Needlefish

Abstract: The Atlantic needlefish (Strongylura marina) is a unique anguilliform swimmer in that it possesses prominent fins, lives in coastal surface-waters, and can propel itself across the surface of the water to escape predators. In a laboratory flow tank, steadily swimming needlefish perform a speed-dependent suite of behaviors while maintaining at least a half wavelength of undulation on the body at all times. To investigate the effects of discrete fins on anguilliform swimming, I used high-speed video to record body and fin kinematics at swimming speeds ranging from 0.25 to 2.0 L s ‐1 (where L is the total body length). Analysis of axial kinematics indicates that needlefish are less efficient anguilliform swimmers than eels, indicated by their lower slip values. Body amplitudes increase with swimming speed, but unlike most fishes, tail-beat amplitude increases linearly and does not plateau at maximal swimming speeds. At 2.0 L s ‐1 , the propulsive wave shortens and decelerates as it travels posteriorly, owing to the prominence of the median fins in the caudal region of the body. Analyses of fin kinematics show that at 1.0 L s ‐1 the dorsal and anal fins are slightly less than 180° out of phase with the body and approximately 225° out of phase with the caudal fin. Needlefish exhibit two gait transitions using their pectoral fins. At 0.25 L s ‐1 , the pectoral fins oscillate but do not produce thrust, at 1.0 L s ‐1 they are held abducted from the body, forming a positive dihedral that may reduce rolling moments, and above 2.0 L s ‐1 they remain completely adducted.

Abstract: A traumatic internal carotid-cavernous sinus fistula due to a penetrating injury caused by a needlefish is described.

Abstract: Marine-related injuries and envenomations are common to the coastal physician. Needlefish injuries, which occur almost exclusively in the Indo-Pacific region, have not previously been reported along the Atlantic seaboard. This case report describes a penetrating injury to the lower extremity from a needlefish. Treatment is guided by general resuscitative procedures as well as antibiotic therapy directed against infections unique to the marine environment.

Abstract: Four species of echinorhynchid acanthocephalans were collected from marine fish off Cat Ba Island, Halong Bay, Gulf of Tonkin, Vietnam, in the spring of 2009. Acanthocephalus halongensis n. sp. (Echinorhynchidae) from the redtail scad, Decapterus kurroides Bleeker 1855 (Carangidae), has a unique proboscis armature with a spiniform basal hook with lateral root and an incomplete receptacle wall posteriorly. Gorgorhynchus tonkinensis n. sp. (Rhadinorhynchidae) also from D. kurroides, has long, slender, winding lemnisci, many epidermal nuclei, and a narrow anterior trunk with a shoulder armed with 20 circles of tightly packed spines, the posterior four circles of which have abruptly larger spines than those in the anterior circles. Neorhadinorhynchus atypicalis n. sp. (Cavisomidae) from the rabbitfish, Siganus fuscescens (Houttuyn 1782) (Siganidae), has the largest number of proboscis hooks per row, testes wider than long, and four clustered cement glands. Micracanthorhynchica kuwaitensis Amin and Sey 1996 (Rhadinorhynchidae) from the spottail needlefish Strongylura strongylura (van Hasselt 1823) (Belonidae) was similar to specimens originally described from the Arabian Gulf off the Kuwaiti coast. These acanthocephalans were collected in small numbers but stood out as uniquely and considerably different from their closest relatives to warrant their reporting. All species of acanthocephalans and their host and geographic distribution are described, and a key to the species of Gorgorhynchus is provided.