The Oyster’s Garter

The extinction risks for many species have been wildly underestimated in a most embarrassing fashion. In this week’s Nature, researchers realized that current extinction risk estimates have failed to account for gender ratio and behavior. In other words, the models assumed that all individuals reproduced in the exact same way, and that’s not true. For example, lots of mammals (gorillas, elephant seals) have a harem social structure in which the number of females determines the reproduction rate, but the total number of males is irrelevant, since only the dominant male gets to reproduce. In species that broadcast spawn, like fish or invertebrates, bigger individuals produce exponentially more (and higher-quality) eggs or sperm than smaller individuals.

I’m not a modeler, so I’m utterly gobsmacked that this problem a) exists at all and b) has just been discovered. Because scientists KNOW that sex ratios and body size play a huge role in reproductive success. I can think of a million examples off the top of my head. For example, many fish are sequential hermaphrodites, changing from female to male (or vice-versa) when they reach a certain body size. So by catching the biggest fish, people remove all the males and the population plummets. Or take the case of the Maine lobster - it’s not the teeny pound-and-a-quarter lobsters keeping the population going, it’s the big monsters that live deep off the continental shelf, so fishing them out is a huge problem. (That’s why Maine has a maximum size limit.) The death of a big male fish or big offshore lobster therefore has much bigger ramifications for the population than the death of a small female fish or wee little lobster.

The authors write:

When we apply our new mathematical model to species extinction rates, it shows that things are worse than we thought,” said Melbourne. “By accounting for random differences between individuals, extinction rates for endangered species can be orders of magnitude higher than conservation biologists have believed.

We’d best fix that, then.

Snails have amazing mucus-superpowers! Most snails and slugs use mucus trails to lubricate their movement, but some freshwater snails have taken slime to the next level. They can actually crawl along on the underside of the water’s surface. How can a wee little snail foot grip something so nebulous?

Science reports on new research on just how the snails are able to move on a low-friction flexible surface. They explain:

The snail’s foot wrinkles into little rippling waves with a wavelength of about a millimetre and this produces corresponding waves in the mucus layer that it secretes between the foot and the air. But because surface tension constrains the deformation of the mucus, the shape of its top surface (in contact with air) doesn’t exactly mirror that of the bottom surface (in contact with the foot). In effect, parts of the mucus film get squeezed, and parts get stretched, creating a pressure difference that pushes the foot forwards.

The snails are not actually gripping the water - they’ve got little bubbles of air in their shells for buoyancy. They’re just using the pressure differential to push them along like a little snaily conveyor belt. Not only is this energy efficient, but the snails able to avoid the perils of crawling along the bottom, where all kinds of obstacles and predators lurk.

Maybe the next incarnation of Real Snail Mail will feature these guys riding tiny jetskis. Why wait for those lazy land snails to deliver messages when you could have a super-efficient water-crawling snail?

A ammonite-shaped sink! Spit on an extinct cephalopod, then watch the water go around…and around…and around….

(I made a new tag for products and toys, so you can see them all under Garter Gear.)

Via Boing Boing

I had all kinds of intelligent things to write, but I’m somewhat under the weather today, so I’ll just link lazily instead.

• Is there too much doom and gloom in conservation outreach? Mark Powell says yes, Rick MacPherson says no, Mark says YES NEENER NEENER, Rick says NO PBBBT. Me, I try to enjoy the gloom as much as possible - all those beautiful opportunities for black humor that my ancestors never even dreamed of. In fact, maybe this discussion can be settled with a klezmer danceoff!

• The New York Times Magazine has a feature on trash in the ocean. It focuses on Alaska, which has the same trash accumulation problem as the Northwest Hawaiian Islands - it’s getting trash from the North Pacific Gyre. Volunteers in the Kenai Fjords picked 30 tons of trash off just one beach.

• Carl Zimmer ponders octopus intelligence in Slate. Come for the high-brow discussion, stay for the  flounder impersonation.

Mieke sent me this lovely photo of Australian nudibranchs a while back. My first thought was, “OMG! Koosh balls of the sea!” My second thought was, “They are TOTALLY doin’ it!” (See the loop of orange eggs in the upper right?)

Nudibranchs are sea slugs - just like land slugs, they are molluscs that have lost their shells. Since they don’t have any hard parts to protect them, they tend to be incredibly poisonous - they are pretty and colorful to advertise DO NOT WANT. Nudibranchs’ chemical defenses are usually stolen from their prey, the toxic compounds or stinging cells serving to protect the nudibranch long after that unfortunate sponge or anemone is but a tasty memory.

Like the mighty banana slug, nudibranchs are simultaneous hermaphrodites and can both fertilize and be fertilized. They can be tender, stroking each other’s tentacles, or debauched, mating in chains (who wants to be in the middle?) or snacking on their partner. (Apparently, unlike their banana slug relatives, nudibranchs do not engage in apophallation. Aren’t you disappointed?)  Sadly, the sexy time comes at quite a high cost - most nudibranchs are semelparous, meaning they die shortly after mating.

With the help of Sea Slug Forum and Nudibranchs of Australia, I think Mieke’s nudibranchs in flagrante delicto are a species of Okenia, possibly Okenia stellata. Want more nudibranchs? National Geographic has stunning photos, videos, and even nudibranch puzzles.

Did anyone else hatch baby chickens in preschool? I always thought the chicks, no matter how fluffy, had an evil gleam in their eye, and was kind of relieved when they were packed off to the farm. Relive those halcyon days with this photoseries on chicken development. Also check out the development of a Cecropia silkmoth from egg to caterpillar to full-fledged moth.

Via Boing Boing

Pepjin Koster, the brilliant inventor of lol oshunz, has collected all the entries. I’m rather partial to the fish-scorning penguins. Wudda!

The town of Skowhegan, Maine has an old jail to sell. They’re building a new jail, and they figure maybe some developer will be able to make use of the old one. But it wasn’t a developer who answered the call, no no - it was PETA! Yes, that’s right, the People for Ethical Treatment of Animals want lease the jail so they can build a Lobster Empathy Center.

From the letter they sent to the Skowhegan commissioner in charge of this stuff:

The center will also feature interactive exhibits that will give visitors the opportunity to experience the horrors inflicted on lobsters caught by humans. The first room that visitors enter will be a large replica of a lobster trap. Visitors can have their fingers wrapped in large rubber bands, which will be left on for the rest of their visit. At that point, they can be moved to a small, filth-strewn glass tank where they will be crammed together and confined for up to an hour. (Lobsters, by contrast, are often confined to supermarket tanks for weeks before being killed.)

The interactive experience won’t be completely realistic–visitors won’t be boiled alive, of course.

Wait, what? They won’t put the visitors into boiling water? Seems kind of half-assed to me. I sent this story to Miriam, and she had a number of suggestions for how PETA could make the experience more detailed:

Will they feed their visitors tasty rock crab for total reality? (Rock crab is a common bait, but is also good to eat for people, just a lot of work.) Will there be an escape hatch for children? Will they notch the ears of pregnant women? Can people “molt” by taking off their clothes and putting on bigger ones, then gaining a lot of weight so they fit?

Myself, I noticed that Skowhegan is near the geographic center of Maine, a good 50 miles (and 90 minutes driving) from the coast. The people who do most of the lobster catching don’t live there, and the people who do most of the eating live far, far away (like Bristol Rhode Island, say, or San Diego) and are unlikely to experience the pains of lobster catching via the Lobster Empathy Center.

Of course, I recognize that the center will probably never come into being. PETA likes to scare up a lot of publicity by making these ridiculous proposals, and far be it from The Oyster’s Garter not to give to them. But it’s also important to be aware that in fact, lobsters seem to be one of the most environmentally sound fisheries in the world. Lobstermen notch the females and throw them back in, so they can keep reproducing, and the traps are designed to let small ones escape. Heck, University of New Hampshire researchers have found that lobsters like the traps so much, trapped big ones keep out the small ones.

Lobsters are most decidedly food, not friends. If a person-sized lobster ever found me scuttling along the ocean bottom, it would eat me in a second.

[Major shout out to the Lunch Bunch List, who pretty much supplied all these links]

Jewelry cast from actual octopus tentacles. I’m not sure if these would please or anger Cthulhu - but they sure are fetching. If Kevin Z wore one of these AND the cnidarian skirt to his defense, surely no force, no matter how non-Euclidean, could resist him.

Via Boing Boing

I was innocently collecting water samples when this peculiar fish started trying to snuggle:

Having no idea what it was, I ignored it until I finished my work. But it followed me back to shore, swimming just underneath my legs:

When we surfaced (the fish still with us), my dive buddy told me that my not so little friend was a remora, and that it was trying to attach to me. AIEEEEEE! Remoras usually hitch rides on sharks or turtles using the suction provided by the plate on their head. The ridges are movable and create a vacuum.

Remoras are thought to be harmless hitchhikers, eating the parasites off its host and whatever else comes by. (Somehow that didn’t make me feel any better - that remora was not so small.) There’s also some neat mythology around them. According to this website:

The ancient Greeks and Romans had written widely about Remoras and had ascribed to them many magical powers such as the ability to cause an abortion if handled in a certain way. Shamans in Madagascar to this day attach portions of the Remora’s suction disk to the necks of wives to assure faithfulness in their husbands absence.

The ancient Romans actually attributed the death of Emperor Caligula to Remoras. They were believed to be fastened onto his ship, holding it back and allowing the enemy ships to overtake it.The Latin name Remora actually means “holding back” (McClane 1998).

Apparently remoras do sometimes attach to divers. Is this because of the drastic decline of shark worldwide, and especially in the Caribbean? Was my remora lonely and desperate? Is this a remora shifting baseline - shark & turtle riders now forced to ride mere divers? Or did my remora and I just have a special moment? Since the remora a) didn’t speak English; and b) swam back out to sea once I got out of the water, the mystery remains.