Almost weekly, I am reminded of how well-intentioned ideas can have unforeseen negative consequences, and aquaculture seems to be particularly vulnerable to this phenomenon. This often occurs when an uninformed group of advocates manage to persuade an equally uninformed group of policy makers and voters that action must be taken to address some terrible menace to the environment and society, all without an ounce of thoughtful analysis. Here are just a few examples that come to mind.

In response to political pressure and claims of devastating impacts on wild stocks (particularly in terms of sea lice infestations), the Canadian government oversaw the removal of salmon farming operations in the Discovery Islands beginning in 2021. There have been no active salmon farms in the area since 2022. And yet, in spite of the incessant chants of “no salmon farms means no more sea lice” from anti-aquaculture activists and assorted pseudo-scientists, a recent study appears to have debunked that unfounded myth. In 2024 sea lice abundance in the region reached some of the highest levels recorded over the previous eight years …with not a single salmon cage in sight.

Sea lice infestations were still observed on juvenile chum and pink salmon “despite the absence of Atlantic salmon aquaculture production between 2022 and 2024.” One of the study’s authors, Lance Stewardson, RPBio., CPESC, and Director of Mainstream Biological Consulting Inc., concluded “This long-term monitoring shows that significant natural sources of sea lice exist. Our findings disprove the claim that salmon farms are the sole driver of sea lice on wild Pacific salmon in the near-shore environment and underscore the need for continued monitoring.” It is also worth noting that the Canadian Science Advisory Secretariat’s 2022 Science Response document indicated there was no statistical correlation between sea lice counts on wild and farmed salmon …but what would they know, right?

The demand for alternative protein sources to feed both traditional terrestrial livestock and aquatic species has grown significantly in recent years. Black Soldier Fly (BSF) larvae have been promoted as a promising feed ingredient for fish, poultry and even cattle. BSF larvae can be produced using food wastes or even animal manure that would otherwise require burdensome disposal processes. Additionally, the resulting frass (mostly composed of droppings) can be used to amend nutrient-deficient soils. In many countries there are still a number of public health concerns related to which types of waste should be permitted for BSF production, but interest in commercialization is continually increasing.

So, what could be the downside of using organic waste to produce protein that could replace fishmeal and soybean meal? While there are well-documented sustainability concerns with soybean meal (deforestation, etc.) and fishmeal (unregulated and unsustainable catches), a number of potential environmental impacts have also been cited for BSF production. A recent study in the UK determined that the total climate impact of BSF meal production ranged from 12.9 to 30.1 kg CO2 per kg of protein for waste-fed and feed-fed systems, respectively. These values were actually 5.7 to 13.5 times higher than for soybean meal and 1.8 to 4.2 times higher than for fishmeal. A number of modifications to the present production methodology would be required for BSF meal to achieve climate impacts lower than those of soybean meal. These include the use of solar energy during the rearing process and adopting alternative drying methods.

And, finally, who could forget those well-meaning advocates for ethanol “enhanced” gasoline several decades back? The goal to reduce pollution from automobile engines was admirable, but when the federal government mandated the inclusion of ethanol in U.S. gasoline supplies, significant corn inventories were diverted from feed production to ethanol plants. Corn prices rose rapidly and this in turn increased prices for soybeans. In most of the U.S. catfish producing region, floating catfish feed doubled in price in less than two growing seasons. Many smaller and less-efficient operations could no longer turn a profit, and as production costs increased and acreage declined many seafood buyers took notice and began to seek out alternative products or suppliers. Tilapia producers in many countries faced similar constraints. Critics of corn-based ethanol point out, among other concerns, that it costs more to produce than gasoline and requires more energy than it yields in the process. Had the mandate required the use of ethanol produced from agricultural by-products the end result would have been more environmentally and economically beneficial, especially for the aquaculture industry.

The lesson? It’s up to us to take the long view to ensure policy-makers understand potential impacts to our industry, and its local, regional and global importance. — C. Greg Lutz, Editor-in-Chief