Photo: Photo taken by Isabel Cristina Avila
In Colombia there are 35 species of sea mammalsof which 29 do so in the Caribbean and 32 in the Peaceful. One of them, perhaps one of the greatest and most charismatic, is the Humpback Whalealso known as the humpback. But also, according to a recent article, they are the most endangered species in the country.
Humpbacks arrive between June and July each year, and remain in the warm waters of the Pacific until November and the first days of December. They do it because during that time, in their usual home, the Antarctica, winter generates even lower temperatures than usual. So they migrate to mate and give birth without this representing a risk to the calves that are usually born with thin layers of fat that would not protect them from frost. (You can see: Beautiful but threatened: the humpback whales that arrive in the Colombian Pacific)
To reach the Colombian coast, including the Panamanian one, these cetaceans, which can measure up to 16 meters and weigh 30 tons, must swim for more than 8,000 kilometers. On his tour of the Southeast Pacific, which includes Chili, Peru, Ecuador, Colombia Y Panamahumpback whales face serious threats.
In February of this year, the World Wide Fund for Nature (WWFfor its acronym in English) published the report Protecting the Blue Corridors, where in addition to visualizing the routes of 845 migratory whales in the world, it highlights the main threats that lie in wait for them.
According to Chris Johnson, World Leader for the Conservation of Whales and Dolphins at WWF, the main threats are industrial fishing, collisions with boats, chemical contamination, plastic and acoustics, habitat loss and climate change. Johnson added that these are risks that whales face globally, “this happens from the Arctic to the Antarctic.” (You may be interested in: Whale watching in the Pacific: from opportunity to threat)
And, in the sense of Johnson’s words, Colombia is no exception. Isabel Cristina Avila is a marine biologist with nearly 30 years dedicated to the study of this group of animals in the country. While she was pursuing her doctorate in environmental science at the University of Freiburg (Germany), focused on making a map to identify risk areas for marine mammals in Colombia. From there came his doctoral thesis. At the beginning of this year, together with his colleague Alan Giraldo, from the Oceanography Group of the Universidad del Valle, he updated the map with a 2020 cutoff.
The results of the investigation, which includes reports made between 1991 and 2020, were published in January of this year in the International Journal of Tropical Biology and Conservation. In Giraldo’s words, what they did in this work was “try to incorporate all the possible information available that mentions these different threats and begin to locate them spatially, in such a way that one can visualize on a map where certain threats are concentrated. Likewise, it is possible to identify areas where there is greater ‘confluence‘ of threats, and others where they are more sporadic”.
The work carried out by Avila and Giraldo, in addition to identifying the areas where the threats are registered, was also able to determine which are the species with the greatest risk in the country. Of the 22 species that register a threat in the three decades studied, the species that face the greatest number of risks are the Humpback Whalethe Caribbean West Indian manatee Y marine tucuxi, with eight specific threats for each. (You may be interested: Eleven days underwater: an unprecedented effort to save corals)
The bycatchthat is, “involuntary capture as a result of being entangled or trapped by nets, lines, traps or other fishing gear”, is the most common threat to all marine mammals in the country, including the Humpback Whale. follows her direct fishing, which in many cases seeks to hunt the animals to use them as bait or to keep them in captivity. “Despite the fact that this is not legal in the country, we observe that it is a phenomenon that continues to occur,” says Avila.
The third threat to humpback whales, as well as to six other species of marine mammals in the country, is the traffic and the boat traffic. As we have in this note, the circulation of boats at high speed, not respecting the recommendations of the environmental authorities -as happens with those used for tourist purposes-, among other reasons, increase the risk of collisions with cetaceans. Additionally, encroachment into whale habitats, as well as noise pollution, is driving these animals away.
“The alteration of oceanic physics, which can be caused directly or indirectly by humans,” is the fourth threat to humpback whales, explains Avila. This, in his words, is “related to changes in water temperature, phenomena such as El Niño and La Niña, changes in currents or changes in ice masses.” Pathogens, which can cause infection and disease, are the sixth threat to this cetacean species. (You can also read: In photos: “planting” corals in the most visited Natural Park in Colombia)
Everything related to the “decrease of resources and loss of habitat”, that is, with the reduction of food, but also with the decrease of the area to inhabit, is part of the sixth threat to humpbacks. Finally, Avila and Giraldo point out, the climate change It is another of the factors that is already affecting the whales that “live”, according to the marine biologist, in the country.
In a study he published with four other colleagues two years ago in the scientific journal of marine sciences of the International Council for the Exploration of the Sea (Ices), Avila showed that humpback whales were arriving in Colombia a month earlier than they did 30 years ago. “The observed change in time of arrival at the breeding grounds could be related to changes in the Antarctic autumn ice mass and the increase in population size in recent decades, but we were unable to determine what factor it is more important to explain the observed trend,” the researchers noted.