Ocean Sunfish - Human Interaction

Human Interaction

Despite their size, ocean sunfish are docile, and pose no threat to human divers. Injuries from sunfish are rare, although there is a slight danger from large sunfish leaping out of the water onto boats; in one instance a boy was knocked off his boat when a sunfish leaped onto it. Areas where they are commonly found are popular destinations for sport dives, and sunfish at some locations have reportedly become familiar with divers. In fact, the fish is more of a problem to boaters than to swimmers, as its immense size and weight can cause significant damage to a boat that strikes one of these fish. Collisions with sunfish are very common in some parts of the world and have caused damage to the hull of a boat, and their bodies can become lodged in the propellers of larger ships.

The meat of the ocean sunfish is considered a delicacy in some regions, the largest markets being Taiwan and Japan. All parts of the sunfish are used in cuisine, from the fins to the internal organs. Some parts of the fish are used in some areas of traditional medicine. If the body does contain toxins, then the marketing and sale of ocean sunfish meat is forbidden in the European Union according to Regulation (EC) No 853/2004 of the European Parliament and of the Council.

Sunfish are accidentally but frequently caught in drift gillnet fisheries, making up nearly 30% of the total catch of the swordfish fishery employing drift gillnet in California. The by-catch rate is even higher for the Mediterranean swordfish industry, with 71% to 90% of the total catch being sunfish.

The fishery by-catch and destruction of ocean sunfish are unregulated worldwide. In some areas, the fish are "finned" by fishermen who regard them as worthless bait thieves; this process, in which the fins are cut off, results in the eventual death of the fish, because it can no longer propel itself without its dorsal and anal fins. The species is also threatened by floating litter such as plastic bags which resemble jellyfish, its main food. Bags can choke and suffocate an individual or fill its stomach to the extent that it starves.

Many areas of sunfish biology remain poorly understood, and various research efforts are underway, including aerial surveys of mola populations, satellite surveillance using pop-off satellite tags, genetic analysis of tissue samples, and collection of amateur sighting data. Recent studies indicate a decrease in sunfish populations that may be caused by more frequent bycatch and the increasing popularity of sunfish in human diet.