Recurrent juvenile stranding of the porbeagle shark Lamna nasus along the South West Atlantic coast

GUSTAVO CHIARAMONTE; ANA JULIA ALARCOS; DIEGO MARTÍN VAZQUEZ; NELSON D. BOVCON; SERGIO M. DELPIANI; LEANDRO N. CHAVEZ; RUBEN F. DELLACASA; EZEQUIEL MABRAGAÑA

Revista del Museo Argentino de Ciencias Naturales

Museo Argentino de Ciencias Naturales Bernardino Rivadavia

Lugar: Buenos Aires; Año: 2024 vol. 26 p. 171 - 184

1514-5158

Strandings of juvenile porbeagles are recurrent in the South West Atlantic (SWA). We provide newbiological information and explore to which haplogroups the juveniles may belong. Fourteen stranding events occurredbetween May 2009 and May 2022 on porbeagle in the beaches of the SWA Argentine coast were identified.Based on a 2019 beached specimen, total length, 83 morphometric measures, and the parasites diversity wereprovided, as well as the COI gene sequences, derived from DNA extraction from muscle tissue, followed by PCR.The sequence matched Lamna nasus (98.76% – 100.00%; n=100), using the Barcode of Life Data System identification.Molecular data show a great genetic diversity in COI sequences, especially between northern and southernhemisphere samples, in accordance with previous studies. In addition, juveniles recorded in northern Argentinecoastal waters differ in COI nucleotide sequences and are located in different clusters in the maximum likelihood(ML) analysis. The haplotype network built showed a star-shaped topology and, as the ML tree, revealed theexistence of three genetically distinct clusters. A partition of the genetic variation into Southern Hemisphere andNorthern Hemisphere groups was observed.