Whale watching tours with Futurismo are much more than trips to see whales and dolphins. They are also an excellent opportunity to gather information about cetaceans.
The latest news, which we know now and with some certainty, is the length of some sperm whales that we observed in São Miguel. The research that biologists have been doing, mainly using the sound of sperm whales recorded underwater during trips, allows to estimate the measurements of the animals.
All these findings are critical for conservation purposes, as population size and age structure are important to assess the health of the species.
Let’s take a concrete example. Cristina Marcolin (a student at the University of Genova, and who was at Futurismo doing her master’s thesis), did an incredible job using acoustic files to find out the size of the sperm whales recorded, via hydrophone, during our whale and dolphin watching tours.
Cristina Marcolin managed to estimate the length of some of our friends and well-known sperm whales that are identified in the Futurismo species catalogue. One of them is a female sperm whale that we named Orca (because of its coloration reminding of orcas). She belongs to a group of at least 10 sperm whales that we have been following since 2003!
Well, now we know even more about Orca, our sperm whale friend.
We estimate that she is 9m long, which means that she is an adult female! To give you an idea, adult females can reach up to 12m and adult males up to 18m.
And how is it possible to estimate the length of sperm whales?
Sperm whales produce a variety of noises that are picked up by the hydrophone, especially the clicks they make. These are usually echolocation clicks, which sperm whales emit during deep dives to capture prey. But they can also be codas, song-like click patterns that characterize each clan and are used to communicate with each other.
It should be noted that whale watching tours are an excellent opportunity to gather information about marine animals. At Futurismo, we usually record the location and some other notes about the observation of a species and we often take photographs that are later used to identify the individuals. Both types of data are already widely used and collected by whale watching boats around the world. However, other types of data such as the analysis of the sound of animals underwater are a little more challenging to collect with tourists and passengers on board, but Futurismo does this job very well.
This is also why Futurismo stands out from so many other whale watching companies in the Azores. We often use hydrophones to look for sperm whales in the ocean and more recently to collect some audio recordings. Until now, these audio files were mainly used to share the amazing sounds with our travelers. In the last year, the use of sounds has gained a new dimension, making it possible to estimate the total body length of sperm whales.
But there is still a curious fact!
Through sound, it is not possible to estimate the size of other species, only of the sperm whales. The knowledge that already exists of the sperm whale, of the spermaceti and its density is the information that allows us to understand the size of the animal.
Sperm whales are a unique species among cetaceans and their most unique feature is their nasal apparatus. They have only one nostril, located in the upper left part of the head. A complex sound production system is present in the head, as shown in the figure below:
Generally, each sperm whale click consists of several pulses. The time distance between two pulses (inter-pulse interval or IPI) is related to the size of the sound-generating organ, the spermaceti. Now, the size of this organ can be used to estimate the size of the head and, therefore, also the total length of the animal, applying some standardized formulas (Gordon et al., 1991; Growcott et al., 2011). Research is wonderful!
For her master’s thesis, Cristina Marcolin implemented an updated and improved protocol aboard our whale and dolphin watching boats to record the clicks of sperm whales after diving. Together with the rest of Futurismo’s biologists team, dozens of recordings were collected and analyzed. Different approaches were used to obtain the IPIs of each individual to calculate the best possible length estimate.
Sperm whales in Sao Miguel
Futurismo’s team of marine biologists estimated more than a hundred body lengths of sperm whales! The majority seems to be less than 12m (ie, there are mostly females or young males, around São Miguel island. And only 28% of the individuals are larger than 12m (ie, they are already adult males). It is necessary to say that the measurement does not necessarily belong to a different individual, as it was not always possible to relate the audio files to the identification of the animal.
We must also say that collecting useful data on board whale and dolphin watching boats is a challenge, and attempts and errors are part of the process. But we also realized that yes, it is possible to do more and better with few adequate methodological adjustments and with the collection of valuable acoustic data for scientific purposes.
We need to emphasize and acknowledge the extra effort made by Futurismo’s crew and biologists, both to gather the information and to learn and inform our travelers about the ongoing research about the underwater wonders of the ocean.
Futurismo and the World Cetacean Alliance
Futurismo is a leader in Responsible Tourism in the Azores archipelago and is also a responsible company for whale and dolphin watching with the international certification of the World Cetacean Alliance – the largest cetacean protection organization in the world. Find out more about our passion for sustainability and the article on sperm whale measurements shared in the WCA monthly newsletter.