The big boys are back on the beach. Adult male elephant seals and their younger brothers are spending a month molting their shaggy skin.
Exactly how many adult males come to the Piedras Blancas rookery is a question some local researchers, members of Friends of the Elephant Seal, set out to answer. It’s impossible to count them accurately — they leave the beach and come back in a different place, and unless one has a distinctive scar or a numbered tag, observers can’t tell one from the next. Population biologists have developed some techniques to help.
FES docent Bill Goodger and FES-sponsored interns went out and counted the adult males during last year’s molting and breeding seasons. They found 240 bulls. Adult females number approximately 5,700, equal to the number of pups born. A previous study of elephant seal survival rates showed that many more males would be expected.
Former FES board president and researcher Brandt Kehoe is examining the numbers and applying what we know about elephant seal life to understand why Piedras Blancas has so few males. He and Goodger are collecting information as to which seals are on the beach to figure it out. Visitors to the site can help by reporting tagged seals.
A color-coded tagging system identifies in which rookery a seal was born: white for Piedras Blancas, red (San Nicolas Island), yellow (San Miguel Island), pink (Farallones Islands and Point Reyes), purple (Gorda) and green (Año Nuevo). Seal pups are tagged before they leave the beach on their first migration, so tags also indicate the seal’s age. The tags are small, an inch and a half long, so they can’t be seen when a seal’s back flippers are folded up. Only a small proportion of seals are tagged — about 10 percent of pups at Piedras Blancas.
All colors of tags show up. If you see a tagged seal, report it to a docent. Docents can then report the tag and other relevant information about the seal. Take a picture of the seal and its tag and submit it to firstname.lastname@example.org.
These boys of summer are molting their skin now because it doesn’t shed a few cells and hairs at a time, the way your dog and cat do. It peels off in chunks once a year. Females and young seals of both sexes molted in the spring.
We see them during the short time they spend out of the water.
Most of their lives are spent deep in the ocean, hunting at 1,000 feet and deeper. Their life at sea, mostly in waters less than 45 degrees, prevents them from growing skin gradually.
Blue-jacketed docents carry samples of it you can touch.
Become a docent and carry your own bag of skin! Friends of the Elephant Seal is interviewing prospective volunteer guides in July and August for training classes beginning Sept. 10. I’ve been doing it for almost 10 years and every day is different. Apply online, www.elephantseal.org (Become a Docent), email email@example.com, or phone 805-924-1628.
Christine Heinrichs’ column appears the fourth Thursday of each month and is special to The Cambrian.