Roundscale spearfish Tetrapturus georgii: morphology, distribution, and relative abundance in the western North Atlantic

• Autores: Lawrence R. Beerkircher, D. W. Lee, G. F. Hinteregger
• Localización: Bulletin of Marine Science, ISSN 0007-4977, Vol. 82, Nº. 1, 2008, págs. 155-170
• Idioma: inglés
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• Resumen

  • Little information has been produced since the mid 1970s about the roundscale spearfish Tetrapturus georgii (Lowe, 1840). The most complete species description was based on examination of four individuals from the eastern Atlantic. On the basis of detailed laboratory examination of 16 specimens, as well as fishery observer information and biological samples from an additional 49 individual specimens, we update morphological descriptions and key identification characteristics of this species for the western North Atlantic. Key characters include lateral scale morphology and position of the anal opening; the scales having rounded and broad anterior bases with usually multiple posterior points, and the anal opening located a distance between 0.48 and 0.81 the height of the first anal fin. Distribution and abundance data for this species based on limited pelagic longline observer reports is updated, suggesting T. georgii is widely distributed in the western North Atlantic but abundant in the Sargasso Sea during winter months. Additonal data on Istiophoridae species ratio that suggests T. georgii may be more common in the western North Atlantic than previously suspected.