MANUSCRIPT - DO NOT CITE WITHOUT PERMISSION Mapping world-wide distributions of marine mammal species using a Relative Environmental Suitability (RES) model K. Kaschner1,2, R. Watson1, A.W. Trites2 and D. Pauly1 1Sea Around Us Project, Fisheries Centre, University of British Columbia, 2259 Lower Mall, Vancouver, BC, Canada, V6T 1Z4 2Marine Mammal Research Unit, Fisheries Centre, University of British Columbia, Hut B-3, 6248 Biological Sciences Road, Vancouver BC, Canada, V6T 1Z4 Running title: RES mapping of marine mammal distributions Key words: habitat suitability modelling, marine mammals, global, GIS, relative environmental suitability, environmental envelope model, distribution Corresponding author: Kristin Kaschner Marine Mammal Research Unit, Fisheries Centre University of British Columbia Hut B-3, 6248 Biological Sciences Road Vancouver, B.C., V6T 1Z4 CANADA Tel: + 604 822 9150 Fax: + 604 822 8180 Email:
[email protected] ************************************************************************************* Submitted to Marine Ecology Progress Series (June 2004) ABSTRACT We developed a large-scale habitat suitability modeling approach to map global distributions of 115 species of marine mammals. Predictions were generated by first assigning each species to broad-scale categories of habitat preferences with respect to depth, sea surface temperature and ice edge association based on synopses of published qualitative and quantitative habitat preference information. Using a global grid with 0.5 degree lat/long cell dimensions, we generated an index of the relative environmental suitability (RES) of each cell for a given species by relating quantified habitat preferences to locally averaged oceanographic conditions in a GIS modeling framework. RES predictions closely matched published maximum range extents for most species, suggesting that our model-based approach for identifying habitat represents a useful, more objective alternative to existing sketched distributional outlines.