Cabrillo museum tours explore tide pools’ miniature worlds.

You don’t need a guide to visit the extensive tide pools below the San Pedro bluffs that stretch from Cabrillo Beach to well beyond Point Fermin.

After all, the pools are a natural formation of rocks and water harboring sea life, and they are readily accessible to everyone at low tide.

But if you don’t take advantage of the free weekend tide-pool field trips led by Cabrillo Marine Museum naturalists Jim Burcheri and George Van Doren, there are a few things about the area you may never know.

For example:

- Kelp, which is plentiful at the tide pools and floats atop the sea just offshore, is the fastest-growing plant in the world and can add 2 feet a day to its length. And it’s a plant of many uses, turning up in such things as ice cream, makeup and medicine. “It’s a fountain of plenty,” said Van Doren.

- Some rocks contain easily overlooked petrified vertebrae of gray whales that lived 10 to 12 million years ago.

- Those loose, oblong rocks that have holes in them aren’t volcanic. Those holes, says Burcheri, were made by rock-boring clams.

- The plentiful lumps of coal aren’t signs that there is a coal mine nearby. Said Van Doren: “A cargo ship foundered back in the early 1900s. It carried coal (that has) been washing up ever since.”

- And nearly every time you take a step on a tide-pool rock, you’re treading on tiny creatures that have attached themselves to it--a shelled limpet or a barnacle that looks like the cone of a tiny volcano. “A lot of people will say they’ve been here many times, but they didn’t realize what they’re walking over,” Van Doren said.

Burcheri and Van Doren offer their 45-minute tide-pool explorations on Saturday and Sunday afternoons. While museum staffers have been taking people to the tide pools for years, regular trips were started last fall. Museum Program Director Larry Fukuhara said they quickly caught on, and most have drawn at least 50 people.

A new series of tide-pool visits starts Saturday at 3:15 p.m. and continues through March 19, with tours beginning at the museum information booth. Times vary each weekend according to the tides; an exact schedule may be obtained by calling the museum. Children under 13 must be with an adult.

The recommended dress, said Fukuhara, is warm clothing and shoes that will not slip on wet rocks--preferably tennis shoes. Cameras are welcome, he said, but plastic bags or buckets are not, because the tide pools are part of a state marine refuge from which nothing may be removed.

“We want to give people a picture of what sea life is all about,” says Van Doren.

And in the process, visitors get a little information about Los Angeles Harbor as well as a talk on how to improve its ecology. That comes as the guides comment on the soft-drink cans, plastic and other debris that invariably washes up on the shore. “We try to get the message across that the ocean isn’t the place to throw your trash,” said Van Doren.

This time of year, too, tide-pool explorers sometimes catch glimpses of migrating whales out at sea.

The trips are definitely hands-on experiences. The naturalists point out spindly purple sea urchins at the bottom of shallow pools, pick up sea hares that resemble large snails without shells, and prompt sea anemones to close with a touch. “When your finger feels sticky, you’re being stung, but its harmless,” said Van Doren.

“This is a high-density, high-diversity area, where you have a lot of things close together,” said Burcheri, drawing imaginary lines around 2 square feet of rock. Within that small space, he said, are various kinds of barnacles, limpets, sea anemones and 8-plate chitons that look like crusty, segmented worms.

But while the tours are hands-on, they’re not intended to be splash-in, although that sometimes happens when people slip into pools in their eagerness to touch an animal. “Some of them get pretty wet,” said Van Doren.

Burcheri said the most frequently asked questions are what the various sea creatures eat--most are vegetarian--and what they do all day.

“Just what do they do?” puzzled Burcheri. The answer is cling to their rocks or skitter around in the pools.