Elasmobranch bycatch associated with the shrimp trawl fishery off the Pacific coast of Costa Rica, Central America

Abstract

Abstract-Demersal sharks and raysare common yet vulnerable components of the bycatch in tropical bottom-trawl fisheries. Little is known about the elasmobranch assemblages associated with most of these fisheries, particularly within the eastern tropical Pacific. This study characterized the elasmobranch assemblage associated with the shrimp trawl fishery along the Pacific coast of Costa Rica. Between August 2008 and August 2012, 346 trawl hauls were conducted at depths of 18-350 m. These hauls resulted in a sample of 4564 elasmobranchs from 25 species and 13 families. The Panamic stingray (Urotrygon aspidura), rasptail skate (Raja velezi), brown smoothhound (Mustelus henlei), and witch guitarfish (Zapteryx xyster) accounted for more than 66% of the elasmobranch abundance within the bycatch. Depth was the main factor influencing the elasmobranch assemblage; species richness was significantly higher at depths <100 m than at other depths. Two groups of elasmobranchs were identified: the first was found in shallow waters (<50 m), and the second was observed at depths of 50-350 m. Sex and size segregation patterns are also influenced by depth. Moreover, we documented the shift of the bottomtrawl fishery toward shallow-water resources-a change that could be problematic considering that elasmobranch diversity is higher in shallow waters.

Chondrichthyan Diversity, Conservation Status, and Management Challenges in Costa Rica

“…These areas accounted for 75 studies (62% of the total number of studies analyzed). Fisheries was the category with most studies (n = 28), and they generally focused on relatively short-term (<10 year) surveys of the elasmobranch by-catch associated with coastal (López-Garro et al, 2009;López-Garro and Zanella, 2015;Clarke et al, 2016) and pelagic fisheries (Whoriskey et al, 2011;Dapp et al, 2013), This list excludes any regional and global-scale study.…”

“…Our review highlighted the lack of studies on deep water (>1000 m) and Caribbean chondrichthyan populations. Given the increasing exploitation of deep water resources (Wehrtmann et al, 2012;Clarke et al, 2016), there are some concerns over the ability of chondrichthyans to sustain high fishing levels in these environments (Simpfendorfer and Kyne, 2009). Similarly, less effort has been given to study Caribbean chondrichthyans in Costa Rica, where reported landings account for less than 4% of national landings (Fournier and Fonseca, 2007).…”

“…Fishing is perhaps the most significant and widespread threat affecting chondrichthyans in Costa Rica (Whoriskey et al, 2011; Dapp et al, 2013;Davidson et al, 2016), as the unique life-history traits of some species, poor landing statistics and limited enforcement make them particularly vulnerable to overexploitation (Frisk et al, 2005;Arias et al, 2014;Trujillo et al, 2015). In Costa Rica, small-scale (e.g., gillnet and bottom long-line fisheries) and shrimp trawl fisheries catch a large number of sharks and rays in coastal environments (Herrera-Ulloa et al, 2011;Clarke et al, 2016Clarke et al, , 2017. In contrast, pelagic longline and purse seine fisheries catch several shark species in the open ocean as their main target or as bycatch (Rojas et al, 2000;Arauz et al, 2007).…”

Bibliometry of marine science and limnology publications (1979-2015) by the Centro de Investigación en Ciencias del Mar y Limnología (CIMAR), Universidad de Costa Rica

“…Jorge Campos and his collaborators from CIMAR published in the 1980s on fishery-related aspects (e.g., Campos, 1983), and Ingo S. Wehrtmann has been publishing about this topic in the last decade. One milestone for this research topic was the foundation of the Unidad de Investigación Pesquera y Acuicultura (UNIP) of the CIMAR in September 2007, which has generated numerous projects and publications, especially regarding deepwater bottom-trawl shrimp fishery and its bycatch (e.g., Wehrtmann & Nielsen-Muñoz, 2009;Clarke, Espinoza, Ahrens, & Wehrtmann, 2016;Villalobos-Rojas, Azofeifa-Solano, Camacho-García, & Wehrtmann, 2017).…”

Abundancia, biomasa y estructura de la ictiofauna demersal en el océano Pacífico de Centroamérica, basadas en datos de prospección pesquera realizados a bordo del B/O Miguel Oliver

“…12 (1): 27-47, enero-junio 2020. ISSN: 1659-455X • e-ISSN: 1659-407X DOI: http://dx.doi.org/10.15359/revmar.12-1.2 de México (Bianchi, 1991;Aguilar-Palomino et al 1996;Rodríguez-Romero et al 2008;León-Chávez et al 2010), principalmente, en grupos específicos como los tiburones o rayas (Clarke et al 2016). Recientemente, Robertson et al (2017) realizaron un análisis taxonómico de peces óseos capturados en aguas profundas del PCC, con ilustraciones y códigos de barras de ADN.…”