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| Freshwater jellyfish advertised for sale in a pet catalog. |
Most of the
time we spend on invasive species issues involves legacy programs like gypsy moth, sudden oak death, and giant hogweed. Excluding them from Oregon is a high
priority for the Oregon Department of Agriculture (ODA). These are big programs
that occur year after year. Smaller issues pop up from time to time, and we
deal with them as they arise. Here are three small invasive species stories
from my week, each with an odd twist.
I took a hotline
call this week from a woman with “jellyfish” in her pond. In my mind, I was
thinking it was probably a bryozoan. There was a call about those last week—but
that’s another story. I told her I doubted it was really jellyfish, but if
she’d send a picture, I’d find someone to identify it. Within an hour, there
were jellyfish pictures in my email box. Dr. Mark Systma at Portland State
University confirmed it. It turnes out a species of freshwater jellyfish is
spreading rapidly around the world.
If you’re
wondering how freshwater jellyfish could spread rapidly anywhere, Google
“freshwater jellyfish” like I did. Note the sponsored ad for: “Floating
jellyfish small (2-pack) $8.99, free shipping on orders over $49!”
My second
story has a “Mouse That Roared” theme. This week, I received three permit
requests for tropical house cricket, Gryllodes
sigillatus. A year ago, the pet food cricket industry was in crisis due to
a virus disease wiping out their breeding colonies. See my earlier blog
(www.oregoninvasivespecies.blogspot.com/2011/05/cricket-crisis.html). The industry wanted to bring in another
species of cricket from Europe. The US Department of Agriculture (USDA) and
other states said okay. ODA did not. Our entomologists had concerns about their
ability to survive outdoors and compete with native species. So we refused to
sign off on USDA permit appications for the new species. Instead, we suggested
the tropical house cricket, which is easy to rear, disease resistant, and can’t
live outdoors. It took a while, but USDA and the industry have come around to
our way of thinking. This mouse that roared is going to have tropical crickets
for supper!
Lastly, a
colleague and I visited with some farmers in Malheur County and looked at
damage to alfalfa fields caused by Belding’s ground squirrels. The squirrels
estivate in the summer, so we didn’t see any of them, but there there were
plenty of burrows. Every 10 feet or so there was another one. Two different
farmers told us you could use up a whole brick of 22 caliber ammunition (500
bullets) shooting ground squirrels from a single spot in a field, then come
back the next day and do it again from the same spot! Either they are really
poor shots, or there are beaucoup ground squirrels. I think its the latter.
The
interesting thing about this to me is that these are not an invasive species. The
ground squirrels are acting like an introduced pest without natural natural
enemies, but they’re not. Ground squirrels were there before the farms. Their
population has just exploded because we’ve planted thousands of acres of succulent
ground squirrel food.
It’s a good
reminder that though most of our problem pests and weeds are foreigners that
have hitchhiked here or were spread by people buying $8.99 two-packs, some are
home grown, and there is nobody out there to blame. Stuff happens, and it all
makes for one very interesting work week!
Dan Hilburn
