West End Excursion
February 6, 2009
Today, SEFI biologists made a special, all-day excursion over Jordan Channel to West End Island to check two elephant seal breeding beaches. This trip is a rarity and a privilege because West End receives an extra level of protection from human disturbance. Literally thousands of seabirds and California sea lions reside here, as well as Steller sea lions and a small but growing population of northern fur seals. No human structures exist on West End. In fact, the United States Congress designated 141 acres of the Farallon Islands – including West End but excluding SEFI – as part of Farallon Wilderness in 1974. This is the smallest designated wilderness in California.
View of West End Island in the distance, from the lighthouse on SEFI. West End Island is completely off-limits during the spring and summer seabird breeding season. During the fall season, biologists visit West End a handful of times to monitor the breeding fur seals. Over the winter, we typically check the elephant seals with just a couple of trips, each time crawling slowly and carefully along the foothill of Maintop and over Raven’s Cliff so as not to scare California and Steller sea lions into the water. On our way to the far western end of the island where the elephant seals breed, we look for sea lions with shark bites or plastic straps around their necks, and record numbers that were branded on sea lions by researchers on breeding grounds elsewhere. The brand number information is shared with the researchers who marked the animals so they can estimate survival and how far the sea lions dispersed from where they were born.
Interns April Ridlon and Ari Waldstein make their way across the guano-covered rocks on West End.
April and Ari with Pastel Cave and the edge of Great Arch in the background.
PRBO Biologist Derek Lee and intern Monica Bond in front of beautiful granite rock formations.
On this trip we found 10 elephant seal cows and 10 pups at Pastel Cave Highlands, and 11 cows and 11 pups and 3 weaned pups on Shell Beach. Shell Beach once supported a harem of more than 200 cows, but the population fell dramatically after large winter storms hit the islands in the 1983 El Niño, and it hasn’t rebounded.
A bull elephant seal weighs about 5,000 pounds – much more than this “little” 150-pound pup! The blood on the bull’s neck is from a fight with another bull for dominance of the harem.
To our delight, we also spotted a group of 24 northern fur seals on Indian Head Beach. Some had been tagged at the Channel Islands in southern California. We read the tags and enjoyed watching and photographing their antics. These sweet-looking but rather aggressive seals were extirpated from the Farallon Islands by Russian and Yankee fur traders a century ago, and are only recently making a comeback here. Fur seals first returned to West End Island in 1995, when 4 individuals were counted. Last year the population had grown to nearly 200 including pups.
Monica and April check out the northern fur seals on the flat below.
This northern fur seal looks sweet but can be rather aggressive.