By Peter B. Wright
The family of “true” billfish includes all the species called marlin, all the sailfish (which are split into the Atlantic and Pacific species with the Pacific sailfish also being found in the Indian Ocean) and several species of spearfish. Swordfish are commonly grouped with these billfish of the Istiophoridae family, but they are technically the sole member of the family Xiphiidae.
All of these fish are part of the teleost group, which are known as bony fishes and are closely related. With the sole exception of the swordfish, billfish vary only slightly in how the different species capture and kill their prey. I am about to explain why the common myth that all billfish use their bill as a sword, or a club, to kill their prey is not correct!