Opportunistic Sightings of Cetaceans in Nearshore and Offshore Waters of Southeast Florida

Abstract

The majority of cetacean research pertaining to the western North Atlantic Ocean has focused on the waters between North Carolina in the United States and the Scotian Shelf in Canada; little is known about cetacean occurrence and distribution in the waters off southeast Florida (FL) where the subject study was conducted. Our study describes opportunistic, ship-based sightings of cetaceans during 1989-2006 in nearshore and offshore waters located in the Gulf Stream between the Bahamas and Palm Beach, FL. Nine species were observed during 60 sightings. For two of the documented species (false killer whale, Pseudorca crassidens, and Fraser’s dolphins, Lagenodelphis hosei), very little existing information was available with respect to sightings and distribution in the study area. The other seven species were observed in waters south of their documented distributions, based on sightings data from dedicated surveys conducted along the US East Coast, but which only extended to central FL. We documented distinctive physical attributes of offshore ecotype bottlenose dolphins (Tursiops truncatus) and described foraging behavior of false killer whales. Our opportunistic observations highlight the importance of conducting regular surveys in this little-researched region. Data gathered during our study may have important implications for cetacean stock assessments and conservation strategies.