Caption: Oceanic whitetip shark and pilot fish. The Oceanic whitetip shark (Carcharhinus longimanus)is distributed in tropical and subtropical waters around the world. It is identified by white markings on the tips of its dorsal, pectoral, pelvic and caudal fins. This species is considered dangerous to humans. It is seen here accompanied by a school of pilot fish (Naucrates ductor) which feed on scraps of food and parasites associated with the shark.
While doing this chore last week, I was rewarded by a series of fish photos I took three weeks ago in Mexico's Tenacatita Bay. As I cut, cropped and centered, I remembered the fun we had with that little fish. I wondered whether this species is found in Hawaii, what the fish eats and how big it gets. When sorting was over, I opened my books and entered the remarkable world of pilot fish.
Caption: Whale shark (Rhincodon typus) about to eat a pilot fish (Naucrates ductor). The whale shark is the largest fish in the world, growing up to 18 metres in length. This harmless, solitary animal is found in tropical and warm waters throughout the world, except the Mediterranean. It is a filter feeder, straining plankton and small organisms from the water. It generates its own suction rather than relying on its forward motion and schooling fish may be eaten at times. The pilot fish is a scavenger well know for its habit of accompanying ships and large fish, especially sharks, in warm waters. Photographed in the Red Sea, Egypt.
Pilot fish unfortunately do not live up to their name. In contrast to what used to be assumed earlier, they do not lead the shark to its prey, but profit from the shark as a commensalist. This includes protection from other predators and profit from leftover food. Sometimes they even “surf” on the shark’s bow wave, i.e. in the water collecting in front of the shark’s nose – an energy saving way of moving.