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Observations on the morphology, ecology, and behaviour of Bathylychnops exilis Cohen
Author(s) -
Stein D. L.,
Bond C. E.
Publication year - 1985
Publication title -
journal of fish biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.672
H-Index - 115
eISSN - 1095-8649
pISSN - 0022-1112
DOI - 10.1111/j.1095-8649.1985.tb04022.x
Subject(s) - biology , mesopelagic zone , morphology (biology) , crustacean , zoology , anatomy , fish <actinopterygii> , ecology , fishery , pelagic zone
Bathylychnops exilis is an unusual north‐eastern Pacific mesopelagic fish of which adults have previously been undescribed and the biology is poorly known. Its sensory and digestive systems are highly modified. Sensory modifications include the equivalent of four functional eyes, well developed nasal rosettes, and lateral line canals up to 4 mm in diameter. Digestive adaptations include a peculiar mouth, large tongue, crumenal organ, and a large caecal stomach. Bathylychnops exilis apparently lacks an anal light organ. Ontogenetic changes occur in the morphology of the head, eyes, body, and coloration. Bathylychnops exilis eats crustaceans and may be medusae and microscopic organisms. Reproduction probably occurs in late summer. Adults occur most commonly at about 500 m depth, possibly in groups, and may be diurnal vertical migrators.