Posts Tagged ‘invasive species


Double Barreled Tree Danger

photography-beaver-ivy-damage-nature-tree-swittersbThe Beaver & English Ivy

The Portland Metro area has pods of English Ivy, a very invasive vine that eventually smothers the host tree. Many volunteers attack the vine in the forests such as in the above image. This habitat area is managed by volunteers, who come in to remove the vine. Unfortunately for this young, Alder tree the Beaver has other ideas for its future.

“Like other exotic species, Ivy has predominantly been spread to areas by human action. H. helix is labeled as an invasive species in many parts of the United States, and its sale or import is banned in the state of Oregon.” (more)


National Invasive Species Week (Think Before You Buy, Plant or Dump)

Well, the Nat’l Invasive Species Week (March 3-8) is a good time to stress the economic impact of invasive species. Here is an Oregon run down of plant species that cause problems.


Madeline Von Foerster’s painting “Invasive Species II”

 “Invasive weeds and pests are more than a gardener’s dilemma. These species are not native to our area and pose a threat to natural areas, human health, and our local economy.

The estimated economic impact of invasive species totals 143 billion dollars per year within the United States. Within the state of Oregon, the impact associated with just twenty-one invasive weed species costs Oregonians $125 million dollars per year in lost agricultural production, fire damage, and control expenses. We all pay the bill through increased food costs, higher taxes, and decreased property values. These impacts clearly show the economic benefits associated with controlling invasive weeds.”

Factor in exotic animals, water borne invasions with the plant and the non-native tweaking of the habitat does have consequences for us all.



Science Teachers Release Non-Natives Into Waterways

Interesting findings by Oregon State University Prof. Sam Chan. When her queried some 2,000 teachers that had run science projects that required the release of the studied critters after the completion of the project…many released them into their immediate environment. Problem is they maybe should not be in that environment.

Apparently, wildlife officials had been baffled by Lousiana crayfish being found in N.E. Oregon waters. Crayfish, gold fish, assorted other non-native-invasive species have been released in that feel good moment by the students and teachers. Now, vendors of critters to science project teachers are releasing instructions to ‘clueless’ teachers on how to dispose of the critters. (Oregonian article by Ian Campbell)

Well, at least our Invasive Gold Fish populations are thriving.


NW Salmon (The Good Intentions of Hatchery Fish)

Salmon Running the Gauntlet (PBS @ Fly Fisherman Anonymous)

This is a pretty informative piece by PBS re the history of NW Salmon and the origins of the hatchery concept. The piece is a portion of a longer show, which you can access via the above link. There are additional spin off pieces about the Columbia River dams.

“Most discussions about the causes of declining salmon runs focus on the four H’s: habitat, hatcheries, harvest and hydropower. But the most important factor may be an ‘I’, as in invasive species.”     (Report here)


Northern Snakeheads (U.S. Distribution Map Updated)

U.S. Geological Survey: Invasive Species Map

Northern Snakehead (Channa argus) Susan Trammel Artist

Snakehead Stuff

Arkansas Snakehead Cleanup Efforts Explains the Problem


Lion Fish Invasive…Kill All of Them…Careful Poisonous



New Zealand Mud Snail (Potamopyrgus antipodarum)

Evolution, adaptation, migration, speciation, invasion, successful reproduction, adaptive radiation. How do you stop this natural process?

“Enter Potamopyrgus antipodarum, the New Zealand Mud Snail. These tiny, aquatic, freshwater mollusks are migrating out of New Zealand, not into it, but their impact on an ecosystem they had no previous place in could have similar repercussions for native species.

Carried by world-trotting humans, these critters made their North American debut in the 1980’s in the Snake River, and have been drifting west ever since. They are now present in Yellowstone National Park.

How do these diminutive invaders hop from river to river, lake to lake, establishing an almost unshakeable presence as they go? Humans again, I’m afraid. The New Zealand Mud Snail is prone to hitchhiking on boats and fishing gear. So a careless or messy angler on an extended fishing trip can spread the little devils far and wide. Mud Snails are quite hardy enough to make the trip as well. They’re so small ( 6mm long, maximum, and sometimes as small as a grain of rice), and they so much resemble tiny flecks of mud, that they often go undetected. They can survive out of water for several days, and can live in many kinds of freshwater environments. They’re even resilient enough to handle low temperatures (anything above freezing) and can pass unharmed through the digestive tract of most fish. Moreover, they reproduce asexually, and are “livebreeders“, meaning they produce a number of perfectly formed little clones, so even one can spawn a colony. New Zealand Mud Snail densities of more than 2 million snails per square yard have been found in Yellowstone Park.

With no natural predators to keep it in check there’s every possibility native snail species will be out-competed into extinction and native plant species overwhelmed. Such an unbalancing presence can decimate other species, such as trout, something that gives dedicated Wyoming, Montana, & Idaho fishing enthusiasts reason for pause.

Efforts are being made to curb the New Zealand Mud Snail invasion.”



China’s Fly Fishing (a warning for the under or is it over managed, “put and take” mentality)

Tilapia (Invasive in SE U.S.)

Tilapia (Invasive in SE U.S.)

BLEAK ALERT! Habitat, Habitat, Habitat!

“Unfortunately, I found that most of streams in Guizhou Province were
hopelessly polluted and devoid of life. And even though I consulted some of
my more proficient fishing buddies and the websites of several fly shops, I
have yet to find a fly that will hook the elusive Chinese mudsucker that
inhabits the ponds around here. The few times I have ventured out all I
have managed to catch are small, curious Chinese children.”

“I realized that if I were ever to catch any Chinese fish I would have to
give up my high-fallutin’ fly fishing ways and resort to Chinese methods.”

“When the Chinese fish, they really don’t like to give the fish a fair
chance. Each person has four or five rods and they chum the water with
bait. Not to mention that the ponds are really small and people line up
shoulder to shoulder around them. I’m sure to the fish, it must seem like
swimming around in a jungle of hooks and bait.”

“The Chinese would like to fish with automatic weapons, explosives, anthrax spores, and weapons of mass
destruction. Unfortunately, the expense and the fear of bodily harm keeps
them from doing this. Instead, they mostly fish with long, collapsible rods
with a bit of monofilament, a bobber, hook, and bait attached. None of this
reel silliness. The bait is usually pellets of what looks like guinea pig
food or a powder that is mixed with water to make a bread dough-like


Fly fishers (take the ‘Clean Angling Pledge’)

Today the Mud Snail is found in fisheries across the western United States, in Idaho, Montana, Wyoming, Oregon and California and is having impacts on populations of Pacific salmon, cutthroat, redband, rainbow and bull trout.

In order to prevent the further spread of these invaders, it is up to each and every angler to be responsible and inspect, clean and dry their gear before traveling between fisheries.


Snakehead Fish (Invasive Freakazoid) Ban the sale of live snakeheads in US!


Why so much press just for a fish? The Northern Snakehead, Channa argus, is no ordinary fish, biologists explain. It is a voracious top-level predator, meaning that it has no natural enemies, and could decimate populations of native fish. About 90% of its diet consists of other fish, though it also eats crustaceans, insects, and plants. In its native range it can live in water with temperatures ranging from 0 to 30 degrees C; it is found in muddy or vegetated ponds, swamps, and slow-moving streams. Snakeheads can breathe air and survive for up to four days out of water, and can survive for longer periods of time when burrowed in the mud. They are capable of traveling over land to new bodies of water by wriggling their bodies over the ground.

Reproducing populations of snakeheads have now been discovered in Maryland, California, and Florida. Individual fish have also been caught in Maine, Massachusetts, Rhode Island and Hawaii.

As of July 9th (2004), a total of fourteen have been caught in the Potomac, with lengths of up to 18 inches, including a sexually mature female ready to lay eggs. For a complete inventory, see: It seems likely that a breeding population has been established, but if it has it will be virtually impossible to eliminate. Explains Florida fisheries scientist Kelly Gestring, once a snakehead population gets established, “neither man nor nature can get rid of them.

This information was put out in 2002 and 2004. The problem continues unabated, particularly in the Potomac system. 


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