A hypothesis to explain onshore records of long-nose lancetfish Alepisaurus ferox (Alepisauridae, Teleostei) in the North Pacific Ocean

Abstract

Long-nose lancetfish, Alepisaurus ferox, is a widely distributed oceanic pelagic predator. It inhabits mainly tropical and subtropical waters, where it spawns and the juveniles feed. Adults may feed within the subarctic waters reaching as far north as Greenland, Iceland, and the Bering Sea. Onshore records of lancetfish exist for the past 250 years. Some authors suggested that lancetfish occurs onshore as a result of hunting. Others thought that the species comes ashore during storms when the fish have become weak as a result of repletion or pathologic invasion by parasites. However, analysis of known onshore records of lancetfish in the North Pacific Ocean shows that in most cases the fishes had empty stomachs, were not infected with parasites, and were found during non-stormy periods. The dates of most onshore lancetfish records in the North Pacific Ocean coincided with periods of strong La Niña events. Hence, lancetfish mortality may be related to sharp changes in oceanic conditions.