By Jan TenBruggencate
Advertiser Columnist

A new book on sharks and rays in the Islands is a lesson in the biology, history and behavior of this class of marine creatures.

"Sharks and Rays of Hawai'i" reviews the 40 kinds of shark and nine types of rays in the Islands, with photographs of each. It was written by zoologist Gerald Crow, the acting curator of Waikiki Aquarium, and writer/photographer Jennifer Crites. If you're interested in sharks and want to keep an up-to-date volume on the bookshelf for reference, this is it. It's an authoritative book, but easy to read.

The last popular shark book with a scientific leaning was "Sharks of Hawai'i" in 1993, written by former Waikiki Aquarium director Leighton Taylor. Popular local volumes since then have included Jim Borg's 1995 "Tigers of the Sea: Hawai'i's Deadly Sharks" and Greg Ambrose's 1996 book, "Shark Bites: True Tales of Survival."

"Sharks and Rays" details the anatomy of sharks, with closeup photography of their scaly skin and their teeth, and color shots of their livers, gills and cartilage skeletons. There are clear discussions of their sensory adaptations, and their feeding habits.

And there are detailed sections on each of the species of sharks and rays found in the islands. Most of the shots are of swimming animals, some of freshly caught specimens, and with rarer species for which fresh shots were not available, there are preserved museum specimens.

An odd fact about sharks is that despite their reputation as voracious predators, they actually don't eat much—often only half a percent of their body weight per day.

"Sharks ... often go for a week or more without feeding," the authors write. And despite all the talk about their strong stomach acid, "sharks digest their food at a slower rate than do bony fish."

Of course some species, such as tiger sharks, feed on all sorts of inedible fare along with their regular fare of other sharks, rays, bony fish, crustaceans, birds and turtles. Other sharks — notably the whale shark — cruise quietly with their mouths open, swallowing tiny forms of marine life called zooplankton.

Another excellent book just on the market is "The Shark Watcher's Handbook," which is an overview of where in the world to see sharks. In Hawai'i, it recommends charter dive trips along the Kona coast of the Big Island and at Molokini crater off Maui, and also at Midway Atoll, which is now closed to visitors, but could be reopened soon.

"Sharks and Rays of Hawai'i," by Gerald Crow and Jennifer Crites, 204 pages, 400 photos, 2002, Mutual Publishing, $15.95.

"The Shark Watcher's Handbook: A Guide to Sharks and Where to See Them," by Mark Carwardine and Ken Watterson, 232 pages, 60 photos, 25 illustrations, 2002, Princeton University Press, $24.95.

Jan TenBruggencate is The Advertiser's Kauai bureau chief and its science and environment writer. Reach him at (808) 245-3074 or e-mail jant@honoluluadvertiser.com.