Shortly after he has gone to sea, Santiago watches the sky and the water for signs of fish. As he does so, his glance onto the surface of the water reveals "the purple, formalized, iridescent, gelatinous bladder of a Portugese man-of-war" that floats closely beside his boat. Hurling an invective after naming it in Spanish--Agua mala [literally "bad water"].
There are two reasons why Santiago hates the Portugese man-of-war:
- Fish do not want to be near this poisonous creature, so it ruins his opportunities to catch fish.
- Countless times, Santiago has been injured by this creature when he has brought in line that on which some of the poisonous filament has attached itself. Stinging "like a whiplash," this poisonous filament has caused his hands and arms to swell and itch from welts similar to those caused by poison ivy or poison oak.
Furthermore, Santiago feels that although there is a certain beauty of the "iridescent bubbles," they are the "falsest thing in the sea" because they hold no value for the fisherman, and they are a negative force against fish that are worthy catches. For these reasons, he loves to watch the sea turtles, who are of "great value," eat them.
This attitude of Santiago's toward the Portugese men-of-war is truly in keeping with the old fisherman's love of the sea and its denizens, even if he does have a "friendly contempt for the huge, stupid loggerheads who happily eat these creatures. For, the "Agua mala" is, as Santiago calls it, a "whore," a negative force that exploits and poisons the fish, unlike the other inhabitants of the sea.