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[EN] The paper summarizes the legth data-mining carried out in recent years in order to obtain a broad overview of the average length over time of the blue shark (Prionace glauca) between years 1997-2021 for the North and South Atlantic stocks. The data-mining was carried out through an intense compilation of records from samples on board commercial trips, experimental and tagging surveys, personal notes from skippers that were voluntarily provided for this scientific contribution through a collaborative science action, as well as through sampling during landings. The length data series was analyzed using GLM models to obtain relative and standardized trend of the mean length over time. The results showed a stable trend of the mean length and a slightly upward in the most recent period for both stocks., [FR] Le présent document résume l'extraction des données de longueur réalisée ces dernières années afin d'obtenir une vue d'ensemble de la longueur moyenne dans le temps des stocks de requin peau bleue (Prionace glauca) de l'Atlantique Nord et de l'Atlantique Sud entre 1997 et 2021. L'extraction de données a été réalisée grâce à une compilation intensive des registres d'échantillons à bord des navires commerciaux, dans le cadre de campagne expérimentales et de marquage, des notes personnelles des capitaines qui ont été volontairement fournies à des fins scientifiques par le biais d'une action scientifique collaborative, ainsi que par le biais d'un échantillonnage pendant les débarquements. La série de données sur la longueur a été analysée à l'aide de modèles GLM afin d'obtenir une tendance relative et standardisée de la longueur moyenne au fil du temps. Les résultats ont montré une tendance stable de la longueur moyenne et une légère augmentation au cours de la période la plus récente pour les deux stocks., [ES] El documento resume la minería de datos de talla de la tintorera (Prionace glauca) realizada en los últimos años para obtener una visión amplia y global sobre la tendencia de la talla media entre los años 1997-2021 para los stocks norte y sur del Atlántico. La minería fue realizada mediante intensa recopilación de registros de muestreos a bordo de buques comerciales, en campañas experimentales y de marcado, en notas personales de patrones que fueron cedidas voluntariamente con fines científicos mediante una acción de ciencia ciudadana-colaborativa, así como mediante registros en desembarcos. Se analizó la serie de datos de talla usando modelos GLM para obtener la tendencia relativa-estandarizada de la talla media a lo largo de los años. Los datos mostraron una tendencia estable de la talla media y ligeramente ascendente en periodos más recientes, para ambos stocks.

[EN] This paper provides an update of standardized catch rates in weight of blue shark using a Generalized Linear Model (GLM) from a total of 7,139 trips carried out by the Spanish surface longline fleet targeting swordfish in the South Atlantic stock for the period 1997-2021. The criteria used to define explanatory variables were similar to those used in previous papers. The main factors considered in the analysis were year, quarter, area, targeting criteria of skippers, gear and the interaction quarter-area. The results indicate that the target criteria of the skippers was the most important factor which explained the CPUE variability followed by gear and in less extent the other factors analyzed. The GLM results explained 84% of CPUE variability in gutted weight. The results showed an increasing trend reaching a peak in 2017 then a slight decrease until 2020 followed by an increased trend in most recent years., [FR] Le présent document fournit une mise à jour des taux de capture standardisés en poids du requin peau bleue en utilisant un modèle linéaire généralisé (GLM) à partir d'un total de 7.139 sorties réalisées par la flottille espagnole de palangriers de surface ciblant l'espadon dans l'Atlantique Sud entre 1997 et 2021. Les critères utilisés pour définir les variables explicatives étaient similaires à ceux utilisés dans les documents antérieurs. Les principaux facteurs pris en compte dans l'analyse sont l'année, le trimestre, la zone, les critères de ciblage des capitaines, l'engin et l'interaction trimestre-zone. Les résultats indiquent que le critère de ciblage des capitaines est le facteur le plus important qui explique la variabilité de la CPUE, suivi par l'engin et, dans une moindre mesure, par les autres facteurs analysés. Les résultats du GLM expliquent 84% de la variabilité de la CPUE en poids éviscéré. Les résultats montraient une tendance à la hausse atteignant un pic en 2017, puis une légère baisse jusqu'en 2020, suivie d'une tendance à la hausse dans les années les plus récentes., [ES] Este artículo proporciona una actualización de las tasas de captura estandarizadas en peso de la tintorera mediante un Modelo Lineal Generalizado (MLG) para un total de 7.139 mareas realizadas por la flota de palangre de superficie española dirigida al pez espada en el stock del Atlántico sur durante el período 1997-2021. Los criterios utilizados para seleccionar las variables explicativas fueron similares a los utilizados en trabajos anteriores. Los principales factores considerados en el análisis fueron el año, el trimestre, la zona, los criterios de direccionamiento de los patrones, el arte y la interacción trimestre-zona. Los resultados indican que el criterio de direccionamiento de los patrones fue el factor más importante en explicar la variabilidad de la CPUE seguido del arte y en menor medida del resto de factores analizados. Los resultados de GLM explicaron el 84 % de la variabilidad de la CPUE en el peso eviscerado. El resultado mostró una tendencia creciente alcanzando un pico en 2017, un ligero descenso hasta 2020 seguido de un incremento en la tendencia en los últimos años.

[EN] This paper analyzes conventional blue shark tagging-recapture records available in the ICCAT database, providing estimates on the growth of this species. Sensitivity analyses were tested selecting different datasets, several transformation equations between TL and FL, a wide range of FL0 values and applying different fitting models. Growth results were compared with each other and with those described by other authors. Historical FLmax values were also reviewed and discussed. The results obtained using several non-linear fits were very similar to each other and generally produced growth models with higher k values and faster growth than those described by other authors using reading-interpretations on vertebrae, [FR] Ce document analyse les registres de marquage conventionnel-récupération de requins peau bleue disponibles dans la base de données de l'ICCAT, fournissant des estimations sur la croissance de cette espèce. Des analyses de sensibilité ont été testées en sélectionnant différents jeux de données, plusieurs équations de transformation entre TL et FL, une large gamme de valeurs de FL0 et en appliquant différents modèles d'ajustement. Les résultats de croissance ont été comparés entre eux et avec ceux décrits par d'autres auteurs. Les valeurs historiques de FLmax ont également été examinées et discutées. Les résultats obtenus en utilisant plusieurs ajustements non linéaires étaient très similaires les uns aux autres et produisaient généralement des modèles de croissance avec des valeurs de k plus élevées et une croissance plus rapide que ceux décrits par d'autres auteurs utilisant des interprétations de lecture sur les vertèbres., [ES] El presente documento analiza registros de marcado-recaptura convencional de tintorera disponibles en la base de datos de ICCAT y proporciona estimaciones del crecimiento de esta especie. Diferentes análisis de sensibilidad fueron ensayados seleccionando distintos sets de datos, varias ecuaciones de transformación entre TL y FL, un amplio rango de valores FL0 y aplicando diferentes modelos de ajuste. Los resultados del crecimiento fueron comparados entre ellos y con los descritos por otros autores. Valores históricos de FLmax fueron también revisados y discutidos. Los resultados obtenidos usando varios ajustes no lineales fueron similares entre ellos y en general produjeron modelos de crecimiento con valores de k más altos que los descritos por otros autores usando lecturas interpretativas sobre las vértebras.

[EN] Standardized catch rates of sailfish (Istiophorus albicans) were obtained from 14,473 trip observations of surface longline fishing targeting swordfish during the period 2001-2019. The nominal effort modelled represented 80.65% of the total effort developed by this fleet during that period. In roughly 28% of these trips at least one individual belonging to this species was found. Because of the low prevalence of this species in this fishery, the standardized CPUE was developed using a Generalized Linear Mixed Model assuming a delta-lognormal error distribution. The results indicate that the overall trend of the standardized CPUE was similar for the Atlantic Ocean and for the East and West stocks. The results showed an increasing trend for the Atlantic Ocean and for the East and West stock reaching a peak in 2015 or 2013, followed by a decreasing trend in the recent years analyzed, although the values remained higher than at the beginning of the series., [FR] Des taux de capture standardisés du voilier (Istiophorus albicans) ont été obtenus de 14.473 observations de sorties en mer de pêcheries palangrières de surface ciblant l’espadon au cours de la période 2001-2019. L’effort nominal modélisé représentait 80,65% de l’effort total exercé par cette flottille pendant cette période. Dans près de 28% de ces sorties en mer, au moins un spécimen appartenant à cette espèce a été rencontré. En raison de la faible prépondérance de cette espèce dans cette pêcherie, la CPUE standardisée a été développée à l’aide d’un modèle mixte linéaire généralisé en supposant une distribution d’erreur delta-lognormale. Les résultats indiquent que la tendance globale de la CPUE standardisée était similaire pour l’océan Atlantique et pour les stocks de l’Est et de l’Ouest. Les résultats indiquaient une tendance à la hausse pour l’océan Atlantique et pour les stocks de l’Est et de l’Ouest, atteignant un maximum en 2015 ou 2013, suivie d’une tendance à la baisse au cours des années récentes analysées même si les valeurs restaient supérieures à celles du début de la série, [ES] Tasas de capturas estandarizadas del pez vela (Istiophorus albicans) fueron obtenidas a partir de 14.473 mareas de palangreros de superficie dirigidos al pez espada, observadas entre los años 2001 y 2019. El esfuerzo nominal modelado representó el 80.65% del esfuerzo total desarrollado por esta flota durante ese periodo. En el 28% de las mareas hubo presencia en sus capturas de al menos un individuo de esta especie. Debido a la baja prevalencia de esta especie en esta pesquería, la estandarización de la CPUE fue realizada mediante un modelo del tipo Modelo Lineal Mixto Generalizado asumiendo una distribución de error “deltalognormal”. Los resultados sugieren una tendencia general de la CPUE estandarizada similar para las áreas del Atlántico total y para los stocks Este y Oeste. Los resultados muestran una tendencia creciente alcanzando picos sobre 2015 o 2013 seguida de una tendencia decreciente en los años recientes del análisis, aunque permaneciendo valores más altos que al inicio de la serie.

Log-normal Generalized Linear Models (GLM) were used to update the standardized catch rates (in weight and in number) of the Spanish surface longline fleet targeting swordfish during the period 1986-2019 in areas of the North Atlantic stock. Factors such as area, quarter, gear and bait as well as the fishing-targeting strategy - based on the ratio between the two most prevalent species and those most highly valued by skippers - were considered. The base case models explained 59% and 57% of CPUE variability in weight and in number of fish, respectively. The increases in relative abundance in number of fish and in weight between the lowest levels in record occurred during the mid nineties and the values reached in the last year considered in the present analyse were around +65%.

Standardized ages specific 1-5+ catch rates in number of fish were updated for a period of 38 years using log-normal General Linear Model (GLM) from 11,842 trips (145,294 fishing days, 262.8 x106 hooks) of the Spanish surface longline targeting swordfish in the North Atlantic stock. The models took into consideration factors such as gear-style and a target variable to allow for the two most important changes in fishing strategy in recent periods. The base case models explained between 41%-46% of CPUE variability. The standardized CPUE for age 1 suggests a very positive phase of recruitments between periods 1997-2012 and also 1997-2019 with an overall mean of around double the relative abundance compared to the 1982-1996 mean level. This positive phase had positive effects on other ages including ages 5+ and the subsequent demographic changes since mid-1990s onwards which could be the main cause for explaining different availabilities by size and age and different average weights and overall CPUEs between different regions-fleets.

Updated standardized catch rates in number and in weight were obtained using General Linear Modeling (GLM) procedures from trips carried out by the Spanish surface longline fleet targeting swordfish in the South Atlantic stock during the period 1989-2019. The criteria used to define factors were similar to those used in previous contributions. The results explained 65% and 71% of CPUE variability in number and weight, respectively, pointing to very stable standardized CPUE and mean weight trends over time. The statistical diagnoses were highly satisfactory.

Fork length-dressed weight relationships on shark species (Prionace glauca, Isurus oxyrinchus, Carcharhinus longimanus and Carcharhinus falciformis) were obtained from 8,331 observations recorded at sea on longliners. Significance of the sex factor was specifically assessed using GLM procedures. Linear and non-linear fits of size-weight data by species were tested. The results obtained were compared with those values provided by other authors using equivalent type of data. Deviation of the predicted versus observer weights were also assessed. Both types of fits tested have provided similar results, their confidence intervals plotted are mostly overlapped and the equations obtained were generally within those confidence intervals. Predicted mean dressed weights at size by species were in most cases quite similar or just mimetic to those obtained using equations previously reported.

Standardized yields of blue marlin were obtained from 1,914 recorded trips (65.1*106 hooks) by the surface longline fleet targeting swordfish in the fishing areas of the Indian Ocean during the period 2003-2017. The observations represent about 90% of the total fishing effort of this fleet during this combined period. Roughly 7% of the trips recorded during this period showed a positive catch of these species (at least one fish). However a part of the observation analyzed were obtained during scientific surveys done in warmer areas where occurrence of this species is more likely but in which the fishing activity was sporadic and it is not currently carried out. Because of the low occurrence and prevalence of this species in this fishery, the standardized yields were calculated using a Generalized Linear Mixed Model, assuming a delta-lognormal error distribution. An overall flat trend was predicted for the whole period considered, with some annual fluctuations. Some other considerations are also discussed.

Standardized yields of sailfish were obtained from 1,914 recorded trips (65.1*106 hooks) by the surface longline fleet targeting swordfish in the fishing areas of the Indian Ocean during the period 2003-2017. The observations represent about 90% of the total fishing effort of this fleet during this combined period. Roughly 50% of the trips recorded during this period showed a positive catch of these species (at least one fish). Because of the relatively low prevalence of this species in this fishery, the standardized yields were calculated using a Generalized Linear Mixed Model, assuming a delta-lognormal error distribution. An overall flat trend was predicted for the whole period considered, with some annual fluctuations. Some other considerations are also discussed.

Scarce bycatches of Cookiecutter Shark (Isistius brasiliensis) is the reason why this species is easier studied through the marks they leave on their prey rather than by direct observation of the shark itself. However, scientific studies that have used ichnology to remedy this lack of knowledge have been probably based on mistaken assumptions transmitted among previous authors without due verification. Despite identifying the problem almost twenty years ago, the authors of this paper were unable to obtain a sufficient number of Cookiecutter Shark specimens until now in order to confirm their hypothesis. This work provides a set of biometrics of Cookiecutter Shark specimens among which worth highlighting is the measure of the lower jaw width (LJW), which was absent in the relevant literature. This parameter is crucial for correcting the linear regression between total length and mouth width on which earlier biogeographical works were based. The new linear regression obtained using LJW was later applied to the bites observed on Swordfish caught in the Gulf of Guinea in 1996. The results show a probability of 0.50 for Cookiecutter Shark attack on Swordfish in the study area (29.4% of Swordfish bitten), and a positive correlation between predator and prey sizes. The lengths of Cookiecutter Shark inferred from bite size on sampled Swordfish revealed a certain geographical disaggregation in the area, with older individuals, probably females, concentrating in waters near the mouth of the Congo River.

The blue shark (Prionace glauca) is the most frequently captured shark in pelagic oceanic fisheries, especially pelagic longlines targeting swordfish and/or tunas. As part of cooperative scientific efforts for fisheries and biological data collection, information from fishery observers, scientific projects and surveys, and from recreational fisheries from several nations in the Atlantic and Indian Oceans was compiled. Data sets included information on location, size and sex, in a total of 478,220 blue shark records collected between 1966 and 2014. Sizes ranged from 36 to 394 cm fork length. Considerable variability was observed in the size distribution by region and season in both oceans. Larger blue sharks tend to occur in equatorial and tropical regions, and smaller specimens in higher latitudes in temperate waters. Differences in sex ratios were also detected spatially and seasonally. Nursery areas in the Atlantic seem to occur in the temperate south-east off South Africa and Namibia, in the south-west off southern Brazil and Uruguay, and in the north-east off the Iberian Peninsula and the Azores. Parturition may occur in the tropical north-east off West Africa. In the Indian Ocean, nursery areas also seem to occur in temperate waters, especially in the southwest Indian Ocean off South Africa, and in the south-east off south-western Australia. The distributional patterns presented in this study provide a better understanding of how blue sharks segregate by size and sex, spatially and temporally, and improve the scientific advice to help adopt more informed and efficient management and conservation measures for this cosmopolitan species.

Standardized catches per unit of effort (in number and weight) were obtained for the shortfin mako (Isurus oxyrinchus) using General Linear Modeling procedures based on trip data from the Spanish surface longline fleet targeting swordfish in the North and South Atlantic Ocean over the period 1990-2015. A base case and two GLM sensitivity analyses were carried out including a MIXED procedure. Area was identified to be the most relevant factor in explaining CPUE variability in all cases. The base case models explained between 40-46% of CPUE variability. The comparison of the standardized CPUEs obtained from the base case and the sensitivity models show a very similar and stable general trend over time regardless of the model used for the North Atlantic stock. The base case and sensitivity analysis using a mixed model also show very similar trends over time in the case of the South Atlantic stock. All scenarios tested suggest overall stable CPUE trends or a slightly increase trend, in the North and South Atlantic stocks respectively.

Standardized catch rates of the sailfish (Istiophorus albicans) were obtained from 10615 trip observations of surface longline fishing targeting swordfish during the period 2001-2014. In roughly 28% of these trips at least one individual belonging to this species was found. Because of the low prevalence of this species in this fishery, the standardized CPUE was developed using a Generalized Linear Mixed Model assuming a delta-lognormal error distribution. The results obtained indicate that the overall trend of the standardized CPUE was similar for the total Atlantic areas and for the East and West stocks. An overall increasing trend was identified for the total Atlantic areas and for the East and West stock for the whole 2001-2014 period with some fluctuations in the most recent years.

Standardized catch rates per unit of effort (CPUE) were obtained for the stock of the North Atlantic blue shark (Prionace glauca) using General Lineal Models (GLM) for a total of 5639 trips of the Spanish surface longline fleet targeting swordfish, during the 1997-2013 period. The main factors considered were year, area, quarter, gear and ratio between swordfish and blue shark catches. The significant model explained the 84% of CPUE variability in blue shark. A major part of this variability was explained by the proxy of the targeting criteria, shown as the ratio between the two most prevalent species caught during the trip; swordfish and blue shark. Gear was identified as the second most important factor. Other factors were also significant, but less important. The standardized CPUE trend obtained suggests a stable trend of the North Atlantic blue shark stock and differs substantially from the nominal CPUE trends observed during the period considered.

The blue shark is the most captured shark in pelagic longline fisheries targeting tunas and swordfish. As part of an ongoing cooperative program for fisheries and biological data collection , information collected by fishery observers and scientific Project from several fishing nations in the Atlantic (EU.Spain, EU.Portugal, Uruguay, Taiwán, USA, Japan, Brasil, Venezuela and South Africa) were analyzed. Datasets include information on geographic location, size and sex. A total of 414428 blue sharks records collected between 1992 and 2014 were compiled, with the sizes ranging from 36 to 394 cm FL (fork length). Considerable variability was observed in the size distribution by región and season, with larger sizes tending to ocsur in equatorial and tropical regions and smaller sizes in higher latitudes. The expected distribution of juvenile and adult specimens also showed considerable variability, and the sex ratios varied between regions and sizes classes. The distributional patterns presented in this study provide a better understanding of different aspects of this species in the Atlantic that can help to promote more informed managemente and conservation measures.

Previous genetic studies of Atlantic swordfish (Xiphias gladius L.) revealed significant differentiation among Mediterranean, North Atlantic and South Atlantic populations using both mitochondrial and nuclear DNA data. However, limitations in geographic sampling coverage, and the use of single loci, precluded an accurate placement of boundaries and of estimates of admixture. In this study, we present multilocus analyses of 26 single nucleotide polymorphisms (SNPs) within 10 nuclear genes to estimate population differentiation and admixture based on the characterization of 774 individuals representing North Atlantic, South Atlantic, and Mediterranean swordfish populations. Pairwise FST values, AMOVA, PCoA, and Bayesian individual assignments support the differentiation of swordfish inhabiting these three basins, but not the current placement of the boundaries that separate them. Specifically, the range of the South Atlantic population extends beyond 5°N management boundary to 20°N-25°N from 45°W. Likewise the Mediterranean population extends beyond the current management boundary at the Strait of Gibraltar to approximately 10°W. Further, admixture zones, characterized by asymmetric contributions of adjacent populations within samples, are confined to the Northeast Atlantic. While South Atlantic and Mediterranean migrants were identified within these Northeast Atlantic admixture zones no North Atlantic migrants were identified respectively in these two neighboring basins. Owing to both, the characterization of larger number of loci and a more ample spatial sampling coverage, it was possible to provide a finer resolution of the boundaries separating Atlantic swordfish populations than previous studies. Finally, the patterns of population structure and admixture are discussed in the light of the reproductive biology, the known patterns of dispersal, and oceanographic features that may act as barriers to gene flow to Atlantic swordfish.

Standardized catch per unit of effort (CPUE) were obtained for the blue shark stock (Prionace glauca) of the Indian Ocean using General Lineal Models (GLM) from a total of 1838 trips of the Spanish surface longline fleet fishing swordfish during the 2001-2013 period. A base-case and two sensibility runs were conducted. The main factors considered into the base-case were year, area, quarter, gear and ratio between swordfish and blue shark catches. The significant base-case model explained the 82% of the CPUE variability of the blue shark. A major part of this variability was explained by the proxy of the targeting criteria defined as the ratio between the two more prevalent species caught during the trip, the swordfish and the blue shark. Other factors were also significant but less important. The standardized CPUE trend obtained in the base-case suggests a stable trend over time of the Indian Ocean blue shark stock. The sensitivity analyses showed similar trend as the base-case but in one of this runs the general trend obtained was slightly more optimistic when the ratio factor is excluded from the model.

The bigeye thresher (Alopias supercilious) is occasionally caught as bycatch in pelagic longline fisheries targeting tunas and swordfish. Still, it is one of the least known and studied of all pelagic sharks, which hinders assessment of the status of its populations. As part of an ongoing cooperative program for fisheries and biological data collection, information collected by fishery observers and through scientific projects from several nations that undertake fishing activities in the Atlantic (Japan, Portugal, Spain,Taiwan, Uruguay and US) was compiled and analyzed. Datasets include information on location, size, sex and, in some cases, maturity stage. A total of 5590 bigeye thresher records collected between 1992 and 2013 were compiled, with sizes ranging from 70 to 305 cm fork length (FL). Considerable variability was observed in size, with tropical regions recording a smaller mean size compared to other regions. The distribution of juvenile and adult specimens also showed considerable variability, and the sex ratios varied between regions and size classes. Median sizes at maturity were estimated at 208.6 cm FL for females and 159.2 cm FL for males. Pregnant females were recorded in the tropical northeast and southwest Atlantic, with these regions possibly serving as nursery areas. The biological and distributional patterns presented in this study provide a better understanding of different aspects of this species in the Atlantic, which can help managers adopt more informed and efficient conservation measures.

This paper describes encounters of five species of marine turtles (C. caretta, D. coriacea, L. olivacea, L. kempii, C. mydas) observed during surface longline fishery in North Atlantic areas (10º-30º N / 15º-35º W) in the 1997-2012 period. A total of 544982 hooks were analyzed; 7.5% came from an experimental cruise which had purposely selected this zone to test the effect of different hook and bait types on bycatch rates of marine turtles. The remainder observations were obtained during routine commercial fishing operations. A total of 438 encounters with marine turtles were recorded over the course of these years, either because the animals bit the bait-hook or because they became entangled in the branchlines. Of these, 89% were released alive. The interaction and mortality rates for species, areas and years combined were 8.0E-04 and 9.0E-05 individuals per hook, respectively. These rates were, however, lower when only recordings from regular commercial fishing were considered. It should not be assumed that the resulting rates are representative of or can be extrapolated to other fishing zones.

The bigeye thresher shark, Alopias supercilious is sometimes caught as bycatch in pelagic longline fisheries targeting tunas and swordfish in the Atlantic Ocean. As part of an ongoing cooperative program for fisheries and biological data collection, fishery observer data from various fishing nations and projects were compiled and analyzed. Those data sets include information on geographic location of the observations, as well as size, sex and in some cases maturity stage. A total of 4371 bigeye threshers were recorded throughout the Atlantic Ocean between 1992 and 2013, with the sizes ranging from 70 to 305 cm FL (fork length). Considerable variability was observed in the catchat- size, with particular emphasis on the tropical region where the mean sizes tended to be smaller than in the other regions. The expected distribution of juvenile and adult specimens also showed considerable variability, and the sex-ratios varied between regions and size classes. Maturity ogives were fitted to data from 642 specimens, with the median sizes at maturity estimated at 208.6 cm FL (corresponding to 349.1 cm TL) for females and 159.2 cm FL (corresponding to 269.8 cm TL) for males. In addition, a segmented regression model (SRM) was used for males, and two breakpoints (Bk1: 122.5cm FL, Bk2: 173.3cm FL) estimated, identifying transitions between the three different maturity stages for male sharks (immature, maturing and mature). Only a few pregnant females were recorded, always with the presence of two embryos (one per uterus), and were distributed predominantly in the tropical northeast Atlantic closer the African continent, and in the southwest region, with those regions possibly serving as nursery areas for this species. These reproductive parameters, and especially the estimated median sizes at maturity and low fecundity, highlight the vulnerability of this species, reinforcing that the bigeye thresher tends to mature at a larger size than the other species of the Alopiidae fami

The occurrence of tiger shark (Galeocerdo cuvier) in the Atlantic Ocean was assessed using at-sea observer data from multiple pelagic longline fisheries (Japan, Portugal, Spain, United States and Uruguay). Geographic positions of 2,764 tiger sharks, recorded between 1993 and 2013 and covering a wide area of the Atlantic were compared with the currently accepted distribution ranges of the species. Most of our records fell outside the accepted distribution ranges in both the Southern and Northern hemispheres. These results strongly suggest that the distribution range of the tiger shark is considerably wider than previously described, particularly over the open ocean

Regions with intense maturation-reproduction processes versus other regions showing less frequent, sporadic and non-existent maturation events were characterized on the basis of the gonadal index of 18,279 female swordfish. Females larger than 145 cm lower jaw-fork length (LJFL) may present high or low gonadal index values depending on the region and season. The highest gonadal indices were observed mostly in areas having Sea Surface Temperature (SST) ranging between 24°-29°C. However, the reproductive activity of females appears to be mainly restricted to the warmer epipelagic layers of the western regions with a deeper thermocline. The size at first maturity of females (LJFL50) was estimated at 146.5 cm LJFL and the maturity function was pm= 1 / (1 + e(-0.1398 (LJFL-146.5))). Qualitative maturity indicators of females support the results obtained using gonadal indices. According to catch rate data by size, sex and region, the presence of males 125- 165 cm LJFL would account for the high prevalence of males in regions where the most intense reproductive processes were observed. The characteristic ‘spawning’ related sex-ratio at size patterns are explained by thi s positive anomaly in these regions favouring males in a ratio up to 9 or 11 times greater than the abundance of females within the same medium size range. The complex reproductive process of this species would point to the practice of courting rituals, which would explain the migratory pattern of this species and its stratification by area-size-sex.