May 31, 2011

science for the fishies

If you've read anything about commercial fishing in the past decade or two, you know that industrial fishing practices range from irresponsible to appalling. The worst practices cause major seafloor destruction and grotesque slaughter of "by-catch," marine life ranging from rough fish to sea turtles. Over the past century, countless fisheries have collapsed under the strain of unsustainable harvest, leaving regional economies in ruins while the global industry trudges blithely to its next victim.

The anonymous fish flesh that you buy frozen and breaded in the supermarket or fast-food restaurant is the product of a shadowy industry where breaches of treaties, boundaries and quotas are routine. Even when a seller makes promises about the origin of a fish, their claims are unreliable and unverifiable, until now.

The Economist reports that a European consortium has developed a DNA-sampling procedure that can ascertain not only which species of fish a fillet came from, but which ocean and population. Right now the technology only covers four major commercial species: cod, hake, herring and sole, but its scope will expand.

The device is not intended for consumers at the end of the supply chain, but for those who buy in quantity. As a consumer, you can help by being curious about fish you buy and responsive to labeling or the lack thereof. This new technology is a welcome development that should bring some honesty to a market that has thrived on obscuring links between products and the sometimes horrendous practices used in harvest.

May 22, 2011

new yard nester

Red-eyed vireos nest in my yard every year. They are wonderful birds and welcome guests, but this year a different vireo seemed to be settling in the yard. I had heard it singing for a week, longer than migrants stick around, but I still did not tell anyone for fear of jinxing it. I thought a blue-headed vireo might be taking up residence!

Both species are common in the eastern U.S., but red-eyed vireos are more widely distributed. Blue-headed vireos prefer higher elevations and deeper forests. When I first came to the South, it was to study neotropical migrants in Nantahala National Forest, and blue-headed vireos were abundant in that rare place.

Aside from reminding me of a special time and place, they are charming in their own right. They used to be called solitary vireos, a terrible misnomer since they almost always occur in pairs, chattering at each other like an old married couple. The only reason I can imagine for their former name is the melancholy tone of their song. That same endearing expressiveness comes through in all their vocalizations.

Also, they look like they are wearing spectacles.

Today I saw their nest just a few yards from my front porch in the lowest limb of a white oak.

May 5, 2011

most courageous scientist ever

History is full of scientists who are heroes: savers of lives, solvers of mysteries, builders of the future. They are, however, a pretty nerdy lot, achieving great feats of the mind like wrestling with mathematical equations, dismembering molecules and exploding paradigms, but rarely performing physical acts of courage and strength. Then there is Ken Sims, volcanologist from the University of Wyoming:

"He didn't have a hammer, so with a hard slam of his fist he broke off a piece of fresh lava. It was shiny, iridescent black, and so hot that, even wearing thermal gloves, he juggled it from hand to hand.

But he had it. The zero-age sample. Through a war zone, up a mountain, down a crater, to the edge of a lava lake, he had it. Now the science, at long last, could begin.

Read the whole shoe-melting tale of Congo's Nyiragongo volcano at National Geographic.

May 1, 2011

successful journey

The white spot near the center of this photo is proof of a successful journey. It is an egg. The female that laid it flew some 1500 miles to get to the meadow behind my house, where she and at least one other monarch butterfly have been fluttering around for a week or two depositing eggs, one at a time, on butterfly weed and common milkweed plants.

Their earliest eggs have already hatched. This weekend I saw caterpillars so small they must have just hatched and a couple that looked like they've had a few good meals. They will eat for several weeks, molt several times, and eventually attach themselves to a leaf or stem with silk, form a hard shell over their bodies and begin metamorphosis into a gorgeous orange, black and white butterfly.

The monarchs flitting about my meadow right now are not so gorgeous. The wear and tear of their flight to and from the mountains of Mexico clearly shows.

Not only are the wing edges tattered, the scales are worn or absent, leaving dull colors. Though monarchs are talented enough flyers to glide on a breeze, she has undoubtedly flapped those wings millions of times. Her abdomen is bare. Despite her appearance, her attitude is pure butterfly: exuberant, whimsical and sunny.

Here she is laying the egg pictured above:

Her offspring with be beautiful and richly colored, and they will seek mates in the meadows of Blount county, lay eggs on the same milkweed plants, and their offspring will grow big, pupate, emerge gorgeous and undertake the journey to Mexico before freezing temperatures arrive. One or two will return next spring, as they have for millions of years.

It all starts with an egg and a tiny caterpillar that will probably never wander from its natal milkweed until it grows wings.