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Researchers from the National Oceanic and Atmospheric Administration (NOAA) have discovered the first ever known warm-blooded fish. The opah fish is round-bodied and has a silver color. Its warm blood enables the fish with a competitive edge in the cold deep waters of the ocean.
The two-meter long fish does not display any characteristics which could indicate that it is a predator. Predators such as sharks, tuna and swordfish are fast-moving and consequently their bodies look like streamlined torpedoes. Surprisingly although the opah looks like a startles frisbee scientists have discovered that it is an active predator.
According to the article in the journal Science the creature also known as the moonfish has the dimension of a tire and can warm itself similarly to how a car radiator does it. The blood vessels in the fish’ gills carry warm blood from the core of the body. The vessels cover other vessels from where the fish breathes, near the vessels and bring in cold, oxygenated blood. This is like a self-made heating system which keeps the brain of the fish sharp and its muscles active so it can swim quickly and grab a prey.
The body temperature in the case of most fish matches the surrounding water. A small number of fish can warm certain parts of their bodies. For example tuna, mako and the great white can warm their swimming muscles and go into turbo mode when they have to. However none of them can heat their entire body like the opah does.
The vital organs of normal fish remain at ambient temperature. So when fish hunt in cold, deep waters they have to constantly have to return to the surface to get warm again. The opah can keep the temperature of its body almost five degrees Celsius warmer than the temperature of the environment. The scientists used temperature monitors on opah fish living off the US coast to discover this.
The lead author of the study, Nicholas Wegner of NOAA Southwest Fisheries Science Center in La Jolla (California) remarked:
“Before this discovery I was under the impression this was a slow-moving fish, like most other fish in cold environments. But because it can warm its body, it turns out to be a very active predator that chases down agile prey like squid and can migrate long distances.”
Image Source: grindtv.com
