A Marine GIS Case Study of Micro-scale Gray Whale (Eschrichtius robustus) Habitat-use Off Vancouver Island, British Columbia

GIS based habitat modeling and a modified form of binary logistic regression were
used to assess habitat-use of gray whales (Eschrichtius robustus) along the south coast of
Flores Island, British Columbia. Principle objectives include the derivation of a resource
selection function (RSF) to determine relative likelihood of use of available bathymetric
depth, slope and complexity features within the study area. Micro-scale pelagic currents
were subsequently incorporated to examine their potential impact on gray whale habitat
use. 877 whale presence observations were contrasted with bathymetric GIS layers to
produce a RSF identifying increased whale occurrence in waters ~10 meters deep, in
combination with areas having higher benthic topographical complexity. Acoustic
Doppler current profiling data were used to derive continuous, dynamic current surfaces
at three separate depths of the water column. The effects of current speed and direction
on foraging whales were found to be negligible, but areas with south flowing surface
currents consistently predicted increased use.