Thursday, July 15, 2021

One fish, two fish

Way back in the wayback, it was sea lampreys invading the Great Lakes. When it comes to invasive aquatic species, the Great Lakes are something of magnets. Zebra mussels. Asian carp. 

Not that New England waters don't hold their own invaders. It's just that, well, our lakes aren't all that Great, so we don't get all that much publicity when invaders invade and start crowding out the natives.

The latest fish story does not, however, take place in the Great Lakes. 

No, right about now, the goldfish invasion is hitting the Land of 1,000 Lakes: Minnesota. And the invasion isn't coming from throngs of goldfish swimming upriver, or downriver. It's coming from pet owners who want out of worrying about whether those little goldfish they got to entertain the kids during covid are going to go belly up and freak the kids out. Or from pet owners who are sick and tired from having those little mouths to feed, from having to keep the aquarium clean and well lit. Or from pet owners too squeamish to commit the cold-blooded murder of their little cold-blooded critters, too squeamish to just be done with it and flush them down the toilet.

So they go the Born Free route and release their no longer wanted goldfish into one of those 1,000 local Minnesota lakes. 
Far from being an innocuous domestic animal, a goldfish freed in fresh water is an invasive species, an organism that is introduced to an environment, can quickly reproduce, outcompete native species and destroy a habitat. And even though they get less attention than invasive organisms such as Asian carp or zebra mussels, goldfish appear to be a growing problem in bodies of water across the United States and around the world....
Goldfish, like their common carp relatives, feed at the bottom of lakes, where they uproot plants and stir up sediment, which then damages the water’s quality and can lead to algal blooms, harming other species.

“Goldfish have the ability to drastically change water quality, which can have a cascade of impacts on plants and other animals,” [Minnesota natural resources specialist Caleb]] Ashling said. “They are a major concern.”(Source: WaPo)

And they don't stay 2" long, either. They can quickly grow to over a foot long, and easily hit weights of four pounds or so. A nine-pounder has even been reported. So has a twenty-pound goldfish.


Goldfish can live a lot longer than your average flushable home tank little fishy: up to 25 years old. Not to mention survive in really cold water - frozen-over lakes - where they can go without oxygen for months. Plus they breed like rabbits. 

One Minnesota county fished out 30,000 - 50,000 goldfish in one day

It's not just a Minnesota problem. In Washington state, they've overrun a lake and are jeopardizing the native trout population. (Although goldfish are edible, people really want to fish for and eat trout, thank you.) In Virginia, a 16" long goldfish was bagged. 

Having seen giant goldfish in the mini-golf course in Orleans on The Cape, I knew they could grow pretty large in koi ponds. But I had no idea that goldfish were thriving in the wild, while raising havoc with water quality and with indigenous fish species. So this story came as something of a shocker. Right up there with blind albino alligators in the NYC sewage system. (Which, unlike the invasive goldfish, don't actually exist.)

So, one more thing to worry about. At least it's gotten my mind off of whether kudzu is going to overrun Massachusetts.

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