You've likely heard the expression "nothing ventured, nothing gained," shorthand for many things in life worth doing involve some level of risk. Conservationists are risk averse by nature, so you might be surprised to learn Alberta Conservation Association (ACA) proposed evaluating channel catfish, a non-native species, for creation of put-and-take fisheries in the province.
Channel catfish are considered an invasive species by some jurisdictions, a designation synonymous with risk. So why would ACA ever consider stocking a non-native, purportedly invasive species? The short answer is that we did our homework, believe the risks are manageable, and are greatly outweighed by the potential rewards. The longer answer involves an ongoing debate that lies at the heart of what it means to be an invasive species.
Dozens of terms have been used in scientific literature over the years to describe non-native species that are considered invasive. Some of these are probably familiar to you, such as alien, exotic, vermin, pest, and noxious—but there are many more. This proliferation of terms, many with negative connotations, has generated controversy in the scientific community.
By way of analogy, imagine if you went to your doctor to have them look at a concerning lump on your shoulder, and they returned a diagnosis of "deadly skin bump." You would probably want a second opinion. The doctor's use of imprecise and value-laden terms would likely undermine your confidence in their ability to accurately and impartially diagnose and treat the lump. The same holds true for the field of invasion biology, which struggles to consistently and objectively define fundamental terms like non-native and invasive.
This struggle became glaringly obvious when we began researching the potential risks of stocking channel catfish in Alberta. We are proposing to stock sterile (i.e., triploid and unable to reproduce) channel catfish, whereas literature concerning this species' invasiveness assumes the fish are capable of reproduction. Even so, channel catfish appear to occupy the mushy middle on the spectrum of invasiveness, neither predictably impactful (think zebra mussels) nor apparently benign (think dandelions). As such, the relevant scientific literature often tells us as much about an individual author's impartiality and risk tolerance as it does about channel catfish invasiveness.
Does this mean we think the concept of an invasive species is invalid or that channel catfish pose no risk? Not at all, but it is a good reminder that assessing risk, an inherently subjective term, involves value judgments. And if you think this is only an issue for researchers in their ivory towers, think again. Brown and brook trout, ring-necked pheasant, and Merriam's turkey are all non-native species currently released for recreational enhancement in Alberta that are considered invasive by some jurisdictions.
Our proposal has not been without controversy. Many are excited by the prospect of fishing for channel catfish, provided the risks are minimized. That's why we've proposed importing sterile, disease-tested catfish to be reared in quarantine for a year prior to evaluation in experimental ponds. Despite these precautions, some view stocking any non-native species as unacceptable. Ideally science informs the debate, but ultimately it is up to society to decide if the risk outweighs the reward. What shouldn't be up for debate, at least in our opinion, is ensuring a future where angling opportunities are maintained or increased for all Albertans.
