Investigating the occurrence of spinner dolphins around Maui Nui, Hawaii Free

Spinner dolphins (Stenella longirostris) occur commonly along Hawaii’s sloping coastlines where they follow a daily behavioral routine of foraging offshore at night on vertically migrating mesopelagic and epipelagic prey and then return to shallower waters to rest during the day. Populations of spinner dolphins have been well documented off Hawaii island and Oahu, but much less so off the other islands. In the Maui Nui region (Maui, Molokai, Lanai, and Kahoolawe), spinner dolphins are sighted regularly, but little is known about their use of the nearshore habitat, which is characterized by much shallower bathymetry than Hawaii island and Oahu. As a result, spinner dolphins in Maui Nui offer a unique opportunity to examine the adaptability of the species to a habitat that would not be considered ideal for their life history needs. To better understand the habitat-use patterns of spinner dolphins in Maui Nui, bottom moored acoustic recorders are being used to examine spinner dolphin presence off west Maui and southeast Lanai. These data are compared to similar data previously obtained from a well-studied spinner dolphin population off west Oahu. Preliminary results from these analyses are presented in combination with data on habitat characteristics and anthropogenic impact.