Abstract
Canada’s inner Bay of Fundy (FIGURE 1) features the world’s largest recorded tidal range (17 m) and is home to one of the preeminent tidal energy sites in the world [1,2]. In 2009, the Fundy Ocean Research Centre for Energy (FORCE) was established in Minas Passage as a test centre for large, commercial-scale tidal in-stream energy conversion (TISEC) devices [3]. One of the main environmental concerns at this site is the potential effect of TISEC devices on migratory fishes.
The inner Bay of Fundy supports a diverse assemblage of fish of both economic and ecological importance, including transboundary migratory species [4,5] and several species of high conservation significance [6] , including Striped Bass, Atlantic Sturgeon, Atlantic Salmon, and American Eel. Installation and testing of TISEC devices at the FORCE site present s uncertain risk of fish-facility interactions. While many fish species are known to move through Minas Passage on a seasonal basis, their spatial and temporal use of Minas Passage has not been well studied and therefore remains poorly resolved. Lack of directed commercial and recreational fisheries within Minas Passage limit the usefulness of traditional mark-recapture tagging techniques. Extreme tidal currents also limit survey methods such as mid-water trawling, gill netting and active acoustic surveys [3,6].
Advances in bio-telemetry technology have given rise to tools that offer the potential to collect information regarding fish presence/absence, movement/migration, activity, behavior, and habitat use that is not easily acquired via traditional methods [7,8].
During 2010-2013, multi-species acoustic telemetry studies [9,10] were conducted to assess the potential for fish interactions with TISEC devices installed within the FORCE test site in Minas Passage. Acoustic telemetry was employed to document the presence and depth preferences of several species, including Striped Bass (Morone saxatilis). This species is represented by the local Bay of Fundy Striped Bass population that spawns within the extreme inner portions of Minas Basin during late May-June and disperses throughout the inner Bay of Fundy for summer-fall feeding. The local population is currently recommended for Endangered status [11]. In addition, transboundary migrants from US populations north of Cape Hatteras, NC may overlap in habitat range with the local population [12,13].
The main objectives of the initial Striped Bass acoustic telemetry study were to: 1) assess the timing and duration of occupancy within Minas Passage and the FORCE test site, and 2) determine swimming depth preferences of sub-adults and adults, and their depth patterns relative to day/night and ebb/flood tidal stages in Minas Passage, a high flow environment. This information is currently being used to model detection probability that will help address questions related to the potential for interaction between Striped Bass and TISEC infrastructure at FORCE.