"Jumping fish school ahead! Prepare nets!" The call that went out was from an experienced sailor. He had worked with merchants that traveled the coat line for many years. When he saw the jumping fish he knew it was the same as seeing gold leaping on the ships.
The jumping fish were a monster that was considered dangerous only to those unaware. The leaping fish didn't leap to attack anyone, they did so because they enjoyed the sun. they would swim as fast as possible to reach the surface then leap out of the water extending their fish as much as possible. From there they would enjoy the sun before falling again. This was the ideal chance to catch them.
Since Walker could see the approaching school of jumping fish, he used his all around appraisal skill and caught up with what was going on easily. He explained this to Midnight who thought that the heavens had opened up and that a heavenly lord of creation had gifted her food that jumped in to her mouth.