We were up early on Tuesday morning the plan being to first head into deeper water before cutting back across to Kisite Marine Park and to Transect 9. No sooner had we left the channel when a small group of bottlenose dolphins were spotted. We made our way over and managed to Mark Recapture them. This is the methodology we use and it means we photograph the dorsal fin of all the dolphins in the group and compare them to other fins we have taken previously to see which dolphins are socialising with each other and there travelling patterns. We were really lucky today as we not only managed to get all of the dolphins on camera but we also got to see some tiny newborns and photograph them as well.
Photographed socialising Bottlenose Dolphins
After observing their behaviour for nearly an hour we resumed our route into deeper water. Suddenly Shafii our captain saw what we had all been hoping for, a large spiralling jump in the distance. Spinner Dolphins! We headed in their direction as quickly as Bardan (our boat) would take us and before we knew it we were surrounded by a group of long snouted spinner dolphins some 70+ individuals strong. With cameras at the ready we began taking as many photos as we could of their impressive and unique spiralling jumps, as well as their dorsal fins for more photo identification. The large group were very sociable and stayed close to the boat jumping and bow riding for well over an hour before we had to end the sighting and head over to Kisite to do our snorkel transect.
A group of over seventy Spinner dolphins travelling south
When we reached transect 9 we all jumped in eager for a cooling dip in the crystal clear ocean and set off on the transect. Within 5 minutes we spotted a green turtle and 2 minutes afterwards we saw Transect 9 resident ‘Squirt’ a large hawksbill turtle who lives on the reef their. By the time we arrived back at base we had recorded an impressive 8 sightings of turtles 3 individual bottlenose dolphin sightings and of course the large and very memorable and rarely seen group of spinner dolphins. All in all an incredible dayon the boat and I have another 4 weeks to look forward to.
The fantasic leaps of Spinner dolphins
This question has been the topic of many scientists, enthusiasts and tourists for many years. There are several theories as to why Long-snouted spinner dolphins (Stenella longirostris) spin, one is that the bubbles created by such a violent spinning of the body acts as a form of communication across a large pod of spinner dolphins (which can often number well over 100). For example, in a state of alertness, this may warn other dolphins of danger. The spinning may also represent a way of dislodging parasites. However, from our observations, a more obvious reason appears to be for fun, whilst they are travelling at speed. As we watched only a few individuals of a pod of around 100 jump and spin over a period of half an hour, it didn’t seem to catch on with the rest of the pod or appear to cause a change in direction or behaviour. It is clear that more research is needed before a consensus is reached as to why these dolphins spin!!
Is spinning for communication, to dislodge parasites or just for the fun of it?
Long-snouted spinner dolphins (Stenella longirostris) are an acrobatic and spectacular species. Their name comes from the distinct way that the dolphins breach. By leaping from the water, up to 3 metres in height, it twists its body and spins round and round on its longitudinal axis up to 7 times. Spinners are quite small cetaceans, they have slender bodies, a three tone colouration and are usually encountered more offshore.
The distinctive three-tone colouration of Spinner dolphins
At this time of year, the seas around East Africa are calm which allows us more opportunities to survey the deeper waters. Last week we took one of these opportunities and travelled south east off of Kisite Island. For an hour we saw nothing but calm waters and a clear horizon, then in the distance we saw some small cetaceans travelling in a southerly direction rather quickly and leaping out of the water! The slender body, three tone colouration and triangular dorsal fin made the species clearly identifiable.
Over 100 Spinner dolphins spotted travelling in deeper waters
Soon were were travelling with around 100 spinner dolphins, around 30 of them were bow-riding and there were several other sub groups around the boat. Then came a moment of awe when we saw some individuals leap and spin spectacularly. We counted up to seven spins in our videos which have been watched many times over! In addition to the video, the encounter gave us some spectacular photos and important data. The dolphins seemed indifferent to our presence and eventually we just switched of the engine, let the current take us north and watched them swim off into the distance!