Whales are a fundamental cog in many marine ecosystems. They have practically no natural predators, given their enormous size. But as with many animals, they do not escape the risks posed by our species: pollution, climate change and overfishing, but not only. For these giants of the sea, the greatest danger is that of being run over. It happens to thousands of specimens every year, due to the crowding of the seas linked to an ever-expanding fleet of cargo ships, which today transport around 90 percent of all goods produced and traded in an increasingly globalized world.
The problem is difficult to solve, and even to quantify, because whale carcasses quickly disappear into the depths of the oceans, often without ships even noticing the incident. But a new, large study coordinated by the University of Washington and which saw the participation of the Italian Tethys Onlus is destined to change the situation, providing for the first time a detailed map of the risk of collisions between ships and large cetaceans at global for four of the most widespread and threatened species by maritime traffic: blue whale, fin whale, humpback whale and sperm whale.
The areas most at risk
The study was recently published on Science, and involved experts from five continents who collected and studied something like 435,000 sightings, coming from government monitoring, reports from the public, satellite tagging studies and even old whaling records. By cross-referencing this information with the routes of the 176,000 merchant ships tracked from 2017 to 2022, the research has shown that the ranges of the four whale species overlap 92% with the routes of global maritime traffic, and identified the areas with a high probability of encounter between whales and ships.
Among these we find the Mediterranean, one of the high risk areas already known together with the Pacific coast of North America, Panama, the Arabian Sea, Sri Lanka, the Canary Islands. The study also highlighted less studied but equally risky regions for cetaceans, including southern Africa, the coast of Brazil, Chile, Peru and Ecuador, the Azores, eastern Asia, and the of China, Japan and South Korea.
Protection measures are lacking
As the authors of the study point out, to significantly reduce the dangers faced by whales, simple safety measures are sufficient, such as a lower speed limit for ships transiting the areas at greatest risk or moving the most vulnerable sea routes offshore. busy. However, similar initiatives (mandatory or even only voluntary) have been taken in very few areas of the planet, mainly on the Pacific coast of North America and in the Mediterranean, and cover just 7 percent of the high-risk areas, which becomes 0.54 percent if you look to the risk hotspots of the blue whale and 0.27 percent for those of the humpback whale.
Paradoxically, many of the most dangerous areas are within marine protected areas, which however, having been established primarily to limit fishing and industrial pollution, do not provide speed limits for ships. “Which would also bring about other benefits” – specifies Anna Nisi, researcher at the University of Washington and first author of the study – such as less underwater noise pollution, the reduction of greenhouse gas emissions and the improvement of air quality, all in all benefit of the populations living along the coasts”.
What can be done?
To reduce accidents, there are interventions that are relatively easy to implement, such as the aforementioned speed limits for ships transiting through risk areas. It would be enough to cover an additional 2.6 percent of the oceans in this way to protect all the areas at greatest risk. And the good news is that for once, with the right political will it shouldn’t be too difficult to achieve it: for all four species considered, in fact, the vast majority of areas at risk of collisions – more than 95 percent – are located along coasts, and therefore within the national exclusive economic zones. This means that each country has the possibility to intervene concretely by implementing protection measures in coordination with the International Maritime Organization (IMO) of the United Nations.
“It’s usually difficult to bring industry and conservation together,” concludes Heather Welch, a researcher at NOAA and the University of California at Santa Cruz and co-author of the study. “To achieve concrete goals, industrial activities often need to be significantly limited, or vice versa. In this case, there is a potentially significant conservation benefit for the whales, with very little cost to the maritime industry.”