Mulling over mollusk mysteries

Vic and I have been working on a photo guide to the marine invertebrates of the Bolsa Chica for the Bolsa Chica Conservancy for several years now. I was nearly done with the project, but Vic pointed out that the riprap lining the new ocean inlet at Bolsa Chica will provide a rocky intertidal zone with opportunities for colonization.

The new bay will have direct access to the ocean, without the need for water to flow all the way from Seal Beach, through Anaheim Bay and Huntington Harbour, and then through a narrow culvert. Consequently, there will be a much wider diversity of invertebrates in the newly restored Bolsa wetlands than the muted tidal system of Inner Bolsa Bay could ever offer.

To learn more about the invertebrates that may make Bolsa Chica their home in the future, we visited Cabrillo Marine Museum in San Pedro and the Aquarium of the Pacific at Long Beach. We also expanded our surveys and photographic forays to include Bolsa and Huntington Beaches, the Huntington wetlands and the tide pools at Corona del Mar and Laguna Beach. We found a lot of species that we’ve never seen in the tidal system of the Bolsa Chica Ecological Reserve.

I finally got tired of unsuccessfully avoiding each wave that lapped onto the sand, then throwing my cross-training shoes into the washer after every beach trip. Call me a wimp, but there are too many nasty things like tar balls to step on for me to feel comfortable going barefoot. I decided that I needed new footgear.

Henry David Thoreau warned us 150 years ago to beware of all enterprises that require new clothes. But I wanted to get up close and personal with the clams, chitons and crabs. Staying dry on the shore just wasn’t cutting it for me, so I bought a pair of waterproof Keen hiking sandals. They’re made for slogging through mud on mountain trails or hiking up creek beds. They work great for the beach and tide pools too. Because the toes are enclosed, I feel much more protected. A bonus is that they’re amazingly comfortable. The only drawback is that they’re ridiculously expensive.

Tide-pooling is a cautious venture. The rocks are covered with living animals that don’t want to be crushed. Just because my toes are protected from the barnacles and anemones doesn’t mean that it’s OK to tread on them.

Vic is happy to watch from the dry side of the intertidal zone. He generally has his eyes to the sky anyway, watching for birds. It’s best that he not get into the water and be blind-sided by a rogue wave.

Identifying the wide variety of shells that wash up on our local beaches has been quite a challenge. The array of limpets, clams and snails is boggling. We’re learning new species each day, from thin, translucent, delicate, yellow jingle shells to raspy, white, spine-covered rough piddock clams.

One of our favorite beach critters is the bean clam. These tiny, colorful clams live in the intertidal zone and are constantly being dug up by the waves. They’re tumbled shoreward on each incoming wave, but they quickly burrow back down on the outgoing wave. Maybe they’re small because they use so much of their energy trying to hang on to their little patch of shifting sand.

Before we started this project, we were content with simple identifications, like being able to tell a California mussel from a bay mussel. But when we started looking at shells closely and using guides such as Robert Morris’ massive “Invertebrates of California” or Sam Hinton’s smaller “Seashore Life of Southern California,” we realized that there were date mussels, straight horse mussels, ribbed horse mussels and more. It’s a challenge. We still can’t tell a Lewis’ moon snail from a southern moon snail.

Most of what we find on the beach are mollusks, or actually their dead remains, the shells. As a biology instructor, Vic is well aware that mollusks are divided into several groups. He tells me that the big subgroup is the gastropods, literally translated from Latin as the stomach-foots. That group includes snails, limpets, abalone and other one-shelled animals, plus sea slugs, which actually have a shell buried in their soft tissue.

The best way to see a good variety of snails is to look for hermit crabs in tide pools. They’ve already grabbed the best empty snail shells for their homes. That is why we leave empty snail shells in the tide pools -- the hermit crabs need them.

Bivalves are mollusks with two shells, or valves. That group includes scallops, oysters, cockle shells and clams, of which there are a great variety.

Chitons are a fairly inconspicuous group of mollusks. Local chitons are bumpy things the size of a finger joint. They spend their lives in shallow depressions that they carve in rocks. Usually they are hunkered down tight against the rock to withstand battering by waves. Octopus and squid make up the remaining group of mollusks, and are rarely seen.

If you like a challenge, visit the beach or a tide pool at low tide. Try to name as many critters in the tide pools as you can, or see how many species of shells you can find on the beach. But just take pictures, not the live animals. You’ll find a different challenge with every new tide.

* VIC LEIPZIG and LOU MURRAY are Huntington Beach residents and environmentalists. They can be reached at [email protected].

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