Researchers Explore Superior Shoal to Uncover Ecosystem Secrets

A research team from Lakehead University has embarked on a significant expedition to study the Superior Shoal, an underwater mountain located at the heart of Lake Superior. This unique structure, which rises nearly 300 metres from the lake bed, may play a crucial role in understanding the region’s aquatic ecosystem. The team, led by associate professor Michael Rennie, spent nine days collecting data and exploring the shoal’s impact on fish populations and biodiversity.

The Superior Shoal, charted for the first time in 1929, lies approximately 70 kilometres from the nearest shoreline, making it a largely uncharted territory within the world’s largest freshwater conservation area. This remoteness has contributed to its status as a scientific enigma. “This is such a unique spot and it’s this crazy mountain in the middle of Lake Superior,” Rennie noted, highlighting the shoal’s potential as a hotspot for biodiversity and fish productivity.

During the expedition, which began in early September, the team aboard the research vessel Blue Heron examined how physical processes like currents and light penetration interact with the biological community of the shoal. Rennie emphasized the importance of understanding these dynamics, stating, “A lot of what we were trying to understand on Superior Shoal is how physical processes like currents, waves, and light penetration interact with the biological community.”

The findings could be particularly relevant for the health of Lake Superior’s trout fishery. Rennie pointed out that several unique strains of lake trout, including redfin, lean, and siscowet, inhabit the shoal. These populations, which survived the collapse of the fishery in the 1960s and 70s due to invasive lamprey and overfishing, may genetically represent the lake trout that previously thrived in the region. “These places like Superior Shoal, no one ever stocked fish there,” Rennie explained. “And those populations have recovered more or less on their own.”

The expedition was supported by a Canadian government grant, facilitating the research team’s extensive work on the shoal. In addition to scientific inquiry, the journey was also documented by filmmakers Yvonne Drebert and Zach Melnich from Inspired Planet Productions. The duo, who have previously explored lake protrusions for their documentary series, were eager to capture footage of the shoal, which has rarely been filmed. Melnich expressed their excitement, stating, “This area has very rarely been explored on camera.”

To enhance their exploration, the filmmakers utilized an advanced underwater robot, or remotely operated vehicle (ROV), equipped to navigate the depths of the shoal. This high-tech device, developed in partnership with Boxfish Robotics from New Zealand, features an acrylic dome capable of withstanding high pressure and correcting underwater optics. With eight thrusters, the ROV can descend to depths of about 500 metres, enabling the team to capture high-quality footage of the underwater ecosystem.

Drebert highlighted the unique interactions they observed between the lake trout and the robot, noting, “The lake trout, especially out at the Superior Shoal, were very friendly with the robot.” The ROV was tethered via fibre-optic cable to the Blue Heron, where Melnich controlled its movements while monitoring the video feed and GPS location.

The footage captured during this expedition will form part of a new series titled Hidden Below: the Freshwater World, set to air on TVOntario in the coming years. Additionally, the filmmakers are producing a science documentary aimed at raising awareness about the significance of underwater mountains and advocating for their protection, similar to conservation efforts for seamounts in the oceans.

Reflecting on the scale and beauty of the Superior Shoal, Drebert remarked, “Exploring Superior Shoal brought home its size and vastness. It was really great to be able to visualize what these mountains actually look like.” The expedition not only aims to deepen scientific understanding but also to inspire broader appreciation for the hidden wonders of Lake Superior and its vital ecosystems.