Comparing them to those living in southern waters, the researchers noted a big difference in the size and weight of the whales – which threatens their survival.
New research by the Aarhus University, Denmark, reveals that endangered right whales in the North Atlantic are living in terrible conditions compared to those living in more southern regions. The alarming results were published in the Marine Ecology Progress Series.
There are between 10,000 and 15,000 right whales in the Southern Hemisphere and, according to the study, they live well. But, unfortunately, the same cannot be said for representatives of the species in the north.
The main factors that threaten the survival of these whales are the lethal attacks of fishing vessels and fishing nets. Their main source of food, crustaceans, also declined due to overfishing, which made whales thin and sick – and less likely to breed. All of this contributes to the current general decline of the species: there are only 410 of them in that part of the world.
To quantify the “thin and unhealthy” state of North Atlantic right whales, Fredrik Christiansen, author of the study, together with an international team of scientists, investigated the animals’ body condition using drones and compared the results with individuals from three other populations of right whales in Argentina, Australia, and New Zealand.
The analyzes revealed that the North Atlantic specimens are in a worse body condition than the southern populations. In addition to affecting their ability to mate, this situation also affects the growth of young whales, preventing them from reaching sexual maturity.
In a note, researcher Michael Moore, from the Woods Hole Oceanographic Institution, in the United States, points out that to reverse these changes, it would be necessary to redirect the ships away from the animals and reduce their speed, in addition to recovering crab and lobster traps and minimizing the noise in the oceans.