Spinner Dolphins in Hawaiʻi: Abundance, Distribution & Demographics

Spinner dolphins are one of Hawaiʻi’s most familiar dolphin species. They have been studied by researchers since the 1970s, and this early work has been instrumental in understanding this species not just in Hawaiʻi but also in other locations worldwide. They can be seen from shore in many locations around the islands, often resting in shallow, sandy bays during the day. Despite their regular close proximity to shore and their long research history, we still know comparatively little about the overall population size, distribution, or age structure of these animals.

The animals in Hawaiʻi are genetically and spatially isolated from the wider Pacific population, which makes them uniquely vulnerable from a conservation perspective. They have important ecological, cultural, and economic value for the community and also have some of the highest levels of exposure to human activities of any marine mammal population in the world. To address these concerns, current research integrates abundance, distribution, movement, and life-history data from Oʻahu, Maui, and Hawaiʻi Island, with focused demographic studies off west Oʻahu and the Kona coast. This work provides essential information on population size, habitat use, and age structure – key elements for effective long-term conservation and management.