Observations of 'pseudoparasitism' involving snake eels (Teleostei: Ophichthidae) in commercially important Black Jewfish Protonibea diacanthus (Sciaenidae) and other teleost species.

Snake eels (family Ophichthidae) are a widespread and highly diverse, but poorly understood group of fishes known worldwide in tropical to temperate waters from inshore to at least 1300 m depth. During the dissections of a commercially harvested large marine sciaenid, the Black Jewfish Protonibea diacanthus (Lacépède, 1802), collected from coastal waters off northern Australia, ophichthids were found encased in the mesenteries in the body cavity. Subsequently, specimens of ophichthids were also collected from the stomach contents of P. diacanthus, suggesting this as the potential source of the ophichthids in the body cavity. Genetic analysis confirmed four species of ophichthids were collected from the body cavity of 19 P. diacanthus specimens. Further investigation has revealed the occurrence of at least three additional ophichthid species from the body cavities of ten Australian teleost species classified in eight different families. Teleost species with ophichthid eels present in their guts were medium to large, opportunistic carnivores suggesting that prey items were targeted rather than incidentally ingested. Preliminary identification of the eels suggests that some may be new Australian records, highlighting an important, but little utilised source of ophichthid specimens for scientific studies. This paper presents the first published report of eels in the body cavity of fishes in Australian waters and is a good example of collaboration and co-operation on collections-based research between various stakeholders in the fisheries industry and of citizen science. [ABSTRACT FROM AUTHOR]