Southernmost record of Isurus paucus Gitart Manday, 1966 (Elasmobranchii: Lamnidae) in the southeast Pacific Ocean

Abstract

Resumen.-Se informa sobre el registro más austral del marrajo de aleta larga Isurus paucus Gitart Manday, 1966 en el Pacífico suroriental. El ejemplar correspondió a una hembra de 310 cm de longitud total, capturada por un pesquero artesanal frente a la costa de Valparaíso, Chile, por un pesquero artesanal cuya especie objetivo era el marrajo de aleta corta, I. oxyrinchus. Los principales caracteres taxonómicos utilizados en la identificación del marrajo de aleta larga que permitieron distinguirlo de la otra especie del género Isurus (marrajo de aleta corta), fueron la forma de la cabeza y hocico, la longitud de las aletas pectorales, la posición relativa de la primera aleta dorsal con respecto al margen posterior de las aletas pectorales y la posición relativa de la segunda aleta dorsal con respecto de la anal. Los antecedentes recopilados indican que la presencia de Isurus paucus no se restringiría a zonas de aguas cálidas, sino que también se distribuye en aguas templadas-frías.Palabras clave: Isurus oxyrinchus, tiburón marrajo de aleta larga, Chile

Updated distribution range of longfin mako Isurus paucus (Lamniformes: Lamnidae) in the North Atlantic

“…The present distribution (Fig. ) is in agreement with earlier studies (Queiroz et al., ; Bustamante et al., ), and confirming the presence of this species in pelagic Atlantic waters. One of the records presented here, an 87 kg specimen caught on 7 August 2008 at 44.88N/40.55W is, thus far, the northernmost reported record.…”

“…The results obtained here represent a thermal niche expansion for I. paucus, since the previously estimated temperatures for one specimen caught in the southeast Pacific Ocean was 18.5°C (Bustamante et al., ), and 22.74°C for the mid‐North Atlantic records (Queiroz et al., ). The present distribution (Fig.…”

Not all fish are equal: functional biodiversity of cartilaginous fishes (Elasmobranchii and Holocephali) in Chile

“…paucus and P . kamoharai are incorporated as new records, and are by‐catch in the pelagic longline fishery targeting swordfish and tunas (Meléndez et al ., ; Bustamante et al ., ). Unconfirmed species are present in all zones and generally reflect low human population density and limited commercial fishing activity in coastal regions such as the oceanic islands and austral south zones, which limit accessibility and specimen collection.…”

“…oxyrinchus and I . paucus ) respectively, are combined under a single mako shark landing category (Bustamante et al ., ). These are examples of a very significant problem that limits interpretation and understanding of the elasmobranch catch due to inadequate recording of landings (Pequeño & Lamilla, ).…”

“…Given that E. brachyurus, E. lucifer and E. unicolor are noted for having a restricted distribution in the north-west Pacific Ocean, these rare-occurrence species could be the result of misidentification of currently undescribed species in the Chilean oceanic Island region (Ebert et al, 2011;Straube et al, 2011). Species such as I. paucus and P. kamoharai are incorporated as new records, and are by-catch in the pelagic longline fishery targeting swordfish and tunas (Meléndez et al, 2006;Bustamante et al, 2009). Unconfirmed species are present in all zones and generally reflect low human population density and limited commercial fishing activity in coastal regions such as the oceanic islands and austral south zones, which limit accessibility and specimen collection.…”