ÁREA DE PUESTA DEL LISTADO Katsuwonus pelamis, ATÚN TROPICAL, EN EL MEDITERRÁNEO OCCIDENTAL

El listado Katsuwonus pelamis es una especie de gran importancia comercial, cuyas capturas representan el 58.1% de las capturas globales de todas las especies de túnidos (FAO, 2019). Aunque el listado es una especie tropical, que principalmente se reproduce en aguas a temperaturas que exceden los 24ºC, las capturas en el mar Mediterráneo son frecuentes, especialmente en las últimas décadas. El Mediterráneo occidental, concretamente el mar Balear, es una zona de puesta para diversas especies de túnidos. El listado es capturado en esta área por la pesquería comercial y deportiva. En este trabajo los individuos muestreados fueron capturados por la pesca deportiva en campeonatos de pesca de altura celebrados en junio y julio en el mar Balear y en agosto y septiembre en el mar de Alborán durante el periodo 2014-2019. El sex ratio (n= 340) de listados (46.5 - 81 cm FL) fue de 1:0.9 (H:M). Se pesaron las gónadas de 329 individuos y su madurez macroscópica asignada, 201 gónadas fueron examinadas histológicamente. El análisis del índice gonadosomático y el examen de las gónadas evidencian que el listado se encuentra reproductivamente activo en el mar Balear (Mediterráneo occidental) coincidiendo en área y época de puesta con el atún blanco Thunnus alalunga. Estos resultados indican que el listado ha ampliado tanto su rango de distribución como sus áreas de puesta. Además, su monitorización es de interés por la su posible impacto sobre otras especies con las que comparte tanto área de distribución como área de puesta en el Mediterráneo occidental

New morphological and molecular evidence confirm the presence of the Norwegian skate Dipturus nidarosiensis (Storm, 1881) in the Mediterranean Sea and extend its distribution to the western basin

The present study confirms the presence of the Norwegian skate Dipturus nidarosiensis (Storm, 1881) in the Mediterranean Sea, by means of morphological traits and molecular markers providing the first record of this species in the Alboran Sea. Cannas et al. (2010) reported D. nidarosiensis for the first time in the Mediterranean from specimens captured in the central western basin, but Ebert & Stehmann (2013) and Stehmann et al. (2015) considered these records "likely refer to the smaller morphotype, Dipturus sp.", a species not yet described. Eight specimens of the Dipturus genus (Rajiformes: Rajidae) were caught off the Alboran Island (western Mediterranean) in 2012, 2013 and 2016, between 620 and 819 m depth. These specimens showed morphometric diagnostic features corresponding to those of Norwegian skates from the Northeast Atlantic and the central western Mediterranean Sea. Moreover, the Alboran individuals were genetically compared to Northeast Atlantic specimens available in GenBank by means of two mitochondrial DNA fragments: cytochrome c oxidase subunit I (COI) and cytochrome b (Cytb). Analyses showed that the Northeast Atlantic Norwegian skate specimens and the Alboran Sea ones were genetically similar and shared haplotypes, corroborating the identification of the Alboran individuals as Dipturus nidarosiensis. However, they were different from other Dipturus species distributed throughout the Northeast Atlantic and the Mediterranean Sea. Our results confirm the occurrence of this deep-sea large skate species in the Mediterranean, although the IUCN Red List of Threatened Species does not consider it possible (Stehmann et al., 2015)Versión del edito

ALBACORE (Thunnus alalunga) REPRODUCTIVE BIOLOGY STUDY FOR THE NORTH ATLANTIC STOCK:YEARS 2020 AND 2021

The ICCAT North Atlantic Albacore (Thunnus alalunga) Research Program was established to enhance knowledge on albacore to provide more accurate scientific advice to the Commission. Funds are provided to the Albacore WG to develop research activities to accomplish several objectives. One of the research objectives is to increase knowledge on reproductive biology for the northern Atlantic stock, maturity schedules (L50) and egg production (size/age related fecundity. In March 2021, Terms of Reference were published by ICCAT. A Consortium integrated by Canada, Venezuela, Chinese-Taipei and Spain presented an offer to collect gonad samples and spines throughout the year and carry out the study of reproductive biology for North Atlantic albacore stock. Results of histological analysis: maturity stages, batch fecundity and seasonal area of spawners are presented as well as the age determined of partially collection of albacore spines. Analysis were done with the total albacore gonads samples collected in 2020 and 2021 for the reproductive biology study of northern albacore.

STANDARDIZED CATCH RATES FOR MEDITERRANEAN SWORDFISH (XIPHIAS GLADIUS LINNAEUS, 1758) FROM THE SPANISH LONGLINE FISHERY. 1988-2018

Standardized relative abundance indices for swordfish (Xiphias gladius Linnaeus, 1758) caught by the Spanish surface longline in the western Mediterranean Sea were estimated for the period 1988-2018. Standardized CPUEs in number were estimated through a General Linear Mixed Modeling (GLMM) approach under a negative binomial (NB) error distribution assumption. Standardized CPUEs in biomass were estimated through a General Linear Mixed Modeling (GLMM) approach under a log-normal error distribution assumption. The main factors in the standardization analysis were fishing area and time of the year (quarter). The standardized indices showed notable annual fluctuations without any definite trend for the period under studyEn prens

STANDARDIZED CATCH RATES OF ALBACORE (THUNNUS ALALUNGA BONNATERRE, 1788) IN THE SPANISH RECREATIONAL FISHERY IN THE WESTERN MEDITERRARREAN IN THE PERIOD 2005-2019

Catch and effort data from the Spanish recreational fishery in the Balearic Sea (Western Mediterranean) were analysed to estimate an index of relative abundance for albacore for the years 2005-2019. Standardized catch per unit effort (CPUE) in number were estimated through a General Linear Mixed Modeling (GLMM) approach under a negative binomial (NB) error distribution assumption. Nominal catch rates and a standardized abundance index are presented along with estimates of 95% confidence limits of the predicted means. These indices show an upward trend from the start of the series 2005 peaking in 2013; followed by a decrease until 2015. For the latest four-year period (2016-2019), the index shows a relatively stable trend fluctuating around a level two times lower than the maximum abundance recorded in the time series.En prens

Informe de resultados de la campaña `Maurit-0911'. Estudio de los ecosistemas de la plataforma y margen contiental de Mauritania

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Demersal fish (hake, other finfish and elasmobranchs) stocks exploited by the European fleet under Fisheries Partnership Agreements signed with Morocco, Mauritania and Guinea Bissau

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