Temporal and spatial distribution patterns of toothed whales in Massachusetts Bay using passive acoustics from ocean gliders

Abstract

Basic information on marine mammal habitat use is necessary for informing ecosystem-based management plans and for mitigating human impacts. Massachusetts Bay is an important marine mammal foraging area in the Gulf of Maine and a region of high human activity, but little is known about toothed whale habitat use, particularly during winter months. Passive acoustic monitoring, particularly from autonomous platforms, provides advantages in studying habitat use in unfavorable conditions. The goal of this work is to use acoustic monitoring to investigate temporal and spatial occurrence patterns of toothed whale species in Massachusetts Bay during late fall/early winter using ocean gliders equipped with passive acoustic recorders. Slocum gliders were deployed in western Massachusetts Bay in 2014, 2015, and 2016. Toothed whales were detected on 92 (72%) of 128 deployment days. Detections occurred more often at night. Ongoing work includes acoustic identification of species and assessing relationships between detections and environmental conditions. These data provide the first evidence of a consistent presence of toothed whales in Massachusetts Bay during late fall and winter, and demonstrate the potential for ocean gliders as a tool to detect toothed whales in areas/times that are difficult to survey with traditional visual methods.