Data for the project: Shifts in habitat suitability for harbour porpoises leads to reduced importance of Marine Protected Areas

Location data from 111 tracked harbour porpoises were collected over the period 1997–2022 as part of a long-term satellite telemetry monitoring program in Denmark. Individual harbour porpoises were fitted with Argos satellite tags after being incidentally trapped in pound nets, which are used in near-shore commercial fisheries in the Inner Danish waters. Argos tags were programmed to make a limited number of daily satellite uplinks and acquire a location at pre-defined times (time of day and duty cycles) to increase the battery lifetime. Duty cycles of the tags varied between 1 and 4 days. Pre-processing of location data included filtering out unlikely locations using the Argos-Filter v7.03 and the removal of locations on land and those collected within 24 hours after tagging to reduce behavioural bias caused by capture and tagging. After the data cleaning process, 9 345 locations collected by 111 harbour porpoises were included in this study with an average tracking duration of 118.5 days per individual (min = 8 days, max = 522 days). Dataset includes coordinates (latitude and longitude ) of each location and the season and time period it was collected.