As a regional biologist in Nova Scotia, starting in 1972, I was involved with several eradication programs that used a standard rotenone-based toxicant of the time. The targets for use were ponds with goldfish, or lakes that had formerly hosted a healthy trout population, but were now filled with perch.
I will restrict my comments to the latter situation.
We completed the work using standard protocols that included stream barriers. In my experience, it was virtually impossible to get a complete kill, which included all life forms that breathe underwater using gills. In time I surmised that, even when carefully applied using boats, the weed beds in the lake’s shallows prevented the toxicant from spreading to 100 percent of the lake. Fish species that were previously in the lake gradually reappeared over subsequent years.
Given the size of the Miramichi watershed, to what extent has the smallmouth bass population already spread? There’s usually a time lag between illegal introductions and their detection.
Individuals and institutions who want to eliminate the bass have my sympathy, but I’m suspicious that this species’ population has spread to a wider extent in this watershed than is presently understood.
In my estimation, as a biologist, this method of killing so many aquatic vertebrates and invertebrates, in an effort to eliminate one other species, and when the probability of success is almost nil, amounts to a tremendous waste of time and money, while creating an ecological nightmare.
Bob Bancroft is a wildlife biologist and the current president of Nature Nova Scotia.
