History of mink farming in southwest Nova Scotia

Mink farming is an important component of the local economy in Yarmouth and Digby counties. The tradition has existed in the region since the 1900s, and many farms built in the 1930s are still in operation. The industry boomed in the 1990s, and with that came intensified production. Today there are fewer farms in operation in the region, but the volume of production is still substantial.

Why are we concerned?

All types of agriculture have the potential to unintentionally damage water quality of nearby freshwaters. Cultural eutrophication is the process in which a body of water is fertilized with excess nutrients from an anthropogenic source. There are many negative consequences associated with eutrophication, including potentially toxic algal blooms, loss of fish habitat, and loss of biodiversity (Figure X). Mink farming operations produce large volumes of high-nutrient waste, including carcasses and feces. Even when properly disposed of, these waste products have the potential to fertilize nearby freshwaters.

The specific concerns surrounding mink farming operations in this region include:

-   Aesthetic value: Taste, colour and odour issues on lakes that have many residential properties

-   Nuisance algal blooms that may be toxic

-   Fish habitat and fisheries resources

-   Persistent organic pollutants and heavy metals bioaccumulate in mink, because they are high-trophic level, and may be introduced to aquatic systems

-  Gulls feeding on compost and waste near mink farm sites may be transporting the nutrients and other contaminants to distant locations, broadening the spatial scope of this issue

 Our study approach

Unfortunately, we lack long-term monitoring data to tell us how these lakes might have changed, or the state they were in before the mink farming intensified in the 1980s-1990s . Instead, we use a paleolimnological approach, where we track changes in indicators preserved in the sedimentary archive at the bottom of lakes (see Methods section). We have strategically selected lakes in the Carleton and Meteghan watersheds that have been monitored by local organizations (e.g., the Tusket River Environmental Protection Agency) and by Nova Scotia Environment. We will study lakes with and without mink farming on their watersheds. This reference/impact, multi-proxy approach will inform whether the nature and timing of any changes can be attributed to the presence of mink farming. Further, this will allow us to differentiate between the effects of multiple stressors, including climate change and/or acidification. 

For more, see the Methods section.