Application of age-length-keys to estimate catch-at-age for the North Atlantic albacore (Thunnus alalunga) stock

This document presents the results of applying two different methods to estimate catch-at-age for North Atlantic albacore (Thunnus alalunga). The Spanish albacore surface fishery size frequency data from 2003 to 2005 have been analyzed by means of MULTIFAN and age-lengthkeys (ALKs) have been derived from readings of sections obtained from sampled dorsal spiny rays of catch landed.Ce document présente les résultats de l’application de deux méthodes différentes visant à estimer la prise par âge pour le germon de l’Atlantique Nord (Thunnus alalunga). Les données de fréquences de tailles de la pêcherie de surface espagnole ciblant le germon de 2003 à 2005 ont été analysées à l’aide de MULTIFAN et des clefs âge-taille ont été calculées (ALKs) d’après la lecture des sections obtenues des rayons épineux de la dorsale échantillonnées de la prise débarquée.Este documento presenta los resultados de aplicar dos métodos distintos para estimar la captura por edad del atún blanco del Atlántico norte. La distribución por talla de las capturas comerciales de las flotas españolas de superficie fue analizada con MULTIFAN. Las claves talla edad fueron obtenidas por medio de la lectura de secciones de radios espinosos muestreados a partir de las capturas comerciales

The Spanish albacore (Thunnus alalunga) surface fishery in the northeastern Atlantic in 2005

The main features of the Spanish albacore (Thunnus alalunga) surface fishery operating during summer and autumn months of 2005 in the northeast Atlantic and Bay of Biscay waters north of 40ºN parallel are presented in this document. The baitboat fleet increased its yield 30%; likewise the troll fleet showed an increased catch of 36% respectively to the 2004 yield. Both fleets increased their nominal fishing effort about 16% in 2005. The size composition of the catches in 2005 obtained by both fleets showed a high proportion of age 2 derived by both methods used to age catches: length slicing and age-length keys, which is in agreement with the high proportion of age 1 present in 2004. However, in the case of age 3, the observed proportion of the catch at age differs contingent on either method applied to age the catch in the case of the troll fleet.Este documento presenta un resumen sobre la actividad pesquera de las flotas de superficie españolas: cebo vivo y cacea dirigidas a la pesca de atún blanco (Thunnus alalunga) que desarrollaron su actividad en los meses de verano y otoño de 2005 en aguas del Atlántico nordeste y golfo de Vizcaya al norte del paralelo 40 º N. La evolución de las capturas y esfuerzo realizado por los barcos de cebo vivo y cacea, mostró un aumento del 30% y 36% respectivamente frente a las capturas del año 2004. El esfuerzo nominal en días de pesca aumentó prácticamente un 16% en ambas flotas. En 2005, la composición de tallas de la captura, mostró un nivel elevado de capturas de edad 2 obtenido con los dos métodos empleados: corte de tallas determinista (“filo de cuchillo”) y claves talla edad, que corresponde a un nivel elevado de capturas de edad 1 observado en el año 2004 en ambas flotas. Sin embargo la proporción de capturas de edad 3 observada difiere dependiendo del método empleado en la obtención de la composición de edades de las capturas de la flota de cacea.Ce document présente un résumé sur les activités de pêche des flottilles de surface espagnoles (canne et ligne traînante) ayant ciblé le germon (Thunnus alalunga) pendant les mois d’été et d’automne de 2005 dans les eaux de l’Atlantique Nord-Est et du Golfe de Gascogne, au nord du parallèle 40ºN. L’évolution des prises et de l’effort déployé par les canneurs et les ligneurs a présenté un accroissement de 30% et 36%, respectivement, par rapport aux prises de 2004. L’effort nominal en jours de pêche a pratiquement augmenté de 16% pour ces deux flottilles. En 2005, la composition par tailles des captures a montré une forte proportion de prises d’âge 2, obtenue à l’aide de deux méthodes, le découpage des tailles et les clefs âge-taille, qui correspond à une forte proportion d’âge 1 observée en 2004 dans les deux flottilles. Toutefois, la proportion observée de prises d’âge 3 est différente selon la méthode appliquée pour obtenir la composition des âges des prises de la flottille de ligneurs

Results on main elasmobranch species captured during the 2001-2011 Porcupine Bank (NE Atlantic) bottom trawl surveys

This working document presents the results on nine of the most important elasmobranch species of the Porcupine bank Spanish surveys during the last decade (2001-2011). The shark species more abundant in these surveys in biomass terms were blackmouth catshark (Galeus melastomus), birdbeak dogfish (Deania calcea), Knifetooth dogfish (Scymnodon ringens), velvet belly lantern shark (Etmopterus spinax), lesser spotted dogfish (Scyliorhinus canicula) and bluntnose sixgill shark (Hexanchus griseus); while sandy ray (Leucoraja circularis), cuckoo ray (Leucoraja naevus) and common skate (Dipturus spp. / Dipturus cf. flossada) were the more frequent Rajidae. Biomass, distribution and length ranges were analysed. Many of these species occupy mainly the deep areas covered in the survey, especially D. calcea and S. ringens.Versión del edito

Results on main elasmobranch species captured during the 2001-2013 Porcupine Bank (NE Atlantic) bottom trawl surveys

This working document presents the results on the most significant elasmobranch species of the Porcupine Bank Spanish surveys in 2013. The main species in biomass terms in this survey were Galeus melastomus (blackmouth catshark), Deania calcea (birdbeak dogfish), Deania profundorum (arrowhead dogfish), Scyliorhinus canicula (lesser spotted dogfish), Scymnodon ringens (Knifetooth dogfish), Etmopterus spinax (velvet belly lantern shark), Dalatias licha (Kitefin shark) Hexanchus griseus (bluntnose sixgill shark), Leucoraja circularis (sandy ray), Leucoraja naevus (cuckoo ray), Dipturus nidarosiensis (Norwegian skate) and Dipturus spp. / Dipturus cf. flossada / Dipturus cf. intermedia (common skate). Biomass, distribution and length ranges were analysed. Many of these species occupy mainly the deep areas covered in the survey, especially D. calcea, D. profundorum and S. ringens

Tintorera

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Results on main elasmobranch species captured in the bottom trawl surveys on the Northern Spanish Shelf

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Results on main elasmobranch species captured in the bottom trawl surveys on the Northern Spanish Shelf

This working document presents the results on the most significant elasmobranch species captured in the Spanish Groundfish Survey on Northern Spanish shelf in 2014. The main species in decreasing order of biomass are Scyliorhinus canicula (Lesser spotted dogfish), Galeus melastomus (Blackmouth catshark), Etmopterus spinax (Velvet belly), Raja clavata (Thornback ray), Raja montagui (Spotted ray) and Leucoraja naevus (Cuckoo ray). Biomass, distribution and length ranges were analysed. The majority of the species showed a decrease in biomass with regard to 2013 when highest values of the time series were reached and a new vessel (R/V Miguel Oliver) was used. The results of this last survey, also on board of R/V Miguel Oliver, seem to return to the values previous to 2013. Introductio

Bluefin tuna (Thunnus thynnus) tagging survey in the Bay of Biscay in summer 2005

A brief summary of the conventional tagging survey carried out during the summer fishing season in 2005 in the Bay of Biscay is presented. A total of 1696 juveniles of bluefin tuna have been tagged, corresponding to group ages 1 and 2. Two different conventional tags have been used. Fifty-one recaptures have been recovered up to date.Le présent document fournit un résumé de la campagne de marquage conventionnel de thon rouge menée au cours de l’été 2005 dans le Golfe de Gascogne. Au total, 1.696 juvéniles de thon rouge ont été marqués, correspondant aux groupes d’âge 1 et 2. Deux types distincts de marques conventionnelles ont été utilisés. Cinquante-et-une marques ont été récupérées à ce jour.Se presenta un resumen de la campaña de marcado convencional de atún rojo llevada a cabo durante el verano del 2005 en el Golfo de Vizcaya. En total se han marcado 1696 ejemplares de 1 y 2 años de edad. Se han utilizado dos modelos distintos de marcas convencionales. Hasta la fecha se han recapturado cincuenta y un ejemplares