The longest journey of a humpback whale: a male traveled 13,000 kilometers to mate | Science | EUROtoday
Humpback whales are among the many animals that journey the best distances. They observe a sample: the mating and breeding season is spent within the heat waters close to the equator, after which journey hundreds of kilometers to the icy seas of the Arctic and the Atlantic or the North Pacific or, within the southern hemisphere, those who bathe the Antarctica. There they feed on fry of anchovies, herring or sardines or, within the Antarctic Ocean, on krill, a tiny crustacean just like shrimp. However, a gaggle of marine biologists has revealed within the scientific journal Royal Society Open Science the longest journey made by a specimen of this species that didn’t observe the sample. A male sighted within the Pacific Ocean, off the coast of Colombia, was seen once more close to Zanzibar, within the Indian Ocean, a while later. Between each locations, identified mating areas, there are greater than 13,000 kilometers. This migration exceeds by virtually 4,000 kilometers the best distance recorded thus far in these cetaceans.
Although there are birds able to touring between the poles and again in the identical 12 months, such because the Arctic tern, amongst mammals, nobody travels as a lot as humpback whales (Megaptera novaeangliae). Abundant previously, intensive looking for centuries virtually wiped them out. The prohibition for the reason that 60s is permitting their restoration, though proper now they solely add as much as 5% of those who existed previously. Their distribution follows a seasonal motion: they spend the summer season within the colder however richer waters of the north or south. With the arrival of winter they migrate in direction of equatorial or extra tropical areas. Due to the hemispheric reversal of the seasons, populations within the northern hemisphere not often overlap with these within the south. The migration is sort of in a straight line, though it will be extra appropriate to say that they transfer in the identical size. Thus, the seven massive populations recognized by the International Whaling Commission within the southern hemisphere descend in latitude to their portion of the Antarctic Ocean when it’s summer season there. For instance, the a whole bunch of specimens that courtroom and mate off the nice and cozy coasts of the east of Colombia and Ecuador coast the American continent till they attain the Antarctic Peninsula, which they see just under on the map. And when winter comes, the pregnant females return to the north to offer start and the males return to search for a mate. That’s why what the whale registered as HW-MN1300828 did is so particular.
“This whale [un macho] was sighted off the coast of Colombia (twice) and then again off the coast of Zanzibar five years later, making it the greatest great distance [trayecto más corto entre dos puntos de una esfera] longest recorded between breeding grounds for a humpback whale,” says Ekaterina Kalashnikova, biologist on the Bazaruto Center for Scientific Studies (BSCC), devoted to ocean analysis in Mozambique and southeastern Africa. Measured on this manner, this whale migrated at the least 13,046 kilometers in a straight line on the sphere that’s the Earth. Such a protracted migration has by no means been recorded in these animals. However, Kalashnikova, the primary creator of this analysis, is satisfied that her journey was for much longer, however there is no such thing as a solution to show it.
HW-MN1300828 was sighted by biologists within the Gulf of Tribugá, within the Colombian Pacific, in July 2013. They noticed it once more in the summertime of 2017 78 kilometers away, in Solano Bay, additionally in Colombia. In the Happywhale registry, a repository of sightings with information on hundreds of whales, it doesn’t seem once more till 5 years later and really removed from there: on August 22, 2022, it’s sighted once more within the Zanzibar channel, between the island of Unguja and the mainland coast of Tanzania, within the southwest Pacific. The information are supported by images, particularly of the caudal fin, the tail fin, of the whale, which features as a fingerprint. “Each animal is identified by examining the posterior contour, pigmentation patterns and other natural notches on the ventral part of the caudal fins,” explains Kalashnikova.
How did you get from Colombia to Zanzibar? They do not know. The almost definitely factor is that on considered one of her annual journeys south, to the Antarctic Peninsula, one thing made her go east, alongside the coast of Antarctica and, on the peak of the African cone, as much as the Tanzanian coast. Although in principle it may have taken the alternative path, in direction of the west, bordering the frozen continent in the wrong way, there’s an virtually insurmountable bodily barrier: the Antarctic Ocean is ruled by the circumpolar present, probably the most highly effective on the planet, which might make it very costly to go. in opposition to the present, when on the alternative aspect he would simply must let himself go. Upon returning, logic additionally means that it ascended in a comparatively straight line to the African latitudes.
Kalashnikova remembers that the journey in that sense, from west to east, has been demonstrated with the songs of whales. Humpbacks are among the many cetaceans which have probably the most elaborate, as they even converse completely different dialects between the completely different teams. Recent analysis has proven that the track, particular to every inhabitants, “evolves, since each year a new addition is added, which is often a fragment of the song of another population of humpback whales, and after a time the entire population begins to sing this slightly modified song,” explains the biologist. Scientists have verified how this evolution has an eastward course, “which means that the same fragments are transferred from west to east through populations; for example, in 2018 a new fragment was sung in Namibia and Mozambique, then in 2019, that same fragment was detected in western Madagascar, and then in eastern Madagascar and Australia.” A piece but to be revealed now compares the songs of the whales of Colombia and people of Zanzibar, exactly the journey of the male that broke the document.
The lengthy journey of male HW-MN1300828 exceeds by at the least 3,715 kilometers the longest distance recorded between two sightings of the identical humpback whale. They first noticed her in January 1997 within the waters surrounding the Antarctic Peninsula and assumed that she got here from the southeastern Pacific, like our protagonist male. This was a feminine and, 15 years later, she was photographed once more in Byron Bay, in japanese Australia. Whether coasting Antarctica or then ascending or straight crossing the southern Pacific, the mammal traveled 9,807 km. If it was the primary route or 9,331 km. if he did it for the second. At the time, both of the 2 represented the best distance recorded till then, in 2012, by considered one of these cetaceans.
The cetacean knowledgeable from the CEQUA Foundation (Chile), Jorge Acevedo, was one of many authors of that analysis on the feminine touring humpback whale. Acevedo, who has not intervened within the present work on the male, highlights in an e mail that “the migrations or longitudinal movements of a few animals from one population to another, it can be said that they do not occur at high frequency.” The typical motion or migration, keep in mind, “is latitudinal from the reproduction area to the feeding area that each population has.” However, different longitudinal actions within the southern hemisphere are more and more changing into identified. In his opinion, it might be due “to the fact that humpback whale populations continue to increase, and perhaps these movements were more common before the whaling period.”
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