Bay Nature magazineSummer 2006

The Ocean

From Collecting to Recollecting

July 1, 2007

We drove to the beach the night before. We slept in the car. My mother woke us in the chilly darkness. At eight years old, I was doubtful about this expedition. But my mother convinced me it would be worth doing on this particular day.

Early that morning at what is now Fitzgerald Marine Reserve, an exceptionally low tide and a full moon would make the reef and its inhabitants more visible than they had been on any of the day trips we’d taken to the tidepools since we’d moved to the Bay Area the year before.

We climbed out of the car and walked to the beach. The doubts I felt during a night spent in a cramped car vanished immediately. Instead of hiding in subterranean safety, thousands of sand crabs were gamboling across the beach in the moonlight. We walked out to the reef, where life was so thick it was like a layer of rain forest painted on the rocks. We caught minute crabs, broken-back shrimp, snails, small sea anemones, and tiny fish called tidepool Johnnies to put in the saltwater aquarium my mother kept at home.

At the north end of Half Moon Bay, Fitzgerald Marine Reserve—run jointly by the San Mateo County Parks and Recreation Division and the state Department of Fish and Game—is still a place where visitors can see an amazing array of creatures, from squabbling hermit crabs to zoned-out harbor seals, all adapted to a harsh but rewarding environment.

My mother was a devotee of this place and of the famous book Between Pacific Tides, by Ed Ricketts (immortalized as “Doc” in John Steinbeck’s Cannery Row) and Jack Calvin. Some call this classic “Ricketts.” We just called it “the Book.”

Anemone devouring crab
A giant green anemone eating a red crab that it capturedwith its tentacles, which are armed with stinging cells callednematocysts. Photo by Ron Wolf.

We all had our favorite tidepooling moments. My sister’s was the naked hermit crab, a sorry sight. In front were the armored head and fierce little claws, but its rear, instead of being tucked into a shell, was exposed as blobby, tender, unprotected against predators. Some other crab must have hijacked its shell. There were no available shells around—they all had snails or crabs in them—so one of us kept an eye on the naked one while the other went up to the beach and brought back empty shells. The homeless crab approached a shell hesitantly, gripped it, ran its antennae over it, and suddenly whirled and jammed its naked rear into the shell. Saved!

Ed Ricketts made his living collecting specimens, and the Book reflects that approach, which can be startling to the modern eye, now that the overriding message on public lands is preservation.

But my mother did want us to collect responsibly. We didn’t take starfish or urchins, because they don’t do well in an aquarium. When we turned over a rock to see who might be underneath, we always turned it back. Not everyone was so careful. People with buckets and crowbars descended on the reef to gather turban snails, mussels, and clams to eat.

Back in the early 1960s and before, college classes on field trips routinely pillaged tidepools for specimens, and students were assigned to make individual collections. Marine biologist John Pearse, emeritus professor at the University of California at Santa Cruz, saw this when he arrived in California in 1959. “They collected everything and laid it out on the beach. It was not so much scientific collecting as school collecting,” he recalls.

My mother gave up the aquarium decades ago, but we kept tidepooling. Over the years since, I’ve returned many times with friends, eager to introduce them to the tidepool life I encountered as a child. When the Fitzgerald Marine Reserve was established in 1969, I liked the idea of protecting the area, but I worried about being excluded.

A little exclusion may have been in order, however. “When Fitzgerald was set up, [the tidepools] had pretty well been scoured clean by school groups,” Pearse says.

Things have changed since then. Under a 2002 master plan, no more than 500 people may go on the reef daily; groups of ten or more must make reservations and go with a docent; and classes below third grade aren’t allowed. Before these rules, 2,000 people visited during some convenient low tides. “It was horrendous,” says Ranger Steve Durkin, recalling bus after bus pulling up. “I was doing more policing than educating.”

Recently I returned to the reserve to find out what had changed and what hadn’t in the years since the area was protected. I learned that the area where we had collected for my mother’s aquarium was just outside the reserve boundary, so some collecting would still be legal with a fishing license. People gather mussels there.

Harbor seals
Harbor seals, year-round residents at the reserve,established a rookery here in 1986. Rangers work to make sure visitorsdon’t approach the seals, which may head for the water when spooked,losing critical time warming themselves or tending to their pups. Photoby Anthony Kent

Inside the reserve, harbor seals established a rookery in 1986, and each spring they give birth to pups. Rangers put up cones with signs warning visitors to stay out of the rookery, but people regularly disregard the signs.

Durkin, who grew up in nearby Pacifica, gives me a tour. He shows me how to find owl limpets by looking for clearings they have grazed in mussel beds. He points out clear borders between groups of aggregated anemones—borders where one group of clones ends and another group of clones begins.

Looking into a tidepool, I notice a rock with an old boring-clam hole with odd shapes sticking out of it. “What’s that?” I ask. Durkin peers intently before explaining. “That’s a predatory snail in the process of eating a limpet!” Like so much that happens in tidepools, this life-and-death drama doesn’t reveal itself immediately, but if you sit and wait, you’ll see events unfold.

Durkin shows me something I could have stepped on a dozen times without noticing, the fossilized rib of an extinct baleen whale. The skull is now at the California Academy of Sciences, he says, and the skeleton is dated at 3 to 5 million years old. The rib itself looks like a branch of petrified wood.

Durkin explains how Fitzgerald’s geology makes great habitat. Because the rock is soft sedimentary mudstone and sandstone, animals like sea urchins, limpets, and boring clams can easily abrade it, creating literal biological niches.

Much of the central California coast is made of similar stuff, but the shelf at Fitzgerald sits near the San Gregorio Fault. “The faulting has created a lot of fractures. The stress fractures create surge channels that allow the water to flow in and out during the tidal cycles,” Durkin says.

We wander around the tidepools, crouching down to stare, waiting to see what emerges. We spot a naked hermit crab. I tell Durkin about the one my sister and I helped out years before. Durkin, who doesn’t even like to turn rocks over, says he prefers not to intervene.

He identifies several species of starfish, and deplores the way people pick them up, ripping them loose, so their clinging tube feet are torn off. An injured starfish will have to hide in a crevice, out of the swirling surf, while it regenerates its feet, which it uses not only for locomotion but also to pry open its bivalve prey. “It’s okay to touch, but we don’t want to tear the sea star off the rock.”

My family called them starfish, but now people often call them “sea stars,” sometimes pointing out that a starfish is not in fact a fish. Rebelliously, I still say starfish. A starfish is not a star, either. Hermit crabs are not reclusive. Sea urchins aren’t children.

I ask Durkin if the reserve shows signs of climate change. Carefully, Durkin says no, but he has seen signs of changing water temperatures, which may have led to changes in the populations of some species. “We’ve seen things becoming more common up here that were more in the south before.” He points out the typically more southerly sunburst anemone, Anthopleura sola, whose radial central markings easily distinguish it from the giant green anemone, Anthopleura xanthogrammica.

Marine biologist Pearse describes the warmer water and the northward-moving anemones as “a good correlation.” The water is a little warmer, and the sunburst anemone is moving north. But scientists are less sure of the actual causation; changes in ocean currents might simply be bringing more larval sunburst anemones to the reef.

One insult tidepools haven’t suffered much is that of invasive species. San Francisco Bay endures a constant onslaught of ambitious intruders. But the coastal edge—with its fluctuating temperature and salinity, and violent surf—is not an easy place for newcomers to gain a foothold.

While the local wildlife can withstand the harsh environment, populations of some species rise and fall based on somewhat mysterious factors. Octopuses, for example. “For some reason we’re on a big slump. We haven’t seen octopuses in a while,” Durkin says.

But there’s been an upswing in nudibranchs, delicate little sea slugs, sometimes beautifully, wildly colored. I’ve seen them in implausible pink, bright yellow, white with glowing orange bumps, and violet with coral appendages. (The colors seem to mean “not edible.”)

I ask about a large chiton called a gumboot (a foot-long mollusk that looks something like a melted brick). I used to see them frequently but haven’t seen any lately. They’re still there, Durkin reassures me, but less common. This is another creature people sometimes thoughtlessly rip loose from the rocks.

Carrying creatures around is also not a good idea. Durkin says he often sees kids with hermit crabs in their hands. When they put a crab down, it will be in new terrain, with unknown enemies. I feel guilty, remembering the aquarium residents we brought back to the reef.

“You learn. I used to collect rocks,” he confesses. Many visitors want souvenirs. “Kids ask, ‘Can’t I just take one?’ I ask them, ‘If someone collected it yesterday, would you find it today?’ They get it.”

Map of Fitzgerald Marine Reserve
Map by Ben Pease.

“[The number of visitors] does take its toll, but the life’s still here. The biodiversity is still here, but some of the abundance is gone.” He sighs.

“Often people say, ‘I see hundreds of schoolkids doing all kinds of damage. Why don’t you close the place down?'” Slowly, emphatically, he says, “You don’t protect something by closing it down.” Educate those kids, and they may turn into protectors.

“These areas are pretty hardy when you get down to it, but collecting can be devastating,” John Pearse says. He notes the recovery he saw at a recent visit to Pillar Point, just south of the reserve. “There were people—and birds—everywhere. Things are changing, I think for the better.”

One sunny afternoon I follow a class of exuberant third graders from Lakeshore Alternative, a San Francisco public school. Their teacher has prepared them well, telling them about the creatures they might see and how to treat the tidepools. On the path to the reserve they race along howling like wolves, but when we get to the water, they slow down, repeat the rules -“no running, don’t turn over rocks, no poking anemones”- and look for rocks with holes made by boring clams, which fascinate them. When they find an occupied hole, a kid exclaims, “We got a boring clam! Right here! A real one! Oh my God!”

Volunteer docent Tina Conway points out some closed sea anemones. Their exteriors are speckled with sand and shell fragments. “Why do they have sand on them?” Conway asks. One kid guesses, “Camouflage?” Conway says, “Yes! And also to protect them from the sun. The sand is like sunscreen for anemones.”

Durkin appears—to cries of “Ranger Steve!”- and goes over the rules again. He shows the group some more tidepool creatures, but then takes off at a run to warn trespassers away from the seals. Conway shows the kids a brooding anemone, with tiny baby anemones budding on its stem.

I look back and see three little girls sprinkling sand on a patch of anemones, which puzzles me until I realize that they are trying to help the anemones by slathering on more sunscreen. These kids would no doubt be quick to find an empty shell for a naked hermit crab. I admire their enthusiastic spirit of protection.

I sometimes wish I had the tidepools almost to myself, as I used to. Personal experience has a double edge. Having scrambled through these tidepools since I was seven, I feel a completely unwarranted sense of ownership, and a corresponding responsibility to guard the place and the creatures there.

I wouldn’t feel right taking tidepool creatures for an aquarium today. I’d be adding another stress to a wonderful place that’s already beleaguered. Like the reserve itself, I’ve changed my focus from collecting to watching and teaching.

I’m glad that some things remain the same at Fitzgerald—children are still being enchanted by tidepool life—and that other things have changed—people are now taught not to overturn rocks wantonly. But they’ll never get me to stop calling them starfish.

Getting There:

Highway 1 at Devil’s Slide north of the reserve has been closed indefinitely for repairs. As an alternative, take Highway 92 west to Highway 1. Head north on Highway 1 toward Moss Beach. The reserve entrance is at the western end of California Avenue. Look for the large “California Avenue” sign and the smaller “Marine Life Refuge” sign just below it.

For tide tables, volunteering information, and tips on responsible tidepooling, go to For tide times, hit the “Visit” link, then click on “Tide Info.”

About the Author

Susan McCarthy is the author of Becoming a Tiger: How Baby Animals Learn to Live in the Wild, and coauthor, with Jeffrey Moussaieff Masson, of When Elephants Weep: The Emotional Lives of Animals.

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