Pool School

At first they just seem like little puddles, hardly enough to fill up a bathroom sink, let alone support entire colonies of creatures.

But when Point Mugu State Park interpretive specialist Cara O’Brien squats down next to a tide pool, the puddle comes alive.

That unmoving squiggle draped across a rock’s surface turns out to be a sandcastle worm. That lumpy brown object huddled in the kelp is actually a California sea hare. And even an empty periwinkle shell has relevance.

“You might look at this and think it would be nice to take home, maybe to make into a pretty necklace or something,” O’Brien said. “But you can throw things out of balance. If people come and pick up these periwinkles, then the poor hermit crab won’t have anywhere to call home.”

October is National Coast Month, when state and federal parks encourage people--especially residents of coastal communities like Ventura County--to get out and explore the seaside. O’Brien said October also marks the beginning of the winter tide pooling season, the ideal time to slip out to the beach at low tide and poke around near the water’s edge.

On Monday, as the sun was setting, O’Brien and Barbara Applebaum, a ranger with the Santa Monica Mountains National Recreation Area, took a group of about 20 people out for a session of twilight tide pooling at Leo Carillo State Beach, right on the Ventura County line, in honor of National Coast Month.

Applebaum passed around a plastic globe to illustrate the evening’s first lesson: Water rules the world.

“Most of the diversity of life we find on earth is found in the ocean,” Applebaum explained. “Tide pools, lagoons and estuaries are where the ocean meets the land. Think of those places as where we have nurseries for the ocean.”

To show the connection between the ocean and human beings, O’Brien pulled out a shopping bag filled with products derived at least in part from the ocean, including imitation sausage links, toothpaste, rice pudding, shampoo and sushi wrappers.

Then they got down to business, scouring the pools for signs of life.

Because of relatively low pollution and a fairly rocky coastline, O’Brien said, the tide pools at Leo Carillo are considered the best between Ventura County and San Diego. Faria Beach and the mouth of the Ventura River near Emma Woods State Beach are also hot spots for local tide pooling.

The city of Ventura’s recreation department frequently leads schoolchildren and groups on tide-pooling trips to the cobbled beach near the mouth of the Ventura River. The next scheduled walk is on Dec. 21.

Within minutes, the group had identified a school of opaleye swimming in one of the larger pools, numerous sea anemones--their green tentacles undulating--and a large ochre sea star.

Laura Bame of Simi Valley, who had brought her 15-year-old daughter along for the event, was clearly surprised at the wealth of life living in the shallow pools.

“I feel awful,” Bame said, feeling the rough surface of a sea castle worm. “I would have just been like . . . and walked right by without looking at it.”

But the find of the day was a pair of California sea hares. The brown, lumpy-looking animals get their name from the long antennae on their heads, but they are actually more like giant sea slugs.

Having recently been traumatized by something--O’Brien’s guess was clumsy humans--the sea hares had squirted out their magenta-colored ink. It filled a tiny tide pool, tinging it with hues of purple and red.