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Northern Bluefin Tuna

Brian Skerry / National Geographic

With a maximum length of 14 feet and weighing up to 1,500 pounds, the giant northern bluefin tuna is one of the top predators of the ocean. It can swim up to 50 miles per hour when pursuing prey and has the unique ability among fish to regulate its body temperature. By conserving heat in cold waters, bluefin tuna can swim long distances between their feeding and spawning grounds—even migrating between North American and European waters several times a year!

Climate Change Impacts

As sardines, herring, and other prey move into different waters in response to global warming, the bluefin tuna will find it more difficult to build up the energy reserves needed to make the long journey to their spawn grounds. This stress factor comes at a time when the bluefin tuna is already severely threatened by overfishing. The Atlantic population has already plunged by nearly 90 percent since the 1970s from overfishing, and conservation groups have urged consumers to avoid eating the highly endangered fish.