During the month of June, BMMRO conducted a visual and acoustic survey throughout the Great Bahama Canyon (NE and NW Providence Channels and Tongue of the Ocean) to assess the behavioural ecology of deep-diving odontocetes, or toothed whales. This was the second of three month long surveys supported by a grant awarded to BMMRO from the US Department of Defence's Strategic Environmental Research and Development Program (contract no. W912HQ-11-C-0038).

The purpose of the study is to improve our understanding of the baseline ecology of six species of cetaceans that inhabit the deep-oceanic waters of The Bahamas. The focal species are Blainville's beaked whales, Cuvier's beaked whales, Gervais' beaked whales, sperm whales, short-finned pilot whales and melon-headed whales. We are integrating existing BMMRO data with new data collected during ship surveys. Our methods include: individual photo-identification, molecular genetics, chemical markers (fatty acids, persistent organic pollutants, and stable isotopes), satellite telemetry and acoustic recordings.

Here is a close-up of a depth-recording satellite LIMPET tag deployed on the dorsal fin of an adult male pilot whale, along with green laser dots providing a 10cm scale.	Pilot whales tagged in Tongue of the Ocean swam north and out of the canyon, and up Florida's east coast!

This inter-disciplinary approach will allow us to characterise the social structure, residency patterns, reproductive biology, diet, foraging ecology, habitat use and population structuring of key cetacean species. Information derived from this study is vital to learning how marine mammals respond to sounds in their environment, such as Navy sonars used during operational training, some of which take place in The Bahamas.

During June, BMMRO's team of seven scientists surveyed over 2,000 km of the canyon waters, resulting in 52 cetacean sightings. Acoustic detections and recordings were made for all of our target species using our 200m towed hydrophone providing information on behaviour (e.g. feeding) as well as helping to derive sperm whale body lengths using recordings of their clicks. When sea conditions allowed, we launched our inflatable boat for close approaches to obtain photographs, biopsy samples and deploy satellite tags. More than 4,500 photographs were taken, 18 tissue samples were collected and 13 satellite LIMPET tags were deployed on 5 of the 6 target species, providing information on movement patterns and habitat use.

A map showing satellite tracks deployed on different species.

We would like to say a special thank you to the crew of the charter vessel Slumber Venture, Captain Carlos, First Mate Keith and of course Chef John!