This post is one of a series on projects supported by the Anderson Cabot Center’s Marine Conservation Action Fund (MCAF). Through MCAF, we support researchers, conservationists, and grassroots organizations around the world as they work to address the most challenging problems facing the oceans.
Author: Asha de Vos, Ph.D., National Geographic Explorer, Pew Marine Fellow, Founder of Oceanswell
The beauty of the MCAF grant is that it can act as an emergency fund should you have a financial shortfall to complete an important project. This is exactly why I applied (this is my second one), and exactly why I am grateful that this grant exists. While we had hoped to photo-ID Bryde’s whales and Omura’s whales, the latter was more elusive than we had hoped, with no sightings through our monthlong field season. However, we did have some incredible encounters with blue whales, Bryde’s whales, and even a pod of very relaxed pilot whales!
During our time on the water, we were able to kick-start the pilot whale photo ID database for Sri Lanka, with great photos of 12 of the individuals we encountered (granted, we were unable to photograph the whole pod or did not get photo-ID quality photos of all of them). When first encountered, this pod was in a mixed group with bottlenose dolphins, but shortly after the two species went their separate ways.
Our time on the water also gave us good photo-ID opportunities with blue whales, and we were able to add 66 blue whales to our existing blue whale catalog. It is important to note that we do not have both dorsal sides and tail fluke photos for every individual in our catalog, which is obviously tricky, but this is the nature of photo-identification work. This is why population estimation is not as straightforward as people think it is.
Asha de Vos has pioneered the study of North Indian Ocean blue whales off the coast of Sri Lanka, dubbing them the “unorthodox” whales when she discovered that they did not undertake the long migrations common to other blue whales.
Most excitingly, we had three encounters with two mother-calf pairs of blue whales. On the first occasion, we were the only boat, so we switched off our engines and observed – this is how we have our best encounters, and we were very careful not to scare the pair or hassle them. The calf spy-hopped, head breached, swam right under our boat, and exhibited some behaviours akin to feeding.
This is really exciting for us because adult blue whales are less demonstrative and do not show this diversity of behaviors (unlike their more showy cousins, the humpbacks). The pair were calm, and we were able to record some interesting data about their behaviors. On the second and third occasions, however, the pairs were surrounded by whale watch boats and we observed significant changes in behavior as they were being charged at from all sides. We also encountered a mother-calf pair of Bryde’s whales, who were, once again, very calm as we did not try to approach them or interact.
Through our time on the water we got some good photographs of Bryde’s whales that will provide another great and rare opportunity to observe, collect data, and truly try to understand a slightly more elusive species in our waters.