Lake Tahoe in winter
More than seventy years ago, commercial fishing in Lake Tahoe was outlawed. The deep, clear lake in the Sierra Nevada had been denuded of its Lahontan cutthroat trout, and state officials have since only allowed recreational fishing.
Now, with interest in eating invasive species on the rise, and with millions of invasive crayfish muddying the lakewaters, commercial fishing of the crustaceans has been instated on Tahoe’s Nevada side. The New York Times has a reporter on the scene, who records the giddiness in the local seafood industry:
In Nevada, made up mostly of desert, the impending availability of a local seafood has made headlines in Reno, less than an hour’s drive northeast. Sierra Gold Seafood, a wholesaler that will sell [a fisherman's] crayfish, trucks in all its products from hundreds of miles away — everything except the Lake Tahoe crayfish now.
“This is it, man,” said Brandon Crowell, whose family owns Sierra Gold, adding that 40 restaurants and casinos in the Reno area had already put in orders.
The tsunami that slammed into Japan in March 2011 ripped this dock from its rightful home in Misawa and took it on a 15-month voyage to Agate Beach, Oregon, where it arrive this week. A metal plaque with Japanese writing helped confirm its origin. The dock isn’t radioactive, though it may have borne a different danger: invasive species.
Last year’s tsunami caused massive devastation in Japan from the coast to up to three miles inland. And as the water receded, it dragged 5 million tons of debris with it into the ocean. Most of the wreckage sank near the coast of Japan, but some 1.5 million tons drifted out to sea under the influence of winds and currents, initially forming a debris field detectable by satellites and then dispersing. Most of the wreckage is still at sea, but items ranging from an empty ship to a Harley-Davidson have been washed up on Pacific Northwest shores since this past winter.
At 50 pounds, the Asian carp can pack up a punch–especially if you get caught in a cloud of jumping fish. “The air is so thick with fish that some bash together mid-flight, showering everyone with a snot-like splatter,” writes Ben Paynter in a Bloomberg Businessweek feature on the invasive Asian carp.
Damaged boats and injured boaters—broken noses and concussions are among the alleged crimes of the Asian carp—aren’t even the biggest problems with the fish. The bottom-dwellers eat voraciously, starving the native fish and quickly outgrowing any natural predators. They’re now in 23 states, and fears are that they will soon invade the Great Lakes.
Drastic policies to protect the Great Lakes, such as completely rerouting the trade through Chicago’s waterways, have made it as far as the Supreme Court even though tracking the fish’s actual location is rather imprecise. (The Supreme Court rejected the request.) eDNA—e for “environmental”—detects the presence of DNA from Asian carp but it can’t tell the difference between 1 and 100 fish or even between a live fish or a few scales. Instead, writes Paynter, researchers have resorted to brute force methods for counting fish in a river: electrocution and poison.
In the Eastern Mediterranean, the pufferfish has arrived. And nobody’s too happy about it. The fish, also known as the silverstripe blaasop or Lagocephalus sceleratus, was first confirmed in Turkey in 2003 and has been spreading throughout the area. The problem with this unassuming fellow is that it contains tetrodotoxin, a neurotoxin that can be deadly to humans and for which there is no known antidote. Consumption of the fish has killed at least 7 people in Lebanon in the past few years, according to The Daily Star, and likely affected many more. A 2008 study found that 13 Israeli patients who ate the blaasop had to receive emergency medical attention at the hospital, where they didn’t recover for four days.
What’s the News: After running aground last week on a remote island off the coast of South Africa, a freighter has leaked over 800 tons of fuel oil, coating an estimated 20,000 already-endangered penguins. “The scene at Nightingale [Island] is dreadful as there is an oil slick around the entire island,” said Tristan Conservation Officer Trevor Glass said in a statement. But even worse, authorities fear that the rats from the soybean-toting ship will swim to the island and destroy the bird population.
What’s the Context:
The Future Holds: Though a salvage tug left Cape Town, South Africa, last Thursday, the earliest it will arrive to help remove fuel is this Wednesday. With little to salvage, authorities say that cleanup is now the main task at hand. As Jay Holcomb, the director emeritus of the International Bird Rescue Research Center, told the New York Times, “Many of the birds have been oiled for over a week, which limits their chances of survival.”
Image: Wikimedia Commons / Arjan Haverkamp
What’s the News: After tracking baby gray catbirds with miniature radio transmitters, biologists found that cats were by far the #1 bird killer: 47 percent of the birds died at the paws of pet and feral felines (out of 80 percent that were killed by predators in general). This echoes some biologists’ view that cats are a destructive, human-assisted invasive species: “Cats are way up there in terms of threats to birds — they are a formidable force in driving out native species,” said one of the authors of the study.
What’s the Context:
Not So Fast: While cats were the biggest threat to birds in this study, the lead author notes that the biggest culprit for bird deaths over all is still building collisions.
Reference: Balogh, Anne L., Ryder, Thomas B., and Marra, Peter P. 2011. Population demography of Gray Catbirds in the suburban matrix: sources, sinks and domestic cats. Journal of Ornithology. DOI 10.1007/s10336-011-0648-7 (pdf)
Image: flickr / emilydickinsonridesabmx
Kudzu: It’s worse than you thought. The invasive plant now covers more than 7 million acres in the United States, mostly in the Southeast but not limited to there. Besides overrunning trees as it spreads like wildfire, the vine also brings another danger: In a study in the Proceedings of the National Academy of Sciences, Jonathan Hickman sounds the alarm that kudzu could cause a spike in ozone, polluting the air.
Ozone, of course, is a good thing when it’s high in our atmosphere, blocking some of the sun’s harmful radiation. But down on the surface of the planet, ozone isn’t such a good thing. It can cause respiratory problems in people and harm plants’ ability to absorb carbon dioxide; it also is a major constituent of smog.
Kudzu’s contribution to ozone levels works like this: Like other members of the pea family, or legumes, Kudzu grabs nitrogen from the air and puts it into the soil. There microbes convert nitrogen into nitrous nitric oxide, one of the pollutants that also comes from automobile exhaust. That gas escapes from the soil and into the air, and undergoes reactions that lead to the creation of ozone [Discovery News].
In 1935, Australia introduced the cane toad to its sugar cane fields to battle beetle infestations–and the ecosystem has never been the same. The toxic toads took a liking to Australia and began spreading through the northeast, killing the native predators like crocodiles, snakes, and lizards that dined on them. A small cat-like marsupial, the quoll, was no exception. In the decades after the toads’ introduction, quoll populations in northern Australia have dipped precipitously. This year, ahead of the toads’ march into the quolls’ last stronghold, the Kimberly region, scientists have found a clever way to save the endangered marsupial: training it to detest the taste of toad so it won’t get poisoned [Los Angeles Times]. And the success of the experiment has suggested a bizarre conservation campaign.
In their research, scientists from the University of Sydney found that other predators like crocodiles and snakes can learn to avoid trouble, because one experience of snacking on a sickening poison toad is usually enough to teach them a lesson. But because the smaller quoll will die from eating a single large toad, it never learns to make that association. So the researchers decided to train the marsupials to avoid the toads using a method known as conditioned taste aversion.
Asian carp—the giant invasive fish that have been moving up the Mississippi River for the better part of a decade–are getting close to the Great Lakes, and in fact some may have already crossed the barrier. For the lakes’ protectors, this is a near-doomsday scenario: Many fear that the ravenous carp could destroy the ecosystem by gobbling up the food that native fish depend on. This week the White House proposed a plan that would devote nearly $80 million to stopping the fish’s advance, but it’s not pleasing many people around the issue.
On one side, many environmentalists, as well as people who rely on Great Lakes fishing for their livelihood, have called on the federal government to shut down locks that connect the river to Lake Michigan. Michigan Governor Jennifer Granholm says, “The economic damage from these carp coming into the Great Lakes system would be irreparable…. They should shut the locks down until they get these other measures in place, and permanently have a solution to separating these two water systems” [Detroit News]. Granholm and other governors from the region met recently to try to craft another solution after the Supreme Court ruled that Illinois didn’t have to close the locks to stop the carp if it didn’t choose to.
This week federal officials said they want to ban the importation of nine large and exotic snake species. The move is designed to quell the spread of those slithering reptiles that have gotten loose and thrived in Florida and especially in the Everglades, and that threaten to spread further across the country.
More than a million of these snakes—including the giant Burmese python, boa constrictors, and several kinds of anaconda—have come to the United States in the last 30 years as pets. But invariably, over the years, some slithered loose — or were released by owners who found their reptile[s] more than they could handle. Today, many thousands nest wild in Florida’s suburban yards, parks and the Everglades [Science News]. At least one of the species, the northern African rock python, is considered dangerous to humans.