Rainbow Trout

Rainbow trout threatens native salmonids, brook trout and Atlantic salmon

What comes to mind when you hear the words rainbow trout? Perhaps you think of a delicious Sausage-Stuffed Rainbow Trout dinner, or if you’re a kid, Rainbow Fish and Ruby meet their long lost cousin. But, have you ever thought of rainbow trout as a threat, a “bully” towards native species of fish? Of course not! After all, they’re rainbow right? Doesn’t that mean they’re just kind and happy? Well, rainbow trout aren’t all lollipops and cotton candy. In fact, they are an invasive non-native species in Canada, threatening our very own salmonids, brook trout and Atlantic salmon.

Rainbow trout is a species of fish that is native to the Pacific drainages of North America. They are included in the top 100 of the world’s worst invasive species. After many years of introductions and transfers, the current distribution of rainbow trout now covers most of North America and many other parts of the world. Fish culturists learned how to artificially breed rainbows and they were first introduced in a California stream in 1872. They were then introduced in lakes and streams that were devoid of fish or that contained only “rough” fish. Rainbow trout were also introduced in streams that contained other, native, species of trout.

You may be thinking, so what? They’re just fish! What harm will they do? Well, rainbow trout compete for the same resources as many other species of fish such as food and habitat. For example, it is a potential threat to the native salmonids of Trout River, including the possibility that rainbow trout may be successfully spawning in the Trout River watershed. Atlantic salmon stocks in Trout River are presently at low levels and their habitat is vulnerable to intrusion by an exotic species. Large rainbow trout of comparable size to large adult brook trout can be aggressive competitors for available habitat within the confines of a small stream. Since all the animals and plants–including us–are linked together in a food chain, everyone is bound to pay.

Let’s say a certain kind of animal only eats Atlantic salmon. The rainbow trout comes in says, “I want to join in the fun!” and together they bully the Atlantic salmon to near extinction in the area. Now the animal is hungry but he has no food, so his kind starts to die off. The predators of these animals are then left with growling stomachs and follow the same path of their prey. The rainbow trout family keeps getting larger and larger, so they boot out all the other kinds of fish. Because there are so many rainbows, the insects will soon be wiped out too. Before you know it, they will have dominated the waters, leaving all kinds of animals foodless, themselves included.

Nature is all about balance, so when something happens, whether naturally or artificially, adaptation is necessary. Most species can’t adapt fast enough and die or move away. When this happens artificially, by invasive species, balance can’t be achieved without help. The Invasive Species Centre (ISC) was founded in March 2011 with the support of the federal government of Canada and the government of Ontario. The ISC focuses on coordination of research, data management, strategic planning, mitigation and response actions, and rehabilitation efforts for the purpose of combating alien invasive species that threaten Ontario’s natural resources and ecosystems. Prevention, management and control methods are also used, such as physically removing the species, or reducing or eliminating it through the use of other living organisms. Individuals can help as well! In 1992 the government of Ontario and the Ontario Federation of Anglers and Hunters established the Invading Species Awareness Program. One of the program’s main goals is to help Ontarians learn about invasive species and how to stop their spread. We can help by not buying, selling, transporting or keeping rainbow trout.