Barriers to Fish Passage in Nova Scotia: The Evolution of Water Control Barriers in Nova Scotia’s Watershed
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Loss of connectivity throughout river systems is one of the most serious effects dams impose on migrating fish species. I examine the extent and dates of aquatic habitat loss due to dam construction in two key salmon regions in Nova Scotia: Inner Bay of Fundy (IBoF) and the Southern Uplands (SU). This work is possible due to the recent progress in the water control structure inventory for the province of Nova Scotia (NSWCD) by Nova Scotia Environment. Findings indicate that 586 dams have been documented in the NSWCD inventory for the entire province. The most common main purpose of dams built throughout Nova Scotia is for hydropower production (21%) and only 14% of dams in the database contain associated fish passage technology. Findings indicate that the SU is impacted by 279 dams, resulting in an upstream habitat loss of 3,008 km of stream length, equivalent to 9.28% of the total stream length within the SU. The most extensive amount of loss occurred from 1920-1930. The IBoF was found to have 131 dams resulting in an upstream habitat loss of 1, 299 km of stream length, equivalent to 7.1% of total stream length. The most extensive amount of upstream habitat loss occurred from 1930-1940. I also examined if given what I have learned about the locations and dates of dam installations, are existent fish population data sufficient to assess the impacts of dams on the IBoF and SU Atlantic salmon populations in Nova Scotia? Results indicate that dams have caused a widespread upstream loss of freshwater habitat in Nova Scotia howeverfish population data do not exist to examine the direct impact of dam construction on the IBoF and SU Atlantic salmon populations in Nova Scotia. Because of the large extent of rivers behind dams, this research suggests that dam construction may havecontributed to the decrease of Atlantic salmon populations or may be currently inhibiting recovery of salmon stocks in Nova Scotia.