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Limited reports of sei whale calls indicate that the whales make low and mid-frequency vocalizations including pulse trains (peak energy at 3 kHz), broadband “growl” and “whoosh” sounds (100-600 Hz, 1.5 s in duration), tonal and upsweep calls (200-600 Hz, 1-3 s in duration), and downsweep calls (100-44 Hz, lasting 1.0 s, and 39-21 Hz lasting 1.3 s). Most recently, downsweep calls (82.3 Hz to 34 Hz) were recorded in the North Atlantic. Scientists believe this is a "contact" call, as sei whales are traditionally observed alone or in small groups of 2-5 whales. Contact over long distances via low frequency sounds may allow dispersed animals to coordinate activities such as feeding or breeding.
Sei whales feed primarily on dense aggregations of copepods, euphausiids (krill), small schooling fish (e.g. herring and anchovies) and cephalopods (e.g. squid). A strong relationship appears to exist between the vertical migration of copepods and sei whale calling rates. Researchers found sei whale vocalization rates increased during the day, when plankton were at depth and then decreased at night, when plankton were closer to the surface. It is hypothesized that calling rates decrease at night while the whales are feeding close to the surface, but increase with social activity during the day when the copepods are more difficult to capture at depth.The sei whale vocalizations on this page that were recorded at the continental shelf break east of New Jersey, mark the first time that sei whales have been recorded/identified in this region. Sei whales typically only travel in pairs or as individuals, however, these vocalizations may be an indication that they are in long-range (>10 km) communication with other sei whales.
- Baumgartner M.F. and Fratantoni, D.M. 2008, "Diel periodicity in both sei whale vocalization rates and the vertical migration of their copepod prey observed from ocean gliders." Limnology and Oceanography. 53(5, part 2): 2197-2209.
- Baumgartner, M.F., Van Parijs, S.M., Wenzel, F.W., Tremblay, C.J., Esch, H.C., and Warde, A.M. 2008, "Low frequency vocalizations attributed to sei whales (Balaenoptera borealis)" Journal of the Acoustical Society of America. 124(2): 1339-1349.
- Knowlton, A., Clark, C.W., and Kraus, S. 1991, "Sounds recorded in the presence of sei whale, Balaenoptera borealis (A)" Journal of the Acoustical Society of America. 89(4B): 1968-1968.
- McDonald, M.A., Hildebrand, J.A., Wiggins, S.M., Thiele, D., Glasgow, D., and Moore, S.E. 2005, "Sei whale sounds recorded in the Antarctic." Journal of the Acoustical Society of America. 118(6): 3941-3945.
- NOAA Fisheries, Office of Protected Resources, "Sei Whale (Balaenoptera borealis)" (Link)
- Rankin, S., and J. Barlow 2007, "Vocalizations of the sei whale (Balaenoptera borealis) off the Hawaiian Islands." Bioacoustics. 16: 137-145.
- Scripps Institution of Oceanography, "Voices in the Sea." (Link)