Giant sunfish sets new record for world’s largest bony fish
It was December 9, 2021 and Gomes-Pereira was answering a call as part of his marine biology work with the Azores Marine Stranding Network and the Atlantic Naturalists Associationa non-governmental organization specializing in ocean monitoring.
The massive, rotting carcasses pose a threat to human health, Gomes-Pereira says. They also pose a hazard to passing ship traffic, which is why the network closely monitors any large remains that drift near the shore.
Similarly, human ships frequently injure or kill large ocean creatures in surface collisions. In fact, it is suspected that the sunfish, also known as the mola, may have died from a collision with a ship, due to a large bruise on its head. The wound contained fragments of red antifouling paint, commonly used under ships.
Without a marine veterinarian on hand, however, it was impossible to determine whether the strike occurred before or after death, Gomes-Pereira says.
After towing the animal to shore, a forklift hoisted it into position so that a crane scale could more accurately measure the behemoth’s weight. After a few minutes of calibration, the scientists knew they had a whopper. (Learn more about one of the world’s largest great white sharks.)
At 6,049 pounds, the mola weighed more than the full starting lineup of an American football team. The specimen also weighed almost a thousand pounds more than the previous one. Guinness World Record Holder for Heaviest Bony Fish—another sunfish of the same species, Alexandrian Molawhich was caught near Japan in 1996. (Fish are divided into two major classes, with sharks and rays being classified as cartilaginous fish and mostly everything else as bony fish.)
According to Gomes-Pereira, who is the main author of a study publish the findings in the Fish Biology Journalthe discovery is both a source of hope and a warning.
“That means the marine ecosystem is still healthy enough to support these large animals,” he says.
However, since the animal may have died due to humans, the mola should also serve as a wake-up call that we still have work to do on conservation, says Gomes-Pereira.
Molas are easy to spot on the surface of the water. The animals can be 10 feet long and tend to enjoy sunbathing. But scientists still have many unanswered questions about these curious creatures.
“We don’t know how long they live or how fast they grow in the wild,” says Tierney Thys, California Academy of Sciences marine biologist and National Geographic explorer. “We also don’t have a good idea of the number of individuals worldwide or the size of regional populations.”
Thys has been studying these questions since 2000, when she received her first grant from the National Geographic Society to study giants.
As for the record animal, it was likely a female aged 20 or older, says Thys, who is also the founder of the Adopt a Sunfish Program.
“Alexandrian Mola is truly one of the great eccentrics of the ocean and although its outward appearance may seem somewhat clumsy and cumbersome, it is in fact a gentle giant that swims through the water with surprisingly graceful wing strokes,” she says.
Another fascinating feature of these goliaths? They begin life as larvae measuring less than a quarter inch. Where spawning occurs, or exactly how the pencil eraser-sized larvae survive long enough to become the largest bony fish in the sea, scientists still don’t know. (Learn about the recent discovery of the world’s largest freshwater fish.)
“The only larval specimen to be genetically verified as M. alexandrini was found off New South Wales, Australia, so this area could be one of the spawning grounds,” says Thys.
“A Colossal Reminder”
While most people are probably more familiar with M. alexandriniclose cousin, the Mola Molasunfish are just one of those animals that inspire “primal curiosity,” says Thys.
“I love going to the Monterey Bay Aquarium so much because sometimes we have the sunfish on display in the million gallon tank alongside hammerhead sharks and tuna. And then when the sunfish appears, people are like, “Oh. Wow! Why ?!’ laughs Thys. “It’s an animal that asks so many more questions.”
To start trying to answer some of them, Thys recently co-wrote the first-ever academic book on the Molidae group, Ocean sunfish: evolution, biology and conservation.
The new world record holder mola will also help to better understand the species. Not only did Gomes-Pereira and his colleagues collect scales, intestinal contents and genetic samples from the animal, which will aid future research, but they also buried the carcass in hopes it could be exhumed. one day and assembled as a museum. specimen.
“It’s a colossal reminder that our ocean still holds so many mysterious surprises,” says Thys.