Megalodon was the biggest fish ever to roam the oceans and while many enjoy indulging in the concept that they may still exist somewhere on earth, The Atlantic Shark Institute (ASI) had to do a double take when one appeared on their fish finder. The scanning technology had picked up what looked to be an enormous fish "about 50 feet [15 meters] long, weighing in at 40 tons" – could it be megalodon?
The answer, disappointingly, is no, but the resulting image does make for a surprisingly convincing megalodon silhouette complete with dorsal fin. As for what the living lump actually was, it turned out to be a school of Atlantic mackerel.
After spotting the giant, ASI said they “waited for one of the rods to go off however, much to our disappointment, the shape started to transition into a large school of Atlantic mackerel that hung around the boat for about 15 minutes,” on Facebook.
“So close, but so far! The Megalodon (Otodus megalodon), disappeared more than 3 million years ago and will likely stay that way, but, for a few minutes, we thought he had returned!”
Followers in the comments were quick to point out the parallels between a memorable scene in Finding Nemo. “And they were like 'Ha,ha,ha,ha! We got you!!!'" they replied.
Obligate schooling fish such as mackerel and herring will line up alongside swimmers of similar size. Their lack of a swim bladder makes them harder to detect in the summer when they form looser schools, but can be detected by SONAR. Such as that used by fishfinders.
At the estimated size of 15.2 meters (50 feet), the outline was on track for megalodon which is estimated to have stretched to 16 meters (52 feet) with finds the size of an adult human (though some people argue we can’t really know for sure how big they were). It’s thought that cold waters may have had something to do with their capacity to go super-sized, but since then modern shark species have kept to more modest body plans.
Megalodon is all well and good for some marine-themed horror, but could they still be out there lurking in the ocean deep? They went extinct millions of years ago, and while an absence of evidence isn't evidence of absence, it would seem unusual for someone not to have spotted a carcass or tooth in living memory.
As for the ocean deep theory, what we know of megalodons indicates they occupied shallower waters and had nurseries in coastal regions. Should they have moved deeper (perhaps to avoid us), you would still expect some sign, as we’re well aware of the giant, deep sea squid species still alive today.
That said, we'd still do a Jurassic Park style sunglasses removal if we saw something like this on fishfinder.