Variation in acoustic activity of North Atlantic right whales in three critical habitat areas in 2004

Abstract

The North Atlantic right whale is a critically endangered species. Five major habitat areas have been defined based on the presence of groups of right whales during different seasons of the year. Autonomous seafloor acoustic recorders, ‘‘pop-ups,’’ have been used over the past five years to identify the presence/absence of right whales in Cape Cod Bay, Massachusetts by detection of right whale contact calls. These recordings have shown the effectiveness of using acoustics to monitor right whale behavior. In 2004, multi-unit arrays of pop-ups were deployed in three critical habitat areas; Cape Cod Bay (January–April), Great South Channel (May), and the Bay of Fundy (August). The presence/absence of right whale calls within range of the array, estimates of the minimum number of individuals calling, the types of calls recorded, and the diurnal patterns of sound production were measured to compare the acoustic repertoire use of right whales in these three habitats. These data were compared to visual survey data in the Bay of Fundy. These results can be used to compare diurnal and nocturnal behavioral patterns of the whales and provide information on behavioral differences between these three critical habitat areas.