I recently met an angler at Lincoln’s Bowling Lake after he called me about a fish he had just caught and had never seen before.
This fish was not a species that has ever been part of Nebraska’s freshwater fauna — or North America’s freshwater fauna. This fish was an oscar, a freshwater fish native to the Amazon basin of South America. How does an oscar end up swimming in Bowling Lake?
Oscars can be possessed and kept in aquariums. Irresponsible aquarium owners take their unwanted fish and release them in local waters. This is not the first time non-natives such as oscars, pacu, tilapia, plecostomus, redtail catfish or even piranha have shown up in Nebraska waters. I am a huge proponent of catch-and-release, but that fish did not go back into the water.
The risk from having tropical aquarium fish released in our waters is minimal, because they likely will go belly-up as soon as our water temperatures start dropping in late fall. Thank goodness for that. However, this occurrence points out one of the biggest threats to our fisheries across the country — illegal releases of undesirable species of fish that compete with desirable fish. There was a recent incident at Calamus Reservoir where there was a risk of zebra mussels being transported illegally there.
What is an unwanted species of fish? That depends on where you are and the species in question. A gizzard shad may be a welcome member of one water body’s fish community while it is the kiss of death to another. In some cases, even sportfish such as largemouth and smallmouth bass, northern pike and even walleye may be invasive, unwanted species. The appropriateness of one species or another depends on the habitat and fisheries management objectives — decisions best left to professional biologists and not some know-it-all carrying a bucket.
This is a major threat to fisheries all across our country. Unwanted species are not being moved around by birds, butterflies or Sasquatch; they are being moved by two-legged human violators and they need to be stopped. A quote in the 2017 Montana Fishing Guide sums it up: “Illegal introductions are made without proper biological analysis and public input, meaning that you the angler had no say in an ill-informed action by self-serving individuals.”
Those fisheries belong to all of us, and I take the health of those fisheries and the quality of my fishing very seriously.