Bottlenose Photo-ID Research

The bottlenose dolphins (Tursiops truncatus) are one of the most cherished marine mammal species in the world! Who does not know the famous Flipper? Well, here in the Azores, they are one of our most frequent sightings and they put a smile on our clients’ faces for their sympathy and acrobatic jumps.Over the years, we felt the need to understand a little more about the groups of bottlenose dolphins that visit us. This is why we captured them on camera to try to identify them. As the bottlenose dolphin groups can be huge, they can be found in pods ranging from a few dozen to hundreds of dolphins. So, with huge amounts of data, photo Identification
work becomes complicated and time-consuming. Therefore, we began by identifying “key animals” with obvious characteristics that we can rapidly recognize.

In this article, the bottlenose dolphins that we’ve been recognizing most, in the last years, will be presented. The first bottlenose dolphin that caught our attention was “Egyptian” (Image 1)! (Yes, it’s a girl, because we saw this
individual pregnant, and after giving birth we saw her swimming with her calf). She was spotted around the year 2000, and she is very easy to identify! Her dorsal fin is very similar to a pyramid … so… Egyptian seemed to be a suitable name for her! She has mostly been observed in a very large group of about 200 dolphins and, in recent years, she’s been sighted quite far from the shore.

Image 1- “Egyptian”
About 2 years later, in this same group, we noticed another animal very easy to identify as well… “Submarine” (Image 2)! Just like “Egyptian”, the identification is done through its dorsal fin.
We don’t know what happened to her dorsal fin as this is not a natural shape. But it may have been cut by either a propeller or a more violent encounter with another species (or even a fight between bottlenose dolphins). Thankfully, the lack of the tip of the fin does not seem to interfere with the animal’s swimming because we still see it in the same group, healthy, and very chubby.
Image 2- “Submarine”
In 2004/2005 we found another easy-to-recognize dolphin… it is very elegant and slender whom we call “Lady” (Image 3).
We think it is a female because it was seen with a calf, however, we can’t confirm it was its calf, as we never saw it pregnant. This animal was easy to identify as it was always the last one of the group and remained at the surface
when the others dived. Every time it came to the surface to breathe, it always came with a very stiff neck, as if it was not able to bend it. It is possible that it has a problem in its spine, or it could be a sign of old age since it
did not dive with the rest group. Additionally, it also seemed to have a problem with one of its eyes. It was a dolphin we all liked to swim with, as it did not stray too far away from us. This could be because it already understood
our activity and knew we were not there to harm it. “Lady’s” group was present in an easy to identify pod as well! In its group, we had many animals that left a trail of bubbles before reaching the surface. We identified this group as the “Bubblemaker group” (Image 4). The “Lady” and “Bubblemaker’s group” were seen for the last time at the end of summer of 2016 on the North Coast of São Miguel Island.
Image 3- “Lady”
Image 4- “Bubblemaker” group
In 2004/2005 we found another one! Our famous “Max” (from the Portuguese word “Maxilar” that means Jaw) (Image 5)! This individual is difficult to identify because we don´t recognize him by the dorsal fin. The characteristic is not something that jumps right into our view. For this guy, we must pay attention to his beak. He does not have all of his upper jaws anymore; we don’t know if he was born that way, or if he got injured. Again, it does not seem to have a great influence on its survival, as he continues to appear frequently and looks like healthy.
Image 5- “Max”
Later on, around 2016, we found “Alvin” (Image 6)! It’s not a dolphin that we see very often, and when its group does appear, it is only seen for a short period of time. It is identifiable by its dorsal fin which appears to have been cut from the animal’s back to the front. Almost as if someone “drew” the dolphin in the incorrect way; drawing the fin the other way around.
Image 6– “Alvin”
In 2018, we observed some faults in three dolphin-flukes. To us, it did not look like it interfered with their movements.
The first to be seen was “Twisted” (Image 7). This has the right side of its tail “curled” or “twisted”. It is a very
curious animal and usually visits our boats.
Image 7 – “Twisted”

The other two dolphins had a section of the fluke cut-off. One individual has a chunk cut off the right side of the fluke; one of our clients gave the name to one: “Halfie” (Image 8). The last appears to have a similar cut in the fluke as “Halfie”, except this time it is on the left side. We identified it as “Majum” (Image 9) … Possibly the cuts were caused by either a propeller or a confrontation or fight with other marine animals.

Image 8- Halfie
Image 9- Majum

Last but not least, we have the most loving of the dolphins … we have “Kiss” (picture 10)! The name has a
reason. The lower jaw of this dolphin is down and look like he is sending kisses. It is always an interesting dolphin to show to our guests, they are always amazed by this animal with such a beautiful characteristic and this does
not disturb when he is feeding.

Image 10- Kiss

So far, we used these individuals for quick identification of the group, but we are deepening this process of photo
identification on this species. Our catalogue already has about 130 individuals divided into 7 different groups. Did you know that Egyptian, Submarine and Twisted have lately been seen in the same group? We still have so much to
discover! Join us on an upcoming trip in search of our beloved dolphins.

Article by marine biologist, Mariana Silva

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