The Washington Post today carried this article detailing new research into how fish eyes work. By studying such diverse ocean fish as tuna and swordfish, scientists have determined an entire class of fish have developed the ability to keep their eye temperatures much higher than the surrounding water. This gives them the ability to see movement at much greater depths than fish without the adaptation. While interesting in and of itself, it's hoped the research will also lead to more efficient long-line lures that will attract the correct fish without causing harm to "undesired" catches of things like sea turtles.