California Coast & Ocean

Slugs: slimy, squishy, icky garden pests; startlingly huge banana-like woodland creepers; snails without the pretty shells—what’s there to like about slugs? It’s hard to imagine that there are thousands of species of slugs that are among the most beautiful, fascinating, and diverse creatures on the planet, but it’s true. The secret is that they’re marine animals that live mostly out of sight of land-dwelling bipeds. Digital underwater photography and video, in combination with the Internet, are bringing awareness and appreciation of these little jewels of the sea to a broader audience.

The sea slugs belong to a subclass of marine mollusks called opisthobranchs, which are closely related to sea and land snails and to slugs. They are soft-bodied, and most have no shells (though some have small or vestigial shells, sometimes hidden inside their bodies). They live in ocean waters around the world. The best known are the nudibranchs, of which there are more than 6,000 named species, with another 800 to 1,000 still undescribed. Along the California coast, 215 species have been identified, with eight to 15 still unnamed.

I first saw a live nudibranch in 1999, when Tim Anderson pointed out a gorgeous Hermissenda crassicornis crawling across his “Fouling Species Study Station” in Bahia Cerritos Marina, on the Los Angeles–Orange County border. (See Coast & Ocean, Winter 1999–2000.) It was not until I was researching last issue’s story on eelgrass, however, that I discovered the on-line resources that are so rich in images and information. I found myself drawn back to these sites again and again, intrigued not just by the extraordinary creatures, but by the community of people who photograph and study them.

This article is greatly abridged. For the full text, see the print edition of Coast & Ocean.

There are many excellent opisthobranch web sites, with abundant photos, videos, and links. A good place to start is Mike Miller's Slug Site (http://slugsite.tierranet.com).