Rainbow trout being pulled out of the water by a fisherman. Photo taken from chesapeakebay.net
Trout have a storied and complicated history in America’s conservation history. Ever since the early days of hatchery breeding – a monumental and often daring effort by Livingstone Stone in California – nonnative invasive trout have grown to dominate nearly every recreational fishery in the country. America’s collective memory has gone so far as to “naturalize” the nonnative Rainbow trout, which represented the state fish of Utah and Colorado until the 1990s.
In the past twenty years, the fate of these nonnatives has changed course. In the 1980s, native Greenback Cutthroat populations slipped to such low numbers in Colorado that the species was considered extinct until a few isolated populations resurfaced. These lone survivors galvanized a movement in Colorado to protect the Greenback Cutthroat, moving to replace the Rainbow as Colorado’s state fish in 1994.
As Laurel, Brendan, and I – the Trout Team at Ucross – have realized, native trout reintroduction is a delicate subject in the Mountain West. Because nonnative trout outcompete nearly every existing fish, native reintroduction projects entail the complete eradication of the existing nonnative trout, along with unintended consequences for invertebrate species that can spread throughout the food web. This is a controversial, time-intensive project to say the least.
Our work this past semester seeks to create a decision-making tool for land managers when considering nonnative trout removal. Although we focused the development of our tool in the context of the Ten Sleep preserve in northern Wyoming, we hope to provide a kind of handbook relevant to areas beyond our study site. So far, our research and interviews have yielded a colorful array of stakeholders and experts in the field, ranging from rotenone (a powerful fish-killing agent) experts to riparian biologists. One of our strangest findings so far surrounds the formula of a less drastic piscicide called Antimycin. While Antimycin seemed to us at first to be a promising alternative, we soon learned that the formula for Antimycin died with its creator, taking it off the market entirely.
As in so many ecological restoration projects, nonnative eradication is as much of a people-problem as anything else. Public opposition in Wyoming to native reintroduction projects is powerful and organized, demonstrating the need, above all, to educate and to communicate with the public as recreational stewards of the land. While our work so far has been remote, we hope to visit Ten Sleep soon to better understand the landscape that we seek to conserve.