Aquaculture’s Turquoise Revolution

On the menu at the Rossmount Inn in Saint Andrews, New Brunswick, on the Atlantic coast of Canada, you may find kelp-wrapped salmon– avocado tartare with sesame cranberry– apple vinaigrette, citrus–soy glaze, cilantro, and chives. It sounds mouthwatering, but this is no ordinary seafood. The farmed seaweed (Saccharina latissima) and Atlantic salmon (Salmo salar) are not only side by side on the plate; they’ve been grown side by side, too. Like the old adage one man’s junk is another man’s treasure, at Cooke Aquaculture in New Brunswick, wastes from farmed salmon provide food for farmed seaweeds attached to ropes downstream, and rafts of blue mussels (Mytilus edulis) are also getting in on the nutrient bonanza. It’s a culturing method known as integrated multitrophic aquaculture (IMTA), which follows from the idea that in natural ecological communities, nutrient waste from one organism is reused as food for the next. In nature, the efficiency of nutrient recycling is not 100 percent, but natural ecosystems are thrifty. Little is truly wasted. Nutrient recycling is at the heart of Thierry Chopin’s dream of a “turquoise” revolution. IMTA, hopes Chopin, will help aquaculture move toward more sustainable systems. Chopin, a professor at the University of New Brunswick and scientific director of the Canadian Integrated Multi-Trophic Aquaculture Network, believes that by shifting from single-species intensive operations to multispecies systems that mimic the functioning of natural ecological communities, we may green aquaculture’s blue revolution—to turquoise.