Crabs: Porcelain CrabCrabs make tasty treats for a wide variety of predators, including humans. To stay out of hungry stomachs, most crabs come out of hiding after dark, when predators have bedded down. So the best crab hunting often takes place at night, preferably under piers, such as the Town Pier in Bonaire, where the pilings are heavily festooned with marine growth. One good way to spot camouflaged crabs is to watch for movements of their telltale eyes and unadorned pincers.
World-renowned naturalists and authors Ned and Anna DeLoach wrote the book on marine-life behavior — literally. Over the years, the couple has authored a series of books covering the behavior and ecology of marine animals in a wide range of diving areas, such as the Caribbean, Central America's Pacific coast, North America's Pacific coast, the Galapagos and the tropical Pacific. Their publications have become invaluble resources for divers across the globe and made them celebrities in the industry. In this article and the video linked below, the DeLoach's offer a collection of valuable tips for spotting some of diving's most elusive — and sought after — critters.
* Description: Although little more than oversize stomachs with mega-mouths attached, frogfish rank as rock stars of the reef.
* Distribution/Habitat: Forty-eight species inhabit tropical and subtropical waters around the world. Although widespread, frogfish tend to occur in traditional population centers — the eastern and southern Caribbean, the Virgin Islands and Belize are prime hunting grounds. On the other side of the globe, the Philippines, eastern Indonesia and Australia boast substantial populations.
* Behavior: Stealth is the modus operandi of all lie-in-wait predators, including frogfish. The masters of camouflage perch motionlessly in fishy habitats where they blend in like ghosts. When prey ventures too close, the secretive hunters’ mouths expand in a flash to 12 times its normal size, drawing in a torrent of water along with their victim. If stealth fails, the opportunistic predators go fishing, using a highly modified first dorsal spine — tipped with a tempting tuft of bait — as a flexible fishing rod.
* Tips: Don’t feel bad if you’ve never found a frogfish. Their furtive ways conceal their whereabouts from divers as well as prey. Compounding matters, frogfish come in a variety of colors, live in a wide range of habitats, are typically no larger than your fist and are rather rare. Fortunately, the oddities are so popular that word of a sighting quickly spreads. So pay attention to guides and other divers. And best yet, once settled, they seldom move far, allowing the same animal to be enjoyed by many.
* Description: Crabs are prolific residents of the reef. Most familiar is the true crab, with a greatly reduced abdomen, and a tail that is curled back under its round and flattened carapace.
* Distribution/Habitat: Crabs make tasty treats for a wide variety of predators, including humans. To stay out of hungry stomachs, most crabs come out of hiding after dark, when predators have bedded down. So the best crab hunting takes place at night, preferably under piers, such as the Town Pier in Bonaire, where the pilings are heavily festooned with marine growth.
* Behavior: As a hedge against predation, a few families of crabs — collectively known as decorators — adorn their bodies with living organisms clipped from the reef, including hydroids, soft corals and algae. The burgled bits are attached to Velcro-like hooks. In most instances the attached animals continue to grow, and might even reproduce.
* Tips: In the tropical Pacific, daytime crab hunting can be rewarding. Look for host-specific species living in symbiotic relationships with complex marine animals: corals, anemones, sea fans, urchins and crinoids. For added security, they can acquire the color, marking and texture of their host. Watch for movements of their telltale eyes and unadorned pincers.
* Description: To survive without the protective shells common to their gastropod kin, nudibranchs — members of a group of shell-less snails known as sea slugs — have evolved a potpourri of potent defenses.
* Distribution/Habitat: Renowned for their kaleidoscopic colors and whimsical shapes, nudibranchs range in size from pinheads to plates. The Caribbean Sea and California have a significant contingent of nudis, however the group reaches its zenith in the Indo-Pacific.
* Behavior: The soft-bodied slugs’ multihued wardrobe advertises their toxic tissue. Other species can secrete thick clouds of acids. Another group thwarts attacks by storing stinging capsules acquired from their diet of hydroids and corals inside an elaborate network of respiratory organs that adorn their back.
* Tips: Think small and search everywhere: Many could fit on your pinkie nail. Don’t believe that all nudibranchs sport bright warning coloration — often species wear camouflage coats of muted earth tones. Many are specialized feeders that mimic a preferred food source where they spend their entire life.
* Description: These stocky ambush predators rely on stealth to disguise their presence. Most species not only change colors to match their surroundings, but they also grow fleshy tabs to enhance their disguise.
* Distribution/Habitat: Scorpionfish inhabit tropical seas around the equator, where they are characteristically found nestled in complex bottom environments that aid their cryptic charade. Lionfish, members of the scorpionfish family native to the Indo-Pacific, move around freely, often methodically stalking their prey in open terrain.
* Behavior: Scorpionfish well deserve their ominous family name — the front dorsal-fin spines of bottom-dwelling species inject a potent poison contained in grooves running along the spines’ length. Stings, although extremely painful, are rarely fatal. An exception is the infamous Indo-Pacific stonefish, which can cause death.
* Tips: Once sighted the animals seldom move, allowing a close approach and prolonged observation. Like most lie-in-wait predators, scorpionfish yawn widely from time to time. It is not known exactly why, but monstrous gapes leave a lasting impression. Stay alert: If a fish yawns once, it often yawns a second time in rapid succession.
* Description: Over-the-top exotic seahorses have become favorites with critter-hunting underwater naturalists. The trick comes in finding them. Most are small, well-disguised bottom dwellers.
* Distribution/habitat: Seahorses associate with a number of habitats in tropical and subtropical seas, from reefs and seagrass meadows to sea fans and drift weed. Because they feed on an endless supply of transient crus- taceans, seahorses prefer areas of calm water where, if undisturbed, they normally remain in the same location for prolonged periods.
* Behavior: Seahorses engage in extended courtship ballets complete with spins, pirouettes, parallel swimming and color changes before the female relinquishes her clutch of eggs for safe-keeping inside a male’s brooding pouch. Two to four weeks later, a series of muscle contractions discharges a few hundred offspring into the world, fully formed and ready to feed.
* Tips: Most commonly sighted species live close to the bottom, with the tip of their elongate tails coiled firmly around a sturdy holdfast. When they do swim, their upright body is powered by a diminutive dorsal fin beating 30 strokes a second. During the past decade, seahorse-watching in the Indo-Pacific has been highlighted by the discovery of more than a half-dozen irresistibly cute pygmy species.
To see Ned and Anna DeLoach's video of these secretive sea critters, click here Hidden Treasures.