A Rocky Life on the Edge

Between the edge of land and the beginning of the sea lies a place like no other on Earth. In the narrow band where surf and turf collide, you can walk across several distinct zones of life in just a few footsteps. In a span of inches and days, evolution unfolds and life-and-death dramas play out between prey and predator.

Intertidal zones are among the Earth’s richest and most dynamic ecosystems. Yet they also are among its most vulnerable. In recent years, the creatures that inhabit the shoreline have undergone changes so dramatic and rapid that scientists now believe they are the result of human pressures.

From a distance, California’s rocky beaches look undisturbed. Boulders remain in the same spots and the tides rise and fall in the same patterns that John Steinbeck observed when he wrote fervently about Monterey Bay’s tide pools in his 1945 classic, “Cannery Row.”

But look closely. Today, a child steps on a rock matted with AstroTurf-like algae and prods some tiny hermit crabs with his finger. But his mother, standing at that same tide pool as a child, saw ochre sea stars and fist-sized owl limpets, feathery seaweed and octopus, black abalone and clumps of mussels.

All along the West Coast, especially in Southern California, the rocky seashore is a vastly different world than it was a generation ago. It is being robbed in many ways, and not just by people who pry mussels and limpets off rocks and bring them home for a bouillabaisse supper.

Climate change has shifted the types of creatures found in intertidal areas, perhaps permanently. The footprints of beachcombers have nearly wiped out many varieties of plants and animals, especially in Southern California. Disease, development of coastal areas and pollution also have taken their toll.

Because these animals live at the junction of land and sea, they are victims of the damage people inflict on both places. Yet they are largely ignored, left to fend for themselves. There are no comprehensive efforts to protect intertidal areas and no strategy to manage them--only a few scattered attempts to patrol a local tide pool.

“For a long time, people thought these systems were really resilient--you couldn’t hurt them,” said Cal State Fullerton biology professor Steve Murray. “What we’ve found out over the past 15 years is we were wrong.”

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It is a fabulous place: When the tide is in, a wave-churned basin, creamy with foam, whipped by the combers that roll in from the whistling buoy on the reef. But when the tide goes out the little water world becomes quiet and lovely. The sea is very clear and the bottom becomes fantastic with hurrying, fighting, feeding, breeding animals.

--John Steinbeck, ‘Cannery Row’

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Willis Hewatt knelt along a rocky beach at Cabrillo Point, which juts out like a granite fist into Monterey Bay. The moon had yanked the ocean away from the shore, and the nooks and crannies were teeming with life.

For two years, Hewatt painstakingly counted every animal that lived along a narrow strip in Pacific Grove 108 yards long and one yard wide.

The year was 1933.

Six decades later, Hewatt’s research has enabled a new generation of scientists to unearth compelling evidence of ecological changes along California’s shoreline.

In 1993, Raphael Sagarin stood in the exact same spot, counting creatures. Sagarin, a doctoral student at Stanford University’s Hopkins Marine Station, located two brass bolts that his predecessor had hammered into the bedrock, so he was certain he was surveying the same strip.

The scientists were amazed by what they found: There were still plenty of creatures, but the mix was considerably different. In all, 46 of 62 species present in the 1930s--sea stars, mussels, crabs, snails, anemones, limpets, worms--showed a significant change in abundance.

One pattern clearly stood out: The populations of a number of species known to inhabit cooler Northern California waters had declined, while ones known to live in warmer southern waters had increased in number.

It was almost as if Malibu had moved to Monterey Bay.

A volcano-shaped barnacle more well-suited to Southern California had colonized the site. So had a worm snail, which cemented itself to rocks, crowding out other life. Porcelain crabs disappeared entirely and once-abundant sea stars dwindled. More than 4,000 dove shell snails--marked with reddish-brown spirals and white spots--were counted in the 1930s, but they had dropped to 255, a 95% decline. Eight of nine southern species increased and five of eight northern species decreased.

Only one explanation seems plausible to the scientists: temperature change. Since the 1930s, the study site had warmed up by 4 degrees Fahrenheit during summers and by an average of 2 degrees year-round. (Temperatures were averaged over a 13-year period for both surveys.)

Oceanographers say temperatures have increased throughout the Pacific since the late 1970s. They suspect this trend is caused by a combination of natural climatic cycles and global warming from man-made greenhouse gases.

“The fact that the pattern was so strong, that almost all southern species increased in abundance and almost all northern species decreased, was very striking to us,” Sagarin said. “There are a number of things that could explain parts of what we saw, but overall the warming climate is the clearest explanation.”

The Pacific Grove site, an ecological reserve at the Hopkins Marine Station, was a perfect natural laboratory because it is inaccessible to the public and spared the impacts of trampling, shell collection and coastal development.

Hewatt’s work, so carefully detailed, offers an everlasting snapshot of a shoreline few people are alive to remember.

“People have images ingrained in their minds of what they think tide pools should look like, and that doesn’t correspond with what they see now,” Sagarin said. “I don’t think intertidal areas will ever be the same.”

Like canaries in a coal mine, intertidal creatures are sending signals that climate change is altering the world’s oceans, scientists say. Some species are ultra-sensitive to slight temperature changes, perhaps because it slows the dispersal of larvae or quickens the spread of disease.

“Intertidal life is the most vulnerable of all marine life,” said John Pearse, a professor emeritus of biology at the Institute of Marine Sciences at UC Santa Cruz. “It’s where the air and land and sea all come together. They’re right on the edge of extremes, so if there are temperature changes or pollution, they are the first to feel the effects.”

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Starfish squat over mussels and limpets. . . . Orange and speckled and fluted nudibranchs slide gracefully over the rocks, their skirts waving like the dresses of Spanish dancers. And black eels poke their heads out of crevices and wait for prey. The snapping shrimps with their trigger claws pop loudly.

--Steinbeck

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Intertidal creatures live in a perpetual state of chaos.

Betwixt and between, they’re not quite oceanic, not quite terrestrial. During low tide, when the moon pulls the ocean away from shore, they are left high and dry, scorched by the sun and picked off by hungry land-based predators. During high tide, they encounter pounding waves and predators that are skilled swimmers. Some survive by hanging on like suction cups. Others burrow into sand or hide in crevices.

While dangerous, the sweep of the tides provides boundless nutrients from the sea for these creatures to feed upon. The intertidal zone measures mere inches in some places, yet it is crammed like a kaleidoscope with a colorful diversity of life.

For centuries, long before submarines and scuba gear, people have been able to peer through this window in the ocean whenever the tide went out. Many of the invertebrate animals and algae they see may look unimpressive, resembling warts or weeds.

One plant looks like red crust on a rock, but it can live almost a century and play a vital role in the seashore’s food web. Some species look like flowers, but they can move along a rock and gobble up prey. The swollen tips of seaweed, so easily trampled, contain sex cells they toss out to reproduce. The algae provide food for plant-eaters such as limpets, and they in turn provide food for flesh-eaters such as sea stars and fish.

“When people drive into the mountains, they spend three or four hours and drive through three or four zones of life. But you can see that in the rocky shore in as little as 15 footsteps,” said Andrew DeVogelaere, research coordinator for the Monterey Bay National Marine Sanctuary.

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He turned over the boulder with his crowbar and now and then his hand darted quickly into the standing water and brought out a little angry squirming octopus which blushed with rage and spat ink on his hand. . . . It was good hunting that day. He got twenty-two little octopi. And he picked off several hundred sea cradles and put them in his wooden bucket.

--Steinbeck

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It can take 70 pounds of pull to pry a limpet off a rock. But that doesn’t stop people from removing them from beaches. Neither do the signs proclaiming “No Take Zone!” and threatening a $1,000 fine.

At any rocky beach, during any low tide, there are always people--whether oblivious or exploitative--who steal the seashore’s treasures. Some use screwdrivers or crowbars. Some use bleach to draw animals out. Some carry buckets or ice chests. What visitors don’t steal, they trample. It’s what Mark Klosterman, Laguna Beach’s marine safety chief, calls “poke and prod and pillage and plunder.”

The entire shoreline of Laguna Beach is a refuge or reserve where collection of anything--even a broken shell--is banned. But there and elsewhere, the prohibitions have had little benefit.

The bans are largely ineffective because they are rarely enforced.

“Without the presence of an enforcement officer out there, literally bucket-loads leave the beach on a regular basis. Everything from starfish to mussels to sea anemones and hermit crabs,” Klosterman said.

During a year of observations at low tides in Dana Point and Laguna Beach, researchers working with Murray of Cal State Fullerton saw at least one person illegally collecting an intertidal creature every 10 minutes.

Southern California’s rocky beaches--about 20% of its coastline--have undergone more severe damage than those in the rest of the state because so many people live nearby. At the Dana Point Marine Life Refuge, as many as 1,400 people--mostly schoolchildren--trample the tide pools during a single afternoon at low tide.

At many beaches, especially from Malibu to San Diego, the most spectacular species--the large-shelled animals and sea stars coveted by collectors and cooks--are gone or depleted.

At San Diego’s Cabrillo National Monument, even though collecting is illegal, owl limpets declined 23% between 1990 and 1995. The survivors are, on average, 10% smaller.

“We’ve lost a lot of what people like to eat, and we’ve lost a lot of the big showy animals,” said Rich Ambrose, director of UCLA’s environmental science program. “That certainly has had a big effect on the ecological community. A lot of those organisms are keystone predators so the whole community will change when they are removed.”

When, for example, sea stars are removed, their prey--mussels--can spread and nothing else will grow there. In some areas of Southern California, even mussels have declined, and scientists have no clue why.

Black abalone have suffered the most dramatic losses. In the 1970s and ‘80s, abalone were piled up on top of each other on California’s rocky shorelines. Now, because of over-harvesting and a disease known as withering foot syndrome, they have almost vanished. The California Legislature in 1997 enacted a 10-year ban on abalone fishing south of San Francisco Bay.

“It doesn’t take too many people going out and collecting for food to have a big impact on these intertidal areas,” said John Engle, a biologist at UC Santa Barbara’s Marine Science Institute. “Some intertidal life can recover very rapidly; others very slowly.”

A large turban snail is 30 to 40 years old, so if a visitor pockets one, it is not rapidly replaced. One 15-minute collecting spree could eliminate an area’s entire population of some plants and animals, such as sea palms, for years to come, according to one study.

Perhaps the most important changes are those among seaweed that most people mistake for beach debris and trample. In many areas, resistant species like turf weed, sea lettuce and coralline algae have crowded out the delicate feather boa, sea palms and rockweed that are more valuable to marine life as food. This, could, in turn, be contributing to declines in the animals.

Some park officials, activists and scientists have broached the idea of closing off some tide pools or limiting numbers of visitors.

For the California Coastal Commission, it’s a particularly thorny issue to close off a beach to save it, said Linda Locklin, the commission’s manager of coastal access. California voters delivered a mandate back in 1972: The Coastal Act requires the commission to protect both public access and marine life--often conflicting goals. So far, the commission has not taken up the issue of limiting access to intertidal areas.

“People are loving [tide pools] to death,” Ambrose said. “We have all these factors hammering our intertidal areas, and we don’t have any management techniques for them.”

***

The smells of life and richness, of death and digestion, of decay and birth, burden the air. And salt spray blows in from the barrier where the ocean waits for its rising-tide strength to permit it back into the Great Tide Pool again.

--Steinbeck

***

The Great Tide Pool has become the scene of the Great Debate.

This is a place almost mythical in its lore--where the protagonist of “Cannery Row,” a biologist named Doc, collected his specimens, and where the real-life Doc, scientist Ed Ricketts, befriended Steinbeck and regaled him with curious tales about marine creatures.

And it is still considered the most spectacular place in the world for diversity of intertidal life. More than 500 species of invertebrates and algae inhabit this rocky shore of Pacific Grove, an area, including the Great Tide Pool, called Point Pinos.

“It’s a place that has almost no limits for life,” said Pearse of UC Santa Cruz.

It also is a place with no limits to the controversy over how far to go to protect the famous seashore.

Pacific Grove is embroiled in a conflict over whether intertidal animals and plants at Point Pinos should be off-limits to everyone--even the world-famous Monterey Bay Aquarium, which removes large numbers of organisms for feeding its otters and filling its exhibits.

Public collection of marine animals is already banned at Point Pinos. But city officials, prompted by a petition signed by 20% of local voters, have asked the state for authority to ban collecting by scientists and the aquarium. The state Department of Fish and Game has refused.

Jim Willoughby, a retired science teacher, initiated the campaign because he believes many of the animals he saw there in the 1970s have vanished. He blames the Monterey aquarium, at least in part.

“The marine life is totally picked over,” he said. “It still looks like a fairyland, but it’s ‘Silent Spring’ as far as the invertebrates.”

There is no scientific data at Point Pinos to back up his claims. The one study in the area found the types of creatures have remained remarkably stable for 25 years, even in areas trampled by many visitors.

No one was more surprised than Pearse, the study’s lead scientist, who expected to find a decline. Pearse said perhaps changes occurred before he began studying the area in 1971. Or perhaps the changes were undetected because they were like those at the nearby Hopkins Marine Center--the abundance of individual animals declined but not the types of species.

In an attempt to resolve the debate, a research team hired by the sanctuary will soon try to decipher what has changed and what caused it. But it’s extremely difficult to study change in an environment where so much change occurs naturally. The aquarium has agreed to stop collecting at Point Pinos during the two-year study.

“The rocky shores here are still vibrant and a beautiful resource, but there definitely have been changes,” said DeVogelaere of the Monterey Bay National Marine Sanctuary.

Much of the decline along rocky beaches is poorly documented, based on anecdotal observations. Two comprehensive long-term monitoring programs have recently begun along California’s rocky beaches, from San Diego to the Oregon border, but they are years away from any conclusions. Even less--virtually nothing--is known about creatures inhabiting sandy beaches.

“We have been negligent in documenting the changes,” Murray said. “Even though these are our most accessible and visible habitats that are known for a diversity of sea life, we have no ability to produce robust scientific data to document the changes in these systems.”

Scientists know that as long as the sea continues to pound the shore, it will attract marine creatures of some sort. But given current trends, will the survivors be only those that are too hardy to destroy or too unappealing to steal?

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A World Within the Tides

Intertidal creatures live in an area that is part land, part water. Within these small tidal zones, a diverse population battles the elements--and sometimes humans--to survive.

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Species in Decline

These intertidal creatures used to be abundant in Southern California, but they have declined for a variety of reasons, including human collecting and disease.

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California mussel

Size: 2 to 10 inches long

Characteristics: Found on rocky shores and in tide pools. Dominates mussel beds, but has vanished from many areas.

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Black abalone

Size: 5 to 6 inches across

Characteristics: Found in intertidal zone. Nearly wiped out by collectors and disease.

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Ochre sea star

Size: 6 to 14 inches across

Characteristics: Found in high intertidal zone. This was the most common sea star, but now is found only occasionally.

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Octopus

Size: A few inches to 12 feet long

Characteristics: Found in shallow coastal waters and inside dens or small caves.

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Owl limpet

Size: Up to 4 inches across

Characteristics: Found on rocks. Collected for food and shells.

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Turban snail

Size: Up to 1.5 inches across

Characteristics: Found in middle tidal zone.

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Note: Not to scale.

Sources: EnchantedLearning.com, UCLA Ocean Discovery Center, UC Santa Cruz biology department, MIT, www.classiccalifornia.com, Monterey Bay National Marine Sanctuary, National Aquarium in Baltimore