Scientists have discovered the first fully warm-blooded fish
Source: Washington Post
By Chelsea Harvey
It’s one of the most basic biology facts we’re taught in school growing up: Birds and mammals are warm-blooded, while reptiles, amphibians and fish are cold-blooded. But new research is turning this well-known knowledge on its head with the discovery of the world’s first warm-blooded fish — the opah.
In a paper published today in Science, researchers from the National Oceanic and Atmospheric Administration (NOAA) describe the unique mechanism that enables the opah, a deepwater predatory fish, to keep its body warm. The secret lies in a specially designed set of blood vessels in the fish’s gills, which allows the fish to circle warm blood throughout its entire body.
Scientists already suspected the opah was special, says Heidi Dewar, a researcher at NOAA’s Southwest Fisheries Science Center and one of the paper’s authors. Most fish who live where the opah does — that is, hundreds of feet deep, in some of the ocean’s darkest and coldest places — are sluggish, thanks to the low temperatures. At these depths, even predatory fish tend to be slow-moving, waiting patiently for prey to come by rather than actively chasing it down. But the opah, which spends all its time in these deep places, has many features usually associated with a quick-moving, active predator, such as a large heart, lots of muscle and big eyes. These characteristics made the opah “a curiosity,” Dewar says.
The opah’s secret first started to come out when NOAA researcher and lead author Nicholas Wegner looked at a gill sample and noticed something intriguing.
FULL story at link.
Image downloaded from flickr NOAA Fisheries West Coast, Opah captured during longline surveys by the Southwest Fisheries Science Center.
Read more: http://www.washingtonpost.com/news/energy-environment/wp/2015/05/14/scientists-have-discovered-the-first-warm-blooded-fish/
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Summer 2016
Some night I'm bored 
Emo--
Nemo--
Yes. Very much! Thank you. I remember Nemo now! Lived down the street from my grandmother
Tunas achieve endothermy by conserving the heat generated through normal metabolism. In all tunas, the heart operates at ambient temperature, as it receives cooled blood, and coronary circulation is directly from the gills.[41] The rete mirabile ("wonderful net"
, the intertwining of veins and arteries in the body's periphery, allows nearly all of the metabolic heat from venous blood to be "re-claimed" and transferred to the arterial blood via a counter-current exchange system, thus mitigating the effects of surface cooling.[42] This allows the tuna to elevate the temperatures of the highly-aerobic tissues of the skeletal muscles, eyes and brain,[39][41] which supports faster swimming speeds and reduced energy expenditure, and which enables them to survive in cooler waters over a wider range of ocean environments than those of other fish
http://en.wikipedia.org/wiki/Tuna
Three in fact, all caught at once. And thus three more examples of this rare deep sea predator are all dead.
Congratulations fishermen!
