First Warm-blooded Fish
The Opah is a large predatory fish that can maintain warm blood and thus maintain higher levels of activity
Fish can keep its internal temperature higher than surrounding water
Opah, also called Moonfish, are large, round fish found in many places around the world, including off the coast of California. It can weigh almost 50 kilograms and be as big around as a car tire. Opah are a mid-level fish, which means they inhabit water anywhere from 50 to 400 metres in depth, where it is dark and very chilly.
Dr. Nicholas Wegner, a Research Fisheries Biologist with the National Marine Fisheries Service in La Jolla, California, recently studied the opah and found that it is able to conserve all of the heat it produces, as a result of continually flapping its large pectoral fins.
Through a mechanism, called a counter-current heat exchange, warm blood continually heats up cold blood, making the opah the first known fully warm-blooded fish. This enables the opah fish to thrive in its inhospitable habitat.
Related Links
- Paper in Science
- NOAA Fisheries release
- CBC News story
- BBC News story
- Not Exactly Rocket Science blog