As the shark goes in for a kill, the electroreceptors may help it hit its target. Even if the salmon gets a short reprieve, the salmon shark can reposition with incredible speed, thanks in part to highly flexible fins and a massively powerful tail. So how can the salmon shark perform at this level of excellence in ice-cold water? Since the vast majority of sharks live in much warmer climes, how does this one prosper here? The salmon shark has an unusual adaptation for surviving in this frigid world, and it's one that enhances every other ability this unique animal has. Amazingly, this fish is warm-blooded. This is an enormous advantage for hunting swift prey in cold water. Warm blood enhances speed, muscle power, and endurance, everything this predator needs. But how does it retain its body warmth while immersed in icy water? The greatest threat to all warm-blooded animals here is heat loss. Hyperthermia stalks the animals as lethally as any predator. Of course, there are the familiar ways of staying warm. Warm-blooded mammals, like sea otters, are clad in a fur coat made of up to 150,000 hairs per square centimeter. The otter must constantly groom this thick but easily matted fur to maintain its insulating properties. It also must maintain a high metabolic rate by eating up to a quarter of its body weight every day just to stay alive. But despite fur coats and high metabolisms, as many as three out of four of these otter pups will not survive their first year. The harbour seal employs a more passive method of staying warm. Blubber. A harvest seal pup is born with quite a bit of this insulating fat. But the pup will only have a 24-day suckling period to build enough blubber to maintain its body heat. The warm-blooded salmon shark has neither fur nor fat for insulation. Yet it can raise its body temperature more than any fish in any water. The internal temperature of most fish is nearly identical to the surrounding water. But not the salmon shark's. Its circulatory system has an unusual mechanism to keep this shark warm in ice-cold water. As cold water passes over the shark's gills, it carries oxygen to the blood. The cool, oxygenated blood then travels through the shark's blood vessels. But on its way to muscles and organs, cold blood is worn by a heat exchange system. Adjacent veins, carrying warm blood from the shark's swimming muscles, transfer heat to cooler blood coming in from the gills. The systems that enable the heat transfer are called rutia mirabilia, or wonderful networks. These allow the salmon shark to raise its body temperature as much as 20 degrees Celsius above the water temperature.
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https://www.youtube.com/watch?v=S8SZdd5psVg