Preliminary Guide to the Identification of the Early Life Stages of Balistid Fishes of the Western Central North Atlantic

摘要

Six of the approximately 40 balistid species, representing four of the 11 genera are found in the western central North Atlantic (WCNA). The most salient characteristic of these moderately-sized fishes which is the basis for their common name, triggerfishes, is their ability to lock the first and longest dorsal spine in an upright position with the second spine. This dorsal spine (trigger) is functional early in the ontogeny of at least one species, Balistes capriscus, and thus may provide defense against predation among pelagic larvae as well as in adults (Matsuura & Katsuragawa 1985). Other unifying morphological features include the absence of pelvic fins; presence of a modified pelvic spine or tubercle; strong teeth in both upper and lower jaws; moderately compressed body covered with thick, plate-like scales that have become, in some species, highly modified directly above the pectoral fin base to form a flexible patch or tympanum; and apposed, relatively broad-based second dorsal and anal fins that are the main source of propulsion. As adults, some species are pelagic while others are demersal and associated with hard bottom substrates and structures.