The artisanal elasmobranch fishery of the Pacific coast of Baja California Sur, Mexico, management implications

Abstract

SUMMARY: Artisanal fisheries in Mexico account for approximately 40% of the total national catch. In 2009, Baja California Sur (BCS) had the second largest catch of elasmobranchs on the Mexican Pacific coast. This paper characterizes and describes the artisanal elasmobranch fishery of Pacific coast of BCS from 2000 to 2010. Sixty artisanal camps were documented, of which 45 targeted elasmobranchs, using primarily gillnets and longlines. We identified 52 elasmobranch species. Gillnetting accounted for 73.5% of the fishing effort and most frequently captured Rhinobatos productus, Mustelus henlei and Myliobatis californica. Longline fishing accounted for 26.5% of effort, most frequently capturing Prionace glauca and Isurus oxyrinchus. The prevalence of juveniles of several species (e.g., Cephaloscyllium ventriosum, Galeorhinus galeus, Isurus oxyrinchus, and Myliobatis californica) within landings suggests that fishing effort may be opportunistically directed at breeding or nursery areas. Despite the dominance of species with wide distributions, we observed a significant biogeographic pattern in the abundance of some species relative to Bahia Magdalena. Results of the present study will be useful to detect changes in the structure of commercially exploited elasmobranch populations, and to provide useful indications for management purposes.Keywords: biogeographic pattern, elasmobranchs richness, fishing effort, Mexican coast, nursery areas, small-scale fishery.RESUMEN: Pesquería artesanal de elasmobranquios en la costa Pacifico de Baja California Sur, México, implicaciones para su gestión. -La pesquería artesanal en México soporta aproximadamente el 40% de la captura total nacional. En 2009 Baja California Sur (BCS) fue el segundo estado con mayor registro de captura de elasmobranquios de todo el Pacifico Mexicano. En el presente trabajo se realizó la caracterización y descripción de la pesquería artesanal de elasmobranquios en la costa Pacífico de BCS del 2000 al 2010. Se registraron 60 campos artesanales, de los cuales en 45 se capturaron elasmobranquios usando como artes de pesca redes y palangres. Se identificaron 52 especies de elasmobranquios. Las redes representaron el 73.5% del esfuerzo pesquero, las especies que se capturaron con mayor frecuencia fueron Rhinobatos productus, Mustelus henlei y Myliobatis californica. Por otra parte los palangres representaron el 26.5% del esfuerzo pesquero, las especies capturadas con mayor frecuencia fueron, Prionace glauca e Isurus oxyrinchus. La presencia de especímenes juveniles de varias especies en los desembarques (p. ej. Cephaloscyllium ventriosum, Galeorhinus galeus, Isurus oxyrinchus, Myliobatis californica) sugiere que el esfuerzo pesquero podría ser oportunista dirigido a las zonas de crianza o de reproducción. A pesar del dominio de especies con distribuciones amplias, se observó un patrón biogeográfico significativo en la abundancia de algunas especies al sur y al norte de Bahía Magdalena. Los resultados del presente estudio serán de utilidad para poder detectar...

Re-defining co-management to facilitate small-scale fisheries reform: An illustration from northwest Mexico

“…Resettlement in Baja was encouraged and incentivized by the federal government starting in the 1970s, following the decline of mainland fisheries [29]. Additionally, ephemeral, seasonal fishing camps are common in the region [30,31]. In this context defining a typical fishing "community" in Northwestern Mexico quickly becomes challenging, as socio-economic characteristics tend to be highly variable across sites.…”

Interactive Governance for Small-Scale Fisheries

“…Additionally, ephemeral, seasonal fi shing camps are common (Cartamil et al 2011 ;Ramirez-Amaro et al 2013 ). In this context, a fi shing "community" on the Baja Peninsula may be hard to defi ne and delineate, and can be considered relatively heterogeneous in cultural and socio-economic form.…”

First record of albinism in the swell shark, Cephaloscyllium ventriosum (Elasmobranchii: Carcharhiniformes: Scyliorhinidae)

“…Because its visual acuity and ability to see bioluminescence would not depend mainly on melanin (Wang et al 2007, Sparks et al 2014, Gruber et al 2016, social interactions with other swell sharks would be possible as well, as was previously suggested for albino elasmobranchs with yellow-orange eyes, caught either in interspecific aggregations (De JesusRoldan 1990) or swimming alone, but with apparently healthy status (Clark 2002, Sandoval-Castillo et al 2006, Reum et al 2008, Lipej et al 2011, Bigman et al 2015, Wakida-Kusunoki 2015. The specimen of Cephaloscyllium ventriosum presented here was considered a mature female, according to Ramírez-Amaro et al (2013). Catching the specimen alive means that it has been able to survive in this environment and avoid predators, possibly by hiding in rocky crevices, which is known a typical behaviour of this fish (Nelson andJohnson 1970, Compagno et al 2005).…”

“…This mass of water is characterized by a mean temperature of <22°C, a salinity of 34‰ * , and upwelling events that promote high levels of primary productivity (MolinaCruz 1984). Although the presence of the swell shark is considered as rare in the fishery landings of southern Baja California Peninsula (Ramírez-Amaro et al 2013), it can be found due to the suitable environmental conditions and food availability, during this specific time of the year (Molina-Cruz 1984). Albinism is an autosomal recessive disorder affecting the production of melanin and caused by the absence or defect of tyrosinase (Wang et al 2007, Bigman et al 2015.…”