BMMRO research associates, Dr. John Durban (U.S. National Marine Fisheries Service) and doctoral student Holly Fearnbach (University of Aberdeen, U.K.) have just completed the fourth consecutive year of October surveys to monitor bottlenose dolphins in the Sea of Abaco, with support from Friends of the Environment.

The aim of this study is to continue BMMRO's 19-year long time series of individual dolphin photo-identification, to monitor population dynamics and health, and specifically to conduct intensive surveys to "rescue" individuals who were lost to the time series during years of low survey effort from 2001-2006.

Almost 1200 miles of survey effort were conducted in the waters between Little Harbour in the South and Green Turtle Cay in the North (see map), between Great Abaco Island and the barrier islands /reefs. Thirty-seven (37) dolphin groups were encountered on 24 survey days, providing information on key areas of distribution and habitat. No dolphins were seen south of Lubbers Quarters, with a notable absence from the traditional "hot-spot" around the Tilloo Bank area. This was similar to the 2009 survey, and may reflect a response to increasing boat traffic in this part of the dolphins' range, and certainly represents a change compared to the 1990s.

Adult female bottltenose dolphin leaping, showing swollen mammaries full of milk. She is a new mother to a young of the year. She was leaping to remove a remora that was attached to her flank.	Adult bottltenose dolphin called 'Roxie' in front of Hope Town Lighthouse.	A bottlenose dolphin neonate, born during the 2010 survey (mother seen before and after).

Seventy (70) individual dolphins were photographically identified, providing key updates to individual life-histories and survival trends. This compares well to the average census for a month-long survey of ~50 dolphins, so this was a very successful year. Four new calves were documented since the 2009 field season (see photo of neonate), indicating population productivity. One calf was lost from 2009/2010 cohort (disappeared during the current field season), and one from 2008/2009 cohort, providing information on mortality. Mark-recapture models will be fit to the photo-identification data to estimate population-wide survival rates, and trends over time. We continued to document calves born to dolphins that were themselves born earlier in our study (new calf documented with Tt162, herself born in 1996; see photo) providing further information on life histories.

As a result of these surveys, John and Holly are working with BMMRO to produce scientific papers on calving seasonality and predation risk, long-term survival trends and the impact of hurricanes, and population structuring through long-term social affiliations; these papers will also form the basis of chapters in Holly's PhD thesis.

Map of tracks and encounter locations

As always, BMMRO thanks John and Holly for their tireless efforts in helping to monitor this population of dolphins.