Factors affecting the fishing impact on cartilaginous fishes in southeastern Spain (western Mediterranean Sea)

Abstract

Summary:We propose a global index of impact based on the relative vulnerability of the local population of every species and the further application of regression trees globally optimized with evolutionary algorithms to study the fishing impact on the cartilaginous fish in southeastern Spain. The fishing impact is much higher in areas of less than 40 m depth within 11 km of the Cape Palos marine reserve. The impact also depends on the state of the sea and the kind of habitat. Deep-sea habitats associated with hard substrata and sandy beds show the highest impact, and sublittoral muds and habitats associated with circalittoral rocks with moderate energy show the lowest impact. The fishing impact changes throughout the moon cycle, showing different day-scale patterns associated with different habitats and different species compositions. Finally, we show that the global optimization of the regression trees can be essential to find some important patterns and that these trees are a useful tool for determining which areas are considered to be more important in terms of protection, taking into account specifically the vulnerability of the local populations.Keywords: Cape of Palos MPA; conservation; cartilaginous fish; fishing impact; regression trees; evolutionary algorithms; vulnerable species. Factores que afectan el impacto pesquero sobre peces cartilaginosos en el sureste español (Mediterráneo Suroccidental)Resumen: Proponemos un índice global de impacto basado en la vulnerabilidad relativa de las poblaciones locales de cada una de las especies y la posterior aplicación de árboles de regresión globalmente optimizados con algoritmos evolutivos, para estudiar el impacto de la pesca en los peces cartilaginosos del sureste español. El impacto de la pesca es mucho mayor, dentro de los 11 km de la reserva marina de Cabo de Palos, en aquellas zonas de menos de 40 m de profundidad. El impacto también depende del estado de la mar y el tipo de hábitat. Los hábitats de aguas profundas asociados a sustrato duro y fondo arenoso muestran los máximos impactos, mientras que, tanto los fondos fangosos sublitorales como los hábitats rocosos circalitorales con moderada energía de las corrientes, muestran un menor impacto. Además, se dan cambios a lo largo del ciclo lunar en el impacto de la pesca, lo que significa que existen diferentes patrones diarios, asociados a distintos hábitats, con distinta composición específica. Finalmente, mostramos que la optimización global de los árboles de regresión es esencial para revelar patrones importantes y son una herramienta útil para determinar aquellas áreas mas importantes en términos de protección, teniendo en cuenta, concretamente, la vulnerabilidad de las poblaciones locales Palabras clave: Área Marina Protegida de Cabo de Palos; conservación; peces cartilaginosos; impacto pesquero; árboles de regresión; algoritmos evolutivos; especies vulnerables. Citation/Como citar este artículo: Mendoza M., Garrido D., Jose M.

A century of fishery data documenting the collapse of smooth‐hounds (Mustelus spp.) in the Mediterranean Sea

“…In the period 1957-1960, the frequency of occurrence of MUSP was 21.9% (Thalassa survey), decreasing to Along the Spanish coast the trend in reduction of smooth-hounds has been documented since the 1960s (Balearic Islands: Massuti, 1971). Recently, the common smooth-hound has been sporadically caught either in surveys (Gouraguine et al, 2011;Massuti & Moranta, 2003) or by local fisheries (Barrull, Mate, & Bueno, 1999;Carbonell, Alemany, Merella, Quetglas, & Román, 2003;Mendoza, Garrido, & Bellido, 2014).…”

Marine protected areas for demersal elasmobranchs in highly exploited Mediterranean ecosystems

“…In this study we applied for the first time, a systematic spatial planning approach focused on elasmobranch species in the western and, in general, in the Spanish Mediterranean Sea. Our results can be used to inform proactive area-based protection for the demersal elasmobranch community inhabiting the Mediterranean waters under Spanish jurisdiction, to avoid a further decrease in their conservation status as it has been already documented in several areas of the basin (Aldebert, 1997;Ferretti et al, 2008;Pennino et al, 2013;Mendoza, Garrido, & Bellido, 2014;Dulvy et al, 2016).…”

“…With this study, we contribute to the knowledge on elasmobranch spatial conservation and management planning in the Mediterranean Sea and the ongoing elasmobranch MPA delimitation (Davidson and Dulvy, 2017;Mendoza et al, 2014). According to our results, marine protected sites in our study region could be extended to increase the percentage of Mediterranean waters protected to achieve Aichi 11 target (10% of the sea protected by 2020) (Amengual and Alvarez-Berastegui, 2018).…”

“…(Coll et al, 2014). Moreover, as it occurs with other abundant elasmobranch species worldwide (Worm et al 2013, Dulvy et al 2014, it has been documented a decrease in the conservation status of these relative common species in different areas of the Mediterranean Sea such as the Gulf of Lions or the Balearic Sea (Aldebert, 1997;Coll et al, 2010;García et al, 2008;Mendoza et al, 2014;Pennino et al, 2013;Rigby and Simpfendorfer, 2015;Simpfendorfer and Kyne, 2009). Also, elasmobranch species are per se an important marine group to focus on because of a range of reasons, including their potential to serve as umbrella species, flagship, or indicator species (Ferretti et al, 2008;Myers et al, 2007;Stevens, 2000).…”

“…Species investigated here represent the most resilient elasmobranch species of the demersal community on the Mediterranean Sea, probably because their life-history traits (skewed towards the lower values of the fast-slow continuum in elasmobrachs (Quetglas et al, 2016)) made them less vulnerable to human activities than other species with similar habitat and trophic requirements. This make data on these species extremely valuable to set initial conservation priorities for the recovery of the wider demersal elasmobranch community of the western Mediterranean Sea, which has been seriously eroded due to high fishing impact in historic and recent times (Aldebert, 1997;Coll et al, 2010;García et al, 2008;Mendoza et al, 2014;Pennino et al, 2013;Rigby and Simpfendorfer, 2015;Simpfendorfer and Kyne, 2009). Nevertheless, it is important to remark that further investigations will be needed for other species, particularly migratory or pelagic sharks and rays, whose ecological requirements might be beyond those encompassed by study species.…”