• Scientists get worried when 4-pound goldfish is hauled from Lake Tahoe

    Scientists believe the massive goldfish may be the result of aquarium dumping, and could threaten the ecosystem of the lake. NBC's Brian Williams reports.

    By Tanya Lewis
    LiveScience

    A new kind of lake monster has been found, in the depths of Lake Tahoe: gigantic goldfish. Researchers trawling the lake for invasive fish species scooped up a goldfish that was nearly 1.5 feet long and weighed 4.2 pounds.

    "During these surveys, we've found a nice corner where there's about 15 other goldfish," environmental scientist Sudeep Chandra of the University of Nevada, Reno, told LiveScience. "It's an indication that they were schooling and spawning." The arrival of the fish, which were probably dumped there by aquarium owners, has Chandra worried — goldfish are an invasive species that could interfere with Lake Tahoe's ecosystem.

    It's unclear whether the giant fish were introduced as fully grown adults, or while they were still small, Chandra said. But even a small creature can have a big impact, if there are enough of them.

    The goldfish are just one of several species of invasive warm-water fishes in Lake Tahoe. "The invasion is resulting in the consumption of native species," Chandra said. What's more, the invasive fish excrete nutrients that cause algal blooms, which threaten to muddy Tahoe's clear waters. [Photos: Giant Goldfish & Other Freaky Fish]

    Fish out of water
    Aquarium dumping has become a common practice in the United States and elsewhere, and it's taking a toll on native wildlife. A recent report on California's aquarium trade found that fish owners and importers are introducing hardy, nonnative aquatic species to California waters. "Globally, the aquarium trade has contributed a third of the world's worst aquatic and invasive species," Williams, who was lead author of the report, told OurAmazingPlanet, a sister site of LiveScience, in January.

    While the exact number of aquarium owners dumping fish is unknown, scientists know the practice is occurring because these species could not have ended up in these waters naturally. Between 20 percent and 69 percent of fish keepers surveyed in Texas admitted to dumping, according to Williams.

    Other ways that invasive species find their way into natural ecosystems include aquaculture, live seafood, live bait, and fishing and recreation vessels. More than 11 million non-native marine organisms representing at least 102 species arrive at ports in San Francisco and Los Angeles alone, Williams has found.

    The invaders include tropical fish, seaweed and snails. One of the nastiest is a deadly type of seaweed known as Caulerpa. A type of algae that produces toxic compounds that kill off fish, Caulerpa was eradicated in 2000 (at great expense) from lagoons in Southern California.

    Don't dump fish
    Aquarium owners should be more careful when disposing of unwanted fish and other animals, Williams cautioned. "It's pretty simple: Don't dump your fish," she said. Instead, she suggests calling the pet shop that sold the fish or your state department of fish and wildlife. (Euthanasia is another option, but simply flushing fish down the toilet can be problematic — for the fish and for your plumbing.)

    So why do people dump fish? Studies of dumping have shown that size and aggressiveness of the fish are two main factors, Williams said.

    The largest pet goldfish, according to the BBC, was a fish named Goldie that was 15 inches (38 centimeters) long and weighed more than 2 pounds (0.9 kg).

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  • Stinging needle ants overtaking invasive Argentines in U.S.

    Benoit Guenard / North Carolina State University

    An Asian needle ant stings a termite in this photo from North Carolina State University. The invasive species are displacing invasive Argentine ants.

    By John Roach, Contributing Writer, NBC News

    A stinging ant from Asia is spreading with a vengeance across the United States and may prove more devastating to people and the environment than the well-established aggressive Argentine ant currently is, according to new research.

    "While Argentine ants cause a lot of damage, Asian needle ants are a really big health threat to humans," Eleanor Spicer-Rice, an entomologist at North Carolina State University, told NBC News.

    The invaders from Asia pack a venomous sting that can cause an allergic reaction in some people. Spicer-Rice said the sting produces small welts that get surrounded by a rash. It itches and hurts when scratched.

    "It is one of those aggravating bites," she said.

    In North Carolina, people routinely go to the hospital with severe allergic reactions "because they are reaching into a woodpile and getting stung by Asian needle ants and they don’t know what it is and what is happening to them. They don’t realize the Asian needle ants are here," Spicer-Rice noted.

    Spread of the needle
    Historic records indicate the ants were in the U.S. as early as the 1920s, but for reasons that are not yet clear, their population has exploded in the past 8 years and they are spreading across the country, Spicer-Rice said.

    She first took note of the Asian needle ants in 2008 while studying a supercolony of Argentine ants in Raleigh. This was unusual. Argentine ants are typically aggressive to other ant species and push them out of their territory. She started to investigate.

    Between 2008 and 2011, she found that Argentine ant populations dropped from a presence in 99 percent of the sites within her study area to 67 percent, while the Asian needle ants expanded from 9 percent to 32 percent. Both ants overlap in about 15 of the sites.

    Why? It appears that the Asian needle ants are able to tolerate cooler temperatures better than the Argentine ants, Spicer-Rice and colleagues report in a paper published online Feb. 8 in the journal PLoS One.  

    All ants essentially hibernate when wintertime hits, but the Asian needle ants "wake up before other ant species wake up," Spicer-Rice explained.

    This head start allows them to build nests, find sources of food, and start reproducing before the other ants get going. This displaces Argentine ants in urban environments as well as native ants in forested areas.

    Ant eats ant?
    Other behavioral traits may also play to the Asian needle ant’s advantage. For example, the Asian needle ants eat other ants.

    "While the Argentine ants aren’t bothering the Asian needle ants for one reason or another, the Asian needle ants may be eating the Argentine ants," said Spicer-Rice, who is preparing a paper on the behavior of the ants for publication. 

    For now, she said people need to learn what Asian needle ants are and that they may be in their yards. Her research shows that toxic baits are effective at killing the Asian needle ants. If widely used, it could slow their spread.

    And spreading the ants are. Spicer-Rice works on a citizen-science project called School of Ants where people send in ants collected in their backyards to North Carolina State University for identification. Today, "Asian needle ants are the most common ants found," she said. "Five years ago, nobody even knew what an Asian needle ant was."

    John Roach is a contributing writer for NBC News. To learn more about him, check out his website.