Tuesday, August 12, 2014

Harbor seal visitor

A harbor seal pup rested on the sand at Piedras Blancas yesterday. He was a cute little guy, immediately recognizable as different from the other youngsters who are already arriving for their fall haul-out.
The adults don't take much notice of the juveniles. This youngster sleeps peacefully among his elders. They all enjoyed the cool, wet kelp as a bed.
Other males continue to work on their fighting skills. Active fighting was mostly in the water.

On the beach, dominance confrontations were confined to threat and retreat, as between these two.

Saturday, July 26, 2014

Cambrian Elephant Seal Column

I now write the Elephant Seal column for the local newspaper, The Cambrian. Here's my first column.

Tattered and torn.

That’s what the adult male elephant seals that are on the beach now look like. Their molting skin is peeling off. It looks awful, but it’s normal.

The adult males return to the beach for a month or so of quiet time in July and August, while they get their new skin for the coming year.

The old skin is brown, contrasting with the pearly gray new skin underneath.

Their skin keeps its scars, so senior seals continue to display their battle history.

Molting skin all at one time, called a catastrophic molt, is unusual for mammals. Snakes peel their skin off to grow, and some insects and crustaceans split their outer skin off, but seal skin just falls off in pieces.

Visitors often ask whether the seals are rubbing their skin off with sand. I’ve never seen a seal do that. They toss sand on their backs, but that’s a way to regulate temperature.

These seals are comfortable in very cold water. They are deep divers, foraging at 1,000 feet deep and more, in the icy waters of the North Pacific. They are warm-blooded mammals and their blubber insulates them against the cold. On the beach, they heat up in the sun, even on cloudy days. The sand gives some protection from the sun.

Summer is the low point for the number of seals on the beach, but that’s relative. There are seals on the beach year-round.

In July and August, the adult males are here, the ones with the big nose (technically, proboscis) that gives them their name. There are lots of them out there, especially at the north end.

Friends of the Elephant Seal posts a sign in the parking lot, directing visitors to the best place to see the seals that day. Seals are always coming and going.
Younger seals of both sexes are migrating and foraging in the open ocean now.
They’ll return to the beach in the fall for a few weeks of rest.

The pregnant female seals are at sea, foraging for food to grow their pups. They left the beach after they molted their skin in May and June.

They’ll return to the beach in December and January to give birth to their pups.

Friends of the Elephant Seal docents who staff the site have samples of elephant seal skin you can touch — ask to see it. They are easily recognizable in their blue jackets. Docents are stationed at the site year-round.

Becoming a docent is a great way to learn about local natural history. Training is free, coming up on Sept. 13, Oct. 11, 18 and 25. Docents serve four three-hour sessions each month.

For more information and to register for the 2014 training sessions, call 924-1626 or use the online docent application: http://www.elephantseal.org/Friends/docent_application.html.

Read more here: http://www.sanluisobispo.com/2014/07/24/3166207/elephant-seal-molting-piedras.html?sp=/99/177/183/429/887/#storylink=cpy

Monday, July 7, 2014

Summer vacation

Lots of visitors discovering the elephant seals! Several good examples of molting easy to see on the beach.
Lots of big, fat males on the beach. They make me think of how many  fish and squid they have eaten to get so big.
These big males show their seniority with their large chest shields. Youngsters sparred in the water, but mostly life was quiet today.
This boy made himself comfortable on his brothers.

Monday, June 30, 2014

Adult males

It's summer, and the adult males are back on the beach.
 This one lets the audience know he's here. He's gained plenty of weight on his post-breeding season foraging migration.
 They are piled up, although this isn't a very busy time of year. The age range is from five years to maturity. Some could be as old as twelve. They are in varying stages of molting, accounting for the brown skin peeling off to reveal gray skin underneath.
Time to settle down and get some rest.

Tuesday, June 17, 2014

A pup's first year

My friend Charmaine Coimbra has created a video following a pup's first year, from birth to the first migration.

She took the photos at Piedras Blancas, documenting the progression from
 birth in January

through weaning in February,

learning to swim in March, and departing for that first migration north to feed in April. She's put music to it and it's a great photo essay.

Thanks, Charmaine!

Friday, May 30, 2014

Molting in May

 A sunny day on the beach. This young male couldn't resist pestering a female who wanted to be left alone.
 This tail looked especially ragged.
 A lot of youngsters, especially males, played in the water.
 Get rid of that nasty old brown skin!
Most were happy just to rest on the sand.

Saturday, May 17, 2014

Sea turtles and domoic acid

Wildlife biologist Heather Harris presented her work on how leatherback sea turtles are affected by domoic acid, the toxin produced by harmful algal blooms. That's kind of surprising, because the jellyfish they eat aren't thought of as being affected by domoic acid. But it turns out, they are.

She doesn't get to see many, but occasionally one washes up on the beach.She was here in 2012 when a tagged female died and turned up on our beach. As a veterinarian, she has been working on turtle health. She necropsied this one and found that she died of a bacterial infection caused by intestinal perforations. She had high concentrations of domoic acid in her urine and gastrointestinal contents. The question to Heather was: where did the DA come from?

Leatherback sea turtles migrate along our Central Coast. While they are here in the fall, they are eating a lot of jellyfish, to bulk up for their long migration across the Pacific Ocean. They weigh more than 1,000 lbs., so they eat huge amounts of jellyfish.

Shellfish, filter feeders such as mussels, bioaccumulate DA, but leatherback sea turtles don't eat them. She needed to look for DA in jellyfish. In 2010, that's what she did. She found DA in nearly every jelly of four different species that she sampled.

"Jellies may add a new dimension to offshore harmful algal blooms," she said.

"Human impacts affect the ocean. We are all connected. Anything we do to alter the environment affects us all."

More of Heather's work is posted on Oikonos.