MEPS 373:173-186 (2008)  -  DOI: https://doi.org/10.3354/meps07666

ABSTRACT: With the development of human activities in offshore shelf waters, the harbour porpoise Phocoena phocoena has become a focal species in relation to management of human activities and marine habitat conservation efforts. In this study, acoustic and visual time series of harbour porpoise occurrence were analysed from the Horns Reef area, eastern North Sea, aiming at resolving periodicity, spatial scale of aggregation and habitat drivers in porpoises. A total of 51 fine-scale surveys and 474 d of hydrophone deployment at 2 stations were analysed by partial least squares regression and spatial modelling in relation to synoptic (spatio-temporal) data derived from a local, high-resolution hydrodynamic model. Small-scale changes in local currents reflecting upwelling driven by the interaction of the semi-diurnal tidal currents with the steep slopes of the bank were the main habitat driver identified from the acoustic as well as the survey data. Spatial modelling based on selected key predictor variables showed the distribution of harbour porpoises to alternate between 2 upwelling cells depending on the direction of tidal currents. The size of upwelling cells was less than 10 km, matching the small-scale spatial structure of survey data as revealed by geostatistical analysis. The findings may have great implications for the design of future protected areas for harbour porpoises, and they indicate that the overlap between areas of concentration of the species and areas targeted by fisheries and the offshore wind industry could be avoided without major changes to current management practices.

KEY WORDS: Fine-scale habitat · Harbour porpoise · Phocoena phocoena · Dynamic habitat modelling · Marine habitat conservation · Marine management · Offshore wind farms · Fisheries

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Cite this article as: Skov H, Thomsen F (2008) Resolving fine-scale spatio-temporal dynamics in the harbour porpoise Phocoena phocoena. Mar Ecol Prog Ser 373:173-186. https://doi.org/10.3354/meps07666 Export citation Share:    Facebook - - linkedIn