Last week, a huge dark specimen of sunfish left biologists and fishermen in the trap of Ceuta perplexed. He had fallen into the nets and before releasing him, they measured, weighed and extracted samples of his DNA: almost three meters from mouth to tail and 3, 20 Wide. They tried to weigh it, but the scale did not hold because it only calculated up to 1. 000 kilos, which the fish easily surpassed. This species is the heaviest bony fish on the planet and very few specimens have been found in Spain in the last decade, none of these dimensions, according to experts.
“It was very exceptional because it would be around two tons. A specimen caught in Japan that measured 2.7 meters weighed 2.3 tons. It is a pelagic species that is difficult to study, but you can see many in the traps “, explains Enrique Ostalé, coordinator of the Estrecho Marine Biological Station of the University of Seville and based in Ceuta.
The capture was on October 4, a few 414 meters from the Ceuta coast, a paradise to see species such as loggerhead and green turtles , whales or dolphins, due to the current that comes from the Strait. Diver Sergio Guzmán dived to comb the catch of that day and alerted six biologists of the finding, who promptly came to the call to analyze the animal. “Two years ago we saw one of more than 500 kilos, but this one was incredible,” sums up the diver. The nets of this Ceutí trap usually capture many specimens of sunfish, which are released immediately along with other species, and last year they managed to raise 572 copies in a single day. None with that majestic, enigmatic and disoriented bearing, as if it had just come out of a huge fish tank, which presented last week’s animal, of the Mola Alexandrini species.
The sunfish, whose scientific name is Mola mola, is a species in state vulnerable – whose population is decreasing, according to the International Union for Conservation of Nature (IUCN) – that plows through the temperate waters of the world’s oceans. “It is not marketed because it can have toxins and it feeds on plaktonic organisms, fish larvae and jellyfish. We have seen many on the Galician coast because they lie on themselves and carry seagulls that deworm them ”, illustrates Eva Velasco, a researcher at the Spanish Institute of Oceanography in Vigo. Velasco is part of the Diversimar project, a guide to marine species that, thanks to citizen collaboration, makes it possible to identify large fish near the coasts of Galicia and the Cantabrian Sea.
“One of the pending doubts of To solve it is to find out why very few sunfish fall in the Barbate traps -on the other side of the Strait- and here so many, probably due to the distributions by currents “, adds Ostalé, a biologist from the research group of the Marine Biology Laboratory of the University of Seville and that has been studying these specimens since 2018 together with the Swiss biologist Lukas Kubicek. Both researchers have published a chapter on this species in the book Ocean Sunfish: Evolution, Biology and Conservation . Ostalé is also the author of the underwater video that reflects how the sunfish leaves the Ceutí trap at a leisurely pace after being 15 minutes hanging from the straps on the deck of a ship to be analyzed by scientists.
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