Chasing Giants: cetacean data collection on board Dream Catcher
When I applied to be an intern at Marine Dynamics Academy, a goal of mine was to be able to see at least one of the three whale species found off the coast of Gansbaai: the humpback whale (Megaptera novaeangliae), Southern right whale (Eubalaena australis) and Bryde’s whale (Balaenoptera brydei). After joining the Dyer Island Cruise’s Marine Big 5 Tours as an onboard intern helping with data collection, I got the opportunity to see all three.
Hearing that interns work with the Marine Big 5 Tours on board the boat DreamCatcher was a dream come true for me as I have always had an interest in marine mammals, and it is a field I would like to pursue in the future. This also gave me the opportunity to see species that I would not get a chance to see at home in Ireland such as the African penguin and the Cape fur seal.
During my internship, I was lucky enough to see all three whale species of Gansbaai. Before coming to Gansbaai I had never seen a whale in person, and nothing beats the first time you see a whale.
My first experience with the whales in Gansbaai was with the shy Bryde’s whale (B. brydei), a baleen whale species that lives off the coast of Gansbaai all year round. I was lucky enough to see a mother and calf swimming together and it made my first time seeing a whale a very memorable experience.
Another unforgettable whale experience on board Dream Catcher, was seeing a small group of three humpback whales (M. novaeangliae) swim alongside the boat, giving everyone on board a chance to observe these beautiful animals. The whales stuck around for about 15 minutes, giving us a chance to note down any behaviour observed and fluke markings for identification. Luckily enough, I was able to spot the humpbacks later on in my internship and this time we were able to observe a duo breaching for several minutes.
However, my favourite experience so far was with the Southern right whale (E. australis). These whales travel to the coast of Gansbaai throughout June to mate and calve and are quite recognisable due to the callosities (rough patches of skin) found on their head. These callosities can be used for identification purposes and for telling individuals apart when there are sightings and strandings. We first spotted two individuals breaching in the distance and soon enough we had two Southern right whales swimming alongside the boat. I will always remember how I felt seeing their tails perfectly out of the water as I watched the whales dive for the first time.
As an intern on the Marine Big 5 Tours, my job was to help with data collection when any whales or dolphins were sighted. This involved noting down the GPS coordinates of where the animal was sighted, as well as the time of the first sighting, sea conditions according to the Beaufort Sea scale, water depth and sea surface temperature. Once this is all written down, the animal must be observed and species, number of individuals, an age estimate and behaviour is noted. The final thing noted down is the time at which the individual moves off or the time at which the boat moves away.
Collecting this data on board the boats is very important as it gives valuable insight into the movement of the whales and where they are more frequently spotted, aiding in distribution studies. As previously said, identification is an important aspect of studies on whales. The callosities of the Southern right whale and the fluke markings of humpback whales allow individuals to be identified which contributes towards population and distribution studies. This also allows whales returning to the waters off Gansbaai to be identified and recorded so that the number of times the whales frequent the area is known.
These experiences with the three whale species of Gansbaai while assisting with data collection on board Dream Catcher have solidified the fact that I want to pursue a future in the field of marine mammal research and have given me valuable insight into how this sort of research is carried out. I am sure that I will be able to use this experience for my future career in the field of marine biology.