Saturday, July 31, 2004

Back in Bass

Two years ago, biologists "reclaimed" Maine's Durepo Lake from introduced populations of largemouth bass (Micropterus salmoides) [translation: they poisoned the lake, killing all fish]. So you can imagine their outrage at the recent discovery of introduced smallmouth bass (Micropterus dolomieu) in the same lake. According to this report from the Bangor Daily News, at least 3 of the fish have been found so far. It is illegal to introduce any fish into any body of water in the state of Maine.

Friday, July 30, 2004

If you can't burn 'em, poison 'em

Researchers in Scotland think they've finally come up with an effective way to fight the invasive shrub Rhododendron ponticum, a Eurasian species thought by some to be the most invasive plant in the UK (what about knotweed :-)). As reported by The Scotsman, field tests have shown that injecting herbicide directly into the plant's stem can kill it within six months, at which point the dead growth can be easily removed. This method of managing infested sites is relatively inexpensive, which is sure to make it a popular choice in the years to come. The ISW fisrt posted about R. ponticum back in November 2003.

Thursday, July 29, 2004

Alewife Arrival

Biologists are fairly sure that they've discovered the alewife (Alosa pseudoharengus) in Lake Champlain, according to this report from It is suspected that the non-native fish traveled from a known population in the St. Lawrence River, via the Richelieu River. This would be the second body of water in Vermont in which the fish has been discovered, the first being Lake St. Catherine in the late 1990's (read a management report here (.pdf)). The alewife, while native to the Atlantic coast of the U.S., has been accidentally or intentionally introduced to many freshwater lakes.

Wednesday, July 28, 2004

Not-So-Rapid Assessment

NatureServe and The Nature Conservancy recently produced a tool to assess the invasiveness of non-native plant species. From the main web page, you can download .pdf versions of the documents, including instructions, data forms, and example assessments. They also released the ranked results of their own assessments (300+ down, only 3200 to go!).

Thanks to a member of the Yahoo! group ma-eppc for posting about this great new tool.

Tuesday, July 27, 2004

Sakhalin Sweet

Giant knotweed (Fallopia sachalinensis), Japanese knotweed's gigantic congener, just doesn't get the attention of its dimunitive cousin. So it was interesting to find a whole article focusing on giant knotweed, and even more interesting that it was written in Japan. The Japan Times published this article about the towering herb, discussing its propensity for invasiveness in the U.S. and Europe. The article also briefly touches on Japan's apparent lack of concern for environmental health.

Monday, July 26, 2004

East is East, and West is West, and never the twain shall meet?

Officials in Alaska are sounding the alarms again, after the capture of yet another Atlantic salmon (Salmo salar), this time in a gillnet at a commercial fishery near Thorne Bay. The press release has a photo of the actual offending fish, along with instructions on how to identify Atlantic salmon and what to do if you catch one.

This story reminded me of when my husband and I traveled to Seattle back in May. After a long, direct flight across the country, my Great Aunt and Uncle picked us up and took us straight to lunch. We were greeted by an incredibly perky waitress, who smiled at us and announced that the special of the day was Atlantic salmon. At this point I started laughing hysterically, probably in part because I hadn't slept in about 22 hours. But it just seemed really funny to me that anyone on the West coast would ever want farmed Atlantic salmon. Especially after we dined on wild caught Pacific salmon later that week.

The ISW first posted about this subject back in May 2002.

Sunday, July 25, 2004

Bigger, Better Bounty

In what may be the best bounty hunting program ever, the Maryland location of Bass Pro Shops Outdoor World has announced that they're offering "Snakehead Reward" gift cards for any snakeheads (Channa spp.) caught in Maryland waters or the Potomac watershed. The bigger your snakehead catch, the better the giftcard, with a $50 card for fish over 24 inches. As an extra bonus, winning fishermen also get a "Snakehead Wrangler" cap from the Maryland Department of Natural Resources. This faq implies the program is for northern snakeheads (Channa argus) only.

Friday, July 23, 2004

Alien Alert!

Want to be among the first to know when a new non-native aquatic species shows up on your doorstep? If so, go register at the NAS Alert System. This "Nuisance Aquatic Species" early warning system, sponsored by the federal government, will send you an email every time a new non-indigenous species is found in the state(s) of your choice. You can also tailor your alerts to be organism-specific, or choose from several of the "invasive species-du-jour" listed at the bottom of the page. The site still has a few kinks to work out (MSIE-specific, no contact info on site, and it's "ruffe" guys, not "ruffie"), but a great service like this is long overdue. I subscribed to all the alerts, of course, and will be sure to feature some of them here at the ISW.

Update: Wow - that was fast! Got my first alert...A Northern snakehead (Channa argus) has been found in a lake in Pennsylvania! Read the alert here, the press release from the Pennsylvania Fish & Boat Commission here, and see the updated USGS map.

Thursday, July 22, 2004

Cogon, take me away!

The Picayune Item has this report about the spread of cogon grass (Imperata cylindrica) in southeastern Mississippi. In it, you'll find information about the introduction of the non-native grass in that state, what measures the government is taking to control its spread, and what you can do as a concerned landowner in the Mississippi area. Part of the continued threat is the availability in the nursery industry of cogon grass cultivars. Bonus points to the Picayune Item for using the plant's scientific name.

Wednesday, July 21, 2004

Fish Sticks

The Plain Dealer is reporting that a pet store owner from Ohio is getting back the four redline snakehead fish (Channa micropeltes) that he was caught with in April...but the fish have been frozen solid. Joe Schultz, proprietor of "Their World," was found guilty of illegally possessing the fish, and sentenced to six months' probation and community service (educating the public about the dangers of snakeheads). Joe's not happy, claiming that the species he had are tropical, and could not have survived in the cold waters of Lake Erie. Unfortunately for Joe, officials at the Ohio Division of Wildlife did not agree. The Ohio Wildlife Council banned the possession, import, or sale of live snakeheads in 2002.

Tuesday, July 20, 2004

PBS Piece

Back at the start of the month, The Newshour with Jim Lehrer did a segment about invasive species. The transcript, which features interviews with several invasive species researchers, can be found here, as can links to streaming audio and video.

Thanks to a member of the APWG listserver for posting about the story.

Monday, July 19, 2004

Beware the Burr Chervil!

Could burr chervil (Anthriscus caucalis) have mutated into the next purple loosestrife (Lythrum salicaria)? According to this article from Today@Idaho, that's what one University of Idaho biologist hopes to find out. While a graduate student at the same university in the early 1990s, Dr. Tim Prather noted that burr chervil was not an aggressive weed. Now Prather notes that the plant is much more common, expanding its geographic range and showing up in unexpected habitats. He hopes that molecular techniques may identify a genetic change that explains burr chervil's sudden success.

Saturday, July 17, 2004

How Now Brown Trout?

PennState Live has a story about research by Dr. Caleb Tzilkowski that focuses on the potential invasive effects of the brown trout (Salmo trutta levenensis). Dr. Tzilkowski, a researcher at Penn State University, is about halfway through a study to estimate the impact of the repeated stocking of these non-native fish by the Pennsylvania Fish & Boat Commission, in streams throughout the state. He has found some evidence that the brown trout are displacing native trout species, but has also found that the brown trout do not appear to have any direct negative effects on endangered ironcolor shiner (Notropis chalybaeus) populations.

Friday, July 16, 2004

More On Goldfish

Seems Indiana is not the only state having problems with burgeoning wild goldfish (Cyprinus auratus) populations. The Baltimore Sun is reporting that there are about 50 large goldfish now residing in a pond in Sewells Orchard Park in that state. There is a grassroots effort underway to contain the problem by netting the goldfish (with adoption likely for the ones they catch). The story also contains an update for a story posted on the ISW last year about using bass to control the goldfish.

Thursday, July 15, 2004

In a pinch

Officials in Toronto are not happy about the spread of the rusty crayfish (Orconectes rusticus) through the rivers and creeks of the region, according to this article from The Globe and Mail. The province of Ontario already has its share of native crayfish species, but none of them seem to have the attitude problem of the slightly larger rusty crustaceans. They are more aggressive than their native cousins, will out-compete them in the grab for food, and tend to have voracious appetites. They're also more likely to attack your toes than to run away if you disturb them. Rusty crayfish are considered native to the U.S., including some of the Great Lakes states, but have greatly expanded their range over the past several decades.

Wednesday, July 14, 2004

Three shall be the number of the counting, and the number of the counting shall be three

Scientists are concerned about the number of black carp (Mylopharyngodon piceus) they're finding in the Mississippi River...even though that number currently stands at three. As reported by MSNBC, the fish have been caught over the last 1.5 years, and are thought to have escaped from catfish ponds, where they are employed to eat snails that carry disease-causing parasites. The carp are supposedly sterile, meaning that the risk of them reproducing in the wild is small, but there is still the possibility of a negative impact on native mollusk populations if these long-lived fish escape into the wild. Read an older ISW post about the black carp problem by clicking here.

Tuesday, July 13, 2004

60 seconds to invasion

As reported by Greenwich Time, a wetlands officer in Greenwich, Connecticut was on a routine inspection of an estate when he accidentally stumbled upon an invasive plant that is only known in a few sites in that state. It turned out that a compost pile filled with dead nursery stock and other materials was also home to a 5 x 20 foot swatch of mile-a-minute vine (Polygonum perfoliatum), a thorny vine that grows almost as fast as its common name implies. Landscapers on the property have been instructed to dispose of the plant separately, preferably by incineration.

Monday, July 12, 2004

Kitty De Carcass (bonus points to any non-Bostonian who gets that ref!)

If you live in Richmond Shire, Queensland, Australia, you can earn some extra money this fiscal year, but you have to have a hankering for cat hunting. According to this story from the Townsville Bulletin, officials are offering $5 AUS for every feral cat (Felis silvestris) carcass brought in by town residents. Animal rights groups are upset, as is to be expected, pointing out that any culling should be done in a humane way. The mayor of Richmond, John Wharton, noted that feral cats dine on several native bird and marsupial species, and claimed that his shire was "...leading the way in wildlife conservation." Where I live, cats are pretty much the only thing keeping moles, voles and chipmunks from completely overrunning the neighborhood. Hope Richmond has some hungry native carnivores out there.

Thanks to Val C. for sending the link to this article.

Sunday, July 11, 2004

Hunting Hydrilla

Scientists think they've got hydrilla (Hydrilla verticillata) under control in the Rio Grande in Texas, according to this report from The Brownville Herald. The surface area covered by the invasive aquatic weed has decreased by about 50% since May 2003. The weapon of choice in this case? Grass carp (Ctenopharyngodon idella), though the scientists point out that there was likely also a benefit from heavy rainfalls that swept some of the hydrilla out to sea.

Saturday, July 10, 2004

In Search Of

Don't forget that there are over two years of posts (almost 700 entries) here at the ISW. Whether the post you are looking for has slipped off the screen, or you want to see what else has been posted about your favorite nasty invader, there's a search bar located in the left column that is here to help you. Atomz, the company that indexes this site, provides reports listing the top words and phrases. The most popular searches for the month of June were for purple loosestrife, feral cats, or some iteration of Japanese knotweed.

Mitey Fine

Scientists from the Agricultural Research Service have honed in on a species of mite that they hope has eyes only for the invasive Old World climbing fern (Lygodium microphyllum). According to this report in Agricultural Research Magazine, populations of the tiny mite (Floracarus perrepae) that prefer the fern have been found in Australia and Thailand. To test the potential biocontrol's appetite, researchers took along tiny sporelings of Old World climbing ferns currently growing in Florida. You can read about previous efforts at controlling this species from older ISW posts. Bonus points to ARS Magazine (as usual) for using scientific names.

Friday, July 09, 2004

A soda apple a day does not keep the USDA away

Agricultural officials in Texas have mobilized following the discovery of tropical soda apple (Solanum viarum) on a ranch in the town of Jasper. As reported at Science Daily, a rapid response team made up of workers from the USDA, Texas Cooperative Extension and weed specialists are now studying the situation to determine the best way to contain the invasion of this federally listed noxious weed.

Thanks to a member of the ALIENS-L listserver for posting a link to the story.

Thursday, July 08, 2004


In the charmingly-titled article "Bullfrog explosion plaguing B.C." CBC News describes the problems British Columbia is experiencing as a result of skyrocketing populations of American bullfrogs (Rana catesbeiana). The bullfrogs were introduced to B.C. almost 80 years ago as part of a marketing scheme to provide frog's legs to the restaurant industry. Many of the frogs were released into the wild after the industry failed. Now there are concerns that the bullfrogs are endangering native frog eating them!

Thanks to a member of the ALIENS-L listserver for posting a link to the story.

Wednesday, July 07, 2004

Sudden Spread

Sudden Oak death (Phytophthora ramorum) continues its spread across the eastern U.S., following its escape several months ago via contaminated California nursery stock. APHIS is reporting (.pdf) that the presence of this fungus has recently been confirmed in Nassau County, New York. Check that document for a list of nurseries across the country where the pathogen has been found. The Beaufort Gazette is reporting that two infected plants have also been found in South Carolina over the past month, marking the first occurences for that state.

Thanks to members of the Yahoo! group ma-eppc for posting about SOD.

Tuesday, July 06, 2004

Parrot Parade

Seems parrots are poised to take over England. According to this report from BBC News, the thousands of wild parrots that call Britain their home are increasing their numbers at a rate of 30% per year. BBC News, after summarizing the results of an Oxford University research project, then goes on to add a slew of anecdotal information from local readers who've sighted parrots in their neighborhoods.

Monday, July 05, 2004

Attack of the Killer Goldfish

The Indiana Post-Tribune is reporting that the state's Spectacle Lake is infested with, of all things - goldfish (Cyprinus auratus). Concerned about the native (?) bass in the lake, local environmentalists are asking the state to remedy the situation by treating the water with rotenone, which will kill -all- fish, and then restocking with bass. This is actually the second time in fifteen years that Spectacle Lake has been overrun with goldfish, which perhaps explains why the state isn't exactly hurrying to fill it with piscicide. Goldfish can destroy bass nests when they kick up bottom sediments. When they reach critical population levels, they can also drop the dissolved oxygen content of the water to a point that is tolerable to them, but deadly to bass. That makes the idea that these folks had last year, to introduce bass to a lake to control goldfish, sound like a bad one.

Saturday, July 03, 2004

Nick of Time?

As reported by the Coolidge Examiner, a National Park Service employee discovered zebra mussels (Dreissena polymorpha) on the hull of a houseboat, fortunately before the boat was launched. The boat was brought to Lake Mead over Memorial Day weekend, all the way from Kentucky. The unlucky boatowner must now wait thirty days before his/her boat can be retrieved from quarantine. This map shows the known distribution of the zebra mussel in 2003 - Arizona isn't anywhere near there...yet.

Friday, July 02, 2004

Snakehead Banners?

Following repeated discoveries of northern snakeheads (Channa argus) in Maryland waterways, that state's Department of Natural Resources introduced a draft regulation this week that make owning the fish illegal. As reported in the Virginian-Pilot, the DNR is painting with a broad brush, proposing to ban 29 different species of snakehead. The Maryland Association of Pet Industries points out that few people own northern snakeheads, and many of the listed species require tropical conditions for survival.

Thursday, July 01, 2004

An Herbe à l'ail by any other name, still stinks

There is an interesting piece by Paul Wiegman in the Pittsburgh Tribune-Review, about his trip to Europe and subsequent discovery of garlic mustard (Alliaria petiolata) in its native habitat. He goes on to wax poetic about the invasive herb's history in North America, and invasives in general. A good read.

Thanks to a member of the Yahoo! group ma-eppc for posting a link to the story.