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suMMARY: gonads of the ne Atlantic black scabbardfish were examined to give an insight into the reproductive biology of this species. it was concluded that black scabbardfish had determinate fecundity because: (i) a distinct hiatus in oocyte size was observed between pre-vitellogenic and vitellogenic oocytes; (ii) vitellogenic oocytes increased in size during the spawning season; (iii) the number of vitellogenic oocytes did not increase during the spawning season; and (iv) the intensity of atresia was low in pre-spawning and spawning ovaries. Fecundity estimates ranged from 73 to 373 oocytes g -1 female. Comparison of developing ovaries from mainland Portugal and Madeira revealed that those from Madeira were more advanced in development, with more cortical alveoli stage oocytes and a higher gonadosomatic index. starting in July, the reproductive development of all females from mainland Portugal was interrupted by a generalised atresia of developing oocytes. Completion of gametogenesis and spawning only occurred for fish from Madeira but some fish from this area also failed to complete oocyte development due to mass follicular atresia of vitellogenic oocytes. the percentage of Madeiran fish that failed to spawn due to follicular atresia ranged from 21.2% in 2006 to 37.4% in 2005.Keywords: black scabbardfish, skipped spawning, fecundity, atresia, Portugal.ResuMen: Estrategias reproductivas en el sable negro (AphAnopus cArbo Lowe, 1839) en el Atlántico nordeste. -Las gónadas del sable negro del Atlántico nordeste fueron examinadas para conocer la biología reproductiva de esta especie. Los resultados sobre el tipo de fecundidad mostraron que la especie tenía una fecundidad determinada en base a los siguientes hechos: (i) hiato entre ovocitos previtelogénicos y vitelogénicos; (ii) aumento de tamaño de los ovocitos vitelogénicos durante el período de puesta; (iii) ausencia de incremento en el número permanente de ovocitos vitelogénicos avanzados durante el período de puesta y (iv) una pequeña atresia en los ovarios antes de la ovulación y durante ella. Las estimaciones de fecundidad se establecieron entre 73 y 373 ovocitos g -1 hembra. La comparación de los ovarios de hembras en desarrollo de aguas frente a Portugal continental y las de Madeira mostró una diferencia significativa en el tamaño medio de los ovocitos entre las dos áreas, y que las hembras de Madeira presentaron una mayor cantidad de ovocitos con alvéolos corticales y un índice gonadosomático mayor. A partir de julio y en hembras recolectadas frente a Portugal de continente, todos los individuos comenzaron a sufrir una atresia generalizada en sus ovocitos, mientras que en las aguas de Madeira, el ciclo reproductivo continúa hasta ovulación. sin embargo, en algunas hembras de Madeira la gametogénesis también se paraliza y todos los ovocitos vitelogénicos son absorbidos vía atresia folicular. el porcentaje de hembras no reproductivas varió del 21.23% en 2006 al 37.4% en 2005.Palabras clave: sable negro, skip spawning, fecundidad, atresia, Portugal. 2009, 19...

Sequeira, V., Neves, A., Vieira, A. R., Figueiredo, I., and Gordo, L. S. 2009. Age and growth of bluemouth, Helicolenus dactylopterus, from the Portuguese continental slope. – ICES Journal of Marine Science, 66: 524–531. In all, 933 bluemouth (Helicolenus dactylopterus) were obtained from bottom-trawl research surveys along the Portuguese continental slope between October 2005 and February 2007 and from commercial landings. Age was determined by reading whole sagittal otoliths, and age estimates were validated by daily growth increment (DGI) analysis. Fish ranged from 5.2 to 44.9 cm, which corresponded to fish between 0 and 30 years old. The mean total length obtained from DGI analysis for age class 1 fish was 8.6 cm, corresponding to otoliths with a mean radius of 1.8 mm. As no statistical differences between sex were observed, the von Bertalanffy growth equation fitted was Lt = 45.50[1 − e−0.05(t+4.01)]. Comparisons with other studies using Hotelling's T2 test and the growth perform index (Ф) are drawn. The growth rates estimated in this study using whole otolith readings were the lowest of all the studies available, and the estimated L∞ is lower then those obtained for Azorean waters and higher than those published for the Mediterranean.

Abstract-The population structure of the blue jack mackerel (Trachurus picturatus, Osteichthyes, Carangidae), in the northeast Atlantic is still unknown. To identify any distinct population units, three areas were selected: waters off Madeira, Peniche (mainland Portugal), and the Canary Islands. Knowledge of population structure is an aspect of the population dynamics of a species that is essential to effectively assess the existence of stocks and manage fisheries. In this study, geometric morphometrics and otolith shape analysis were successfully applied for population identification. Multivariate analysis of variance (MANOVA) revealed no body shape differences between males and females in each area studied, and therefore the sexes were combined for the analysis. The results of the discriminant analysis showed that a low misclassification occurred among areas; 78.0% of individuals were correctly classified. MANOVA performed on the otolith normalized elliptic Fourier descriptors revealed significant areal differences, but no difference between sexes. An overall classification success of 73.3% in the canonical discriminant analysis was achieved. These results indicate the usefulness of both otolith and body shape analysis for differentiation of blue jack mackerel stocks from the northeast Atlantic and indicate the existence of at least three distinguishable populations of this species.

The reproductive patterns of Helicolenus dactylopterus are presented; the species is zygoparous. The first photographic record of three embryonic stages in the intraovarian gelatinous matrix is also presented.

Comber is an important bycatch species in the trawl fishery both in the Mediterranean and the Atlantic. Age and growth studies have been restricted to the eastern Mediterranean and no methodologies were ever applied to ensure accuracy and precision. In this study a total of 471 otoliths from specimens ranging from 12 to 26 cm were used. Precision indices showed a high level of agreement between readers and no evidence of systematic disagreement was obtained. To estimate fish growth and due to the absence of individuals smaller than 12 cm, three approaches were used to estimate the von Bertalanffy growth parameters: whole otolith readings, back calculation and a combination of both methodologies. Akaike's information criterion suggests that the back calculation approach was the best one for describing comber growth: ]. Natural mortality estimates varied between M = 0.44 year −1 and M = 0.48 year −1 while estimates of the fishing mortality varied between 0.12 year −1 and 0.16 year −1 and the exploitation rate between 0.20 and 0.27. ARTICLE HISTORY

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suMMARY: though whole otoliths are commonly adopted in age assignment of black scabbardfish, this study showed that sectioned otoliths are more appropriate because growth increments are more evident and ageing of larger specimens is easier. Vertebrae are not the most appropriate structure for ageing but, in the absence of otoliths, this structure may be useful in age assignment of this species. to verify possible differences between age and growth among specimens from the southern ne Atlantic, 1075 sectioned otoliths from specimens from mainland Portugal, 436 from Madeira and 107 from the Azores were analysed and the distribution of length-at-age obtained for each sex and region was determined. significant differences were obtained in the comparison of the distribution of length-at-age between Madeira, the mainland and the Azores. the von Bertalanffy growth model was applied to back-calculated mean length-at-age data from Madeira (L t = 1586 [1 -e -0.119(t+2.282) ] females; L t = 1461 [1 -e -0.146(t+1.441) ] males) and mainland (L t = 1354 [1 -e -0.170(t+2.040) ] females; L t = 1240 [1 -e -0.208(t+1.654) ] males), and significant differences in the growth equations were obtained. Furthermore, a regression tree model was used to investigate how growth is conditioned by reproduction. the results showed a clear separation between individuals from the two areas, both females and males from the mainland (non-reproductive individuals) being characterised by a lower gonadosomatic index and a lower age.Keywords: Aphanopus carbo, black scabbardfish, whole and sectioned otoliths, vertebrae, precision estimators, age and growth.ResuMen: Edad y crecimiento en el sable negro (AphAnopus cArbo Lowe, 1839) del sur de Atlántico nordeste. -A pesar de que los otolitos enteros son adoptados normalmente en lecturas de edad del sable negro, este estudio mostró que los otolitos seccionados son más apropiados porque los incrementos de crecimiento son más evidentes y facilita la asignación de edad en los peces de mayor talla. las vértebras no son las estructuras más apropiadas para asignar la edad del sable negro, pero en ausencia de otolitos, esta estructura puede resultar de utilidad en dicho proceso. Para verificar posibles diferencias entre la edad y el crecimiento de especimenes viviendo en el sur del Atlántico nordeste, 1075 otolitos seccionados de ejemplares de sable negro de Portugal continental, 436 de Madeira y 107 de Azores fueron analizados, y se obtuvieron las distribuciones de tallas por edad por sexo, en cada región. Fueron observadas diferencias significativas en la comparación de las distribuciones de talla por edad entre Madeira, continente y Azores. el modelo de crecimiento de von Bertalanffy fue aplicado a los datos retrocalculados de talla media por grupo de edad de Madeira (L t = 1586 [1 -e -0.119(t+2.282) ] hembras; L t = 1461 [1 -e -0.146(t+1.441) ] machos) y continente (L t = 1354 [1 -e -0.170(t+2.040) ] hembras; L t = 1240 [1 -e -0.208(t+1.654) ] machos), y fueran encontradas diferencias significativas en...