Posted on 05/18/2015 12:38:10 PM PDT by Red Badger
Over decades of studying the oceans' fishes, some species have been found to have partial warm-bloodedness. But scientists say the opah, or moonfish, circulates heated blood — and puts it to a competitive advantage.
"Nature has a way of surprising us with clever strategies where you least expect them," according to NOAA Fisheries biologist Nicholas Wegner, who works in the Southwest Fisheries Science Center in La Jolla, Calif. In a news release about the finding, Wegner said, "It's hard to stay warm when you're surrounded by cold water but the opah has figured it out."
The opah is not a small animal; it's roughly the size of a car tire and often weighs more than 100 pounds. In the past, it was often viewed as a fairly complacent dweller of water that's hundreds of feet deep.
Now researchers say the opah also uses internal warmth to help it move quickly and efficiently — and kill prey such as squids and smaller fish. As the researchers describe in the journal Science, the fish relies on an internal heating system that seems to have been developed in frigid waters.
From the National Oceanic and Atmospheric Administration Fisheries:
"Satellite tracking showed opah spend most of their time at depths of 150 to 1,300 feet, without regularly surfacing. Their higher body temperature should increase their muscle output and capacity, boost their eye and brain function and help them resist the effects of cold on the heart and other organs, Wegner said.
"Fatty tissue surrounds the gills, heart and muscle tissue where the opah generates much of its internal heat, insulating them from the frigid water."
Heat is generated from the opah's large wing-like pectoral fins, which were previously thought only to help it swim fast enough to catch prey.
The agency's researchers say they found an unexpected design tweak in the opah's gills that sets it apart from other fish: a counter-current heat exchange in which blood vessels carrying warm blood are twined around vessels that are bringing oxygen — and cold temperatures — from the gills. The design helps the opah maintain endothermy (warm-bloodedness).
"The fish had an average muscle temperature about 5 degrees C [roughly 41 degrees Fahrenheit] above the surrounding water while swimming about 150 to 1,000 feet below the surface," NOAA says.
Revelations about the opah's blood temperature come after a moonfish was captured in a striking photograph off the California coast earlier this year, an encounter that was seen as part of a surge in opah sightings off the western U.S. coast.
Opah have more commonly been spotted in Hawaii — including at fish auctions.
Of the flavor, National Geographic has reported:
"Opah are unusual in that different parts of their body look and taste different, the biologist explains. The upper part of the fish looks like tuna and tastes like a cross between tuna and salmon, he says. But their pectoral muscles — the ones that power the fins on the side of the body — look and taste a bit like beef."
Correction May 18, 2015
In an earlier version of this post, we incorrectly note that 5 degrees Celsius is roughly equivalent to 9 degrees Fahrenheit. In fact, it is equivalent to 41 degrees Fahrenheit.
I don't want someone thinking that the Oprah-fish can raise him/herself to cookin' temperature, is all. The amount of difference is significant, but relatively slight.
Thank you for educating us out here.
Nice lookin’ fish ... I’d rather see an Opah than an Oprah ...
Oprah? Well yes, she is that rotund.
From Front and side views!..................
I want a fish that cleans itself, batters itself and fries itself then washes the dishes when I'm done!..................
Maybe the easiest way to explain it is that the difference between the freezing and boiling temperatures of water in Fahrenheit is 180 degrees F (212° - 32°). The Celsius scale is based on that difference and it’s 100°C (0° freezing and 100° boiling). So the proportional difference is 100 vs. 180, or 5/9. That doesn’t really help much doing a conversion, but it at least explains why the separation between degrees of temperature in Celsius is larger. Frankly, it’s enough to know that 22C is perfect, anything over 28 is warm to uncomfortably hot, and if there’s a minus in there don’t freak out unless it’s in double digits.
Breed a cow that has the texture of and the taste of ahi tuna and salmon...Winner!
With genetic engineering ANYTHING is possible!.................
That’d be my favorite kind of fish right there!
Prolly was Lake Erie perch.
Please superimpose the Moochell salt-sucker face on that bad boy!
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