Characterization of the pelagic shark‐fin trade in north‐central Chile by genetic identification and trader surveys

Abstract

Shark fins have become a highly valued commodity with the major Asian fin-trade centres supplied from global sources, including Chile. With growing concerns about the resilience of shark populations to heavy fishing pressure, there is a need for better information on shark landings to aid management efforts. In the widespread absence of shark landing records especially by species, monitoring the fin trade has been proposed as a way to assess species exploitation levels. Here, the first species assessment of the Chilean shark-fin trade was provided. The goals of this study were to (1) determine the species composition and relative species proportion of sharks utilized in the fin trade, (2) determine the relationship between fin trader market names and species and (3) assess trader accuracy in identifying shark fin species based on fin photographs. Fins were analysed from two different fin drying facilities (n ¼ 654) (secaderos) and two fin-storage warehouses (n ¼ 251). In contrast to official government landing records that only document four species in the landings, molecular species identification of the fins demonstrated that at least 10 pelagic shark species are present in the north-central Chilean shark fin trade: Alopias superciliosus, Alopias vulpinus, Carcharhinus obscurus, Galeorhinus galeus, Isurus oxyrinchus, Isurus paucus, Lamna nasus, Prionace glauca, Sphyrna lewini, Sphyrna zygaena. The species composition of the fins from the secaderos was P. glauca (83Á9%), I. oxyrinchus (13Á6%), L. nasus (1Á7%) and A. superciliosus (0Á2%). There was generally good agreement between market names and single shark species for the trade categories 'Azulejo', 'Tiburon', 'Tintorera', 'Cola de zorro' and 'Martillo'. In contrast, the market category 'Carcharhinus' consisted of a mixture of at least five species. The molecular results also identified two species (S. lewini and I. paucus) not previously recorded in Chilean waters. The fin identification survey given to nine regional traders demonstrated that they were highly accurate in recognizing pictures of fins from P. glauca and I. oxyrinchus. The overall strong concordance between market categories and fins from single species and the trader accuracy in survey fin identification suggests that monitoring the Chilean fin trade by market names will provide a reasonably accurate picture of the volume of sharks landed by species.

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

“…Besides, I. paucus and I. oxyrinchus exhibit significant overlap in their distribution range, sharing similar ecological niches, fishing threats, and external morphological characteristics (Compagno 2001, Compagno et al 2005. Sebastian et al (2008) reported I. paucus by molecular DNA analysis of fins obtained from fin-storage warehouses in Chile that suggest unreported captures of this species. This background information suggests an extension of the known species range to more temperate waters, which until now was thought to be limited to tropical areas.…”

Claves taxonómicas, basadas en la morfología de la aleta caudal, para la determinación de tiburones (Chondrichthyes; Elasmobranchii) de las costas de Chile

“…En este sentido, Hernández et al (2009) han sido una excepción, puesto que estos autores emplearon la aleta caudal (considerando además otros elementos) enfocados en la determinación de la aleta caudal de algunas especies involucradas en el comercio de aletas, restringiéndose así a unas pocas especies de interés comercial como son: Prionace glauca, Isurus oxyrhinchus y Lamna nasus. Así mismo, Sebastian et al (2008) y Hernández et al (2010, obtuvieron la caracterización de algunas especies pelágicas, en las costas de Chile mediante la determinación genética de las aletas de tiburones, incluyendo la caudal.…”

“…Sin embargo, tanto para C. obscurus como para C. falciformis, mediante nuevos antecedentes bibliográficos, se puede confirmar su presencia en el centro norte de Chile, aumentando las especies chilenas de 56 (Sáez et al 2010) a 58 especies (Sebastian et al 2008, FISHWISE 2011 2 ).…”

Clave taxonómica del Superorden Squalomorphi de Chile (Pisces: Elasmobranchii)

“…Al respecto, cabe señalar la confirmación de la presencia de Isurus paucus en la zona centro de Chile, captura efectuada el 2004 en Caldera y Paico, y cuya presencia fue también registrada en marzo del año 2007 en el Pacífico suroeste (32º30'S, 74º30'W) en Caleta Portales, Valparaíso (Bustamante et al 2009), que junto con Sphyrna lewini (conocida en el Perú) no han sido confirmados en los registros de pesquerías artesanales e industrial, aumentando el rango de distribución de ambas especies (Sebastian et al 2008).…”