Improving codend selectivity in the fishery of the deep-sea red shrimp <em>Aristeus antennatus</em> in the northwestern Mediterranean Sea

Abstract

Summary:The deep-sea red shrimp Aristeus antennatus is one of the most valuable demersal resources in Catalonia (northeast Spain), and Palamós is the most important harbour for this fishery in the area. Here, a management plan published in 2013 established the use of a 40-mm square-mesh codend (40s), replacing the previously used 50-mm diamond mesh codend (50d). The objective was to decrease the amount of juveniles in the catches, but the regulation did not bring the expected results. In this study, we measured and compared the selectivity of the 40s and the 50d in this fishery. In addition, we experimented with the use of a 50-mm square-mesh codend (50s). According to our results, the 40s had a lower 50% selection length (L 50 ) than the 50d, while the 50s had a substantially higher L 50 than the other two. A transition analysis showed an increase in yield per recruit after the second year from a hypothetical implementation of the 50s. Our conclusion is that the 40s does not have a higher selectivity than the 50d, which (at least partially) explains the failure to reach the management objective in Palamós. Conversely, the use of a 50s would significantly benefit the fishery, increasing gear selectivity and yield per recruit.Keywords: codend selectivity; Aristeus antennatus; mesh configuration; yield per recruit; transition analysis; bottom trawling; NW Mediterranean Sea.Mejora de la selectividad del copo en la pesquería de arrastre de la gamba roja, Aristeus antennatus, en el Mediterrá-neo noroccidental Resumen: La gamba roja, Aristeus antennatus, es uno de los recursos demersales más valorados en Cataluña (noreste de España). Palamós es el puerto pesquero más importante para esta pesquería en la región. Una orden ministerial regulatoria y específica para este puerto, publicada en 2013, estableció la utilización de un copo de malla cuadrada con abertura mínima de 40 mm (40s), reemplazando el copo de malla romboidal de 50 mm (50d) utilizado hasta la fecha. El objetivo era disminuir la cantidad de juveniles en la captura, pero la regulación no consiguió los resultados esperados. En el presente estudio, se midió y comparó la selectividad del copo de 50d y 40s en esta pesquería. Además, se experimentó el uso de una malla cuadrada de 50 mm (50s). Los resultados mostraron que el copo de 40s presentaba una talla de retención del 50% (L 50 ) menor comparado con el copo de 50d, mientras que el de 50s tenía una L 50 considerablemente mayor que los demás copos. El análisis de transición mostró un aumento del rendimiento por recluta (Y/R) después del segundo año desde la hipotética implementación del copo de 50s. Nuestra conclusión es que el copo de 40s no tiene una selectividad mayor que el copo de 50d, explicando (por lo menos en parte) la falta de consecución de los objetivos de gestión en la pesquería de gamba de Palamós. En cambio, el copo de 50s mejoraría significativamente a la pesquería, aumentando la selectividad del arte y el Y/R.Palabras clave: selectividad del copo; Aristeus antennatus; configuración de la mall...

Male Deep-Sea Shrimps Aristeus antennatus at Fishing Grounds: Growth and First Evaluation of Recruitment by Multilocus Genotyping

“…Thus, the codend cover captures organisms escaping from the codend ( Figure 1 ). The codend cover was directly attached to the funnel end of the net which was 1.5 m wider and longer than the codend to maintain a good flow of water and avoid masking the codend mesh (see [ 3 ]). The codend in this study is commonly used for commercial purposes in the Palamós fishing ground, whereas the codend cover was legally authorised for this scientific sampling procedure.…”

“…For instance, in the western Mediterranean, demersal stocks are subjected to high capture rates that are often above sustainable levels [ 2 ]. The blue and red shrimp, Aristeus antennatus (Risso, 1816) (Crustacea, Decapoda), is a typical target fish species of the demersal fisheries of northern Spain [ 3 , 4 ]. The commercial fishing of this species takes place by bottom trawling in submarine canyons, and near shallower waters, at depths of between 400 and 800 m [ 5 ].…”

Genetic Demography of the Blue and Red Shrimp, Aristeus antennatus: A Female-Based Case Study Integrating Multilocus Genotyping and Morphometric Data

“…This approach took advantage of previous genetic information in the same fishing ground on the breeding behavior of the species [19] and on the growth, recruitment, and geographical origin of A. antennatus males [20]. The results reported here fill the existing gap in the genetic demography of females, which is the most relevant sex in A. antennatus fishery [28].…”

“…The average price ranks from 24.14 euros/Kg for small shrimps to 83.03 euros/Kg for the extra-large ones, but seasonal fluctuations are common according to catches and market demand [ 27 ]. The small size category is composed of males and females, whereas larger size groups are only represented by females [ 28 ]. Females are longer lived (with a life expectancy of 5/6 years) [ 25 , 29 ] and are the most pressured by fishing, especially in summer [ 4 , 7 ].…”

Mitigating unwanted catches in the southern Iberian hake stock fisheries: Improving fishing technology vs market control policies

“…However, the effectiveness of these modifications are gear-and fishery-specific (Broadhurst et al 2007). For instance, some studies show that squaremesh codend improves age selectivity compared with diamond-mesh codend of a similar size in a variety of trawl fisheries (Kayka et al 2009, Gorelli et al 2017). It has also been proved that the T90 netting (a standard codend mesh turned 90 degrees) significantly increases the selectivity for some species in Northern European trawl fisheries (Herrmann et al 2007, Bayse et al 2016 and in the Mediterranean Sea (Deval et al 2006, Tokaç et al 2014.…”