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Saving a Sea of Strange
The Endangered Species Act now protects 22 species of coral. Here are the four freakiest.

Coral is weird stuff. Reefs can stretch for miles, but the actual animal (yes, coral’s an animal) is pretty tiny—a single polyp attaching itself to other polyps to form massive undersea ecosystems. Coral have tentacles, mouths, and exoskeletons. Some look like fans. Some look like trees. Others look like brains. And they range from the rock-hard to the soft and slimy. But many of the 6,000-plus coral species have at least one thing in common: they’re in trouble.

Climate change is wiping out reefs all over the planet. The oceans absorb atmospheric carbon, so as CO2 increases, the seas become more acidic and corrosive to species with calcium-carbonate shells and exoskeletons (see “Hot Tub Time Machine”). Rising water temperatures can also bring disease. Needless to say, coral is in tight spot.

That’s why the National Oceanic and Atmospheric Administration recently upgraded the status of 20 corals to “threatened,” raising the total number of protected coral species to 22. NOAA originally proposed listing 66 species, but after years of scientific review and public comment, the agency decided to whittle it down to 20. (This is still the biggest, baddest conservation move the agency has ever made, so we’ll take it … for now.)

Coral's not just strange, it's also important. One-quarter of all ocean species depend on them for food and shelter. And we, in turn, rely on those species for food, livelihoods, and recreation. In fact, NOAA estimates the value of coral reefs to humanity at almost $30 billion per year.

So, in honor of NOAA’s decision, let’s take a moment to celebrate the oddest anthozoans on the Endangered Species List.

Frogspawn Coral

Most of us would probably mistake frogspawn coral (Euphyllia paradivisa) for an anemone. And we’re not the only ones. When clownfish are stuck in an aquarium without their stinging anemone friends, with whom they enjoy a cozy symbiotic relationship, they nuzzle up instead to frogspawn, whose tentacles also pack a poisonous punch (but not for the clownies).

Native to American Samoa, frogspawn coral, which also resembles a gelatinous sack of frog eggs, prefer shallower waters away from rough waves. Several species of opportunistic shrimp seek sanctuary from predators in these venomous corals.

(Sounds pretty, right? Well, you can get a 60” x 40” framed picture of shrimp hanging out among frogspawn for just $99.99. Why? Because Internet.)

Pillar Coral

As its name suggests, this species of coral (Dendrogyra cylindricus) grows straight up, with some columns standing as high as 10 feet. Sometimes, when a pillar gets too big for its britches, the sea will knock it over. Don't be sad: the pillar will keep growing, and a new pillar can grow from the fallen stub.

This is why I argue that scientists should reclassify the species as Dendrogyra chumbawambacus.

Found in the Caribbean Sea and the western Atlantic Ocean as far north as Florida, pillar coral is vulnerable to ocean acidification, rising water temperatures, and hurricane waves that have a tendency to tear its towers down.

Though, they get up again.

Elkhorn Coral

Elkhorn coral (Acropora palmate), whose branches resemble elk antlers, grow as fast as two to four inches a year. The horns’ nooks and crannies provide crucial habitat for myriad species, including lobsters and fish. This is why NOAA considers elkhorn to be one of the most important corals for reef growth and development.

But this coral isn’t nice to all marine species. Although elkhorn coral gets most of its energy via photosynthesis by way of a symbiotic relationship with algae, it also devours the small fish and zooplankton that get trapped in its tentacles.

Elkhorn was once the most common coral in the Caribbean, but on top of getting clobbered by the usual climate suspects, a bacterial disease known as white pox is wiping them out. And where does this white pox come from, you ask? Well, the answer is human poop. (This is why we can’t have nice things.)

Staghorn Coral

Like elkhorn coral, staghorn (Acropora cervicornis) owes its name to a cervid it’s never met. In this case, the male deer.

Staghorn and elkhorn—not to be confused with Foghorn Leghorn—gained “threatened” protections back in 2006, but their outlook remains dire. According to government scientists, staghorn coral has declined 98 percent throughout its range since the 1980s.

Staghorn and elkhorn primarily reproduce asexually, with new colonies forming off of broken pieces, similar to pillar coral. But once each year, the polyps pump out massive quantities of sperm and eggs in a sexual explosion. The gametes float out into the sea where they can collide with millions of other gametes from other polyps. It’s basically an ocean orgy.

If they get lucky, an egg will meet a sperm and form a coral larva. And someday, that larva will land on a ripe patch of seafloor and start a colony of its own. Hopefully, NOAA just gave those upstarts a fighting chance.

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OnEarth news blogger Jason Bittel contributes to Slate and serves up science for picky eaters on his website, Bittel Me This. He lives in Pittsburgh with his wife and two tiny wolves. (Note: wolves may be Pomeranians.) MORE STORIES ➔
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And despite their resilience and ability to spawn adorable pun-filled news reports (, these beauties are on the endangered list. I do not want to live in a world devoid of clownfish.