Return from the North

Adult males are starting to arrive at Piedras Blancas! It's the time of year when they return to the beach and start dividing it up among them, the better to greet the females when they arrive in late December.

It's the beginning of the season, so this bull, who arrived last week on the south end of the beach, may yet move on to another rookery. An adult male arrived Sunday on the north end of the beach but was gone the next day.



So much of the sand was washed away in last winter's storms, there is little beach left above the high tide line at the north end. Whether females will choose it for their pups remains to be seen. This vista shows high tide Monday 22 November. It was a high tide that day, the full moon, but not as high as it might be. Even so, the water comes right up to the base of the cliffs.


That's not an issue for these juveniles, fat and well-developed. The pups can be washed out to sea.

Beach changes

Lots of elephant seals, mostly juveniles, are on the beach. More seem to be arriving. The new trail opens up more viewing area at the north end. One rested on his back under water, showing his light belly under a foot or so of water.

One small female gave birth to an undersized pup, a fetus really, which did not survive. There were a few early births last year. Even the ones that are large and apparently fully developed don't survive when they are born outside the usual season. I don't know whether anyone knows anything about these early births.

One day after the new moon, the tide was high today, although not as high as it will be during the winter. There's hardly any beach above high tide line at the north end. I'm concerned about any mothers who arrive on that beach at low tide to have their pups. They probably won't survive. We'll see how the season progresses.

In the docent training last weekend, USGS Wildlife Biologist Brian Hatfield asked docents to report all shark wounds and scars. He said he has expected to see an increase in shark attacks, but hasn't documented that. In October, a surfer was killed by a shark about a hundred miles south of Piedras Blancas, at Vandenberg, http://www.msnbc.msn.com/id/39800366.

These Royal Terns are still enjoying life on the beach, too. A few Heerman's Gulls are there, as well. I didn't see the rare Ivory Gull reported at Pismo Beach to the south, http://www.sanluisobispo.com/2010/11/08/1361991/ivory-gull-san-luis-obispo-county.html.

Southern Elephant Seals are helping map the ocean floor in Antarctica, http://www.newscientist.com/article/dn19687-surveyor-seals-reveal-secrets-of-antarctic-depths.html?DCMP=OTC-rss&nsref=environment.

Daniel Costa, a marine biologist at the University of California, Santa Cruz, glued electronic depth sensors onto the heads of 57 elephant seals and tracked their movements in the Bellingshausen Sea off the Antarctic Peninsula between 2005 and 2009.

"Seals are ideal because they go places where no one else has gone, and they don't need a battery to drive them," says Costa.

Thanks to this research team for your work and your partners, elephant seals!

Squid

Danna Staaf, who received her Ph.D. for her studies in reproduction and early life of Humbolgt Squid, or, as she puts it, squid sex and babies from Stanford University earlier this year, came to Cambria to tell Friends of the Elephant Seal docents about them. Humboldt Squid are a favorite food of Elephant Seals.

She calls herself a 'cephalopodiatrist,' http://cephalopodiatrist.com/

http://scientificblogging.com/squid_day/.

Here we are snapping squid beaks at each other. I learned a lot I didn't know about squid: that they hatch from eggs, about the size of a grain of rice when they start. She had some microscopic video of these tiny babies. They have chromatophores on them even when they are that small, the color cells that allow squid to change color instantaneously, http://tolweb.org/accessory/Cephalopod_Chromatophore?acc_id=2038. I was fascinated by the organs, changing color on this tiny organism. They grow from that tiny start to full size, four feet or larger, in a year. Like elephant seals, they are difficult to research because they live deep in the ocean.

Significantly for elephant seals, Humboldt Squid migrate down in the water column during the day, about 300 meters, 1,000 feet, to a low-oxygen zone where most of their predators can't hunt them. Fish such as tuna need lots of oxygen in the water.

Elephant seals, on the other hand, get oxygen from the air they breathe, so they are not limited by the amount of oxygen in the water. That would make for good hunting for elephant seals. It's a question some researcher may even now be designing a study to investigate.

Thanks for coming to Cambria, Danna! And sharing what you know about squid with us.