The influence of whalewatching on the behaviour of migrating gray whales (Eschrichtius robustus) in Todos Santos Bay and surrounding waters, Baja California, Mexico

This study investigated the influence of whalewatching boats on behaviour gray whales their migratory route in Todos Santos Bay, near port Ensenada, Baja California, Mexico. The objectives were: (1) to compare swimming direction and velocity presence absence vessels, when other were fishing, cruising or drifting; (2) contribute scientific data improvement regulations for Bay surrounding waters. During winters 1998 1999, theodolite tracking was undertaken from a lighthouse tower located northern Island. both years, migration corridor about 2.5km wide at Islands; this is relatively narrow compared shore stations along coast (USA). Sightings separated into northbound southbound routes variability whale analysed by circular statistics. migration, not different vessels boats. variable, however, statistically during with (p = 0.007) 0.02). Whale showed significant differences without migrations (northbound, p 0.04; southbound, < 0.001). Analysis did yield either migrations. In addition, head-on approach changed whales’ 0.05) 0.015) significantly an towards rear flanks. Although Mexican law explicit concerning manoeuvres around groups, additional suggestion made here prevent unintentional approaches.