The billfish is fixed at the apex of the oceanic food chain. Composed of sailfish, marlin, spearfish, and swordfish, they roam the pelagic waters of the Atlantic and are easily recognized by their long, spear-like beaks. Noted for their speed, size, and acrobatic jumps, billfish have for centuries inspired a broad spectrum of society. Even in antiquity, Aristotle, who assiduously studied the swordfish, named this gladiator of the sea xiphias--the...