When you first had your heart broken, chances are your mother and your grandmother told you to forget about the person who jilted you and added: “There are many fish in the sea.” It turns out that they were more right than they knew — about fish, at least.
A recent Australian study determined that the oceans are filled with many more fish than scientists suspected. In fact, the study concludes that the global biomass of fish is 30 times higher than was previously thought.
Why the incredible undercount of fish? Because most of the world’s biomass of fish falls in the category of mesopelagic fish, which live in the dark depths of the ocean at levels 200 to 1000 meters below the surface. The populations of those fish have been underestimated because the fish have remarkable sensorial capabilities and are incredibly adept at avoiding detection and capture by fishing nets. Their true number was revealed only when acoustic detection devices were used.
Mesopelagic fish are otherworldly looking, with their jutting jaws and special sensory devices, but they play an important role in the oceanic ecosystems. They rise at night to feed, then sink back to the depths to take their craps — a process which transfers carbon from the ocean’s surface to its deepest depths. The decarbonization of the surface helps to keep the oceans healthy.
Curious, isn’t it — after millennia of fishing and sailing the oceans, and hundreds of years of careful scientific study, humans still know so little about the oceans and their inhabitants that we underestimated the fish population by a factor of 30. What else don’t we know about the waters that cover most of the Earth’s surface?