Depletion of trophy large-sized sharks populations of the Argentinean coast, south-western Atlantic: insights from fishers? knowledge

ALEJO J. IRIGOYEN; GASTON TROBBIANI

NEOTROPICAL ICHTHYOLOGY

SOC BRASILEIRA ICTIOLOGIA

Lugar: Porto Alegre; Año: 2016 vol. 14

1679-6225

Globally, sharks are impacted by a wide range of human activities, resulting in many populations being depleted. Trophylarge-sized sharks of the Argentinean coast, the sand-tiger Carcharias taurus, the copper Carcharhinus brachyurus and thesevengill shark Notorynchus cepedianus are under intense sport and artisanal fishing since the 50?s decade. However, thecurrent and historical information for the assessment of its populations status is scarce. The aim of this work was to analyzethe status of conservation of these species through the gathering of expert fishermen knowledge (FK) on semi-structuredinterviews. Abundance variation perception between the beginning and the end of fishermen careers revealed a critical statusfor the species study (means variation between -77 and -90 %). Furthermore, a best day´s catch analysis reinforce this result inthe case of the sand tiger shark. The school shark Galeorhinus galeus was included on this work with the objective of contrastFK with formal information available of catch-per-unit-effort (CPUE) time series. Both sources of information, despite arenot comparable, shows declines ~ - 80%. The critical conservation situation of study species needs urgent managementaction, particularly for the san tiger shark which could became regionally extinct before the reaction of stakeholders occurs.