Showing posts with label Oceans. Show all posts
Showing posts with label Oceans. Show all posts

Saturday, July 23, 2011

Beware! The Blob

I’ve tried to write about the Blobfish (Psychrolutes marcidus) before, but gave up due to lack of information. It was first suggested to me about a year and a half ago, and has been suggested a few times since then. I think I’ve found enough information about it and its close relatives to do it justice. First things first, though: the Blobfish does not look like a deflated Ziggy.

Image from the Telegraph

















Yes, that is a picture of the Blobfish, and yes, that picture makes it look like someone let the air out of Ziggy’s oversized head. However, that picture was taken of a dead specimen on a research boat, right before it was pickled in formaldehyde. Blobfish don’t rely on swim bladders to remain buoyant like other fish, because the pressure of half a mile of water would squish the air right out of them. Instead, their flesh contains a gelatin-like substance that is nearly equal to the density of water. This means they can float effortlessly in the water, but makes it look like they melted above the surface. As to what they really look like, this is a much better picture:



















These fish, who now resemble their Sculpin brethren much closer, bob along the ocean floor around the coast of Australia and New Zealand. There, they eat whatever floats or crawls by—mostly crabs, snails, and octopuses1.

Everyone seems to think Blobfish are lazy. Yes, they are adapted to using as little energy as possible to eat and move, but they are not deadbeats. While other fish spawn and leave, the Blobfish is an attentive parent. They will clean and sit on the eggs, protecting them from parasites and predators.

More efficient fishing methods have caused no end of trouble to all kinds of sea creatures. Trawling the ocean floor for crustaceans also picks up bycatch like the Blobfish. Callum Roberts and other scientists are worried about the future of this majestic fish. While it’s not officially listed as endangered, the government is certainly worried about it.

Public knowledge about bycatch in general, and the Blobfish in specific, is growing. Professor Roberts has certainly been trying to get the word out. There is also this British kids’ show that depicts the Blobfish fairly accurately, as well as adorably. They also sound like British Zoidbergs, which seems appropriate.

Photobucket

1You can argue all you want about the proper plural of “octopus.” There isn’t one.

Sunday, November 14, 2010

Jabberjaw

I was looking through IUCN’s Species of the Day list and found something adorable. It fits the two facial features that define “cute”—big eyes and a short snout. Unlike most members of its group, it has been known to play by grabbing vegetation and trailing it behind itself as others give chase. It exhibits curiosity with man-made objects. It has a cutesy name that sounds like an embarrassing nickname.

It’s a six-foot long shark.

Image by Steven Campana

















Where the Porbeagle (Lamna nasus) gets its name no one is quite sure. The commonly cited combination of “porpoise” and “beagle” seems awkward to me, but there are a number of other etymological theories to pick from. They are built for speed, with crescent tails for powerful strokes, keels on the base of the tail for balance, and large gills for better efficiency. These adaptations help them chase after mackerel and other schooling fish to eat.

Their playful antics have been widely documented. They play tag using kelp, as mentioned above, as well as playing catch with driftwood. They will also poke at fishers’ balloon floats, and appear to be confused when they pop. The phrase “mindless killing machines” is so frequently thrown around with sharks, but the Porbeagle’s actions are causing a number of shark experts to question that concept. Other sharks (including the infamous Great White) have been described as “curious,” but they only have one tool with which to explore the world, and it’s filled with enough teeth to turn the object of their curiosity into mincemeat.

Despite their potential danger (see previous statement regarding teeth and mincemeat), the Porbeagle hardly attacks anyone - ever. The International Shark Attack File lists 5 total attacks, fatal and non-fatal, from the Porbeagle in 2003. Compare that to the Great White Shark with 244 fatal, unprovoked attacks. In fact, looking at the rest of the list, anything with fewer attacks than the Porbeagle either have no teeth, are impossible to find, or are too small to be a threat to humans. The infrequency of attacks may be due to the fact that “if the water is warm enough for you to be swimming, it is too warm for the porbeagle,” but it seems that this is a very docile shark.

One place the Porbeagle will fight ferociously is on a fishing line, and for good reason. Overfishing in the north Atlantic caused population crashes that devastated not only the shark, but the fishing industry that created the problem. These incidents have led to regulations to limit Porbeagle catch. Earlier this year, CITES set trade regulations in place to help save this playful, docile “mindless killing machine.”

Wednesday, May 26, 2010

My Hovercraft is Full of Eels

A spokesperson for EDGE e-mailed me, hoping to get me to plug their fundraiser. I think they do a great job of informing the public about strange animals, and could definitely use your £2 (about $2.88 if the online conversion calculator is correct).

This month’s animal I found after I discovered that the IUCN Redlist highlighted a new species every day. Looking through past Species of the Day, I saw some familiar faces1, and a few new ones. One that caught my eye, featured in January, was the European Eel (Anguilla anguilla).

Image from the BBC














The lifecycle of the European Eel is confusing, surpassing many arthropods in complexity2. Spawning and hatching take place in the Sargasso Sea, the same area that makes up the Bermuda Triangle. As transparent, ribbon-shaped larvae called leptocephali, they eat whatever plankton is available to them. As they grow, the Gulf Stream carries them to the coast of Europe, where they metamorphose into round, but still transparent larvae called glass eels or elvers. Once at the coast, they migrate en masse up rivers and streams. Videos of this seem reminiscent of something you might have seen in a health class.

After finding their way upstream, the eels gain pigment and size in a third metamorphosis, after which they are called yellow eels. Here they spend their time eating small arthropods and growing. Then after a number of years (between five and twenty) they undergo a fourth metamorphosis to adulthood (finally!), gaining larger eyes and a silvery coloration, all the better to survive the open ocean3. However, they have to get to the ocean first, and they will even cross land to get there. Eventually, they find their way back to the Sargasso Sea, mate, die, and the process starts all over again.

There is one main cause for them to go from not listed in 2012 to critically endangered in 2008. They’re delicious. They work as sushi, as soup, smoked, and even as pie. There are eel farms, but those only collect the glass eels and raise them from there. Breeding is still done the old fashioned way, and if that doesn’t increase along with the increased global demand, they will be literally eaten up.

Research into captive breeding (read: more effective farming) is ongoing by fisheries who don’t want to see that size of a drop in a main export. Please don't read that as bitter, as industry support is one of the better methods of conservation. The Monterey Bay Aquarium has set up a program known as Seafood Watch, which educates the public on which seafood is sustainably harvested, and which is being overfished to death. So, watch what you eat.

1 These are some featured animals from the last year that have been posted here: the Goliath Frog, the Vancouver Island Marmot, the Indiana Bat, the Sailfin Lizard, the Brown Hyena, the Boreal Felt Lichen, and the Chinese Giant Salamander.
2Though, their lifecycle isn’t quite as confusing as Malaria. To be fair, I’m not sure I’ve seen any lifecycle as confusing as Malaria.
3Wikipedia says that they lose their stomachs at this stage. I couldn’t verify that anywhere else, but it wouldn’t surprise me. A number of insects do something similar: the larva’s job is to eat; the adult’s job is to breed.

Tuesday, December 23, 2008

I'm Not Dead

Last month, Phantom Midge made a wonderful suggestion for an EUT that I hadn’t thought about. I had known about it for ages, and, like her, had been pronouncing it wrong for years1. Somehow, without any foreknowledge, I’m managing to post this on an exceedingly appropriate day, as today is the 70th anniversary of its discovery as a living animal.
Image from Dinofish









Order Coelacanth (pronounced See-la-canth) had been well documented since 1836, and fossils show that it lived for 345 million years between the Devonian period and the end of the Cretaceous period, when the dinosaurs died out. This must have come as a big surprise for the West Indian Ocean Coelacanth (Latimeria chalumnae) caught by fishermen off the coast of South Africa in 1938. These fishermen were friends with the curator of a small, local museum, and she would frequently check through their catch for anything interesting. Needless to say, something interesting was, in fact, found. Dinofish, who seem to be experts on this matter, have the whole long story on their site in far more detail than I can manage.

Coelacanths spend most of their time in deep (90-200m) caves, where they suction feed on any fish smaller than their head. Exceedingly sensitive eyes, along with an electro-sensory organ help them hunt. These are not small fish, getting up to about 6 feet in length and weighing about 175 pounds, thus surpassing the other “Living Fossil” fish I wrote about2. Coelacanth tail fins are split into three fleshy sections, and all eight of their fins move in a mesmerizing, visualized wonderfully—as always—in an ARKive video.

I was surprised the Coelacanth is listed at all, much less as Critically Endangered. I thought there would be far too little information on its numbers and habits to be called anything other than Data Deficient. Analyses of populations in 1989 suggested that there might only be 500 individuals left. The low population, ironically enough, might be attributed to by-catch. This could explain why all the natives were so perplexed when the Europeans got excited by the catch of a fish they knew to be inedible3. Since then, conservation and outreach programs have given fishermen the tools to release the fish directly back to the murky depths from which they came.


1In Freshman Zoology, I made a list of letter combinations that made an “s” sound. “Coe” always annoyed me, because I’ve never seen it outside of biology.
2Wikipedia has some nice articles about the term “Living Fossil.” Coelacanths are a “Lazarus taxon,” while the Australian Lungfish falls into the wider “Living Fossil” expression. I don’t think I’ll ever get a chance to write about an “Elvis taxon.”
3Never underestimate the local population when it comes to ecology.

Friday, May 9, 2008

Horseshoes

I have been slacking and I know it. I graduate from the warm, quiet womb of my liberal arts college at 1:00 this afternoon, so I’ve been trying to set up a summer job and a grad school, and the blog has fallen by the wayside. I should be on schedule during the summer.

Greg e-mailed me an article about an endangered rat from Australia that people are desperately trying to protect. Unfortunately, there seems to be little information on the little rodent, but I thought you readers might be interested. This week’s animal is one I’ve looked at for a while, and I’ve just now gotten around to writing about it.
Image from Marine Biologial Laboratory















Three years ago, I worked in the Shores department at the Columbus Zoo. One of the scariest looking denizens of the touch pool was the Horseshoe Crab (Limulus polyphemus). With its fierce-looking eyes and pointy tail, it intimidated some of the visitors. It didn’t help that many people thought it was a baby stingray1.

That scary-looking tail (formally called a telson) is about as sharp as a dulled pencil, and just about as dangerous. When adults migrate en masse onto the dry high-tide zone to lay eggs, flipping is a definite possibility. Right side-up, they present an armored shell to any seabirds. Upside-down, they are a bowl of seafood2. The long telson allows them to right themselves, hopefully before any hungry seagulls show up.

The eggs they lay hatch into “trilobite larvae,” who look enough like their namesake. These stay buried for a few weeks, until the right high tide rolls in. They then swim like mad until they are below the intertidal zone. A few days later, they molt into juveniles, and start living on the bottom, living in deeper waters as they age. As adults, they aren’t exactly picky about what they eat; they live off of whatever animals have burrowed into the sand.

I know, they’re not actually listed as endangered, but there are a number of people worried about their conservation. There are two main uses for them, both of which costal states are setting limits on. The first is use as bait for eel and conch fishing, and this seems to be the largest source human-induced mortality in the Horseshoe Crabs. The other use is in medical research, as they are harvested for their literal blue blood (it’s copper-based). This can be used to test pharmaceuticals, but don’t ask me how. Research and education programs are popping into existence to try to help save the Horseshoe Crab before it gets listed.


1Alas, the Touch-A-Shark pool had shut down years before.
2Upside-down, they also look like face-huggers from Alien.

Tuesday, April 15, 2008

Buzzsaw

This will not be the first time I’ve written about things with exciting nasal protuberances. I don’t find these noses ugly—they all do nifty things, and I can’t help but write about them.
Image from Elasmodiver













The rostrum of Green Sawfish (Pristis zijsron) is no exception. It uses its saw mainly for feeding—swiping at unsuspecting fish, stunning and injuring the intended prey, or raking up tasty crustaceans from the seafloor. The Sawfish is closely related to sharks and rays, and, like them, has sharp scales called denticles; these have been modified to form the “teeth” of the saw. Catching food is not the only thing the rostrum is good for, as it is lined with motion- and electric- sensing pores to find buried prey. That, and if anything happens to appear threatening, it couldn’t hurt to have a spiky protrusion on… um… hand.

I thought Wikipedia had a typo when it stated that the Green Sawfish grew as large as 7 meters—surely, they must mean feet. Nope. This is a big fish. They reach maturity at 14 feet. Think of the length of a typical bedroom. A little more than half of that is filled with a fish that looks halfway between a shark and a ray. The other five and a half feet is a nose with spikes. Don’t worry; humans are much too large to be considered prey, though you might not want to provoke them.

The Green Sawfish is the most common sawfish. It’s also critically endangered. That doesn’t bode too well for the other species. In fact, the Common Sawfish (Pristis pristis) is pretty close to becoming extinct. The biggest threat to all sawfish is accidental by-catch by the fishing industry. Let’s face it, with a proboscis like that, getting tangled in nets would not be pleasant. Less frequently, they are caught on purpose—for meat, for oil, or for an interesting six-foot long spiky thing. As of yet, they are only beginning to set conservation measures into place.