sea urchins

Northern California’s next kelp forests might be growing in a lab

Carly Naim, COURTHOUSE NEWS SERVICE

Kelp once formed “underwater rainforests” on the California coast, but these fragile ecosystems have largely disappeared. At a marine lab near the Bay Area, scientists are trying to bring them back.

On a rainy day in September along a craggy slice of California shore, some young bull kelp floated around in a cement tub as if enjoying a bubble bath.

Unlike some of their kin elsewhere at this marine laboratory, ecologists had collected these specimens earlier that day. The scientists working here at UC Davis Bodega Marine Laboratory hope the kelp will grow, reproduce and eventually spore — an essential step for restoring the kelp forests that once flourished off the coast of Northern California.

This species — Nereocystis luetkeana, commonly known as bull kelp — is the foundational species in kelp forests, an ecosystem that provides habitat and food for countless other marine animals and plants.

An algae, it only lives for a year but can grow up to a foot per day and reach heights of nearly 100 feet. That’s taller than many trees.

Sadly, California’s kelp forests are in what researchers call “massive decline” as climate change disrupts natural processes in the Pacific Ocean. In around the past 10 years, they estimate more than 90% of these ecosystems have disappeared.

Read more at https://www.courthousenews.com/northern-californias-next-kelp-forests-might-be-growing-in-a-lab/

Sonoma Coast, Wildlife, , , ,

How smashing 5.6m urchins saved a California kelp paradise

Katharine Gammon, THE GUARDIAN

Pollution, warm oceans and hungry urchins devastated Pacific kelp. Now, thanks to divers with hammers, one of the world’s most successful rehabilitation projects has helped it rebound

On an overcast Tuesday in July, divers Mitch Johnson and Sean Taylor shimmy into their wetsuits on the back of the R/V Xenarcha, a 28ft boat floating off the coast of Rancho Palos Verdes, south of Los Angeles. Behind them, the clear waters of the Pacific are dotted with a forest of army-green strands, waving like mermaid hair underwater.

We are here to survey the giant Pacific kelp, a species that once thrived in these ice cold waters. But over the past two decades, a combination of warm ocean temperatures, pollution, overfishing and the proliferation of hungry sea urchins that devour the kelp has led to an 80% decline in the forest along the southern California coast.

In recent years, scientists have staged a comeback – mounting one of the largest and most successful kelp restoration projects in the world. To do so, they’ve recruited an army of hammer-wielding divers to smash and clean up the voracious urchins. Today’s trip is a chance to see that success up close.

Read more at https://www.theguardian.com/us-news/2025/aug/31/california-pacific-kelp-forest

Habitats, Wildlife, ,

Scientists solve mystery of what is killing sea stars

Christina Larson, ASSOCIATED PRESS

The cause of sea star wasting disease turns out to be a bacteria called Vibrio pectenicida.

Scientists say they have at last solved the mystery of what killed more than 5 billion sea stars off the Pacific coast of North America in a decade-long epidemic.

Sea stars – often known as starfish – typically have five arms and some species sport up to 24 arms. They range in color from solid orange to tapestries of orange, purple, brown and green.

Starting in 2013, a mysterious sea star wasting disease sparked a mass die-off from Mexico to Alaska. The epidemic has devastated more than 20 species and continues today. Worst hit was a species called the sunflower sea star, which lost around 90% of its population in the outbreak’s first five years.

“It’s really quite gruesome,” said marine disease ecologist Alyssa Gehman at the Hakai Institute in British Columbia, Canada, who helped pinpoint the cause.

Healthy sea stars have “puffy arms sticking straight out,” she said. But the wasting disease causes them to grow lesions and “then their arms actually fall off.”

The culprit? Bacteria that has also infected shellfish, according to a study published Monday in the journal Nature Ecology and Evolution.

Read more at https://www.ap.org/news-highlights/spotlights/2025/scientists-say-they-have-solved-the-mystery-of-what-killed-more-than-5-billion-sea-stars/

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Groups unite to replant Sonoma Coast kelp forest

Cole Hersey, NORTH BAY BOHEMIAN

This July marks the first summer planting of lab-grown bull kelp along specific sites on the Sonoma coast by the Greater Farallones Association and NOAA.

On a sunny afternoon just north of Bodega Bay, two large troughs of water bubbled in the sunlight, toward the ocean. Swirling in the eddy of bubbles were slimy forest green blades of kelp. Julieta Gomez, the Greater Farallones Association (GFA) kelp restoration specialist, explained that these were blades of lab-grown bull kelp, a tall brown algae that towers dozens of feet over rocky coastlines like a tree.

Bull kelp forests were once a common sight along beaches all across Marin and Sonoma counties. But over the last decade, they have been almost entirely wiped out from the West Coast, only surviving in small pockets between Santa Barbara and Alaska. In Marin and Sonoma, their numbers have been wiped out by nearly 90%, replaced by vast areas of urchins, called urchin barrens. One such barren reaches hundreds of miles from Marin County, all the way to the Oregon border, according to work conducted by UC Davis researchers.

Read more at: https://bohemian.com/groups-unite-to-replant-sonoma-coast-kelp-forest/

Habitats, Sonoma Coast, Wildlife, ,

Scientists grappling with persistent and alarming collapse of North Coast’s bull kelp forests

Mary Callahan, THE PRESS DEMOCRAT

Five years after marine scientists first sounded the alarm about a sudden collapse of the bull kelp forest off the Northern California coast, the state of the ocean offers little prospect of recovery any time soon.

Where lush stands of leafy kelp once swayed amid the waves, providing cover to young finfish and forage for abalones and other creatures on the ocean floor, a stark new world has materialized — one dominated by millions of voracious purple sea urchins that have stripped the ocean floor down to rock in some places. Were a tender frond of new kelp to sprout, it wouldn’t stand a chance of surviving long.

The barrens left behind are a stark and alarming contrast to what is typically one of the most thriving marine environments — seasonal kelp forests that support a rich ecosystem with life stretching from the sea floor to the surface, and up the food chain, supporting recreational and commercial fisheries and home to some of the North Coast’s most iconic wildlife, including abalone and sea otters.

The kelp forests also are a key barometer for the wider health of the world’s oceans, and without some recovery, their future as biodiverse stores for marine life and people hangs in the balance.

Laura Rogers-Bennett, a veteran biologist who works out of the UC Davis-Bodega Marine Lab, likened the kelp forest to a great floating woodlands stretching hundreds of miles along the coast.

“To lose 95% of your forest in a year and a half, that’s a catastrophe, an ecological disaster, and it’s had so much socioeconomic impacts, as well,” she said.

Read more at: https://www.pressdemocrat.com/article/news/scientists-grappling-with-persistent-and-alarming-collapse-of-north-coasts/

Climate Change & Energy, Habitats, Sonoma Coast, , , , , , , , ,

Colorful sea star stricken by disease vanishes from most of the West Coast

Darryl Fears, WASHINGTON POST

Six years after it was stricken by a wasting disease off the northern California coast, the sunflower sea star – one of the most colorful starfish in the ocean – has all but vanished, and the domino effect threatens to unravel an entire marine ecosystem.

The cause of the sea star’s demise is a mystery, but it coincided with a warming event in the Pacific Ocean, possibly tied to the climate, that lasted for two years ending in 2015. It heated vast stretches of water in patches, and likely exacerbated the disease, according to a new study released Wednesday.

“I’ve never seen a decline of this magnitude of a species so important,” Drew Harvell, the lead author of the study, published in the journal Science Advances, that documented the sunflower sea star’s retreat into possible extinction off California and Oregon.

If the study had a purpose, she said, it was to call attention to the sea star’s demise so that federal officials would take action to list it as endangered and work to save it, possibly with a breeding program using sunflower stars that are surviving in parts of Washington, Alaska and Canada.

“It’s big news and cause for major management action,” Harvell said. “We felt there wasn’t enough attention.”

Read more at https://www.adn.com/nation-world/2019/02/01/colorful-sea-star-stricken-by-disease-vanishes-from-most-of-the-west-coast/

Habitats, Sonoma Coast, Wildlife, , , ,

California extends ban on abalone fishing until 2021

Mary Callahan, THE PRESS DEMOCRAT

California fish and game commissioners on Wednesday extended the ban on recreational abalone fishing another two years to give the ailing species more time to recover from a near-total collapse on the North Coast.

The vote continued until April 2021 an existing closure approved a year ago in the wake of a sharp, multi-year decline in the popular fishery, with no signs of a rebound, a key state official said Tuesday.

“There’s no positive news,” said Sonke Mastrup, environmental program manager for the Department of Fish and Wildlife and the lead expert on abalone matters. “We’re still seeing starving abalone this last season during the surveys. We’re still seeing fresh empty shells.”

The closure had been expected but is nonetheless a painful reminder of the uncertain future of a cherished tradition that brings friends and family together and is often passed down from one generation to the next. It could be years before abalone hunting on the level seen in recent decades along the Sonoma and Mendocino coasts, the prime destination, is allowed again, Mastrup said.

Read more at om/news/9058818-181/california-extends-ban-on-abalone?ref=related

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