Southernmost presence of the Guadalupe fur seal (Arctocephalus townsendi) in the Mexican South Pacific

Abstract

This note constitutes the first report of the Guadalupe fur seal (Arctocephalus townsendi) for Oaxaca. This subadult male was found stranded on a beach in Cerro Hermoso, in the Lagunas de Chacahua National Park (PNLC). This record is highly relevant because the normal range for this fur seal is farther north, in Guadalupe Island and a recolonization site in the San Benito Archipelago, more than 1,300 km from the stranding location. This is the southernmost report for A. townsendi and the first case for Oaxaca, increasing the number of known marine mammal species for this area in the Mexican South Pacific. Because of the current population growth of this otariid, we highlight the necessity of tracking these atypical sightings over time. All Rights Reserved

Biological observations and first stranding record of Mesoplodon peruvianus from the central Pacific coast of Oaxaca, Mexico

“…The marine mammals knowledge of the coasts of Oaxaca has increased in recent years with recent records based on occasional sightings (Meraz 2003), strandings (Meraz and Becerril-Morales 2004;Meraz 2007;Lira-Torres 2007;Villegas-Zurita 2015;Villegas-Zurita et al 2015;2016) and marine mammal surveys from the coast (Meraz and Sánchez-Díaz 2008). In total, 18 species have been recorded for the state of Oaxaca (Bastida-Zavala et al 2013;Hernández-Guillen 2016) and our work add a new species with the confirmation of the presence of Mesoplodon peruvianus.…”

“…Each stranding event is handled on a case-by-case basis between areas depending of available resources, personnel and logistics (Norman et al 2004). This network will gather and compile information related to cetacean and other marine mammal strandings, their distribution, mortality and seasonal occurrences (e. g. Villegas et al 2015, Hernández-Guillen 2016, Villegas-Zurita et al 2016.…”

“…Cetacean species richness in Oaxaca includes 14 species (Meraz and Sánchez-Díaz 2001;Meraz 2003;Meraz and Becerril-Morales 2004;Lira-Torres 2007;Meraz 2007;Meraz and Sánchez-Díaz 2008;Bastida-Zavala et al 2013;Castillejos-Moguel and Villegas-Zurita 2013;Villegas-Zurita 2015), of these Stenella attenuata, S. longirostris, Tursiops truncatus and Megaptera novaeangliae are the most common, being S. attenuata the most abundant (Meraz and Sánchez-Díaz 2008). To date no reports of any Mesoplodon species occurring at Oaxaca's coasts has been published.…”

<b> MAMÍFEROS DE GUERRERO<B>

“…Este error en la identificación ha ocasionado que algunos autores hayan mencionado la presencia de A. townsendi en Guerrero como parte de su área de distribución (Belcher y Lee, 2002). El único registro de A. townsendi que existe en el Pacífico Sur Mexicano es para Oaxaca (Villegas Zurita et al, 2015), mientras que el registro para Guerrero corresponde a A. galapagoensis.…”

“…Este registro no es considerado parte del área de distribución de la especie como tampoco aquellos registros reportados para Colima (Ortega-Ortiz et al, 2013), Oaxaca y Chiapas (Gallo-Reynoso y Solórzano-Velasco, 1991) ya que todos corresponden a registros de individuos aislados (Ceballos, 2014). La presencia de estas especies de lobos marinos en el estado podría estar relacionada a los eventos de El Niño de 1982-1983(Quinn y Neal, 1987) y 1997-1998, ya que se ha visto que este fenómeno puede promover condiciones que permitan que individuos puedan desplazarse fuera de sus áreas de distribución (Aurioles-Gamboa et al, 2004), o como se ha observado con otras especies de pinnípedos en México, estos registros forman parte de eventos atípicos de dispersión de individuos de diferentes especies de pinnípedos (Villegas-Zurita et al, 2015).…”