Fish o' the Day - electric eel

Not really an eel, but a member of the knifefishes (Order Gymnotiformes), Electrophorus electricus is certainly one of the more impressive fish you could hope to see. Reaching six feet in length and weighing up to 40 pounds, the electric eel inhabits rivers and creeks in South American river basins like the Amazon and the Orinoco. They're obligate air-breathers, with a heavily vascularized mouth lining that acts as a lung. They get as much as 80% of their oxygen from the atmosphere, and must come to the surface to gulp air every ten minutes or so. They generate electricity using three pairs of abdominal organs that make up about 80% of their body mass. Electrophorus actually produces two different types of electrical impulses. High voltage blasts, generated by stacks of thousands of electroplaques, may be of 500 volts and generate a current of about an amp. Low voltage pulses, generated by the Sach's organ, are used primarily for electrolocation. There is some ability to control the intensity of the impulse, employing lower voltages for hunting while saving the really powerful blasts for when needed. They've got a lot of energy in reserve, and are capable of producing intermittent shocks for periods of over an hour.

Little known fact - the male electric eel may use saliva to make a nest, into which the female may place almost 20,000 eggs.

Good video here...

It's Commencement Day

With a head full of doubt, and a road full of promise...


decide what to be and go be it.

Good luck, guys.

For the smell of it

Some interesting interdisciplinary work going on at the University of Bath to investigate the sense of smell in hammerhead sharks. Chemist Jonathan Cox is collaborating with fluid mechanics experts to examine the way in which the unique head structure of the sharks facilitates water flow through their nasal passages. CT scans of museum specimens were used to design a model of the head and nasal chambers. The model was then used in in a flow chamber to investigate the manner in which olfactory information is collected as the shark moves through the water.

So...

...who's seen this? I mean the off-Broadway show, The Rap Guide to Evolution by Baba Brinkman. It is, apparently, the real deal.

They're still fishing on the Gulf Coast

Spoke with a former student and friend who operates two charter boats out of Orange Beach. I had left him a message last week inquiring about setting up a possible fishing trip during our beach stay next week, and actually felt a little guilty when the severity of the oil spill disaster became more clear. As of now, however, the slick is being held off the Florida coast by a friendly northerly wind. Boats are still fishing - apparently a lot of cobia being taken. Artificial reef fishing is still yielding red snapper - catch and release only. Two future FODs.

Anyway, the fam may be able to make a fishing trip. At least until the wind changes.

Great Carrier Reef

As of now, the world's largest artificial reef is still free of oil. The USS Oriskany, a 1950s-era carrier, was scuttled off Pensacola in 2006 in about 200 feet of water. It has provided a unique dive site, with the upper platform reaching 70 feet below the surface and the main deck at about 130 feet. As of now, the oil is still some 90 miles away from the site. Hoping the winds stay favorable - but it's almost surely just a matter of time.

Fish o' the Day - goosefish

A friend and former colleague (Hi, Don) asked today whether I had done an FOD on the anglers. There's apparently an article on them in the new Discover magazine, which I'll have to check out. Actually, the anglers include a pretty wide variety of fish belonging to almost 20 families. The sargassumfish, which we discussed a few weeks ago, is in the Family Antennariidae, while the really funky deep-sea guys belong to a variety of families in the Superfamily Ceratoidea. We'll get to them eventually. Tonight, let's talk about a little more user-friendly angler - one you might have dined on.

The goosefish, Lophius americanus is also sometimes known as the American angler. It's found in the Atlantic off the American coast, in depths ranging from just a few feet to over 1000. They can be large, up to 4 feet and 50 pounds. They're eye-catchers too, dorsoventrally flattened with a very broad head and a big mouth equipped with sharp, rearward-directed teeth. The first dorsal ray is modified into a lure, as is often the case in the anglers. The pectoral fins are modified into leg-like extensions that help them crawl along the bottom.

It's harvested for its flesh, which is sweet and white, not unlike lobster. Just don't tell people what they're eating.

The lure in action? Here you go...

Someone let the fences go...

...here at Small Southern and we do, in fact, need a gunslinger. But for now, I'm hanging up my shooting irons. Somebody else can fight the bad guys for a while.



But there's always tomorrow.

Fishing

Hope to do some of the recreational variety next week, if I can find oil-free waters. This is about the commercial variety, though. New research appearning in Nature Communications and summarized at Science Daily indicates that the decline of oceanic fish stocks may be even more severe than we thought. So much so, in fact, that today's British trawl-fishing fleet must expend 17 times the effort to catch the same tonnage of fish than the sail-powered fleet of the 1880s. The greatest decline has been in halibut, although haddock, plaice, cod, and other have also shown dramatic falls.

Just in time for the download of my new IPod companion. I'll be "reading" Callum Roberts' The Unnatural History of the Sea, which deals with our long history of overuse of marine resources. So, expect updates.

So, who's the kid with the prominent brow ridge?

A new study in Science details the results of a draft of the Neanderthal genome, based on DNA extracted from 40,000 year old bones found in Croatia. The results indicate a strong possibility that Homo sapiens may have interbred with Neanderthals after departing Africa, perhaps 80,000 years ago.

Fish o' the Day - ladyfish

Return of FOD.

As we prepare for some time on a threatened coast, I'll focus on one of the more obvious fish species that tourists see off Gulf beaches. The ladyfish, Elops saurus, is one of several species in the Familiy Elopidae, and they're found throughout coastal waters of the temperate and tropical Western Atlantic. In fact, they don't handle cold weather well at all and have been reported as a component of cold-water fish kills. The long, slender body is silvery and covered with tiny cycloid scales. Their large, terminal mouth is equipped with a nice set of sharp teeth. E. saurus are sometimes referred to as ten-pounders (thought that's a giant) or (mistakenly) as skipjack. A more common size is a couple of feet in length, and a couple of pounds. They move up and down Gulf beaches like those on Santa Rosa Island in large schools, feeding voraciously on schools of baitfish. They can provide good sport if you can get into a feeding frenzy with some light spinning tackle or a fly rod.

The elopids are close relatives of tarpon and bonefish, and share with them the eel-like leptocephalus larva. After offshore spawning, the larvae apparently move into estuaries to develop.

Channel Island eagles

A new study coming out in PNAS is interesting from a couple of standpoints. For one, reintroduced bald eagle populations on California's Channel Islands may have to use different food sources than their predecessors in the islands. Evidence indicates that eagles that lived in the islands 30,000 years ago fed primarily on seabirds. This remained the preferred diet until introduced sheep became a staple in the middle of the 19th Century. Then, the eagles were KO'd by DDT in the 1960s. The reintroduced birds, with the seabird population recovering but diminished and no sheep available, may be living it up on seal carcasses or the endangered island fox.

Interesting enough, but the techniques being employed are kinda cool too. The research, described here at Science Daily, is employing stable isotopes in bones and feathers to determine the source of the eagles' nutrition. Different prey types leave a different stable isotope signature, which may allow biologists to develop an understanding of eagle feeding habits that will help make their reintroduction efforts a success.

We're seeing more and more bald eagles in our local wilds every year, but our guys seem to prefer a fish diet. You'd think such prey would be available in abundance in the Channel Islands, but eagles are notoriously opportunistic. If there's abundant carrion, they'll take it. Ben Franklin was right.

Hunting hypothesis

We've heard (and talked) a lot about how hunting by the Clovis peoples may have led to the mass extinctions of the Pleistocene and shaped the modern fauna of North America. Apparently, aboriginal Martu hunters in Australia's Western Desert are doing some shaping of their own. There aren't many of them - 800 or so. But their habit of setting the brush afire to flush their favored prey, the monitor lizards they call goanna, is reshaping the region and its biodiversity. The Martu have an easier time finding goanna in freshly burned plots. So, they routinely burn small patches of desert brush and turn the habitat into a patchwork of freshly burned plots and areas of recovering vegetation. The resulting mosaic turns out to be ideal to support high biodiversity in the region.

Now, here's an interesting scenario. To facilitate discussion about this rather unusual case of humans actually living in apparent harmony with a natural system, a group of Martu will travel to a conference at Stanford for an upcoming conference. There's a meeting that I'd like to see.

Finals over...

...grades posted, putting the final touches on a semester. Very eventful, and a cherry on top tomorrow. Then my youngest walks with her Master's on Saturday. Two in eight days - not bad.

Let's see how much catching up I can do tonight, before I run out of steam.

Here's to Rosie...

...and her dark chocolate. The Maginot Line between NSM and brain injury. Better buy a fresh bag, Rosie. We're gonna need it.

Can't sleep...

Lots of activity at Small Southern in the next few days before Commencement. Then off to the beach for a week to celebrate my mom's 90th birthday. That's right... a week on beautiful Santa Rosa Island, playground of my youth. Just in time to watch the oil roll in. For some reason, I've had this movie on my mind all week. Overdramatic, I understand. The world's not coming to an end. And, for once, I hope the neo-cons are right, for once, and the projected impacts are overblown. But I can't help but think my family and I have purchased a front row seat for the end of an era, the inevitable result of the path that our nation chose thirty years ago...

No...

...I haven't forgotten about you. It's choke time at Small Southern. Be back when finals are done.

OK, it's about a fish...

Other than that, no comment. Just no comment.