Cauliflower, rice or lobe? Getting to know common corals | News, Sports, Jobs

As you swim or paddle over a reef and peer down at a colorful coral, you may find yourself wondering: What is that?

Oceangoers determined to identify what they are seeing underwater can simplify their task by getting to know Hawaii’s most common corals. Once you know what to look for, many become easily recognizable. Among these are cauliflower, finger, lobe, rice and sandpaper rice corals.

Cauliflower corals (Pocillopora genus) are branching, hard corals that come in shades of cream, tan, rose and more rarely, green or purple. Like the vegetable they resemble, they are covered with small distinctive bumps called “verrucae.”

Finger corals (Porites compressa) are fingerlike in size and shape and tend to be grayish in color, though some are blue or pale yellow.

Lobe corals (Porites lobata) resemble the lobes of a brain and are frequently yellow-green, but may also be tan, gray-green or bluish-gray.

“Rice corals” (Montipora genus), such as brown rice and blue rice corals, are “plate corals” whose polyps, or “tuberculae,” look like kernels of rice spread on a plate. Sandpaper rice coral (Montipora patula) resembles tan-colored sandpaper more than it does rice; it is almost smooth in appearance and occasionally is found with a purplish cast.

In shallow, snorkel- and dive-friendly waters, “reef-building” corals dominate. These corals need sunlight. Without light that allows photosynthesis to occur in their plant cells, or zooxanthellae, they could not survive. Hawaii’s most common corals are all reef building.

In depths of less than 10 feet where wave action is fairly moderate, cauliflower corals take center stage. Yellow or brown lobe corals seem to prefer the zone just below cauliflower corals. Finger corals are relatives of lobe corals and prefer a light to moderate surge; they occur to depths of 60 feet. The shapes of the fingers change according to the depth, with differing shapes indicating separate colonies. Knowing a coral’s depth and surge preferences can help in identifying it.

Fragile-appearing corals, such as lace and wire corals, may need either greater depth or quieter, more protected locations in order to thrive. Some of these can be deceptive; they may look fragile but can withstand surprisingly strong surge action.

If a particular coral reminds you of something – antlers, fingers, lace, lumps, plates, mushrooms, wires, cauliflower, snowflakes and so on – you will probably not be far wrong in guessing what kind of coral it might be.

Once general type is established, coral identification becomes more challenging. Mushroom corals do indeed resemble mushrooms, but come in multiple varieties. Deciding whether a mushroom coral is classified as oval, granulated, Vaughan’s, fragile or distorted requires a keen eye and a bit more knowledge.

Some corals don’t need light because they lack zooanthellae. Orange and pink cup corals, for example, prefer shaded cave roofs and overhangs often found in deep water. Black corals, also deep water denizens, likewise have no zooanthellae. More than 15 black coral species – each unique in its own way – inhabit Hawaiian waters. The Au’au Channel between Maui and Lanai houses several varieties.

When viewing corals underwater, the cardinal rule is look but don’t touch. To learn more about identifying corals without ever getting wet, visit the Maui Ocean Center. There, you will find a treasure trove of living corals and can increase your skills in no time.

* Pam Daoust is a contributing writer for Maui Ocean Center. “Ka Mo’olelo Moana,” or “the Ocean Story,” is a monthly column submitted by Maui Ocean Center staff members. The center is open from 9 a.m. to 5 p.m. daily in Maalaea. For more information, call 270-7000.

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