The researchers used data from acoustic recordings collected from an array of 10 bottom-mounted marine autonomous recording units (MARUs). Continuous 24-hour recordings units were deployed in the sanctuary for four consecutive three-month periods during 2009. The MARUs were placed three to six miles apart, and the arrays shifted seasonally to areas within the sanctuary having high whale concentrations.
Humpback whale songs were recorded in distinct time periods during spring and fall. No songs were recorded during summer and winter, although humpback whales remained in the area. Songs were most common in the spring, and occurrences of singing increased significantly before and after migration periods.
Forty-three song sessions, each lasting from 30 minutes to eight hours, were used to track individual singing whales. Most of the singers were actively swimming; the patterns and rates of their movement ranged from slow meandering to a faster directional movement. In one case, two singers were tracked at the same time, suggesting a potential reaction by one singer to the presence of the other.
Marine mammal researchers could also use passive acoustic localization and tracking methods to better understand the geographic distribution, abundance, and densities of cetacean species, many of which are threatened by human activities. These applications may help inform and enhance marine mammal conservation and management efforts
|Contact: Shelley Dawicki|
NOAA Fisheries Northeast Fisheries Science Center