Marine mammal demographics off the outer Washington coast and near Hawaii

Abstract

This report summarizes work conducted in 2008-2010 to understand the seasonal occurrence and distribution of marine mammals in or near active Navy ranges off Washington and Hawaii. Long-term acoustic recording and monthly visual surveys have been conducted off the outer Washington coast since 2004 as part of an effort to monitor for marine mammals within the boundaries of the proposed expansion area of the Quinault Underwater Tracking Range (QUTR). This effort was designed to characterize the vocalizations of species present in the area, determine the year-round seasonal presence of all marine mammal species, and evaluate the distribution of marine mammals near the Navy range. Small boat visual surveys were conducted in the range, resulting in sightings of a broad range of marine mammal species throughout the year. Two High-frequency Acoustic Recording Packages (HARPs) have been deployed near the QUTR, data from which provide information on the seasonal presence of a broad range of marine mammal species. In 2008 a longterm acoustic monitoring study off the coast of Hawaii was started in cooperation with regular visual surveys conducted in the region. HARP recordings of tropical odontocetes, which may be used as reference recordings for future long-term monitoring efforts within the Hawaii Range Complex, have also been obtained, providing the first information on the seasonal occurrence of odontocetes in this region gained from long-term passive acoustic monitoring.