Harbour seal GPS tracks - SeaMonitor deployments (N. Ireland)

Telemetry studies are a useful tool for assessing potential interactions between marine biota and anthropogenic activities. For seals, that are exposed to multiple threats stemming from, for example, aquaculture and commercial fisheries alongside specifically noise-generating activities such as shipping, oil and gas exploration and marine contraction projects, GPS-GSM tags can be used to track movements in near-real time across large spatial extents for a period of several months. This information can then be used to assess interactions between seals and these potentially impactful anthropogenic activities. Here, we focus on tracking the behaviours and distributions of rehabilitated juvenile harbour seals, that may be particularly vulnerable to disturbance from human interference. Using Fastloc technology, which requires less than 1 second at the surface to obtain a fix, tags were programmed to record a location roughly every 15 minutes, subsequently providing high resolution data on seal movements. Tags also had an inbuilt time-depth recorder, programmed to log summarised dive events (summarised using a broken-stick algorithm to 10 inflexion points including the maximum depth). Together this information was transmitted by the GSM mobile phone network when a seal came within range. This data is/was collected as part of the INTERREG funded SeaMonitor project, with an aim to better understand the dive behaviour, movements, space use (alongside interactions with anthropogenic activities), and survival of rehabilitated juvenile harbour seals (Phoca vitulina) from Northern Ireland.