search for food.  A few times they turned and either surfed with the waves or swam (and leaped!) through them.  Here's a selection of my favorite images of the dolphins interacting with the waves.  As this is my first time seeing Bottlenose Dolphins off Bodega Head, I can't help sharing a few!





Bottlenose Dolphins aren't common in this area.  This is at the northern end of their range.  I remember hearing about Darris Nelson's report of them at Doran Beach in 2012, and there have been a few other observations, but if you see them, consider yourself lucky!

One more picture to wrap up.  What do you know, we saw a dolphin in the sky on our walk back!


Tuesday, September 16, 2014

Change in the weather

Did anyone else see those wonderful clouds in the early evening of September 16th?  I'm sure many of you did.  Here are a few of my favorite views.  Everywhere you looked there seemed to be something different and magical going on.




Monday, September 15, 2014

Subsidy

About a week ago, while driving into work, I noticed a few Turkey Vultures (Cathartes aura) feeding in a grassland.  By itself that sighting wasn't unusual, but the exact location was a little oddI hardly ever see vultures feeding there.  It was close to the road, so I decided to walk out to take a look at what they were feeding on.


I expected it to be some sort of mammal or bird...but my eyes opened wide to see this:


An Ocean Sunfish (Mola mola)!  The vultures were eating this Ocean Sunfish in a grassland at least 120 feet from the bluff edge!

So one of the first questions is, how did the sunfish get there?  It's seems unlikely that a vulture could lift such a large prey item.  It's more likely that the sunfish washed up on the beach, and then a mammal (e.g., Coyote?) carried it into the grassland.

As I was photographing the sunfish, I noticed some movement along one edge.  Looking more closely, I realized an insect with strong black and yellow markings was landing on a torn area of the sunfish:


I don't have a lot of experience identifying insects in this group, but I think this might be a Western Yellowjacket (Vespula pensylvanica).  Please correct me if I'm wrong.

The yellowjacket was actively carving out a piece of the sunfish!  Here's a sequence of images documenting the event, until just before the yellowjacket flew off with its prize:


This is a very nice example of a spatial subsidy"movements of nutrients, detritus, prey, and consumers among habitats" — as defined by Gary Polis and colleagues in 1997. (See Polis, G.A., W.B. Anderson, and R.D. Holt.  1997.  Towards an integration of landscape and food web ecology: The dynamics of spatially subsidized food webs.  Annu. Rev. Ecol. Syst.  28: 289-316.)

Inspired by the work of Gary Polis, ecologists have been increasingly interested in the movement of resources and energy between distinct ecosystems — such as from the sea to the land.  In this case, the Ocean Sunfish, normally found in the open ocean, was washed up onto a sandy beach, and then probably carried by a terrestrial mammal to a coastal grassland where it then served as food for land birds (vultures) and terrestrial insects (yellowjackets).  I couldn't help wonderhow often do yellowjackets eat Ocean Sunfish in grasslands?