A Sleuth’s Guide to Tide Pool Treasures

he California coast is home to a treasure-trove of fascinating creatures that one doesn’t have to scuba dive or snorkel to find. An exceptional viewing opportunity sits a stone’s throw from The Resort at Pelican Hill,® in the tide pools at Crystal Cove. Teeming with spectacular sea life, the pools can be accessed via the Historic District at the park’s midpoint or Pelican Point to the north.

“Tide pools are where the sea meets the land,” said Sara Ludovise, director of education for the Crystal Cove Conservancy. “One of the reasons we have such cool tide pools is because our cliffs have concretions, or rock blisters, that formed millions of years ago.” The concretions resulted from boulders falling from the cliffs to the beach, leaving large, sometimes flat rocks that were ideal homes for tide pools.

The ever-changing water level in intertidal zones means that only the hardiest of aquatic souls can survive life in a tide pool. Plants and animals, said Ludovise, “have to adapt to both underwater living and to the sun, heat and air when the tide goes out twice a day.” Changing ocean conditions present further challenges, according to the president and CEO of the conservancy, Alix Hobbs. “We’re starting to see more drastic tides and storm events, and that’s causing increased stress on all the animals,” she said.

Sea creatures are also increasingly susceptible to pressure applied by people, Ludovise said, noting that visitors are prohibited from removing anything from the tide pools. “A shell might look like nothing is living in it, but a lot of these creatures discard their shells and take up residence in a larger one. If we remove the shells from the habitat, that is a potential problem for the growing marine creature looking for his next home.” Perhaps most importantly, any living thing removed from the shore cannot survive outside its natural environment. The tide pools are explored by millions of human visitors each year, and if everyone took home a souvenir, the impact on the ecosystem would be devastating.

Tide pool dwellers are visible and their rocky habitats accessible only during low tide, ideally when the water falls below 1½ feet. (Find tide charts at tide-forecast.com and other online sites.) A note of caution: The rocks can be sharp and slippery, so wear sturdy shoes that you won’t mind getting wet.

Tide pool sculpins are small fish that live almost exclusively in tide pools. They have a homing ability that allows them to locate pools they have adopted, returning each time the tide goes out. They can briefly breathe air to evade predators or find a new pool when an older one dries out.

Aggregating anemones collect bits of broken shells on their bodies for camouflage and sun protection. Each anemone in a cluster is actually a clone of the original anemone that colonized the spot. Two genetically different colonies will use their stinging tentacles to wage war for territory.

Hermit crabs use their hard shells to protect their abdomens, and move into discarded snail shells as they grow. They can fight fiercely over a perfect shell; if you find a tight circle of them, a shell exchange ritual might be taking place. Once they secure a new home, they quickly leave the group.

Giant keyhole limpets, a relative of snails, feed on algae by scraping at it with their teeth-covered tongues, known as radulae. Their shells are covered with a rubbery mantle, except for a hole on their back that is used to filter water over the gills.

Sandcastle worms live in colonies and construct honeycomblike fortresses of hardened sand. At low tide, they hide behind a small shield, called an operculum, presenting their feathery tentacles only when fully submerged. The tentacles catch plankton and more sand grains, which they sort to repair their homes.

Warty sea cucumbers feed on marine detritus. When frightened, they can eject their entire digestive tract as a diversion to allow them to escape.

Ochre stars are voracious predators that eject their stomachs from their mouths to dissolve the shells of hapless prey. Along with other California sea star species, they were recently impacted by a disease that caused their soft bodies to melt. Because they help prevent populations of mussels from overtaking tide pools (by eating about 80 mussels a year each), ochre stars are essential to this ecosystem.

Purple sea urchins feed on algae, especially giant kelp. Control of sea urchin populations by predators like sea stars and sea otters is important to keep California kelp forests healthy. Sea urchin cells and DNA are being used in the search for cures for Alzheimer’s and other degenerative diseases.

Commonly found in mussel beds, the tentacles of the giant green sea anemone are packed with stinging cells that allow it to capture prey and defend against predators. These cells can’t pierce human skin; they feel sticky rather than painful.

California sea hares have rabbitlike protrusions on their heads that they use to taste and smell. They gain their coloration from the algae they eat and can vary in color from dark red to bluish green. When startled, they release a cloud of purple ink.

Striped shore crabs dart from cracks in rocks and defend themselves with small claws. They can spend a long period of time out of water, returning only to moisten their gills. These omnivorous crabs feed on algae and smaller invertebrates (animals lacking a backbone).

California mussels grow in large beds on rocky shores. Under the right conditions, they can grow to 8 inches in length and live up to 20 years.

THE RAREST OF THEM ALL

Abalone are large marine snails with an inner shell composed of iridescent mother-of-pearl. Hunted to near extinction, abalone are now protected but remain endangered. They are a rare sight in tide pools.

The California two-spot octopus can change skin color and texture to blend in with its surroundings. Because it feeds on shelled mollusks and arthropods, piles of discarded shells may be a telltale sign of an octopus lair.

Spanish shawls are a type of sea slug called a nudibranch. They feed on sea anemones and hydroids, storing their stinging cells in gills on their back. Their bright violet-and-orange coloration warns predators of their toxic payload.

By land or by sea, a guide can add flavor to your coastal experience. Join one of the many docent-led tide pool walks the conservancy hosts throughout the year, listed at crystalcove.org/events; or, if you prefer a private tour, local outfitter Expert Active can arrange one. Do-it-yourselfers can bring along our handy guide and be their own sea life sleuth.

_{Ian Fries, who provided the sea life descriptions above, is a lifelong marine biology buff who was inspired by countless childhood beach excursions to Crystal Cove. He is a senior at Reed College in Oregon. Rex Barnard, a local sea life photographer, generously donated eight of the images in this guide. Other photographs courtesy of National Park Service (hermit crab), Roban Kramer (sea cucumber), Ed Bierman (Spanish shawl), Elyssa Fournier (California mussels).}