The Mysterious World of Bull Kelp

Northern California Coast centering on Fort Bragg and Mendocino.

Kelp Squiggles are a Sign

The yellowed, hand-drawn 1880s nautical survey for the stretch of Pacific waters that covers the southern section of Mendocino county coastline has one outstanding feature: a thick curving line stretching from the top of the navigational map to the bottom indicating an unbroken kelp bed along this coast (see below). On close inspection this curving line is made up of thousands of small inked squiggles. The line of squiggles hitches ocean-ward in a squared off protrusion at one of the few points on the coastline that has a name: Saunders Landing. The line of squiggles indicates the bull kelp that thrived in the cold, rough waters off the coast of Sonoma and Mendocino counties before they were even counties. That hitch is the bull kelp of Saunders Reef, a persistent kelp bed whose glistening tubular kelp we can see today from the pullout on Route 1. These magnificent organisms might be direct descendants of the bull kelp of the 1800s.

Looking out at Saunders Reef, 15-foot waves break one hundred yards out and push massive volumes of water in amongst the fragments of the continent, the chimneys and rock outcroppings that stand up along the rugged coastline. The kelp and seaweed ecosystems need to be rejuvenated by the energy and dynamics of winter storm systems, spring winds and seasonal upwelling—the conveyor belt of feedstock for the planktonic and algal base of the food chain. This upwelling of nutrients provides the resources the bull kelp need for its prodigious spring-time growth, from a tiny, fragile leaflet at the ocean bottom in March, to the massive sixty-foot stipe and bladder streaming up to 60 magnificent blades by July. In turn this churning ocean and kelp forest supports the sea birds wheeling overhead, the flash of a seal thrashing salmon in the surf, migrating whales, other fish species and so much more.

+ Click to enlarge

1881 hydrologic survey chart, US Coast & Geodetic Survey, Bourne Rock to Schooner Gulch, CA. NOAA archives. Kelp scan overlay, kelp squiggle highlight and enlarged by Josie Iselin.

This stretch of coast is traditional Kashia territory, where summer villages would be established to collect seaweed (ʔoṭʰono), abalone, mussels and urchin. The massive bull kelp bed—c^hanamá (bull kelp in Pomo)—viewed from the high cliffs or washing up in huge piles of massive wrack, in the tight coves and long beaches farther north is an integral part of this coastal richness. In 2015, 700 acres of Sonoma coastline was reestablished as Kashia territory. This transfer of coastal stewardship back to the humans that managed its ocean plentitudes for self-sufficiency for 12,000 years, marks, hopefully, a reversal of the perverse tendency of non-Indigenous humans to mine resilience out of these rich ocean waters and surrounding landscapes. The Russians established Fort Ross, just south of the Pomo reserve, in 1812 to hunt sea otters and establish an agricultural depot to support their colonies in Alaska. Soon after, logging interests decimated the redwood forests of the north coast, constructing chutes jutting off the treacherous coast to slide the massive logs onto schooners waiting offshore.

There is no doubt that if the growing population of European Americans on California’s north coast had found value in forests of the sea, like they found in the forests on land, they would have figured out how to harvest it for commercial gain. In 1911–1912, the abundant kelp beds of the northern Pacific coast were considered potentially valuable as a source of potassium, an essential ingredient in the growing commodity of fertilizer. The US Department of Agriculture commissioned surveys of the kelp beds of the American Pacific Coast and Alaska, with the Saunder’s Reef bull kelp recorded as kelp bed Number 35. But by 1915 synthetic manufacture of fertilizers was burgeoning and the bull kelp of the North Pacific fell back beneath the surface of economic consciousness. Today, the bull kelp forests of Sonoma and Mendocino are regaining attention, not because of abundance but because they are disappearing. The great bull kelp beds along this stretch of California Coast are virtually gone. Saunders Reef is one of the only substantial strongholds of kelp remaining.

Sea Otter and Sunflower Sea Star: Are They Here?

No. There are no sea otters along this rugged coast.

Sea otters have not swum regularly in Northern California waters since they were extirpated in the fur trade by the 1880s. Without predation by sea otters, red abalone grew large and abundant along the northern California coast, and recreational abalone diving (no scuba, just free-diving allowed) became a favored way to connect to the coast, the ocean, and to family across generations. This ab-diving community created economic opportunity in former mill towns along the Mendocino coast. Until more recently, sea otters were reviled by fishers and abalone divers alike as “rats of the sea,” competing for abalone and commercially valuable red urchin. Now that the kelp has declined and abalone along with it, sea otters are acknowledged as an important part of a healthy kelp forest system. The first conversations about sea otter reintroductions are happening on the Northern California coast.

No, they are no sunflower sea stars here either.

Since a sea star wasting disease wiped out the population in 2013 and 2014, Pycnopodia have not been found in Northern California waters.

Photo by Marco Mazza

Red abalone under bull kelp

Photo by Marco Mazza

What’s Driving the Economy Now? Humans as Top Predator

The economic drivers of California’s north coast communities continued to change, with other characters from the kelp forest becoming major factors in the boom and bust economies of Mendocino and Sonoma. Fishing out of Bodega Bay and Noyo Harbor at Fort Bragg has always been one of the more stable livelihoods for local residents, especially as the adjacent saw mills declined. Both harbors open onto productive fishing grounds for salmon, groundfish, crab, and shrimp, but in 1977 the Subsurface Progression dive shop opened in Fort Bragg to service the increasing number of recreational abalone divers coming to the north coast to free-dive for red abalone.

The abalone diving of the north coast became legendary throughout the state, not just for the prize—dinner-plate-size abalone brought back to the surface to barbecue for Sunday dinner with family—but as importantly, for the experience of the bull kelp forest in its true abundance. Diving with only mask and snorkel amongst the understory kelp with bull kelp above, searching for the right sized abalone, is a near religious experience. The rough and cold water conditions make the challenge of ab-diving even more treasured. The abalone shells nailed to wood fences all over Sonoma and Mendocino counties signal a spiritual connection to the kelp forest that is palpable when talking to any abalone diver. Usually missing during these years of red abalone abundance was the acknowledgement that this wonder for humans was possible because their main predator, the sea otter, was gone.

The recreational abalone fishery was an economic boon to the town of Fort Bragg, where the saw mills had shut down. Motels and restaurants popped up to service the diving tourists who would access the cold Pacific waters from small coves between the soaring cliffs or from the beach at Little River/Van Damme State Park, a white sand beach looking out on a historic bull kelp bed filling the cove from the cliffs to the south to the caves and shoreline to the north. (Notice the rounded image at the top of this page: this is Van Damme Bay today…no bull kelp at all). This recreational passion is on hold with the collapse of the kelp forest ecosystem. The abalone fishery was closed in 2018 and SubSurface Dive Shop is no more.

Uni is the roe, or gonad material, from healthy sea urchin. It is a delicacy as sushi around the world.

Sushi Means Uni Gets Hot

In the late-’80s and early 1990s, human activity again mimicked the top predator role that had been emptied by the sea otter fur trade a century earlier. Sushi came to the US, Japan’s economy was hot, and a market for fresh uni, or sea urchin gonads, suddenly emerged. Diving for red sea urchin by walking along the bottom with a hookah line for air, became a fishery managed by the California Fish and Wildlife agency, supporting 10–15 urchin dive boats out of Noyo Harbor by 2011. The prize were the abundant, ancient, softball-sized, red-spiked Mesocentrotus franciscanus, or red urchin. Thousands of pounds could be easily plucked off the ocean floor and brought up to the dive boats in baskets. Millions of pounds of urchin were landed and processed. No one paid attention to the smaller purple urchin, (except the sunflower sea stars, a constant presence in these waters until 2014). The red urchin fishery made lots of money until recent years. The overpopulation of purple urchin and the resulting collapse of the kelp forest has flipped the color scheme of the ocean bottom; urchin barrens are mostly purple with just a few red urchin in the mix. The red urchin fishery has been in free fall. But there are now more than a few groups trying to ranch purple urchin, which means feed them kelp in tanks, fatten them up, and market them as luscious, tasty uni.

Abundant Kelp in 2008

Shaded yellow bars indicate El Niño warming events, red bar the warm ocean “blob,” and dashed line starfish wasting disease.

Meredith McPherson et al, 2021.

As a result of the human predation of abalone and the red urchin, the prime herbivores in the kelp forest, the bull kelp thrived. It was cyclical in abundance as is typical, but in its boom years it was resplendent. California Fish & Wildlife flew small planes to survey the kelp canopy and created a first database of kelp abundance, but by 1984, satellite data could be used to determine kelp canopy from above, and created a much better graphing of bull kelp abundance on the Mendocino and Sonoma coasts. The satellite data clearly shows the three-four year cycles of bull kelp canopy fluctuations with 2008 being a boom year of all boom years. In a photograph of Van Damme State Park in July of 2008 the tubular bull kelp is massed so densely on the surface of the water that a heron could walk from one side of the bay to the other, without getting its feet wet. The abundance below this mass on the surface was known to recreational divers, scientific researchers, tribal members and to the beachcombers encountering the great masses of bull kelp tangles that accumulated regularly on the beaches, especially after the first winter storms. According to satellite monitoring, 2012 and 2013 were the last years of kelp abundance on the north coast.

Bull kelp, Van Damme 1988 Diagram

From 1993 report on bull kelp abundance in Van Damme Bay, CA Department of Fish and game, Marine Resources Division.

Bull kelp, Van Damme, 2008

Photo by Ron Levalley

Bull kelp, Van Damme, 2017

Photo by Josie Iselin

Bull kelp, Van Damme, 2021

Photo by Josie Iselin

Regime Shift

Top: Urchin eating kelp at Van Damme, 2017
Photo by Josie Iselin

Bottom: Purple urchin barren
Photo by Abbey Dias

And then it went away. Sea star wasting disease was first detected at the end of 2013 and felled all sea stars on the west coast during the years of 2014 and 2015. Millions of sunflower sea stars, before now unassuming in its role as purple urchin predator, vanished from the waters. Simultaneously an ocean heat wave, known as “The Blob”, plus an El Niño event, parked a large mass of warm water offshore raising the surface temperatures by as much as 2.5 degrees Celsius—a huge amount. The warm water on the surface did not allow the deeper colder waters to rise up, putting a lid on the upwelling of critical nutrients. The third event, surmised to be a result of the previous two, was an explosion in purple sea urchin abundance. The annual surveys of the Mendocino and Sonoma coast done by Reef Check reported that the purple urchin numbers as measured before and after the sea star wasting disease/Blob events increased by over 3,000%. And these hungry purple urchins (though native to these waters) with no predators, are eating the kelp. Lots of it. Kelp canopy mapping and monitoring have shown a greater than 96% loss in bull kelp canopy in many places along the coast.

Many places along the Sonoma and Mendocino coasts have had a complete regime shift from kelp forest to urchin barren, a rocky bottom with nothing but spiny purple urchin covering the substrate. Bull kelp has adapted by moving inshore where urchin are uncomfortable in sandy and wave splashed zones. It is now not uncommon to see bull kelp growing in the intertidal zone, short stiped, but mature bull kelp washing up on beaches.

Kelp Restoration Efforts Abound

And many folks have jumped in to do something about the dramatic loss of kelp; urchin divers and researchers alike have organized kelp restoration projects at a number of sites along the North Coast, including at Fort Ross, Albion Cove, Noyo Harbor and more. Kelp mapping and drone surveys by the Tribal Marine Stewardship Network, CA Fish & Wildlife, The MPA Collaborative Network and The Nature Conservancy are targeting small sections of coastline to determine local kelp abundance. Kelp restoration guide books have been written and working groups set up to establish best practices and encourage collaboration across sectors. The power of organized volunteer dive crews as well as commercial urchin divers to clear urchin from restoration sites has been proven. The marine labs at Bodega Bay and Moss Landing are hives of activity, growing baby bull kelp to outplant on different substrata. One project alone is a collaboration between three labs at different universities, a federal marine sanctuary, state agencies, a non-profit, and the lab itself.

Photo by Rachael Karm/NOAA

Baby bull kelp growing under grow lights at Bodega Marine Lab (UC Davis and Hughes Lab) to be out planted on the Sonoma Coast.

Photo by Rachael Karm/NOAA

Perhaps most importantly the community at large has become aware of the importance of the kelp forest to the health of all the other organisms—both below the surface and above—to the health, biodiversity, and richness of the coastline they cherish. The Noyo Center for Marine Science has been a “help-the-kelp” hub for the communities of Fort Bragg and the Mendocino coast. It has received funding to further this mission by developing a marine science center on 11.5 acres overlooking the Pacific, adjacent to recently protected coastal bluffs that make up the western section of the city of Fort Bragg. This was the Georgia Pacific lumber mill site, the historic economic driver of the city, now evolving into a blue economy, thanks to hard work and foresight by city and community leaders acting together.

Like the Kashia Pomo Coastal Reserve to the south, the reclamation of coastal property within Fort Bragg by humans experimenting with how to restore resilience into the kelp forest ecologies just offshore is a welcome relief. The mining of resilience out of ocean systems has been such a common endeavor by non-Indigenous communities for so long, it will be hard to swivel human needs and desires away from extractive and environmentally detrimental practices. But these two spaces on the high bluffs overlooking the turbulence and energy of this section of the California coast offer great hope.

Resources

This is just the beginning. Please go to our Northern California Resources Page to learn more about the kelp work being done in this region.