The thousands of ships that move every day from one part of the ocean to another herd whales together to the point that only 8% of their habitats are safe from maritime traffic. These are the conclusions of a work published this Thursday in the magazine Science by Anna Nisi’s team in which, after cross-referencing data on global maritime traffic and whale habitats, they found that global maritime transport overlaps 92% of cetacean habitats.
The global shipping industry has become a worrying source of whale mortality worldwide, with ship strikes contributing to unsustainable mortality rates for several populations, including species on the brink of extinction.
“There are critical risk points in all oceans except the Southern Ocean,” Nisi explains to elDiario.es. “Our analysis shows that whales are exposed to enormous maritime traffic, creating a widespread risk of collisions between whales and ships. At the same time, current protections are limited: less than 7% of the most dangerous areas contain any type of management measure intended to reduce the risk of collisions.
A global risk
For this work, Nisi and his team combined whale locations (around 435,000 sightings for four species with a global distribution from hundreds of datasets) with Automatic Identification System (AIS) information up close. of 176,000 large ships to identify critical ship collision points. for blue whales, humpback whales, fin whales and sperm whales.
Hot spots exist in all oceans except the Southern Ocean. Less than 7% of the most dangerous areas contain any type of measure to reduce the risk of collision
Anna Nisi
— Researcher at the University of Washington and lead author of the study
“Some particularly notable risk areas include the west coast of North America, several regions along the coasts of South America, the Mediterranean, the Azores, the coast of southern Africa, northern Indian Ocean, the Australian coast and the East Asian coast. » explains Nisi.
In addition to revealing that maritime traffic reduces the natural range of cetaceans, the authors demonstrate that only a small effort to expand ship strike mitigation measures, such as implementing reduction zones speed of ships, would be very effective: reducing this circulation in only 2.6% of the ocean, could considerably reduce fatal collisions in all high-risk areas.
“There are simple and effective interventions that can reduce the risk, including reducing ship speeds and changing ship routes to avoid areas important to whales,” says the lead author. “Therefore, our analysis indicates that these measures should be expanded to better protect whales. The good news is that many shipping companies are eager to participate in these types of programs.
It is estimated that currently more than 100,000 large cargo ships are plying the oceans and by 2050 an increase of 1,200% is expected. “Several lines of evidence indicate that existing records of ship strikes represent only the tip of the iceberg of the shipping industry’s current and future damage to marine biodiversity,” noted researcher David Sims and his colleagues. colleagues in a recent analytical article published in the magazine. Nature.
The new “whalers”
Natacha Aguilar, marine biologist at the Canary Islands Oceanographic Center (IEO/CSIC) who works on the study of cetaceans, recalls that in certain regions of the world, it is estimated that mortality due to collisions of large whales far exceeds the legally recorded figures. authorized. due to human impacts, and that this mortality prevents the recovery of many populations even when they are no longer the subject of whaling.
“Just as land traffic is regulated in areas where protected species, such as the lynx, live, we must do the same at sea,” says Aguilar. “We must demonstrate that we can prevent senseless whale deaths by increasing human responsibility and organizational capacity. »
We must demonstrate that we can prevent senseless whale deaths by increasing human responsibility and organizational capacity.
Natasha Aguilar
— Marine biologist at the Canary Islands Oceanographic Center (IEO/CSIC)
“Death due to collision of large cetaceans is a cause recognized as very important and significant in different parts of the planet, coinciding with routes of intense maritime traffic,” explains Antonio Fernández, professor of veterinary pathology at the University of Las Palmas (IUSA-ULPGC). ). However, he emphasizes, there is a bias or a lack of information compared to other causes of whale death. “In most cases, when they appear dead floating or on the beaches, adequate autopsies are not carried out by specialists (veterinary pathologists) to correctly determine the cause of their death, which constitutes a bias in the conclusion of the results of this work, although this in no way minimizes the importance of deaths due to collisions of these large mammals and their impact on the population.
The case of the Canary Islands
Natacha Aguilar points out that one of the species mentioned, the sperm whale, is precisely a hot spot for collisions in Spain. “In the Canary Islands, the abundance of sperm whales has been halved in just a decade, placing them on the brink of local extinction,” he points out. According to him, reducing collisions is a duty to protect marine macrofauna; There is mortality of cetaceans, sharks, turtles and other species. “This requires a combination of training, technological, operational and awareness-raising measures,” he says.
Thanks to the forensic analyzes carried out by Antonio Fernández and his team from the ULPGC, in the Canary Islands, the identification of the death of cetaceans exists. “Here we have a collision mortality rate of 1.8 sperm whales per year (over the last 25 years), although in the last two years (2023-2024) only one sperm whale has died due to a collision,” he said. “In the Canary Islands, some shipping companies are implementing mitigation measures. Having references to when and where these cetaceans are found throughout the year is essential to providing this information to vessels.
In the Canary Islands, some shipping companies are implementing mitigation measures. Having references to when and where these cetaceans are found throughout the year is essential to providing this information to vessels.
Antonio Fernández
— Professor of Veterinary Pathology at the University of Las Palmas (IUSA-ULPGC)
Aguilar recognizes that technological projects are being developed in the Canary Islands to improve the detectability of large cetaceans through thermal detection, with the collaboration of rapid transport companies. “They also arranged for us to provide collision avoidance courses to their bridge teams,” he says. “But it should be mandatory for all shipping companies transiting cetacean habitats, worldwide.” He says more needs to be done, such as dynamic measurements of route changes and speed. “Speed kills, but society must also be informed that buying everything Made in China [y alimentar este sistema de tráfico marítimo intenso]kill the whales.
