By Shelby Rosten
One of the primary methods we use to collect data on the humpback whales in the Gulf of Chiriqui is taking photos of their tails. Each humpback has a unique pattern on its flukes that can be used to identify it year after year. While out in the field we take pictures of as many flukes as we can, which can be challenging because humpbacks don’t fluke every time they dive.
When we get back to the lab, Kristin edits the pictures by cropping them and adjusting the brightness so all of the features stand out. First, I compare the flukes to all those already seen this season. So far, we have seen 70 individual whales and six of them have been seen on two days! After that, I compare all new flukes to the catalog which contains 778 individuals. Some matches are really easy…
And some are tricky...
Using these data, we can estimate the size of the population of whales that come to the Gulf of Chiriqui to breed. Additionally, these photos are shared with scientists working all along the Pacific coast of the Americas and Antarctica to see where else these whales go. Whales seen here have also been observed in feeding grounds off the coast of Antarctica and Chile as well as adjacent breeding grounds in Central and South America.
Our field season happens to coincide with the rainy season in Panama. This is not necessarily a bad thing. We have come to love the overcast days because it means the tropical sun is not beating down on us so strongly. Another bonus is that when the skies are really dark, the humpback whale blows are easier to see. It usually doesn't rain all day and we can get out and work for at least a few hours. However, sometimes large storm systems move through and we might lose an entire day or two. Luckily we have plenty of work to keep us busy on land, and it's always good to catch up on rest after many long hours in the boat.
We have been lucky to see whales breaching almost every day we have been doing surveys this year. No matter how many times we see this, it's always a huge thrill to see such a large animal propel themselves out of the water! It also makes it quite easy to find groups of whales when one or more is breaching like this, since the giant splash they make can be seen from miles away.
By Colin Perkins-Taylor
The 2019 field season has been incredible so far, and I don’t think I will ever get over the fact that I get to study whales every day. Even on the slow days when it takes us an hour or two to find a whale, we never lose hope and always manage to find another individual or group. We also have seen a whale breach every day, so that doesn’t hurt either….
I am a rising senior at Swarthmore College here working with Dr. Matt Leslie from the Biology Department at Swarthmore. He studies cetaceans using drones and genetics. Specifically, he studies the differences between species, populations and individuals to determine if species and populations are unique, and determine if they need specific conservation plans. With the drones, we collect aerial photos and accurate altitude data to measure whales in various ways: their body length, head length, tail length, body width, etc. These details allow us to understand the size and health of the humpback whales here in Panama, and compare them to other populations. In addition, by collecting aerial images of groups of whales, we can better understand individual roles in social interactions. For instance, in a competitive group interaction, many male humpbacks tend to pursue a female; by combining genetic information from skin biopsy samples collected for each whale (including if the whale is a male of female) with the drone photos, we can determine which individual is the female and her position in relation to the male “pursuers.”
All of this probably sounds a little easier on paper than it actually is. Fieldwork always comes with challenges, and we’ve had our share, especially with the drone part.
Just a few weeks ago we were setting up a new drone for the first time back at Swarthmore. Matt and I flew it a little bit on our college campus before coming here. In addition, a fellow student at Swarthmore built an entire laser altimeter (LIDAR) system from scratch in less than three weeks; he finished the day before we left!! This system measures the distance from the drone to the whale, vital information needed to calculate the size of the whale. The first challenge we had to figure out a way to install it on the drone, which took some creativity. Then, in the field the LIDAR had several errors that required troubleshooting before the measurements could be collected.
While it has been challenging, in a matter of a few short weeks, we are now measuring whales! It’s been a great learning experience, and I’m hopeful that we have learned from all our mistakes and it will just be smooth sailing from here on out!
by Shelby Rosten
The 2019 field season is underway and off to an awesome start! On our first day we encountered two competitive groups and collected fluke IDs from 20 individuals. Within each group there is one female and a bunch of males fighting for the chance to mate with her. We also saw some mom and calf pairs which were adorable.
The second day of the season yielded an incredible opportunity: hearing a whale’s song without a recorder! We had seen a whale from a distance and Pulo, our captain, brought us right to the spot where we saw it. When we arrived, we could hear his song through the hull of the boat. Matt, one of our team members, leaned over the side of the boat and stuck his head in the water to get a better listen. When he said that it was super loud underwater, I immediately wanted to try it and it was amazing.
Humpback whales sing complex songs composed of a hierarchy of elements called units, phrases, and themes. These elements are repeated in a consistent pattern to form songs and songs may be repeated for over an hour. All males in an area sing the same song, however, the song changes over time. While scientists are not sure exactly what the purpose of singing is, it is thought to be a way for the males to advertise their fitness to females in the area or to help male space themselves out in the environment. Because sound travels so well in water, this advertisement can be heard over vast distances and let all the females know that this guy is ready to mate. Over the past six months, I have been working on identifying the units present in songs from Islas Secas, Coiba National Park, and Islas Perlas. I was super excited to be able to hear these guys sing in real life. It’s like finally getting to go to a live concert of your favorite band! The grand finale to his performance was a beautiful breach right off the bow of the boat. If this start is an indication of what’s to come, we are in store for a fantastic field season!