Recently, I came upon an article that made me do a double take. The title indicated that large goldfish were becoming an invasive problem in waterways. A bit of research revealed that goldfish can, indeed reach large sizes, depending on their environment. This provided a question that I have had for some time. Goldfish are, of course, illegal to use as bait. I once thought that the reason was humanitarian, as the fish are usually thought of as pets. The real reason is their ability to grow to large sizes in the wild. Being a type of carp, they can become a rather nasty invader.
This got me thinking that it would be a good idea to look at some other invasive species. Of course, space prohibits covering them all, so we will look at a few better known ones.
First up is the rusty crayfish. These large, aggressive critters probably got distributed by anglers dumping their bait into the water when done fishing. The problem with rusties is habitat destruction. Their aggressive nature and voracious appetite leads them to crowd out native species. They are, however, reported to be delicious for human consumption. Although I have eaten crayfish numerous times, and find them delicious, I have never had the opportunity to try a rusty. Maybe someday.
Not all invaders are fauna. There are also some among the flora. One of these is didymo, colloquially referred to as “rock snot.” This algae attaches itself to rocks and other hard objects in the water. Enough of it can make swimming, fishing and other activities undesirable.
This slimy invader is mostly spread by humans. This often happens when the algae adheres to the soles of waders and to such things as paddles, anchors, etc. Prevention is a bit of a nuisance, but it is necessary. Gear should be cleaned thoroughly, and treated with either a 2% bleach solution, 5% saltwater solution or dishwashing detergent. Dry your gear in the sun for 48 hours. These things are necessary when even small traces of the algae are found.
The round goby, native to Eurasia, has become a problem, especially in the Great Lakes. These invaders are small, and they are actually rather cute. The cute looks are deceiving. Although small, they are aggressive and voracious. They can often outcompete native species.
Zebra mussels are one of the best known of all invasive species. They are believed to have arrived here in the ballast tanks of ocean going ships. Regardless of how they got here, they have spread like wildfire. They pose a number of problems. First of all, they filter foods needed by native fish. They also attach themselves to native mussels, thereby incapacitating them. They will attach themselves to just about anything, and can grow into gigantic clusters. They clog water intakes of power plants, resulting in millions of dollars in removal costs. I enjoy watching magnet fishing videos on You Tube. Just about everything pulled in is covered with these critters. They have no use as food for humans. I can personally think of only example of their usefulness. An artist near Erie ground up the shells, then mixed them with resin and cast them into statues. I have one of them, a statue of the Presque Isle Lighthouse in Erie. As you can see in the photo here, by East Brady photographer Jodie Beabout, these mussels are really tiny. Despite their size, they are big trouble.
I’m going to close out with something disturbing. The possibility has arisen of the transmission of Chronic Wasting Disease or, I should say, a related prion based disease, to humans.
Two hunters, out of the same camp, who both ate deer from a CWD area, developed Creutzfeldt-Jakob disease. Both died of the disease.This is far from conclusive.Much more research has to be done. It is not a reason for panic.
Email: salmonangler1@gmail.com