recent article sea lion decline and related fish migrations
Posted: Tue Jan 05, 2010 2:15 pm
The lack of Stripers may be related. Who really knows.......
Sea lion decline points to tough year
By MEGHA SATYANARAYANA / MediaNews Group
Created: 01/05/2010 02:30:47 AM PST
Tourists watch sea lions on boat docks at Pier 39 in San Francisco last month. But now, almost all of the sea lions are gone. (Ben Margot/Associated Press file photograph) The recent exodus of a large California sea lion colony at Pier 39 in San Francisco was visually stunning, said local marine biologists, but it's normal, and likely happening in Santa Cruz as well.
"This time of year, this is exactly what's going to happen," said Pat Morris, research coordinator at Ano Nuevo State Park. The males may be heading elsewhere, she said, in the endless pursuit of the small fish they eat.
It has been a strange year for the large marine animals along the California coast, even with near normal water and weather patterns, Morris said.
Nancy Black, a marine biologist who leads whale watching tours from Fisherman's Wharf in Monterey, says she's seeing fewer sea lions now, maybe 40 or 50 vs. the normal 300 or 400. The southern migration of gray whales was later this year, she said, probably because warming temperatures delayed the ice formation that typically sends the animals on their way.
"They're staying up there longer," Black said. "It was very noticeable this year." In contrast, there are more Risso's dolphins feasting on an abundance of Humboldt squid, which could be feeding on the fish the sea lions like, sending them off in search of more bountiful waters.
"In the sea, everything's all interrelated," she said. "Things like that happen every few years." It's been a bad year for sea lions and Brandt's cormorant, both of which frequent Ano Nuevo Island, Morris said. In spite of a normal birth rate for sea lions, some 75
percent of the sea lion pups born on the Channel Islands starved, abandoned by their mothers. Morris said a plausible explanation is that food was too deep to reach, too far north or too far off the coast. Mothers wouldn't be able to feed themselves and get back with enough food for their pups.
At Seal Rock at Lighthouse Point this summer, surfers passed within feet of some 70 yearlings too weak to scuttle off or respond. The Marine Mammal Center, based in Sausalito, was overwhelmed with starving yearlings.
"Mom took care of them until they were nine months old, but once they were on their own, they couldn't make it," Morris said.
The cormorants laid fewer eggs and abandoned their chicks in June and July. Only 10 percent to 20 percent of the normal number of cormorant chicks reached independence this year at Ano Nuevo and failed entirely in San Francisco, Morris said.
She doesn't have exact numbers, but believes western gull numbers dipped this year. And a bird called the rhinoceros auklet was forced to diversify its food gathering from a single type of fish, carrying multiple fish species in their beak to their hungry young.
Yet krill eaters, such as baleen whales, did well, which is strange, as normally if fish eaters fail, so do krill eaters. It was like an El Niño year in some ways, Morris said, where water is warmer and there is less food for larger animals such as whales, birds and sea lions.
"It was a devastating year for some species," said Guy Oliver, a UC Santa Cruz research biologist.
But there was no El Nino, and this has some researchers worried, as the weather phenomenon is scheduled to appear in 2010. Morris said sea lions are well-studied because they are a stably populated marine mammal species, but 2010 could be the third consecutive year the animals have had trouble having babies.
Sea lion decline points to tough year
By MEGHA SATYANARAYANA / MediaNews Group
Created: 01/05/2010 02:30:47 AM PST
Tourists watch sea lions on boat docks at Pier 39 in San Francisco last month. But now, almost all of the sea lions are gone. (Ben Margot/Associated Press file photograph) The recent exodus of a large California sea lion colony at Pier 39 in San Francisco was visually stunning, said local marine biologists, but it's normal, and likely happening in Santa Cruz as well.
"This time of year, this is exactly what's going to happen," said Pat Morris, research coordinator at Ano Nuevo State Park. The males may be heading elsewhere, she said, in the endless pursuit of the small fish they eat.
It has been a strange year for the large marine animals along the California coast, even with near normal water and weather patterns, Morris said.
Nancy Black, a marine biologist who leads whale watching tours from Fisherman's Wharf in Monterey, says she's seeing fewer sea lions now, maybe 40 or 50 vs. the normal 300 or 400. The southern migration of gray whales was later this year, she said, probably because warming temperatures delayed the ice formation that typically sends the animals on their way.
"They're staying up there longer," Black said. "It was very noticeable this year." In contrast, there are more Risso's dolphins feasting on an abundance of Humboldt squid, which could be feeding on the fish the sea lions like, sending them off in search of more bountiful waters.
"In the sea, everything's all interrelated," she said. "Things like that happen every few years." It's been a bad year for sea lions and Brandt's cormorant, both of which frequent Ano Nuevo Island, Morris said. In spite of a normal birth rate for sea lions, some 75
percent of the sea lion pups born on the Channel Islands starved, abandoned by their mothers. Morris said a plausible explanation is that food was too deep to reach, too far north or too far off the coast. Mothers wouldn't be able to feed themselves and get back with enough food for their pups.
At Seal Rock at Lighthouse Point this summer, surfers passed within feet of some 70 yearlings too weak to scuttle off or respond. The Marine Mammal Center, based in Sausalito, was overwhelmed with starving yearlings.
"Mom took care of them until they were nine months old, but once they were on their own, they couldn't make it," Morris said.
The cormorants laid fewer eggs and abandoned their chicks in June and July. Only 10 percent to 20 percent of the normal number of cormorant chicks reached independence this year at Ano Nuevo and failed entirely in San Francisco, Morris said.
She doesn't have exact numbers, but believes western gull numbers dipped this year. And a bird called the rhinoceros auklet was forced to diversify its food gathering from a single type of fish, carrying multiple fish species in their beak to their hungry young.
Yet krill eaters, such as baleen whales, did well, which is strange, as normally if fish eaters fail, so do krill eaters. It was like an El Niño year in some ways, Morris said, where water is warmer and there is less food for larger animals such as whales, birds and sea lions.
"It was a devastating year for some species," said Guy Oliver, a UC Santa Cruz research biologist.
But there was no El Nino, and this has some researchers worried, as the weather phenomenon is scheduled to appear in 2010. Morris said sea lions are well-studied because they are a stably populated marine mammal species, but 2010 could be the third consecutive year the animals have had trouble having babies.
