Challenges in Monitoring Fish and Marine Mammals in the Megatidal Waters of the Upper Bay of Fundy

Tidal energy developments at the FORCE (Fundy Ocean Research Centre for Energy) test site in Minas Passage, Bay of Fundy, have necessitated a monitoring and research program to address the potential risk of turbine – marine biota interactions.  Methods used to collect data on fish movements through the test site have included mid-water trawls (with sonar), and acoustic tracking of significant species, including those of high commercial value (American lobster) and endangered (Bay of Fundy striped bass and Atlantic salmon) or threatened species (Atlantic sturgeon and American eel). Tag transmission detections demonstrate that the FORCE test area forms part of the migratory corridor for both lobster and numerous fish species, with some making multiple, near daily passes through the passage. The environmental effects monitoring program also incorporated examination of the seasonal abundance of fishes captured in local intertidal weirs.  Schools of Atlantic herring attract harbour porpoises which have been monitored in and around the FORCE site using a series of C-POD hydrophones (autonomous cetacean echolocation click detectors).  The biggest challenges faced in sensing both fishes and marine mammals in Minas Passage have been flow-induced noise effects on receiver and hydrophone detections when average water column current speeds exceed 2 m/s.