Tagging and recapture activities carried out by the Spanish Confederation of Responsible Recreational fishing (ceprr) with the Scientific Coordination of the Spanish Institute of Oceanography (IEO) in the Mediterranean (2008-2011)

During the 2008-2011 period, 1548 specimens of tuna and tuna-like species were tagged by the Spanish Confederation of Responsible Recreational Fishing (CEPRR) with the scientific coordination of the Spanish Institute of Oceanography (IEO). Of these, 1031 bluefin tuna were tagged with conventional tags, whereas 10 other specimens of the same species were tagged with pop-up satellite electronic tags in the Mediterranean. Five pop-up electronic tags remained on the adult specimens up to 110 days. In this period, the specimens stayed in the tagging area except for one of them, which reached Algerian waters in the winter. Similarly, 333 long-finned tuna and up to 184 specimens belonging to other species such as swordfish, little tunny, bonito, frigate tuna and spearfish, were also tagged. Eight bluefin tuna were recaptured, including one adult tuna which was found in the same area where it was tagged (Balearic Islands) 1343 days after release. A juvenile tuna tagged in the Mediterranean was recaptured more than two years after release in the Cantabrian Sea. Over the 2008-2011 period, the IEO provided a number of training courses on conventional and electronic tagging techniques at the different ports where tournaments and/or tagging and release campaigns were carried out. This promoted participation of the CEPRR in the tagging design of the GBYP-ICCAT Atlantic-wide Research Programme on Bluefin Tuna, as well as strategic and scientific interest.Postprin

Contribución al estudio biológico de la tintorera (Prionace glauca) capturada accidentalmente en la pesquería de palangre de superficie de pez espada en el Mediterráneo occidental

Blue shark (Prionace glauca) bycatches in the Spanish surface longline fisheries in the Mediterranean targeting swordfish (Xiphias gladius) from 1999 to 2001 represented 2% of the total catch. Information from onboard observers during 861 fishing sets in 26 longliners indicated that the highest catches were made in area 4-35000 (Alboran Sea) which represents 75.6% of the total observed catch of blue shark. The observed CPUE are from 5.5 to 34.1 kg/1000 hooks. Mean size at capture (LJFL) was 141.6 cm (SD=35.88). The proportion of females from the total was 0.5.Les prises accessoires de requin peau-bleue (Prionace glauca) des pêcheries espagnoles à la palangre de surface qui ciblent l’espadon (Xiphias gladius) dans la Méditerranée entre 1999 et 2001 ont représenté 2% de la capture totale. L’information recueillie par les observateurs à bord de 26 palangriers visant l’espadon durant 861 opérations de pêche a indiqué que les plus fortes captures se produisent dans la zone 4-35000 (mer d’Alboran) qui représente 75,6% du total de la capture observée du requin peau-bleue. Les CPUE observées se situent entre 5,5 et 34,1 kg/1.000 hameçons. La taille moyenne de capture (LJFL) était de 141,6 cm (DS=35,88). Le pourcentage des femelles par rapport au total était de 0,5.Las capturas de tintorera (Prionace glauca) como especie accesoria en las pesquerías españolas de palangre de superficie dirigido al pez espada (Xiphias gladius) en el Mediterráneo entre 1999 y 2001 representó el 2% de la captura total. La información tomada por observadores a bordo durante de 861 caladas en 26 palangreros de pez espada indicó que las mayores capturas se producen en el área 4-35000 (Mar de Alborán) que representa el 75.6% del total de captura observada de la especie. Las CPUE observadas se encuentran entre 5.5 y 34.1 kg/1000 anzuelos. La talla media de captura (LJFL) fue de 1 41.6 cm (DE=35.88). El porcentaje de hembras respecto al total fue de 0.5

Relación entre los índices de abundancia estandarizados de las almadrabas y la Oscilación del Atlántico Norte (NAO).

The aim of this study is to describe the possible relations between the NAO (North Atlantic Oscillation) climate index and the standardised catches in the Spanish traps in the Straits of Gibraltar from 1981 to 2011. There is a significant negative relationship regarding the probability of obtaining catches in traps that are greater than the average for the period based on the NAO index.Versión del edito

Updated standardized joint CPUE index for bluefin tuna (Thunnus thynnus) caught by Moroccan and Spanish traps for the period 1981- 2012.

Relative abundance indices of bluefin tuna (Thunnus thynnus) caught by the Moroccan and Spanish traps in the area close to the Strait of Gibraltar were estimated for the period 1981- 2013. Standardized CPUEs were estimated through a General Linear Modeling (GLM) approach under a negative binomial error distribution assumption.Versión del edito

UPDATED STANDARDIZED CATCH RATES IN NUMBER FOR SWORDFISH (Xiphias gladius L.) CAUGHT BY THE SPANISH LONGLINE FLEET IN THE MEDITERRANEAN SEA, 1988- 2013

A General Linear Modeling (GLM)approach to analysis of variance was used to analyze swordfish logged catch rates in number of fish from 24 , 239 trips carried out by the Spanish surface longline fleet addressed to this species in the Western Mediterranean f or the period 1988 - 2013.Postprin

Updated standardized catch rates in number and weight for swordfish (Xiphias gladius L.) caught by the Spanish longline fleet in the Mediterranean Sea, 1988- 2013.

A General Linear Modeling (GLM) approach to analysis of variance was used to analyze swordfish logged catch rates in number of fish from 24,239 trips carried out by the Spanish surface longline fleet addressed to this species in the Western Mediterranean for the period 1988 -2013.Versión del edito

Campañas de marcado de atún rojo juvenil (Thunnus thynnus) juvenil coordinadas por el IEO, previstas en el Programa ICCAT-GBYP y realizadas en el Estrecho de Gibraltar durante Noviembre de 2011 y enero de 2012

This paper presents the results of conventional tagging surveys on juvenile bluefin tuna conducted in the Strait of Gibraltar during different periods of 2011 and 2012 with two vessels from the port of Algeciras that usually fish using pole and bait in that area. The campaigns were carried out within the framework of the Enhanced Research Program for Bluefin Tuna (Thunnus thynnus) (GBYP). In 36 days of activity, a total of 1389 bluefin tuna were tagged, weighing an average of approximately 15 kg, ranging between 7 and 40 kg. In 46% of the specimens, two different tags were placed, and the forecasts established in the Tagging Plan within the ICCAT-GBYP were achieved.GBYP-ICCATPostprin

Análisis de los resultados de las Campañas de marcado de Atún rojo (Thunnus thynnus) del “Tagging GBYP-ICCAT 3ª Fase realizadas en el Golfo de León y Estrecho de Gibraltar durante 2011-12

In the Gulf of Lion Campaign 109 bluefin were tagged with conventional tags measuring between 74 cm and 108 cm fork length (LH). Five of these specimens had an electronic mark mini-patt placed on them. The campaign of the Strait of Gibraltar took place from 5/10/12 to 21/11/12 with 117 days at sea with a total of 1,477 bluefin marked of which 1,432 copies were marked, mainly with a double mainstream brand mark, 20 individuals with an electronic type pop-up (mini-pat) and 25 more fish with internal electronic tags. The tagged fish measured between 70 cm and 130 cm fork length (LH). Likewise, the biological samples which were scheduled were obtained for more than 40 samples of bluefin tuna of all sizes.Postprin

UPDATED STANDARDIZED JOINT CPUE INDEX FOR BLUEFIN TUNA (THUNNUS THYNNUS) CAUGHT BY MOROCCAN AND SPANISH TRAPS FOR THE PERIOD 1981- 2011

Relative abundance indices of bluefin tuna (Thunnus thynnus) caught by the Moroccan and Spanish traps in the area close to the Strait of Gibraltar were estimated for the period 1981- 2011. Standardized CPUEs were estimated through a General Linear Modeling (GLM) approach under a negative binomial error distribution assumption.Postprin

Posible influencia sobre el comportamiento migratorio del atún rojo (Thunnus thynnus) de las distintas estrategias de marcado electrónico utilizadas en las almadrabas y en jaulas de engorde

The Spanish Institute of Oceanography has been carrying out diverse research projects since 1997 on stock structure and on migration patterns of bluefin tuna (Thunnus thynnus), using the method of electronic tagging of adults. The results are provided to the stock assessment process of this species that the ICCAT Scientific Committee conducts periodically. The tagging is carried out in traps and fattening cages, observing marked differences in the movements of tunas that were tagged in the water from those that were brought on board for tagging. In the latter case, differences were also observed in the behavior of tunas that were released outside the codend of the trap from those that were released together with the rest of the shoal that was in the trap. With regard to the tagging and release of tunas in the fattening cages, it was observed that the behavior after tagging is related to time the tunas spent in the farming installations. The conclusion was reached that this type of tagging affects the natural behavior of bluefin tuna in the first phase, after which they continue with their normal biological cycle and their return to the natural habitat.En prens