Micro-scale habitat use of humpback whales around Maui Nui, Hawaii

Each winter, thousands of North Pacific humpback whales (Megaptera novaeangliae) migrate from their high latitude feeding grounds in Alaska to mate and calve in the shallow tropical waters around the Main Hawaiian Islands. Previous studies on humpback whales in Hawaii have focused on the whales’ acoustic behavior and their general distribution within the islands, but little is known about small-scale habitat preferences. Off the island of Maui, anecdotal reports from commercial operators and researchers tell of clusters of whales within the breeding area. However, to our knowledge, no studies have been conducted to examine the phenomenon of micro-scale aggregations. A pilot study using passive acoustic monitoring with Ecological Acoustic Recorders (EARs) was conducted from January through early March 2016 at three sites off Maui, using male singers as a proxy for relative whale abundance. Root-mean-square sound pressure levels (SPLs) were calculated to compare low frequency acoustic energy (0-1 kHz) betwe...