Broad Geographic Distribution of Roundscale Spearfish (Tetrapturus georgii) (Teleostei, Istiophoridae) in the Atlantic Revealed by DNA Analysis: Implications for White Marlin and Roundscale Spearfish Management

• Main Authors: Bernard, Andrea M., Shivji, Mahmood S., Rodrigues Domingues, Rodrigo, Hissa Vieira Hazin, Fabio, Ferreira de Amorim, Alberto, Domingo, Andres, Arocha, Freddy, Prince, Eric D., Hoolihan, John P., Wagner Silva Hilsdorf, Alexandre
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: NSUWorks 2013
• Subjects: Fisheries management; Species identification; Kajikia albida; Mitochondrial DNA; Billfish; Genetics and Genomics; Marine Biology; Oceanography and Atmospheric Sciences and Meteorology; North Atlantic
• Online Access: https://nsuworks.nova.edu/occ_facarticles/357

The recent validation of the roundscale spearfish (Tetrapturus georgii) within the western North Atlantic has introduced new complexities in the management of the overfished white marlin (Kajikia albida) in this region due to historical and contemporary misidentification between the two morphologically similar species. Compounding the management challenge for white marlin, which is currently assessed as a single Atlantic-wide stock, is an unclear picture of the extent of the roundscale spearfish's overall Atlantic distribution. By using genetic tools (mitochondrial DNA ND4L-ND4 locus sequences) for species identification, we confirm that the roundscale spearfish has a much broader distribution than previously known, including the central North Atlantic and much of the western South Atlantic to at least 28°52′S. This much wider Atlantic distribution of the roundscale spearfish sympatric with its morphologically similar congeners, the white marlin and longbill spearfish (Tetrapturus pfluegeri), raises further management complexities: it increases the geographic scale for species misidentification in catch records that form the basis for stock assessments and uncertainty in currently accepted white marlin biological parameters. Additional vigilance in obtaining accurate species identification by improved fishery onboard observer training and incorporation of genetic tools is recommended for informing management of white marlin, longbill spearfish and roundscale spearfish throughout the Atlantic.