Marine research association Tursiops has proposed that Spain’s Ministry for Ecological Transition and Demographic Challenge (Miteco) create a dynamic model using thermal cameras and artificial intelligence to alert vessels sailing in Balearic waters to the presence of sperm whales, encouraging them to reduce speed and help prevent collisions. The waters around the Balearic Islands are a critical habitat for sperm whales, and collisions with vessels are one of the main threats to the survival of the species, which is classified in the Mediterranean by the International Union for Conservation of Nature (IUCN) as “endangered”.
“We believe proposals to reduce speeds across very large areas are difficult to implement because of shipping companies’ transport needs. That is why we have been working for some time on modelling the factors that explain the distribution of sperm whales in the Balearics. It is similar to predicting human movement. If we know the main workplaces, residential areas, shopping districts and restaurants, for example, we can predict where people are likely to travel. That helps determine where to build roads or install and regulate traffic lights.
“With sperm whales, the idea is to do something similar. We are working to map their mobility patterns, which depend not on houses or cities, but on seabed types, depth, orientation and slope, as well as oceanographic features such as surface temperature and salinity. We are modelling and mapping distribution in the Mallorca and Menorca channels. The aim is to create a dynamic model that alerts ships to where these animals are likely to be, so they can reduce speed in conflict zones,” explained Txema Brotons, founder and scientific director of Tursiops.
A biologist specialising in cetaceans and acoustics, Brotons is regarded as one of the leading experts on whales and dolphins in the Balearics. He studies not only the impact on sperm whales but also the effect of human activity on dolphins.
In 2015, he led research showing that bottlenose dolphins living in Balearic waters move further offshore during the peak tourist season. The study also found that the dolphins’ ability to hear sounds is reduced by boat traffic. His team used hydrophones to measure how noise pollution in the Pityusic Islands affected dolphins’ ability to hear one another’s whistles, concluding that communication range decreases significantly with increased underwater noise.
The next step is to determine whether the animals can adjust their vocalisations to overcome high decibel levels, something recently confirmed in pilot whales living in the Strait of Gibraltar, the busiest shipping route in the Mediterranean. A vessel passes through every 4.8 minutes, with around 300 ships crossing daily.
Researchers attached recording devices to around 20 long-finned pilot whales, capturing nearly 1,500 vocalisations alongside ambient noise levels.
They observed the whales in different scenarios — diving deeper, interacting with others or searching for food — and the study concluded without doubt that the whales raise the volume of their calls as sea noise increases.
Even so, no matter how much they “shouted”, the whales were unable to match the level of noise pollution. For every decibel of noise generated by maritime traffic, pilot whales increased the volume of their vocalisations by an average of 0.5 dB. “Shouting” was not enough to prevent their communication from being disrupted by vessel noise.