Can modelled harbour porpoise distribution based on satellite tracking be validated from static acoustic monitoring

• Main Authors: Mikkelsen, Lonnie, Riget, Frank Farsø, Sveegaard, Signe, Kyhn, Line Anker, Amundin, Mats, Carlén, Ida, Carlström, Julia, Ljungqvist, Cinthia T., Wennerberg, Daniel, Koblitz, Jens, Benke, Harald, Teilmann, Jonas
• Format: Conference Object
• Language: English
• Published: 2015
• Subjects: Harbour porpoise; Phocoena phocoena
• Online Access: https://pure.au.dk/portal/da/publications/can-modelled-harbour-porpoise-distribution-based-on-satellite-tracking-be-validated-from-static-acoustic-monitoring(58e7abe2-e798-454f-863e-56bd4c8b76aa).html; http://havforsk2015.geus.dk/index.shtml

Species distribution models are increasingly being used to model habitat suitability from positioning records. Here we use satellite locations from 15 tagged harbour porpoises ( Phocoena phocoena ) in the western Baltic Sea to model suitable habitats using the species distribution model MaxEnt (Maximum Entropy modelling). The basic principle of MaxEnt is to compare environmental variables at positions where porpoises have been ‘observed’ with environmental variables at a random selection of positions in the landscape. The data set with one position per day yielded enough data to make reliable models for two seasons, summer (Jun-Aug) and autumn (Sep-Nov). The model showed large differences in habitat suitability within the study area and among our environmental variables salinity, temperature and distance to coast had the most explanatory power. These results were consequently compared to harbour porpoise occurrences obtained from a large scale study based on static acoustic monitoring of porpoises using C-PODs, covering the same area. Results from the acoustic study revealed the same pattern as the MaxEnt model; both showed a strong gradient in porpoise occurrence/habitat suitability from west to east, and the two data sets had an exponential correlation.