|Freak weather wreaks havoc on marine life|
Posted by North Coast Diver on August 09, 2005 at 15:50:39:|
Mysterious El Niņo-like pattern disrupts coastal ecosystem
By CAROL BENFELL
The wild salmon didn't show up at Bodega Bay. Sea birds on the Farallon Islands abandoned their nests and died. Increasing numbers of sea lions are following the fishing boats, grabbing the catch off the hooks.
All along the North Coast, hungry sea creatures are responding to a freak weather year that only now shows some sign of easing.
Scientists don't know why the coast is experiencing El Niņo-like conditions when it's not an El Niņo year. Some think it's related to global warming; others say it's too soon to say.
"It's a mystery," said Bill Sydeman, director of marine ecology at the Point Reyes Bird Observatory. "The birds, mammals and salmon are being affected, but we don't know the mechanism that's driving it."
In most years, spring along the Sonoma County coast brings strong north winds that churn up the ocean, dragging up cold water and rich nutrients from the sea floor to the surface to feed birds, salmon and other ocean life.
This year, the strong north winds didn't come. They were stalled, apparently by the same weather system that dripped rain on the North Bay until June.
"There's a strong tie between the ocean and the atmosphere. It's been a strange meteorological year, and the ocean is probably doing something equally strange," said Bruce MacFarlane, a fisheries biologist with the National Marine Fisheries Service, part of the National Oceanic and Atmospheric Administration.
Without the winds, there was no upwelling and no nourishing soup of krill and plankton. The number of rockfish larvae - an important source of food for sea birds - also declined sharply, studies showed.
It was the worst year on record for birds at the Farallon Islands, Sydeman said. Scores of Cassin's auklets, relatively rare gray and white birds that feed primarily on krill, abandoned their nests and died. Some cormorant species failed to breed at all. The hatch rate of common murres and Western gulls was half what it is in normal years, Sydeman said.
"If it's just one year, they'll bounce back next year," Sydeman said. "The question is whether this is a long-term change or a spike."
It remains unclear if it's related to global warming, but Sydeman said it's possible.
"We know it's going on, we know it's having ecological effects. The most compelling reason to me is that we don't have any other explanation," Sydeman said.
Steve Morgan, a marine ecologist at UC Davis Bodega Marine Laboratory, thinks otherwise.
"I think it's premature to make any links," Morgan said. "It's definitely unusual and has important economic and ecological impacts, but it's not that far out of the norm."
Salmon also are adjusting to the loss of krill. Commercial fishermen from Fort Bragg to Bodega Bay said it's been a lean salmon season, and anglers aren't getting their bag limits.
State Fish and Game Department figures show there are plenty of salmon out there. But the salmon are staying out in the ocean instead of moving toward the coast and up rivers.
They're eating anchovies and sardines because they can't get krill, said Chuck Wise, a Bodega Bay commercial fishermen.
"It's pretty slim pickings right now," Wise said. "When I look at the flesh of the fish, they're pale. The red color comes from eating krill, and there's a definite lack of krill."
The sea lions, which feed on salmon, also are feeling the pinch of hunger. They're showing up in greater numbers than usual to grab salmon off fishermen's hooks, said Dave Yarger, president of the Fisherman's Marketing Association of Bodega Bay.
"Our last trip was so disastrous we just quit," Yarger said. "The sea lions ate the fish before we could get it to the boat."
It's as if the North Coast skipped summer, said John Largier, an oceanographer at the Bodega Marine Laboratory.
"March, April, May, June and July are when we have the upwelling and the winds. We've missed them," he said.
There are some hints that the phenomenon may be passing, and scientists hope conditions will return to normal in the fall.
The north winds still are weaker than usual, but they are starting to pick up, said Warren Blier, science officer for the National Weather Service.
Warmer-than-usual waters appear to be cooling. MacFarlane's sampling trip in late June showed water temperatures 5 degrees higher than normal at the Golden Gate but within the normal range at Point Arena.
In Oregon, where waters were 10 degrees warmer than normal earlier this year, the upwelling has returned, said Bill Peterson, an oceanographer with the NOAA's National Marine Fisheries.
"It's really weird," Peterson said. "Ocean production has been delayed three or four months. I don't think it's ever happened that late before."
"I hope the winds keep blowing strongly for a month or two. If it stays cold in winter, we'll get off to a good season next spring," Peterson said.
But no one is sure what will happen next, and a lot of ecological damage already has been done, scientists said.
"Things may be settling back to a little more normal, but the biological impact has been pretty severe," said Steven Bograd, an oceanographer with the National Marine Fisheries. "It's still a serious situation."
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