El atún blanco (Thunnus alalunga) del Mediterráneo occidental

The situation of the Spanish fishery of albacore (Thunnus alalunga) in the western Mediterranean during the last years is presented. Catch data, fishing effort, CPUEs and size distributions are presented by gear and spatial-time strata. The mean annual catch of albacore in the last ten years reaches 310 MT, which makes a temporary alternative fishing method to the longline fisheries of swordfish. The finding of spawning areas around the Balearic Islands and the information from CPUE analyses by strata, in the future, could contribute, from a qualitative point of view, to important biological information of the species in the western Mediterranean.Le présent document fait état de la situation de la pêcherie espagnole de germon (Thunnus alalunga) dans l’ouest de la Méditerranée au cours de ces dernières années. Les données de capture, l’effort de pêche, les CPUE et les distributions de tailles sont présentés par engin et par strate spatio-temporelle. La capture annuelle moyenne du germon ces dix dernières années a atteint 310 t, ce qui offre aux pêcheries palangrières d’espadon une alternative temporaire. L’existence de zones de frai autour des îles Baléares et l’information que fourniront les futures analyses de CPUE par strate spatio-temporelle et par engin de pêche pourraient apporter, d’un point de vue qualitatif, d’importantes informations biologiques sur l’espèce dans l’ouest de la Méditerranée.Se expone la situación de la pesquería española del atún blanco (Thunnus alalunga) durante los últimos años en el Mediterráneo Occidental. Se presentan datos de captura, esfuerzo, CPUEs y distribuciones de tallas por arte y estrato espacio-temporal. La captura media anual de atún blanco para los últimos diez años alcanza las 310 Tm., lo que supone una alternativa temporal a la pesca de pez espada con palangre de superficie. La existencia de áreas de reproducción en torno al archipiélago Balear, unido a la información aportada por futuros análisis de CPUE por estrato espacio-temporal y arte de pesca, podrían aportar, desde el punto de vista cualitativo, importante información biológica sobre la especie en el Mediterráneo Occidental

Análisis preliminar del efecto de las oscilaciones climáticas sobre la condición física de la melva (Auxis rochei) post-reproductora en el Mar de Alborán

The Mediterranean Sea is considered by several authors as a hot-spot of Climate Oscillation, such as the North Atlantic Oscillation (NAO) and the Arctic Oscillation (AO). However, information about the effect of the climate oscillations on the fitness of the species is still scarce. In this context, bullet tuna is an important migratory species with a substantial socio-economical value, whose fisheries might be affected by the effect of certain climatological conditions. In fact, these atmospheric oscillations trigger a chain of hydrodynamic events, leading a change on the timing, destinations, and success of the migratory species in their search for spawning grounds. This study relies on the hypothesis of a correlation between the physical condition of the post-spawning bullet tuna and climate oscillation indexes. For that purpose, 151 individuals of bullet tuna, Auxis rochei, were collected in the traps of Ceuta (Alboran Sea) during three different years, (1983, 1984 and 2014). The physical condition index was calculated, and later statistically correlated with the climate oscillation indexes proposed. Significant differences were found between the physical condition of A. rochei and the average accumulated NAO index. Moreover, for age class 3+ we obtained a significant correlation with atmospheric oscillations.Postprin

Nuevos datos científicos sobre desembarcos de especies asociadas realizados por la flota española de palangre de superficie en el Mediterráneo en 1999 y 2000

(New scientific data on by-catch landings of the Spanish longline fishery for swordfish in the Mediterranean during the years 1999 and 2000). This document presents data on by-catch commercial landings (except tunas and tuna-like species) of the Spanish Mediterranean longline fishery of swordfish during the years 1999 and 2000. Between 61.3 and 70% of the reported landings of by-catch are represented by large pelagic sharks. The blue shark (Prionace glauca) makes up 45% of the landings.Ce document présente les données concernant les débarquements de prises accessoires (thonidés et especes voisines exceptés) de la pêche palangrière espagnole d’espadon pendant les années 1999 et 2000. Les grans requins constituent 61,3 et 70% des débarquements déclarés de prises accessoires. Le requin peau-bleue (Prionace glauca) constitue 45% des débarquements.Se presentan datos de desembarcos comerciales de especies asociadas (excepto túnidos y afines) de la pesquería española de palangre de superficie de pez espada en el Mediterrá neo en los años 1999 y 2000. Entre el 61.3 y el 70% de los desembarcos de especies asociadas reportados están representados por grandes tiburones pelágicos, destacando las capturas de tintorera (Prionace glauca) que suponen el 45% de los desembarcos

Tracking bluefin tuna cohorts from east Atlantic Spanish fisheries since the 1980s

Relative abundance and mean size at age analyses were performed for the catches of three Atlantic Spanish fisheries, in search of an exceptionally abundant cohort in the recent history of the eastern Atlantic and Mediterranean bluefin tuna stock. Length distributions of baitboat fisheries, both in the Bay of Biscay and areas close to the Strait of Gibraltar as well as trap catches from the Spanish Atlantic coast were converted to age distributions using age length keys from calcified structures. Results do validate indirectly the ageing method. The 1994 cohort was clearly tracked for juveniles and young adults, 3 to 7 years old, in baitboat catches, and also for older specimens, 9 to 11 years old, in the trap fisheries. Based on these results, it is suggested that the juvenile and young adults fisheries in the western part of the Iberian Peninsula are interconnected between one another and with the Balearic Islands area of the western Mediterranean, as it is the nearest spawning ground described and because it is also supported by tagging and other studies.Afin de trouver une cohorte exceptionnellement abondante dans la récente histoire du stock de ton rouge de l’Atlantique Est et de la Méditerranée, on a procédé à une analyse de l’abondance relative et de la taille moyenne par âge des captures réalisées par trois pêcheries espagnoles de l’Atlantique. Les distributions par tailles de deux pêcheries de canneurs dans le Golfe de Gascogne et dans les eaux proches du Détroit de Gibraltar, ainsi que les prises des madragues de la côte atlantique espagnole, ont été converties en âges à l’aide des clefs taille-âge obtenues à partir de la lecture de structures calcifiées. Les résultats valident indirectement la méthode de détermination de l’âge. La cohorte de 1994 affiche une forte indication présente chez les juvéniles et les jeunes adultes, de 3 à 7 ans, capturés dans les pêcheries de canneurs ainsi que chez les spécimens d’âge plus avancé, de 9 à 11 ans, pêchés à la madrague. Ces résultats suggèrent que les pêcheries de juvéniles et de jeunes adultes de la partie occidentale de la péninsule ibérique sont interconnectées entre elles ainsi qu’avec la zone des îles Baléares, en Méditerranée occidentale, étant donné qu’il s’agit de la zone de frai la plus proche et qu’il existe des indices de cette relation d’après les études de marquage et d’autres études.Para encontrar una cohorte excepcionalmente abundante en la historia reciente del stock de atún rojo del Atlántico este y Mediterráneo, se realizó un análisis de la abundancia relativa y la talla media por edad de las capturas de tres pesquerías atlánticas españolas. Las distribuciones de tallas de dos pesquerías de cebo vivo, en el Golfo de Vizcaya y en aguas próximas al Estrecho de Gibraltar, así como las capturas de las almadrabas de la costa atlántica española, fueron convertidas a edades mediante el uso de claves talla edad, obtenidas a partir de la lectura de piezas esqueléticas. Los resultados validan indirectamente el método de determinación de la edad. La cohorte de 1994 presenta una fuerte señal que pudo ser encontrada en los juveniles y adultos jóvenes, 3 a 7 años, capturados en las pesquerías de cebo vivo y también en especimenes mayores, 9 a 11 años, pescados con las almadrabas. Con esto resultados se sugiere que las pesquerías de juveniles y adultos jóvenes de la parte occidental de la península Ibérica están interconectadas entre ellas y con el área de las Islas Baleares, en el Mediterráneo occidental, puesto que es la zona de puesta más próxima y porque también hay evidencias de esta relación mediante el marcado y otros estudios

Segregación espacial por sexo de la tintorera en el Atlántico Este y

The main aim of present study was to analyze the spatial and temporal trends segregation by sex of blue shark (Prionace glauca) in the Eastern Atlantic and Western Mediterranean Sea from the individual bycatches by Spanish surface longline fleet. Our results indicate significant differences in the use of space between males and females. Thus, in low latitudes, within the observed range, sharks are mixed, but from North 38 degree of latitude tend to segregate. In the case of length, a similar pattern is observed, in low longitude sexes appear overlapped, and while to high longitude tend to appear segregated. All these results suggested segregation by sex in the Mediterranean where sharks are grouped in single-sex schools.Postprin

Correction: Atlantic Bluefin Tuna (Thunnus thynnus) Biometrics and Condition

Correction: Atlantic Bluefin Tuna (Thunnus thynnus) Biometrics and ConditionPostprint4,411

Atlantic Bluefin Tuna (Thunnus thynnus) Biometrics and Condition

The compiled data for this study represents the first Atlantic and Mediterranean-wide effort to pool all available biometric data for Atlantic bluefin tuna (Thunnus thynnus) with the collaboration of many countries and scientific groups. Biometric relationships were based on an extensive sampling (over 140,000 fish sampled), covering most of the fishing areas for this species in the North Atlantic Ocean and Mediterranean Sea. Sensitivity analyses were carried out to evaluate the representativeness of sampling and explore the most adequate procedure to fit the weight-length relationship (WLR). The selected model for the WLRs by stock included standardized data series (common measurement types) weighted by the inverse variability. There was little difference between annual stock-specific round weight-straight fork length relationships, with an overall difference of 6% in weight. The predicted weight by month was estimated as an additional component in the exponent of the weight-length function. The analyses of monthly variations of fish condition by stock, maturity state and geographic area reflect annual cycles of spawning and feeding behavior. We update and improve upon the biometric relationships for bluefin currently used by the International Commission for the Conservation of Atlantic Tunas, by incorporating substantially larger datasets than ever previously compiled, providing complete documentation of sources and employing robust statistical fitting.WLRs and other conversion factors estimated in this study differ from the ones used in previous bluefin stock assessments.Postprint4,411

On the Variability of the Length Weight Relationship for Atlantic Bluefin Tuna, Thunnus thynnus (L.)

Following extensive review, a model of the Atlantic bluefin tuna (ABFT), Thunnus thynnus (L.), length–weight relationship for the eastern Atlantic and Mediterranean (RW = 0.0000188 SFL3.01247; Ec 1) is presented on the basis of samples of ABFT spawners, with an average value of index K = 2.03 ± 0.15SD, collected by the Atlantic traps of Portugal and Spain in the Strait of Gibraltar (1963; 1996–1998; 2000–2012), and a set of samples of juvenile fishes from ICCAT–GBYP (n = 707). The resulting model (Ec 1), together with the model used for the eastern stock assessment (RW = 0.000019607 SFL3.0092; Ec 2) and a recently adopted by ICCAT Standing Committee on Research and Statistics (SCRS) (RW = 0.0000315551 SFL2.898454; EAST) are analyzed in using a bi-variant sample [SFL (cm), RW (kg)] of 474 pairs of data with the aim of validating them and establishing which model(s) best fit the reality represented by the sample and, therefore, will have the greatest descriptive and predictive power. The result of the analysis indicates that the model EAST clearly underestimates the weight of spawning ABFT and that model Ec 2 overestimates it slightly, being model Ec 1 that best explains the data of the sample. The result of the classical statistical analysis is confirmed by means of the quantile regression technique, selecting the quantiles 5, 25, 50, 75, and 95%. Other fisheries and biological indicators also conclude that the model EAST gradually underestimates the weight of ABFT spawners (of 2–3 m) by 9–12.5 %, and does not meet the criterion that for RW = 725 kg (Wmax), SFL = 319.93 ± 11.3 cm (Lmax).Cort, JL.; Estruch Fuster, VD.; Neves Dos Santos, M.; Di Natale, A.; Abid, N.; De La Serna, JM. (2015). On the Variability of the Length Weight Relationship for Atlantic Bluefin Tuna, Thunnus thynnus (L.). Reviews in Fisheries Science & Aquaculture. 23(1):23-38. doi:10.1080/23308249.2015.1008625S2338231Aguado-Giménez, F., & García-García, B. (2005). Changes in some morphometric relationships in Atlantic bluefin tuna (Thunnus thynnus thynnus Linnaeus, 1758) as a result of fattening process. Aquaculture, 249(1-4), 303-309. doi:10.1016/j.aquaculture.2005.04.064Block, B. A., Teo, S. L. H., Walli, A., Boustany, A., Stokesbury, M. J. W., Farwell, C. J., … Williams, T. D. (2005). Electronic tagging and population structure of Atlantic bluefin tuna. Nature, 434(7037), 1121-1127. doi:10.1038/nature03463Chapman, E. W., Jørgensen, C., & Lutcavage, M. E. (2011). Atlantic bluefin tuna (Thunnus thynnus): a state-dependent energy allocation model for growth, maturation, and reproductive investment. Canadian Journal of Fisheries and Aquatic Sciences, 68(11), 1934-1951. doi:10.1139/f2011-109Cort, J. L., Arregui, I., Estruch, V. D., & Deguara, S. (2014). Validation of the Growth Equation Applicable to the Eastern Atlantic Bluefin Tuna,Thunnus thynnus(L.), UsingLmax, Tag-Recapture, and First Dorsal Spine Analysis. Reviews in Fisheries Science & Aquaculture, 22(3), 239-255. doi:10.1080/23308249.2014.931173Cort, J. L., Deguara, S., Galaz, T., Mèlich, B., Artetxe, I., Arregi, I., … Idrissi, M. (2013). Determination ofLmaxfor Atlantic Bluefin Tuna,Thunnus thynnus(L.), from Meta-Analysis of Published and Available Biometric Data. Reviews in Fisheries Science, 21(2), 181-212. doi:10.1080/10641262.2013.793284Fraser, K.Possessed. World Record Holder for Bluefin Tuna. Kingstown, Nova Scotia: T & S Office Essentials and printing, 243 pp. (2008).Fromentin, J.-M., & Powers, J. E. (2005). Atlantic bluefin tuna: population dynamics, ecology, fisheries and management. Fish and Fisheries, 6(4), 281-306. doi:10.1111/j.1467-2979.2005.00197.xHattour, A.Contribution a l’étude des Scombridés de Tunisie. Université de Tunis. Faculté des Sciences, 168 pp. (1979).Karakulak, S., Oray, I., Corriero, A., Deflorio, M., Santamaria, N., Desantis, S., & De Metrio, G. (2004). Evidence of a spawning area for the bluefin tuna (Thunnus thynnus L.) in the eastern Mediterranean. Journal of Applied Ichthyology, 20(4), 318-320. doi:10.1111/j.1439-0426.2004.00561.xKoenker, R., & Bassett, G. (1978). Regression Quantiles. Econometrica, 46(1), 33. doi:10.2307/1913643Koenker, R. (2005). Quantile Regression. doi:10.1017/cbo9780511754098Milatou, N., & Megalofonou, P. (2014). Age structure and growth of bluefin tuna (Thunnus thynnus, L.) in the capture-based aquaculture in the Mediterranean Sea. Aquaculture, 424-425, 35-44. doi:10.1016/j.aquaculture.2013.12.037Perçin, F., & Akyol, O. (2009). Lengthâ weight and lengthâ length relationships of the bluefin tuna,Thunnus thynnusL., in the Turkish part of the eastern Mediterranean Sea. Journal of Applied Ichthyology, 25(6), 782-784. doi:10.1111/j.1439-0426.2009.01288.xPercin, F., & Akyol, O. (2010). Some Morphometric Relationships in Fattened Bluefin Tuna, Thunnus thynnus L., from the Turkish Aegean Sea. Journal of Animal and Veterinary Advances, 9(11), 1684-1688. doi:10.3923/javaa.2010.1684.1688Rooker, J. R., Alvarado Bremer, J. R., Block, B. A., Dewar, H., de Metrio, G., Corriero, A., … Secor, D. H. (2007). Life History and Stock Structure of Atlantic Bluefin Tuna (Thunnus thynnus). Reviews in Fisheries Science, 15(4), 265-310. doi:10.1080/10641260701484135Sinovcic, G., Franicevic, M., Zorica, B., & Cikes-Kec, V. (2004). Length-weight and length-length relationships for 10 pelagic fish species from the Adriatic Sea (Croatia). Journal of Applied Ichthyology, 20(2), 156-158. doi:10.1046/j.1439-0426.2003.00519.xTičina, V., Grubišić, L., Šegvić Bubić, T., & Katavić, I. (2011). Biometric characteristics of small Atlantic bluefin tuna (Thunnus thynnus, Linnaeus, 1758) of Mediterranean Sea origin. Journal of Applied Ichthyology, 27(4), 971-976. doi:10.1111/j.1439-0426.2011.01752.

Growth of the Atlantic bonito (Sarda sarda Bloch, 1793) in the Atlantic and Mediterranean area of the Strait of Gibraltar

The reading of skeletal parts has been widely used as a method for assessing growth in fishes. The objective of this work has been the determination of age and growth of the Atlantic bonito (Sarda sarda) in the Mediterranean and Atlantic areas of the Strait of Gibraltar. The identity of the population of bonito in the two areas has been demonstrated by tagging experiments, showing migrations through the Strait. In this study three different skeletal parts have been used: the otoliths, the precaudal vertebrae and cross sections of the first spine of the first dorsal fin, from 272 individuals. Specimens ranged in size from 24.0 to 71.5 cm (fork length) were caught between 1980 and 1983. As a result of this work, we made a size-age key from which we estimate the following mean sizes for each age class: Age 0: 37.03 cm; Age I: 51.71 cm; Age Il: 57.04 cm; Age III: 63.15 cm; Age IV: 71.0 cm. On the basis of the Ford-Walford method, L∞= 80.87, t0= -1.7, and K= 0.352. In consequence we can express the Von Bertalanffy equation in this way: Lt = 80.87 [1 - e- 0.352(t+1.7)]El objetivo de este trabajo es la estimación de la edad y del crecimiento del bonito (Sarda sarda) en las áreas atlántica y mediterránea adyacentes al estrecho de Gibraltar, cuya identidad poblacional ha sido evidenciada por experimentos de marcado, que han confirmado migraciones a través de dicho estrecho. En este estudio se han utilizado tres tipos de piezas duras: otolitos, vértebras precaudales y secciones transversales del primer radio espinoso de la primera aleta dorsal, en un total de 272 individuos. Las muestras se recogieron entre 1980 y 1983. Las tallas muestreadas (longitud a la horquilla) estuvieron comprendidas entre 24,0 y 71,5 cm. Como resultado se presenta una clave talla/edad a partir de la que se deducen las tallas medias para cada edad . Edad 0: 37,03 cm; Edad I : 51,71 cm; Edad Il: 57,04 cm; Edad III: 63,15 cm; Edad IV: 71,0 cm. Mediante el método de Ford-Walford se estimaron los valores de L∞ = 80,87, t0 = - 1,7 y K= 0,352. La ecuación de Von Bertalanffy queda expresada como sigue: Lt = 80.87 [1 - e- 0.352(t+1.7)]Versión del editor0,000

Informe sobre la pesca de tunidos y especies afines en el Mediterraneo y region suratlantica espaNola Coleccion de datos del aNo 1984

Centro de Informacion y Documentacion Cientifica (CINDOC). C/Joaquin Costa, 22. 28002 Madrid. SPAIN / CINDOC - Centro de Informaciòn y Documentaciòn CientìficaSIGLEESSpai