Barrels of Fun

It is such fun to find opisthobranchs, especially nudibranchs, when diving. They can be so intricately colored and lively in their ways - the instant favorites of many people who stick their heads under California's offshore waters.

Nudibranchs are also such fun to photograph, almost a sure-fire way to preserve the pleasant memories of diving on film, with great macro-shots just about every time.

But nudibranchs are not the most fun-filled creatures to try to preserve in ways other than on film. There is nothing sadder-looking than a gloriously beautiful Spanish shawl nudibranch that's been put in a jar of formaldehyde. Its former brilliance may now be a drab gray, at best.

There are, however, some opisthobranchs that are always fun to see, no matter where they are or what state they're in. These members of the families Acteonidae and Cylichnidae are "barrels of fun" really, for they form attractive, solid barrel-like shells, and hence are called "barrel snails."

Furthermore, the fact that barrel snails don't really look that much like those well-known nudibranchs makes them even more fun to learn about. And there is a lot to learn, for unlike those fancy nudibranchs, barrel snails tend to be overlooked, not only by casual beachgoers, shell collectors and divers, but even by serious researchers.

That's too bad. The striped barrel snail (Rictaxis punctocaelatus) is actually quite common all along the California coast, in sandy and silty areas. It tends to cruise around, either along the surface of the soft sea floor, or plowing through the muck. Its shell is not as barrel shaped as some other barrel snails and may, at first glance, appear to be a snazzy type of olive snail. But its body has the distinctive head-shield of all members of the opisthobranch order to which it belongs, the Cephalaspidea.

The striped barrel snail is the only California representative of the Family Actoenidae. Its shell is rather small at less than an inch in length, but typical for that family. The more numerous members of California's Family Cylichnidae tend to be even smaller.

The common barrel bubble snail (Acteocina culcitella) is the smallest to be found, usually only about a quarter of an inch long. It ranges from Monterey, south, often in abundance, in intertidal mudflat areas - not the normal fun places that most divers like to explore. The white barrel bubble snail (Cylichna alba), is only slightly larger, but has a much larger range of virtually all north polar regions, so it can be found, not only along the Pacific Coast, but also in the North Atlantic, including European shores.

Barrel snails are carnivorous and feed on various small animals that also inhabit areas of soft sediment. Some species eat worms, others foraminiferans, others small snails. Like all opisthobranchs, they are hermaphroditic. They lay their eggs in gelatinous sacs that they attach to the soft bottom by means of thin threads.

As with so many opisthobranchs, how common barrel snails are, and actual locations to be able to find them sort of roll around no definite reason. For many years, therefore, barrel snails will hardly be seen, even by those who know what they are. But then, all of a sudden, their numbers will explode and they will be all over the place, en masse, seemingly by the bucketful. When this occurs, then fun can also happen. Divers can add lots of nifty close-up shots of barrel snails to add variety to their collection of more colorful nudibranch pictures, and beachgoers can look for the empty remains of barrel snails to add to their collection of more colorful shells. And any photo collection or shell collection that includes some of these is sure to be unique.

All this, of course, only adds to the fun of exploring the marine world. Because a big part of the fun of diving is never knowing what will show up, even in oft-dived, familiar sites.