A blue whale was seen in the Red Sea off the coast of Eilat, for what is believed to be the first time ever on Tuesday. A fisherman first spotted the whale Tuesday morning, and later, a group of marine biologists caught the 20-meter-long mammal on video underwater.Blue whales are usually found in the North Atlantic Ocean and southern hemisphere. It is very rare for them to journey so far from their native habitats, making Tuesday's sighting very surprising to experts.The world's largest mammal, blue whales can grow up to 30 meters (98 feet) in length. They used to be abundant in the world's oceans but were hunted to near extinction. Now, with conservation efforts, blue whale populations are beginning to grow, although they are still considered endangered.