Video Credit: Atlantic Naturalist
The measurement using a forklift resulted in almost three tons: A dead sunfish that was discovered off the coast of the Azores holds the new weight record among the representatives of the group of bony fish, marine biologists report. The bizarre giant may have died in a boating accident, according to the findings.
From salmon to flounder: Most fish belong to the so-called Osteichthyes - the group of bony fish is actually the most species-rich of all vertebrates. What distinguishes them is their fully or partially ossified skeleton. This is in contrast to the structures found in the cartilaginous fishes (Chondrichthyes), to which sharks and rays belong. When it comes to the maximum body masses in the fish kingdom, the latter are clearly ahead: some whale sharks can reach a weight of up to around twelve tons. As for the bony fish, the sunfish hold the record. This family of fish are unusually oval-shaped open-ocean dwellers that feed primarily on jellyfish.
Almost half a ton heavier
The previous record holder was a specimen of the species Mola alexandrini discovered off the coast of Japan in 1996. The fish was 272 centimeters long and weighed 2300 kilograms. But now the scientists working with José Nuno Gomes-Pereira from the Atlantic Naturalist Association in Horta (Portugal) report an even heavier specimen. The animal was found floating dead near the island of Faial in the Azores archipelago in December 2021. After the carcass was successfully landed, it became clear that it was a spectacularly large specimen of sunfish. So the marine biologists of the Atlantic Naturalist Association were summoned to examine the find more closely. They performed morphological and genetic analyzes to identify the species and recorded the fish's physical characteristics. The weight was determined by a measuring device while a forklift lifted the carcass.
First of all, it was confirmed that it was not a specimen of the more well-known sunfish species Mola mola: Based on the characteristic hump structures in the head area of the fish and the genetic findings, the scientists were able to clearly assign the animal to the species Mola alexandrini. The measurement of the fish resulted in a length of 325 centimeters. This record size for sunfish was also reflected in its weight: the scientists determined 2744 kilograms. The Mola alexandrini sunfish from the Azores is almost half a ton heavier than the specimen from the coast of Japan, making it the new record holder among bony fish. The maximum weight of this species is therefore even more than twice as high as that of the mola mola sunfish, which weighs up to 1320 kilograms, the scientists emphasize.
Possible victim of boat accident
As part of their investigation, the team also looked into how the giant might have died. As they report, they discovered a dent in the animal's head area, which was about twelve centimeters deep. More far-reaching tissue changes in the area of this point pointed to a strong impact as the cause. Traces of red paint, as is typical for the keel of boats, finally rounded off the picture: apparently the fish had been rammed by a watercraft. However, scientists could not determine whether the impact occurred before or after death. Thus, the cause of death of what is now the heaviest known specimen of a bony fish remains uncertain, write Gomes-Pereira and his colleagues.
Source: Atlantic Naturalist Association