Movement and spatial use of Odontocetes in the western main Hawaiian Islands: results of a three-year study off O'ahu and Kaua'i

Abstract

Understanding the impacts of anthropogenic activities on animal populations requires knowledge of their population structure, sizes and ranges. In Hawaiian waters this type of basic information has been lacking or is restricted to areas where conditions have been more favorable to research efforts, namely the eastern main Hawaiian Islands. As part of an effort to reduce uncertainty regarding the population, range and abundance of odontocetes in the western main Hawaiian Islands, and to help inform Navy impact assessments, we undertook small-boat based research efforts off O'ahu (2010) and Kaua'i (2011 & 2012). A variety of field methods were used, including photo-identification, collection of biopsy samples for genetic studies, and satellite tagging. There were 191 odontocete sightings, 183 identified to species. 102 biopsy samples were collected from 7 species. 30 satellite tags were deployed on 5 species: pygmy and false killer whales, bottlenose and rough-toothed dolphins, and short finned pilot whales. Our efforts substantially increased what is known in particular about the movements and habitat use of these 5 species of odontocetes in the western main Hawaiian Islands.