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Nudibranch Facts, by the Numbers

THERE ARE TWO KINDS OF DIVERS: THOSE WHO ARE BONKERS ABOUT NUDIBRANCHS and those who ought to be. For those in the second category, here are some nudibranch facts. First, as the name “nudibranch” suggests – it’s from the Greek for “naked gills” – nudibranchs absorb their oxygen from the water through external breathing structures located on their backs. There’s great variation in gill architecture among the many species of nudibranchs, from flamboyant to demure. And

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Nudibranch Colors Shout Out Nudibranch Defenses

WITH FLAMBOYANT SWAGGER, NUDIBRANCH COLORS CALL ATTENTION TO THEIR SLUGY TORSOS – and that’s the point. As beautiful as they are, nudibranchs’ bright markings are statements telling potential predators to leave them alone. In brief, nudibranch tissues tend to be foul-tasting, if not toxic. Nudibranch’s colors are warning signs to potential predators that they’ll regret attempts to dine out on their nudibranchy flesh. There are other nudibranch defenses in the mix, as well. Some have

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The Ultimate Wreck Dive You’ll Never Do

HIDDEN IN THE BLACK SEA FOR MORE THAN 2,400 YEARS, an ancient Greek shipwreck sits tantalizingly intact, awaiting visitors – one mile below the surface. It’s the ultimate wreck dive nobody will do except with ROV’s or manned submersibles. The 75 ft-/23 m-long ship, believed to be a trading vessel dating from about 400 B.C., sits on the bottom tilted towards its starboard side, with its mast still erect, its rowing benches in place, its

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 Diving with Manta Rays: Atlantic Giant Manta Encounter

DIVING WITH MANTA RAYS WAS SORT OF A DISTANT FANTASY. I just wanted to see them. The giant Atlantic mantas I had seen in the past were fast-moving and, mouths agape, totally focused on sweeping up the plankton they make their livings on. Suddenly here, there, gone. Spending extended time in close-up choreography with one of these gentle giants was not in my vision. Until it was. The dive was at Flower Garden Banks National

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Manta Ray Facts, by the Numbers

1)  THERE ARE TWO SPECIES OF MANTA RAYS – OCEAN MANTAS (MANTA BIROSTRIS) AND REEF MANTAS (MANTA ALFREDI). M. birostris is also sometimes known by the names giant ocean manta and Atlantic giant manta. Mantas are the largest members of the ray family and among the largest fishes in the sea. 2) Oceanic mantas are found worldwide, often reported as swimming great distances across oceans. They generally prefer tropical and subtropical waters. 3) Reef mantas are

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This is a Photo of Arrow Crabs. Really!

IT MAKES SENSE THAT YELLOWLINE ARROW CRABS would want to hang out with long-spined sea urchins. After all, it should be a gimme that these crustaceans with 10 long, thin legs would seek to blend in with urchins whose most visible features are long, thin spines. On the other hand, the sources seem to put Stenorhynchus seticornis all over the place – atop sponges, sea fans and other gorgonians, under and next to sea anemones.

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Bluehead Wrasses on an Egg Raid – An Awesome Video

AS A STUDENT OF LIFE UNDER THE SEA, I’m always curious about behaviors. So when, on a dive, I saw a pack of little yellow initial-phase bluehead wrasses streaking toward a distant point, naturally I followed them. They were almost certainly on an egg raid. Blueheads are notorious for plundering the egg nests of other species of fish, particularly damsels and blennies. BLUE HEADS & YELLOW BODIES To be clear, bluehead wrasses get their name from the

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The Difference Between Jellyfish and Comb Jellies

WHAT’S THE DIFFERENCE BETWEEN JELLYFISH AND COMB JELLIES?  They both come in blobby shapes and gelatinous, transparent bodies. But comb jellies – ctenophores – are entirely different from their oceanic jellyfish neighbors. Most importantly: They don’t sting. And some of them put on fantastic light shows. Note that I said “neighbors,” not “cousins.” The difference between jellyfish and comb jellies runs far deeper than the absence of stinging.  Recent research suggests that combs evolved with

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Fish Hunting Parties

ANIMALS IN THE OCEAN ARE ALWAYS LOOKING FOR FOOD (and trying to avoid being food). Some times it involves more than one animal. On Bonaire, one year, I encountered several instances of group fish hunting. Sort of. There’s a known phenomenon called Nuclear Hunting in which a small eel (like a goldentail moray) and one or more other fishes (like rock hinds) meet up, identify a nearby coral head as a target site and race toward

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 Nematocysts & the Science of Sting

NEMATOCYSTS ARE OCEAN STINGERS’ SECRET WEAPONS. In fact, they are the stingers. The way in which nematocysts sting is a story of the sneaky, harpoon-like ordnance of Phylum Cnidaria – jellyfish, coral and gorgonian polyps, sea anemones, fire corals and hydroids. If you happen to touch a sea anemone, a sea plume or coral tentacles (which you shouldn’t do), you’re likely to not feel their sting. Actually, you’ve probably been stung, ineffectively. Those animals’ stingers

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