[CINC] Article

[Ron Dreher]

A rare sight in the channel: Steller sea lion 


Peter Howorth 






 


 


 






A Steller sea lion lounges in the sun atop a buoy floating off Santa Barbara
Harbor.

. 


. 


 


 


 


 


 


 


 

June 8, 2008 7:42 AM

Santa Barbara Harbor has had a rare guest over the past few days: a Steller
sea lion. This is only the third time a Steller sea lion has been seen in
the Santa Barbara Channel since the 1982-1983 El Ni0x96o event. At that
time, two small rookeries existed at San Miguel Island. Historically,
Steller sea lions once had a rookery at San Nicolas Island also, marking the
southern range limit for this species.

Why this species disappeared from Southern California is unknown. It was
always living on the edge here, in water that was warmer than the rest of
its range. It may be that the 1982-1983 El Ni0x96o event tipped the balance,
with the water becoming just too warm. The same event may also have resulted
in a redistribution of prey species to colder waters farther north.

Steller sea lions range from Japan and Russia across the Aleutians to
Alaska, then down the west coast of North America to central California.
Their southernmost breeding colony is now on A0x96o Nuevo Island, north of
Santa Cruz, California.

Throughout their range, Steller sea lion stocks plummeted in the 1980s and
1990s. Some researchers believe that overfishing of key prey was
responsible. According to the National Marine Fisheries Service, which has
jurisdiction over this species, other problems included accidental take from
fisheries throughout the range, entanglement in synthetic debris, illegal
shootings, contaminants, and disease.

To better manage this species, NMFS divided the Steller sea lion population
into two stocks. The western U.S. stock, which is federally listed as
endangered, ranges from southern Alaska across the Aleutians. This stock has
declined dramatically over the years.

The eastern U.S. stock, considered threatened, ranges from southern Alaska
to California. Although the eastern stock has shown some increase in
population over the past few years in Alaska and British Columbia, numbers
have been declining in central California. In northern California and
Oregon, stocks have been relatively stable since the 1980s. The overall
trend for this stock appears to be for a slow decline in the south and a
moderate increase in the north of the range.

Steller sea lions got their name from their discoverer, a German surgeon and
naturalist aboard the Russian ship Vitus Bering. Steller had plenty of time
to describe the new species: in 1742, he was shipwrecked on Bering Island,
in the far north. With only sea lions and sailors for company, Steller
dutifully recorded his observations until the crew was rescued.

Throughout their range, Steller sea lions begin having their pups and
breeding from late May through early July. At birth, the pups weigh 35 to 50
pounds, more than double that of their southern kin, the California sea
lions. The pups nurse for a year or more, although they also catch their own
meals after several months of age. The adult diet consists of large
schooling fish, including pollack, often called black cod in the markets.
They also eat squid and octopi.

Adult males can be huge; a really large specimen can weigh nearly 2,500
pounds. By comparison, the young male at Santa Barbara weighs about 750
pounds. Females are much smaller, with the largest ones weighing in at under
800 pounds.

Since 1983, Steller sea lions all but disappeared locally. I observed one
adult female in 1989 off Refugio. Sharon Melin, a researcher with NMFS
observed a juvenile male at San Miguel Island a few years ago. The
individual hanging out near our harbor was the third seen in this region
since the 1982-1983 El Ni0x96o, according to the NMFS.

Peter Howorth is director of the Santa Barbara Marine Mammal Center

 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.rain.org/pipermail/channel_islands_naturalist_corps/attachments/20080608/e42c83aa/attachment-0001.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: image/jpeg
Size: 3128 bytes
Desc: not available
URL: <http://www.rain.org/pipermail/channel_islands_naturalist_corps/attachments/20080608/e42c83aa/attachment-0002.jpe>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: image/jpeg
Size: 8965 bytes
Desc: not available
URL: <http://www.rain.org/pipermail/channel_islands_naturalist_corps/attachments/20080608/e42c83aa/attachment-0003.jpe>