Of all the marine life I see in the ocean, corals for me are the hardest to sort out.  A lot of them look like rocks; others appear soft and feathery; some are thin, flat and fanlike; a few are fat, round and cuplike.  Or wiry.  The first time I saw wire coral I thought a piece of junk had gotten stuck in the reef. 

A coral’s lifestyle is no easier to figure.  All are carnivores, but some have plants growing inside them.  Others host no plants at all.  And these sedentary creatures’ closest relatives are jellyfish, the oceans’ drifters. 

It’s enough to make a marine science writer want to skip the whole subject. 

But there’s hope for me yet.  During a visit to a big, new bookstore last week-end, I found a 2005 book called “Corals of Hawaii” by Douglas Fenner.  Dr. Fenner, a coral taxonomist, is chief biologist at the Department of Marine and Wildlife Resources in American Samoa.

I have several other coral field guides in my library, but this one speaks my language.  Literally.   Fenner, bless him, provides English names to each species, giving us Latin-impaired folks a leg up on learning our corals.

Another concept I love in this book is the presentation of Hawaii’s five most common corals on the same page.  “Learn these first,” writes Fenner, “and right away you will be able to identify many or most of the coral you see!”

  This enthusiastic writing is infectious.  This biologist obviously loves corals and wants other people to love them too.  Or at least be able to call them by name.

So I learned some.  Hawaii’s five most common corals are lobe, finger, cauliflower, rice and sandpaper rice coral in that order.  Large colonies of lobe coral, Fenner says, are some of the world’s oldest animals.

The author doesn’t give a ballpark figure here, but the Waikiki Aquarium’s web site had the answer:  The largest lobe coral colonies in Hawaii are about 600 years old.

Here are some other items of interest I found in my new coral guide:

• Most of us know our islands are traveling northwest on a geological plate, but how fast are they going relative to our fingernails?  The Pacific plate goes as fast our nails grow, about 4 inches per year.
   

• Since stony corals grow their own plants and make their own rock gardens, you don’t have to decide whether they’re animal, vegetable or mineral.  They’re all three. 
   

• The plants that live inside reef-building corals pay exorbitant rent. About 80 percent of the food these plants produce goes straight to the coral animal.
   

• Coral plants put up with this high cost of living because the animals’ waste products provide excellent fertilizer.  Also, corals’ hard skeletons provide protection for the plants.

I hope I meet Dr. Fenner some day.  I like people who have passion for their field, plus he makes me feel better about not knowing my corals.  “Telling coral species apart is not easy,” he writes, “and you need all the help you can get.”

“Corals of Hawaii” is my kind of help.