Bimini Dolphin Research

Report # 14

Yet another tropical wave made its way over Bimini on Tuesday bringing much rain, lightning and wind for the rest of the week. Out of seven trips scheduled for this week only Wednesday's trip was cancelled due to unsafe weather conditions. Wave height and wind speeds varied much over the week, ranging between 1- 4 foot waves and wind speeds 3-15 knots. Out of the six survey trips conducted only one resulted in no sightings. Monday's survey trip resulted in a sighting of six spotted dolphins comprised of 3 juveniles, 2 adults and 1 calf. We had two succesful encounters (more than 15 minutes long) with all 6 dolphins and one short encounter with only the 3 juveniles. The two adult males were seen nudging the ventral sides of the female juvenile with their rostrums, and belly to belly swimming was observed during these two encounters. Tuesday's survey trip resulted in 3 sightings, one of bottlenose dolphins and two of spotted dolphins. An encounter was attempted with the crater-feeding bottlenose dolphins but the drift and the wave height made it hard for us to stay over the location they were feeding at. The groups of dolphins in the second (5 individual spotted dolphins) and the third (12 individual spotted dolphins) sightings joined, and three attempts to swim with this group of 17 individuals resulted in very short encounters. The spotted dolphins kept traveling towards the S or SW when people entered the water. Thursday's survey trip resulted in one sighting of 17 spotted dolphins of which only 8 individuals were interested in swimming with us. This group was comprised of 2 adults, 4 juveniles and 2 calves. Aggressive and play behaviors were observed between the juveniles, followed by sexual bouts; the two male calves were also observed displaying sexual behavior towards one juvenile. On Friday's survey trip, we had one sighting of spotted dolphins and one sighting of bottlenose dolphins (only 1 bottlenose dolphin). The size of the spotted dolphin group was 12 when first sighted, but split into two groups (one of 4 and one of 8 individuals) before the first in-water encounter was attempted. The group of 8 spotted dolphins interacted with us for about 15 minutes; the group was comprised of 2 adults, 5 juveniles and 1 calf and sexual/aggressive behaviors were observed once more. On Saturday, we sighted only 1 bottlenose dolphin and did not attempt any encounters. As a reminder, we are working with Bill and Nowdla Keefe's Bimini Undersea (their dive boats and dolphin trips) for our research vessels. We are based on Bimini and go out about five miles or so from the island to search for dolphins. Until next week, Xenia