Humpback Whale Songs Tracked, Tied To Movements

Using acoustic monitoring techniques, marine scientists at the National Oceanic and Atmospheric Administration have complied the first detailed description linking humpback whale movements and location in the Northwest Atlantic Ocean with specific songs the whales sing.

"Passive acoustic tracking has enabled us to localize humpback whale song to study the movements of individual whales, and to relate the singing to specific behaviors.  This has never before been accomplished for singing humpbacks on a northwest Atlantic feeding ground," said Sofie Van Parijs, the study's co-author and head of the passive acoustics group at the Woods Hole Laboratory of NOAA's Northeast Fisheries Science Center (NEFSC).

In a press statement, Van Parijs said that whale sounds have been monitored and acoustically recorded for years, but new developments in computer software applications and methods have enabled her team to "mine" the data. 

"Passive acoustic tracking of humpback whales and other cetacean species provides an opportunity to collect data on movement patterns that are difficult-or impossible-to obtain using other techniques," said lead author Joy Stanistreet.

The researchers studied the ocean noise in a known feeding ground for humpback whales and other marine mammals at the Stellwagen Bank National Marine Sanctuary in the southern Gulf of Maine. 

They found the whales typically frequent the sanctuary between April and December and feed on sand lance and other small schooling fish.  Humpback whale singing in the sanctuary usually occurs from April through May, following the spring migration from southern waters, and from August to December before the return fall migration. During the summer, humpbacks remain in the sanctuary but generally do not sing while they feed.

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. 

The study, published in the journal PLOS ONE, demonstrates the potential applications of passive acoustic tracking and monitoring for marine mammal conservation and management.