Occurrence, site-fidelity and abundance of bottlenose dolphins (Tursiops truncatus) in Broadhaven bay, northwest Ireland during long-term construction of a gas pipeline

摘要: Abstract During the construction of a pipeline from an offshore gas field in northwest Ireland, shore-based watches and opportunistic boat-based photo-identification surveys for bottlenose dolphins Tursiops truncatus were undertaken. Seven years data used to investigate influence Construction-Related Activity (CRA) on occurrence bay where made landfall. CRA varied substantially over seven included dredging, pipe-laying, rock armouring as well seismic surveys. While individual activities could not be examined isolation, there was no evidence aggregated or season influencing occurrence, despite greater number days during summer months. There weak support year, but lower rates did correspond with more days, vice versa. The uncorrected (marked animals, only) corrected (accounting unmarked individuals) annual abundance estimates lowest coefficient variation 67 (95% CI = 62–84; CV 0.08) 140 106–174; 0.12) 2010, which comparable neighbouring region west coast Ireland. Of well-marked individuals approximately 50% re-sighted two re-sightings within high 70%. Overall, little suggest that extended period resulted short- long-term reduction bay. However, given relatively coarse spatial temporal scale it possible assess fine-scale movements, such redistribution response immediate area. To better inform management mitigation practices, emphasis should placed designing robust monitoring programmes focus beyond displacement sole indicator impact.