Tag Archives: sea urchins

Along the North Coast, mixed news about the health of the undersea kelp forest 

Mary Callahan, THE PRESS DEMOCRAT

Aerial surveys conducted each year to gauge abundance in the iconic kelp forests off the North Coast showed a slight improvement last fall, offering a glimmer of hope for the recovery of the coastal marine habitat, the California Department of Fish and Wildlife has reported.

But conditions for the “bull kelp,” an annual type of seaweed — especially off Sonoma County — have become so bleak in recent years that even a reported doubling of the forest canopy during last year’s growing season has done little to bring the underwater habitat back to full strength, scientists said.

Despite patches that resemble the historic ecosystem in some ways, large swaths of ocean floor off the North Coast remain devoid of bull kelp and other fleshy algal species, prompting continued starvation among common marine herbivores like red abalone and urchins, they said.

Even with growth in the overall canopy last year, data indicates the kelp off Sonoma and Mendocino counties covered at least 95 percent less surface area in 2016 than it did in the banner year of 2008, said Cynthia Catton, an environmental scientist with the state wildlife agency.

The apparent expansion of the kelp canopy “is deceptive,” said Sonke Mastrup, environmental program manager for the agency’s invertebrate program, “because 2016 is still way below anything we would consider normal.”

Read more at: Along the North Coast, mixed news about the health of the undersea kelp forest | The Press Democrat

Filed under Habitats, Sonoma Coast

UC Davis study: North Coast water changes affecting marine life 

Mary Callahan, THE PRESS DEMOCRAT

Scientists at the UC Davis Bodega Marine Laboratory say a new study shows that the response by certain aquatic animals to warming ocean temperatures may make them more vulnerable to growing acidification, a secondary effect of climate change already measurable off the Sonoma Coast.

The research showed that organisms called bryozoan changed the composition of their skeletons in warm water to ones that quickly dissolved when exposed to water of higher acidity, causing the animals to shut down, lead author Dan Swezey said. He said the study mimicked condititions expected to be widespread by the end of the century.

The findings suggest that some marine life faced with adapting to a shifting ocean environment may be in a double bind when confronted with the “one-two punch” of global warming, a university representative said, with implications for sea stars, sea urchins, coralline algae and other ecologically significant marine life that depend on mineralized skeletons containing magnesium.

UC Davis spokeswoman Kat Kerlin likened the bryozoan to a “canary in a coal mine.”

“Our results add to this growing body of evidence that ocean acidification is a threat for lots of marine animals that are producing hard shells and skeletons,” said the study’s co-author, Eric Sanford, a professor of evolution and ecology. “But that might be increasingly true if the trend of acidification is combined with this trend of warming oceans.”

Read more at: UC Davis study: North Coast water changes affecting marine life | The Press Democrat

Filed under Climate Change & Energy, Sonoma Coast, Wildlife

North Coast kelp beds ‘like a desert’ this year

Mary Callahan, THE PRESS DEMOCRAT

Abalone diver Richard Hayman already had been observing troubling shifts in underwater conditions off the North Coast when he found himself gazing around the ocean floor in Arena Cove with a new level of alarm.

“It’s like a desert out there,” he recalled, describing a barren underwater landscape stripped of vegetation by colonies of purple urchins that vastly outnumbered the mollusks he sought. It looked, he said, “like a fire went through.”

During 25 years of diving, Hayman had come to know the area offshore the Mendocino County town of Point Arena as a source of succulent abalones, abundant and plump with meat.

 In June, he came ashore with his limit of three, despite a substantial reduction in the number of shellfish he saw. But they were so withered that, once removed from their shells, the creatures weighed less than a third of what they normally would.

“They’re starving to death,” the Calistoga man said. “It’s obvious.”

Hayman, 52, was among a dozen veteran divers who recently shared their observations at the midway point to the 2016 red abalone season, which resumes Aug. 1 after a month-long break and runs through November.

What they revealed was near consensus that all is not as usual out there, off the edge of the land, beneath the waves.

Scientists had predicted as much just before the season’s April 1 start, describing an unprecedented collapse of the North Coast’s iconic bull kelp forest and the resulting gloomy outlook for the abalone fishery and the overall ecosystem.

Divers reporting in over the past few weeks — people like Napa diver Andy Treweek, 55 — witnessed as much in some areas, where they discovered a few undersized abalone living on near-barren ocean floor.

Read more at: North Coast kelp beds ‘like a desert’ this year

Filed under Sonoma Coast, Wildlife

Collapse of kelp forest imperils North Coast ocean ecosystem

Mary Callahan, THE PRESS DEMOCRAT

How to help: State scientists are seeking help with data collection and other activities, as well as observational accounts, photos and videos related to the urchin barren. Shared images and information should, if possible, include the date, location and depth at which they were acquired. Contact Cynthia Catton at Cynthia.Catton@wildlife.ca.gov or 875-2072.

Large tracts of kelp forest that once blanketed the sea off the North Coast have vanished over the past two years, a startling transformation that scientists say stems from rapid ecological change and has potentially far-reaching impacts, including on several valuable fisheries.

The unprecedented collapse has been observed along hundreds of miles of coastline from San Francisco to Oregon. The region’s once-lush stands of bull kelp, a large brown alga that provides food and habitat for a host of wildlife species, have been devoured by small, voracious purple urchins. In the most-affected areas, denuded kelp stalks are almost all that remains of plant life.

Scientists have described the landscape left behind as an “urchin barren.” Other factors, including warmer water, also are to blame, they say.

“It’s no longer a kelp forest,” said Cynthia Catton, an environmental scientist with the California Department of Fish and Wildlife, stationed in Bodega Bay.Laura Rogers-Bennett, another Bodega Bay scientist, said it is as if whole terrestrial forests were disappearing, only in this case they are underwater and out of sight.

“A lot fewer people swim through the kelp forest,” she said. “But if they do right now, they‘re going to really see that there are huge changes that have taken place in the last year and a half or so.

”The discovery has taken shape as California scientists and policy makers are raising a broader alarm over the ebbing health of ocean waters, pointing to their increasing warmth, acidity and other conditions that have affected wildlife and the fishing industry.

Read more at: Collapse of kelp forest imperils North Coast ocean ecosystem | The Press Democrat

Filed under Habitats, Sonoma Coast, Wildlife