Bay of Fundy research to shed more light on fish and tidal turbines interaction

December 29, 2022, by Amir Garanovic

Some of the Bay of Fundy’s most exciting research continued this year in a large, collaborative effort to better understand how fish move through the Minas Passage and calculate the risk that they may encounter a tidal energy device.

As marine renewable energy activity continues to grow – with exciting developments from Sustainable Marine, BigMoon Power, DP Energy, and Nova Innovation – there are still important research questions to answer, in particular, around marine life.

Many perceive the greatest potential risk of tidal turbine operations as collisions between marine animals and turbine blades. These types of interactions are difficult to observe directly both because of the fast flowing, turbid waters of tidal energy sites and because of the limitations of monitoring instruments that have been designed for use in more benign marine environments.

International research has been generally encouraging – for example, Scottish research in 2021 found that porpoises avoid turbines, especially at higher water flow rates – but more work remains to understand the unique conditions of the Bay of Fundy and, in particular, the perceived risk to fish.

RAP – the Risk Assessment Program for tidal energy – aims to do just that. Now completing its third year, RAP is a collaborative effort between Acadia University, Fundy Ocean Research Centre for Energy (FORCE), Marine Renewables Canada, Mi’kmaw Conservation Group, Confederacy of Mainland Mi’kmaq, Ocean Tracking Network at Dalhousie University, and local fishers to observe the distribution and movement of nine different species of fish in the Bay of Fundy ecosystem.

Working together, the team is designing RAP as a tool to estimate the probability that fish may encounter a tidal energy device. They are creating this tool by combining two things – a real-time flow atlas that tracks the movement of the tidal current, and a fish atlas that tracks acoustically tagged fish as they swim past a network of subsea acoustic receivers in Minas Passage, FORCE informed.

RAP ocean data is collected from various sources, including high resolution X-band marine radar installed at the FORCE site and at Cape Sharp. The radar data is validated by subsea current data to create a ‘flow atlas’. The radar can measure unique flow features in high resolution that affect the distribution of fish.

This environmental data is combined with fish data to create a ‘fish atlas’. Acoustic tags are surgically implanted in fish that are then released back to the wild. These fish transmit a signal captured by a network of 12 acoustic receivers which allows the research team to learn more about their movement in the Minas Passage.

The fish atlas is an unprecedented collaborative effort to collect, combine and analyze multiple data sets of hydroacoustic fish-tagging studies – both existing and new. The studies cover nine species: alewife, American shad, American eel, Atlantic salmon, Atlantic sturgeon, Atlantic tomcod, spiny dogfish, striped bass, and white shark. The species were chosen based on historic tagging data availability, conservation concern and value to commercial, recreation, and Mi’kmaq fisheries.

As important as the data is the process – RAP is a collaborative effort, that welcomes knowledge, expertise and perspectives from academia, Indigenous, industry, government and community groups. It provides regulators, rights holders, technology developers and other stakeholders a practical approach to estimating risk.

The next step in the RAP program is to calculate the likelihood that striped bass will encounter a turbine, and expanding this risk measurement to the other eight species in the fish atlas, according to FORCE.