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During August through September 2018, strandings and mortalities of smooth dogfish (Mustelus canis [Mitchill, 1815 [Carcharhiniformes: Triakidae]) occurred on Brighton Beach and Coney Island Beach (Brooklyn, New York). Each of the 8 smooth dogfish examined grossly exhibited hemorrhagic meninges, turbid and pink to red cerebrospinal fluid, and soft and friable olfactory lobes. Wet mounts of the cerebrospinal fluid and brain showed intense infection by scuticociliates in each smooth dogfish. Histopathologic examination of the infected brain revealed intensity-dependent necrotizing meningoencephalitis. We identified the scuticociliate as Philasterides dicentrarchiDragesco, Dragesco, Coste, Gasc, Romestand, Raymond, and Bouix, 1995 (Philasterida: Philasteridae). Small-subunit ribosomal deoxyribonucleic acid (SSU rDNA) sequences (604 base pairs) generated from our specimens were identical (100% nucleotide similarity) to morphologically validated GenBank sequences identified as P. dicentrarchi (JX914665). The 18S phylogenetic analysis revealed that all of the GenBank sequences identified as "Miamiensis avidus," except for the type culture sequence KX357144 (which, as per the International Code for Zoological Nomenclature, objectively comprises Miamiensis avidusThompson and Moewus, 1964sensu stricto), represent P. dicentrarchi. Hence, mortalities of leopard sharks (Triakis semifasciata Girard, 1855 [Carcharniformes: Triakidae]) and of zebra sharks (Stegostoma tigrinum [Forster, 1781] [Orectolobiformes: Stegostomatidae]) in the Northeast Pacific Ocean represent infections by P. dicentrarchi, which have been misidentified as M. avidus previously, and that no evidence exists of M. avidus infecting an elasmobranch. We also provide a comprehensive list of scuticociliates reported to infect fishes and host species infected worldwide.
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http://dx.doi.org/10.1645/24-147 | DOI Listing |
J Parasitol
July 2025
Southeast Cooperative Fish Parasite and Disease Laboratory, School of Fisheries, Aquaculture, and Aquatic Sciences, College of Agriculture, Auburn University, Auburn, Alabama 36830.
During August through September 2018, strandings and mortalities of smooth dogfish (Mustelus canis [Mitchill, 1815 [Carcharhiniformes: Triakidae]) occurred on Brighton Beach and Coney Island Beach (Brooklyn, New York). Each of the 8 smooth dogfish examined grossly exhibited hemorrhagic meninges, turbid and pink to red cerebrospinal fluid, and soft and friable olfactory lobes. Wet mounts of the cerebrospinal fluid and brain showed intense infection by scuticociliates in each smooth dogfish.
View Article and Find Full Text PDFIntegr Comp Biol
June 2025
Florida Atlantic University, Department of Biological Sciences; University of Washington Friday Harbor Laboratories.
Dermal denticles (scales) are important in influencing the movement of water around a shark's body. To date, most of the research on denticle morphology and their impacts on hydrodynamics has focused on the lateral flank of fast-swimming species. One understudied region where these interactions may be important is the nares of sharks.
View Article and Find Full Text PDFJ Exp Biol
April 2025
Museum of Comparative Zoology, Harvard University, 26 Oxford Street, Cambridge, MA 02318, USA.
Fish swimming has classically been modeled as a rearwardly propagating wave of increasing amplitude and fixed frequency, based on kinematic data from large numbers of species in captivity. However, recent work on sharks swimming in natural environments has suggested that anterior and posterior body segments oscillate at different frequencies from each other. We attached accelerometer, gyroscope and magnetometer data loggers to the anterior and posterior body sections of smooth dogfish, Mustelus canis (n=4), and released these individuals in the wild.
View Article and Find Full Text PDFJ Fish Biol
May 2025
Department of Biological Sciences, University of New Hampshire, Durham, New Hampshire, USA.
Estuaries support diverse fish and invertebrate communities, including resident species that rely on estuarine habitats year-round and transient migratory species. The unique movement patterns of these animals connect habitats within and far beyond the estuary and are integrally linked to fisheries management objectives. With a focus on Chesapeake Bay, this study leveraged data from collaborative acoustic telemetry networks in the northwest Atlantic to assess habitat use and phenology of movements for seven species of fish (cownose rays, dusky sharks, smooth dogfish, alewife, striped bass, common carp, and blue catfish) and one invertebrate (horseshoe crabs).
View Article and Find Full Text PDFJ Morphol
September 2024
Department of Biological Sciences, Purdue University, West Lafayette, Indiana, USA.