A Photographer Documents Kelp Forests’ Decline and Efforts to Bring Them Back

In our attempts to restore kelp forests, hungry sea urchins should not be villainized, says Kate Vylet. “Everything’s just trying to survive.”

Just beneath the waves along the Pacific Coast, from Alaska to Baja California, grow underwater forests that rival any on land. Kelp stalks can grow to 100 feet, forming a towering canopy of fronds. The structures support tiny invertebrates, fish, birds, and mammals, and help sustain fisheries and tourism.

Given the ecological and economic importance of these vast hidden habitats, scientists became alarmed 10 years ago when a mysterious disease and an unprecedented marine heat wave battered them, leaving behind only patches of surviving forest. Marine scientist and underwater photographer Kate Vylet has spent the past decade documenting the changes off the central California coast and the efforts of scientists and volunteers to preserve and restore the vibrant habitat. One of her photographs, “Of Blades & Spines,” won the 2023 Big Picture Grand Prize for Aquatic Life from the California Academy of Sciences.

Kelp in Good Health

Sunlight breaks through the canopy of a kelp forest. The fronds at the surface are dense enough to support the weight of egrets and herons as they spear fish hiding among the blades. Meanwhile, visitors like Brandt’s Cormorants (below) zip through to catch a bite. “They go blasting past you and come up with a fish,” Vylet says.

A cormorant bird swims underwater, rays of sunlight shining through dense kelp plants.
A Brandt’s Cormorant dives through the kelp forest in search of a fishy lunch. Monterey, CA Photo: Kate Vylet
Fish swim through a kelp forest underwater, sunlight breaks through the surface illuminating the blue water.
A shoal of blue rockfish swims through a classic California kelp forest. The canopy is so thick it blocks out the sun, casting a turquoise shade across the reef. Carmel, CA Photo: Kate Vylet
A colorful underwater forest of kelp and other plants.
A thick forest of baby bull kelp sway in the surge. This thicket is a group of spring recruits that rode in on a good upwelling. Carmel, CA Photo: Kate Vylet
Viewed from just beneath the surface of the water, a heron stands on a floating log.
Perched atop a floating log, a Great Blue Heron scans the canopy for piscine prey. Carmel, CA. Photo: Kate Vylet
A group of purple fish and a jellyfish swim by underwater plants.
Blacksmith damselfish circle a Pacific sea nettle, looking for an opportunity to take a bite. Monterey, CA Photo: Kate Vylet

Snails and crabs graze on kelp, and the rocky seafloor is home to sponges, sea squirts, and other invertebrates. “There isn’t a single inch unoccupied,” Vylet says. For human divers and snorkelers lucky enough to visit, it’s like being in a terrestrial forest, she adds, with one key difference: “You’re flying through it rather than walking.”

Urchin Invasion

Purple sea urchins are critical to a healthy kelp forest. The echinoderms use their sensitive tube feet to catch drifting kelp blades and pass them into their mouth (slide 2, below). Messy eaters, urchins break seaweed into smaller pieces, which other creatures consume.

Urchins eating a blades of kelp.
Purple urchins chew on a blade of giant kelp that fell from the canopy above. Carmel, CA. This image won the 2023 Big Picture Grand Prize in Aquatic Life. Photo: Kate Vylet
A close-up photo of a sea urchin mouth surrounding by dozens of reaching tube feet.
Looking at the underbelly of a purple urchin, its “teeth” are visible in a mess of spines, tube feet, and its tiny claws known as pedicellariae. Carmel, CA Photo: Kate Vylet
Dozens of purple sea urchins surround a denuded kelp stalk.
Purple urchins pile on a giant kelp growing in the middle of an urchin barren, displaying their active grazing behavior. Carmel, CA Photo: Kate Vylet
A single urchin on a kelp stalk.
A lone purple urchin swings on a single stipe of giant kelp above a barren. Carmel, CA Photo: Kate Vylet

In a thriving habitat, urchins hide from sunflower sea stars, their main predator, in rocky crevices. But a decade ago a perplexing wasting disease obliterated the stars; then historic underwater heat waves weakened cold-loving kelp. With the balance upset, urchins shed their shyness: They “went nuts,” says marine ecologist Mark Carr from the University of California, Santa Cruz. “They came out of cracks and crevices looking for things to eat.” They devoured living kelp, leaving behind desolate “urchin barrens” (slide 4, above), where few other creatures can survive.

The Rescue Effort

Communities up and down the Pacific Coast are working to restore the forests. Volunteers with Reef Check don scuba gear to survey biodiversity and kelp health (below). “Monitoring is key,” says Dan Abbott, who leads the kelp forest program at the California-based nonprofit. Other volunteer divers take a direct approach by smashing urchins with hammers (slide 4, below).

But the creatures shouldn’t be villainized, according to Vylet. “The invisible gears of climate change are shifting the ecosystem,” she says. “Urchins are responding and so is the kelp. Everything’s just trying to survive.”

Two divers float at the surface above a beautiful drifting blade of kelp.
A dive team of volunteer community scientists floats on the surface above a giant kelp, pausing to chat after a dive collecting data for Reef Check, a nonprofit marine conservation organization. These kelp forest ecological surveys are conducted every summer and generate foundational data on the condition of California kelp forests. Carmel, CA Photo: Kate Vylet
A scuba diver holds a clipboard next to a kelp stalk.
A volunteer community scientist surveys a kelp forest and collects monitoring data for Reef Check. Carmel, CA Photo: Kate Vylet
A sea otter swims underwater, its bristly face near the camera.
A southern sea otter dives into the kelp forest in search of a salty snack. Otters help maintain kelp forest patches by feeding on the healthy, plump urchins found within them. Carmel, CA Photo: Kate Vylet
A scuba diver hit an urchin with a hammer.
A volunteer diver for the Giant Giant Kelp Restoration Project smashes a purple urchin with a hammer within an experimental plot reef as part of an urchin culling effort. The project is led by local recreational divers who aim to restore kelp forests by killing urchins. Monterey, CA Photo: Kate Vylet

Facing this reality, researchers in central California are increasingly focused on protecting healthy patches, where sea otters (slide 3, above) help keep urchins in check. Ultimately, Vylet says, saving kelp forests will require reducing carbon emissions as well as hands-on conservation: “Maybe we can help the kelp forest adapt to this new environment.”

This story originally ran in the Summer 2023 issue as “Kelp Forest Adrift.” To receive our print magazine, become a member by making a donation today.