By the Numbers: Tunicates, Different from Sponges

Not everything that looks like a sponge is a sponge. Covered by the “tunics” that give them their names, outwardly, tunicates resemble sponges and can be hard to tell apart from them. But their internal architecture is much more complex than sponges.  IT’S THE “TUNIC” PART OF TUNICS’ ANATOMY THAT GIVES THEM THEIR SUPERFICIAL RESEMBLANCE TO SPONGES. The stiff, cellulose coverings that conceal tunicates’ inner workings may be very different from sponges’ walls of individual

Read more

Stingrays, Eagle Rays, Manta Rays: An Uplifting Tale

Rays are the other star-power cartilaginous fishes, outnumbering sharks in species and matching them in variety of lifestyles. Stingrays lurk on the seafloor, Eagle Rays soar above the reef, Manta Rays cruise the oceans. Did I mention Star Power?  WITH FLATTENED BODIES, RAYS HAVE TAKEN THE PECTORAL FIN/HYDRODYNAMIC LIFT CONCEPT so far as to develop their pectoral fins into broad “wings.” Eagle and manta rays’ wings let them soar through the open waters like…well, eagles…flapping and

Read more

Damselfish: Small, Shy, Feisty

 Damselfish like Threespot, Dusky and Bicolor Damsels don’t have the celebrity status of more charismatic members of Family Pomacentridae like Clownfish or the in-your-face visibility of Sergeant Majors. But they’re feisty little guys who deserve attention – and, in fact, encountering Threespot Damsels (and the Damselfish Stare of Intimidation) are among my favorite things on the reef. EVERYBODY KNOWS ABOUT CLOWNFISH AND SERGEANTS BUT OTHER MEMBERS OF THE DAMSELFISH GROUP – like Blue and Brown

Read more

What are Copepods? Essential to the Web of Life

 What are Copepods? They’re tiny, ungainly crustaceans. Often barely visible to us, they aren’t on anyone’s must see list. But they’re everywhere in the oceans, and one of the foundations of the web of life in the sea. Appreciate them. NOBODY GOES DIVING TO LOOK AT COPEPODS, AND IF THEY DO SEE THEM THEY’RE LIKELY TO BE GROSSED OUT. Generically, they’re just tiny crustaceans, mostly almost invisible, vaguely similar to shrimps and crabs, that happen

Read more

Fire Corals: Sneaky, Painful & Masters of Disguise

What are fire corals? Well, they’re not true corals, although their talent for stinging certainly lives up to the fire part of its name. The tiny animals behind them are hydrocorals, hydroids that build calcium carbonate dwellings. They’re closer to jellyfishes than to the stony corals they sort of resemble.  THE FIRST THING TO SAY ABOUT FIRE CORALS IS A WARNING: THEY LOOK TOTALLY INNOCENT. But touching them, presumably accidently, has caused many a diver

Read more

Benthic & Pelagic Fishes: Defining Oceanic Lifestyles

Describing pelagic fishes is easy: They swim, feed and just hang out in the open ocean, a pretty consistent pattern across many ocean-going species. Describing benthic fishes is something else. They live at the bottom of the ocean but they go about their lives in a bunch of differing ways – above, on and sometimes in the seafloor. Some may engage in all three approaches. IF TOLSTOY HAD WRITTEN ABOUT MARINE LIFE, he might have

Read more

Why Are Flounders Flat? Because it Works.

Flounders are famously fishes that start out with typical-fish body shapes and morph into bottom-dwelling flatfishes that live sideways, with both eyes on the same side. As weird as this sounds, they’re highly successful survivors and predators. But why are flounders flat? And how do they get flat?  FLOUNDERS ARE THE FISHES THAT PABLO PICASSO MIGHT HAVE DREAMED UP – all the parts are there, just arranged differently. And Peacock Flounders obviously would have been

Read more

How Do Flying Fishes “Fly?” Well, Actually, They Glide.

Why do flying fishes fly? To escape predators, to flee from surprises like boat engines next them, perhaps to entertain you during the ride to a dive site. In any event, they earn their names by propelling themselves out of the water and gliding for long distances on broad pectoral fins. Torpedo-shaped and silvery, sometimes with markings in subdued colors, they’re not especially exotic visually. But they’re impressive both underwater and in the air. YOU’RE

Read more

Do Sea Urchins Sting? No, But They Hurt All the Same

What are sea urchins? Members of Class Echinoidea, they’re distant cousins of starfishes that boast imposing defenses and bad reputations. Do sea urchins sting? Not really. It’s more that they impale. But, if you don’t bother them, these oceanic pincushions won’t bother you. The trick is in not accidentally bothering them. RATHER THAN APPRECIATING SEA URCHINS, MOST PEOPLE FLEE FROM THEM, CAREFULLY. After all, the likely result of interacting with these oceanic pincushions while doing

Read more

Sea Turtles Fake Out Predators with Decoy Turtle Nests

When leatherback and hawksbill sea turtles finish laying their eggs in newly dug nests on a beach, they pull a fast one on would be egg poachers. They create trails and decoy turtle nests a distance away from their real egg caches, scientists say in a new paper. ON THE NATURE DOCUMENTARIES, THE PROCESS OF SEA TURTLES NESTING ON THE BEACH is both charming and straightforward: Momma turtles crawl up the sand, dig a hole,

Read more