Obviously, the sailor had little or no experience with the commercial fishing industry practices. By catch, or what I refer to as bykill, has always been ramped. In the commercial shrimp industry, particular in North Carolina and the Gulf of Mexico, the bykill ratio is about 100 to 1. Yep, for every pound of shimp, there is about 100 pounds of other species that are killed.
Same holds true for long-liners and trawlers, but the ratio is not nearly as high. It's right up there, and there is nothing that is done with the bykill other than it's tossed overboard. I've seen 20-acre rafts of dead fish behind shrimp boats as their catch is sorted on the deck of the shrimp boat in the morning sun after a night of dragging nets. As the bykill is tossed overboard, various species of gamefish, barracuda, shark, jacks, blackfin tuna, and even dolphin can be seen ripping through the floating carnage.