Fin whale song patterns in Southern California and the Gulf of California

Abstract

The most common fin whale calls, 20 Hz pulses, are often produced in regular, stereotypic sequences termed songs. The main variability in songs comes from the differences in the duration of the interval between successive pulses, the interpulse interval (IPI). Data recorded between 2000 and 2012 in Southern California and 2004 to 2010 in the Gulf of California were analyzed for temporal and geographic patterns in fin whale songs. During this time, fin whales in Southern California and the Gulf of California produced four song types with distinct IPI sequences. Two common songs in Southern California were the short doublet and the long doublet and they were detected year-round. The IPIs in the short doublet song have been increasing over the long term, while the IPIs in the long doublet song showed no long-term trends but were seasonally variable. In the Gulf of California, the most common songs were the short triplet and the long triplet. These songs were detected in Gulf of California year-round, although their occurrence decreased August through October. There was some exchange of sons between the two areas that might point to seasonal movement of parts of these populations.