Recent winter sightings of minke whales (Balaenoptera acutorostrata) in the South Atlantic Bight

About

The summer feeding grounds of the minke whale (Balaenoptera acutorostrata) in the western North Atlantic are well-documented, but its winter distribution and the location of its calving grounds are currently unknown. Sporadic winter sightings and strandings in the Caribbean and Florida suggest an offshore breeding and calving area somewhere in this region (Mitchell 1991). We present recent sightings of minke whales in the South Atlantic Bight during winter, and examine these together with historical sighting and stranding records from the region. We conducted monthly aerial surveys at two proposed U.S. Naval training exercise areas in Onslow Bay, North Carolina (June 2007 to April 2011) and off Jacksonville, Florida (January 2009 to April 2011). Minke whales were observed nine times (13 individuals) in the Jacksonville site: six singles, two pairs, and one mom/neonate pair with an adult escort. In the Onslow Bay site, minke whales were encountered twice (one single and one mom/calf pair). All sightings occurred in winter, between late December and February, in waters offshore of the continental shelfbreak. A review of historical (1980-2010) sightings (n=22, provided by the North Atlantic Right Whale Consortium) and strandings (n=6, provided by NOAA Fisheries) in the mid- and southeast Atlantic, revealed that most minke whale sightings occurred during winter and spring (15 and 4, respectively), rather than in summer and fall (3 and 0, respectively). Most winter sightings (10 of 15) occurred off Florida, while all spring and summer sightings (7) occurred off North Carolina and Virginia. All strandings were of calves and occurred in North Carolina, with most in winter and spring (5 of 6). These data suggest that the southeastern U.S. may be an important habitat for minke whales in winter, and may include their calving grounds.