Boat Harbour Fish Population Assessment

Boat Harbour, surrounding wetlands and tributary watercourses, and the downstream estuary were surveyed between September 23 and October 10, 2019 to identify, enumerate, and characterize the fish community. Active and passive approaches resulted in the capture of 522 fish: 16 in Boat Harbour, 104 in the wetlands and watercourses, and 402 in the estuary. In total, five species were captured, with only three species found in Boat Harbour. Captured fish were measured (to determine their overall condition) and released alive, with a subset retained for liver somatic index (LSI), gonadosomatic index (GSI), and tissue burden (metals and organics) analyses. Overall, fish were in good condition, with similar LSI and GSI values among most locations/groups—although small sample sizes for the subset of fish lethally sampled must be acknowledged as a constraint for some endpoints. Of the nine metals measured, most did not show significant differences among locations or when compared to reference fish. Organic analyses measured 17 dioxins and furans, and 9 PAHs. Nine dioxins and furans were found in fish tissues, but only one furan was found above the lower quantification limit. Five polycyclic aromatic hydrocarbons were found in fish tissues, with many well above reference fish and the post-hoc control tomcod (Microgadus tomcod) concentrations. Though no statistical tests were possible due to low sample size, our organic analyses data suggest organic tissue burdens may play a role in the impoverished fish community in Boat Harbour and associated habitats.