Bottlenose dolphins

17 Oct Week 5 Mozambique: Work with dolphins and skeletons

Day 34 (20th September 2017): For the past three days –prior to this date- we had no launches due to strong westerly winds and bad weather. During this time I was able to finish the entering the first four months of boat logs from 2016. We also had a new volunteer, Amelia, who came in couple of days ago and we have been busy showing her the ropes and daily tasks.

Today, the weather had finally calmed down, the three of us headed out for the early morning launch. In time we encountered a loose pod of bottlenose dolphins; some were surfing close to the shore, trying to catch the waves, while the others were a bit further out at around 10 m depth. We sat back assessing the situation, the dolphins behaviour indicated they were not keen on having their activity interrupted. One was ‘chuffing’, a type of aggression display where the dolphin blows loudly through the blowhole as a warning, and another have a tail-slapping display, where its tail hits the water’s surface. Observing, and respecting, such behaviour is vital to keeping the distance of in-water encounters with cetaceans to a minimum. Angie recorded the behaviour and we shortly left the area, moving on to find another pod which included a mother and calf.

During the first drop-in, we saw an amazing circle-swim interaction of the mother and her calf, during which we noted the calf had an infection on the side of its body. During the second drop-in, it seemed the pod had other plans and they only briefly swan by. Back on the boat and on separate occasions we saw a female humpback whale travelling with her calf, escorted by a male and all heading in a southerly direction.

Happy with our sightings we concluded our 2-hour trip, after which the other volunteers and I headed to the beachfront for a land-based survey. To our surprise we spotted a few bottlenose dolphin close in to shore, poking their beaks out above the water’s surface. Since Sabrina and I were so used to seeing humpback whales since day one here in Ponta, and Amelia had seen one the day before, it was somewhat refreshing to see something new during the land-based survey.

Bottlenose dolphins
Bottlenose dolphins

Day 35 (21st September 2017): Today Angie sent Sabrina and I ahead to the launch site to look out for dolphins while she and Amelia stayed behind at the office to sort out the gear. It did not take us long to spot some bottlenose dolphins surfing and jumping out of the waves close to shore. We watched them, clearly enjoying themselves, for at least half an hour before moving on. It was pure torture to see how close the dolphins were, and we secretly hoped they would stick around to make things easier for the trip. They seemed to be teasing us with their pure delight. Shortly after Angie, Amelia, the crew and the guest s arrived. We informed Angie of the sighting, we could only assume they had headed north and were hopefully not too far away. Just as we predicted it did not take us long to find the pod, although it seemed there were a lot more than we had initially seen. We had two drop-ins and the dolphins seemed keen to interact, with the swimmers and each other. There was a lot of social and circle-swimming interactions, as well as social sexual interactions where males get very close to females, rubbing their bodies against them. There were also bubble trains, a social behaviour where males produce a series of bubbles followed by a popping sound in the presence of female consorts. We soon moved on to see if we could find any whales.

Following the trip, I worked with Amelia in the laboratory on the skeletons. We spent some time working on the Antarctic fur seal and have made some progress on the rear flippers, and are half way towards removing the hot glue stuck between the femur’s bony knob and the innominate socket. Time and patience has paid off with this tricky task. We ended the day with a land-based survey.

Day 36 (22nd September 2017): Due to strong wind the launch today was cancelled. Amelia and I once again headed back to the laboratory to work on the skeleton. All of the hot glue was finally removed, thus freeing the two femurs from the innominates as well finding the missing pieces which happened to be the unfused bone of the innominate. Both of the front flippers now have most of the phalanges and the bones that make up its palmar area.  For verification purposes I took photos and sent them to Angie to make sure everything is correctly in place and nothing looks completely off. The next few days are a public holiday in Mozambique and South Africa which means the weekend is already fully booked. We finished the day with our usual afternoon land-based survey before heading back for preparations for the upcoming weekend trips.

Work on the fur seal skeleton
Work on the fur seal skeleton
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