Squatina occulta, Hidden Angelshark

• Autores: Awruch, C. A.; Barreto, R.; Charvet, P.; Chiaramonte, Gustavo Enrique; Cuevas, J. M.; Faria, V.; Paesch, L.; Rincon, G.
• Año de publicación: 2020
• Idioma: inglés
• Tipo de recurso: artículo
• Materia: Chondrichthyes; Squatiniformes; Squatinidae; Hidden Angelshark
• Institución: Consejo Nacional de Investigaciones Científicas y Técnicas

The Hidden Angelshark (Squatina occulta) is a medium-sized shark (to 160 cm total length) endemic to the Southwest Atlantic inhabiting waters from Rio de Janeiro, Brazil, to Buenos Aires Province, Argentina and likely further south to the northern Patagonia-Argentine region. It is mainly found on the continental shelf at depths of 10-150 m, but has been found at depths to 350 m. The species' low reproductive potential (litter size of 4-10 and a possible three-to-five-year female breeding cycle) together with its susceptibility to capture in both trawl and gillnet gear makes it highly susceptible to population depletion. Angel sharks are heavily fished in southern Brazil and significant reductions have been documented there. In the period from 1988 to 2002, on the continental shelf of southern Brazil, the abundance of Squatina species was reduced by approximately 85%, and benthic trawl fishing continued to intensively exploit this population in more recent years. In the same region, scientific fishing cruises conducted between 1986 to 2001 using bottom trawls revealed that the frequency of occurrence and CPUE (in kg/hour and number of individuals/hour) of this species was reduced by 80% confirming trends observed in commercial fisheries. In Argentina, trawl catches of Squatina underwent a reduction of 58% in the years 1992-1998, showing a continuing negative trend since then. These are the equivalent of a >99% reduction over three generation lengths (46.5 years), however there may be other areas within its range where fishing intensity is not as high. The catch and trade of this species has been banned in Brazil since 2004, but it is still targeted illegally and caught as bycatch and sold in markets. Given the species' relatively low productivity, the presence of intensive fisheries throughout the species' range, and the level of localized reductions reported, the Hidden Angelshark is inferred to have undergone a population reduction of over 80% over three generation lengths (46.5 years) across its range, and is therefore assessed as Critically Endangered A2bd.
Fil: Awruch, C. A.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; Argentina
Fil: Barreto, R.. Instituto Chico Mendes de Conservacao Da Biodiversidade; Brasil
Fil: Charvet, P.. Universidade Federal do Paraná; Brasil
Fil: Chiaramonte, Gustavo Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia". Estación Hidrobiológica de Puerto Quequén (sede Quequén); Argentina
Fil: Cuevas, J. M.. Wildlife Conservation Society; Estados Unidos
Fil: Faria, V.. Universidade Federal Do Ceara; Brasil
Fil: Paesch, L.. Dirección Nacional de Recursos Acuáticos; Uruguay
Fil: Rincon, G.. Universidade Federal Do Maranhao.; Brasil