Incidencia y significancia de las estructuras císticas en ovarios de gádidos

Fish regulate egg production by atresia. Sometimes, oocytes are encapsulated in cystic structures that might remain in the ovary for months, altering female reproductive potential in future spawning seasons. Ovaries of Atlantic cod (Gadus morhua, L.) from the Flemish Cap and European hake (Merluccius merluccius, L.) from the Galician Shelf (NW Spain) were analysed from 1999 to 2006. The prevalence and abundance of ovarian cysts were estimated. Cyst prevalence increased with female size and/or age for both species, and decreased with high condition factor in hake. Cyst intensity does not correlate with any analysed factor. The size/age structure of spawning stock biomass and female condition could affect the prevalence of cysts in the ovaries, though it does not seem to affect cyst intensity in the ovary. Further research is needed to determine cyst resorption time and the impact that it has on egg production and consequently on stock reproductive potential.Los peces regulan la producción de huevos a través de la atresia. En ocasiones, los ovocitos son encapsulados en estructuras quísticas que podrían permanecer en el ovario durante meses, alterando el potencial reproductivo de las hembras en estaciones de puesta posteriores. Se tomaron ovarios de bacalao (Gadus morhua, L.) de Flemish Cap y de merluza europea (Merluccius merluccius, L.) de la costa gallega (NO España) entre 1999 y 2006. Se estimó la prevalencia e intensidad de quistes en estos ovarios. En ambas especies la prevalencia de hembras con quistes aumentó con la talla y/o edad y disminuyó al aumentar el factor de condición en el caso de la merluza. La intensidad de quistes no se correlacionó con ninguna de las variables estudiadas. La estructura de talla/edades del stock reproductor y la condición de las hembras podría afectar la prevalencia de hembras con quistes. Son necesarios más estudios para determinar el tiempo de reabsorción de estos quistes y las consecuencias que esto puede tener en la producción de huevos y por tanto en el potencial reproductivo de los stocks

Análisis descriptivo de la supervivencia y el tiempo de demora en el proceso diagnóstico-terapéutico del cáncer de pulmón en mujeres y su relación con la mortalidad

Faltan palabras clavesEl cáncer de pulmón es la mayor causa de muerte relacionada con el cáncer en mujeres. Existen claras diferencias en la biología, historia natural y respuesta al tratamiento entre hombres y mujeres con esta enfermedad. Una literatura emergente está proporcionando una base biológica para apoyar estas diferencias. Teniendo en cuenta estos antecedentes, la presente Tesis Doctoral pretende profundizar en el conocimiento del cáncer de pulmón en las mujeres, con la hipótesis de que el tiempo de demora que se genera en los diferentes niveles de todo el proceso clínico-diagnóstico-terapéutico del cáncer de pulmón tiene una influencia definitiva sobre el pronóstico final y, por tanto, en la supervivencia. Para ello, se estudió la supervivencia de las mujeres con diagnóstico de cáncer de pulmón, se determinaron los tiempos medios de espera en los diferentes niveles de atención en nuestro hospital para esta patología y su evolución en el tiempo, y se analizó la relación entre la demora en el diagnóstico y el tratamiento y la mortalidad por cáncer de pulmón en mujeres. Se ha realizado un estudio retrospectivo, mediante cohortes históricas, recogiéndose 240 casos de cáncer de pulmón en mujeres en 15 años desde 1994, estableciéndose los tiempos de estudio como: Tiempo desde la fecha de inicio de los síntomas hasta la primera consulta con un médico (demora atribuible a la paciente); Tiempo desde esa primera consulta hasta la fecha de la prueba que estableciera la base diagnóstica (demora diagnóstica); Tiempo desde la fecha de la prueba base diagnóstica hasta el inicio del primer tratamiento, ya fuera cirugía, quimioterapia (QT) o radioterapia (RT), (demora terapéutica); y Supervivencia: tiempo desde la fecha de la prueba tomada como base diagnóstica hasta la fecha de éxitus/última consulta. Entre los principales resultados, la supervivencia media fue de 40,3 meses, pero no hemos encontrado un aumento de la misma a lo largo del tiempo. Con respecto a las variables de tiempo, no supusieron una influencia significativa en la supervivencia, sólo la demora diagnóstica mostró significación, aunque sólo en el estuio bivariante. Se determinaron los tiempos medios de espera en los diferentes niveles de atención, no encontrando diferencia significativa a lo largo del tiempo durante el período de estudio. Por tanto, concluimos que la supervivencia del cáncer de pulmón no ha aumentado sustancialmente durante la última década, los tiempos medios de espera en los diferentes niveles de atención no se han modificado de manera significativa a lo largo del tiempo durante el período de estudio, y éstos no influyen de manera significativa en la supervivencia de las mujeres con cáncer de pulmón

The Use of Daily Growth to Analyze Individual Spawning Dynamics in an Asynchronous Population: The Case of the European Hake from the Southern Stock

Daily growth patterns and their relationship with reproduction was analyzed in the European hake from the Galician Shelf, where it shows a very protracted spawning with three spawning peaks. The daily growth analysis was performed in otoliths of adult females on the transversal section of the sagittae otolith. Daily increments were measured from the border to the nucleus in females until they were discernible. Results show that daily growth of females decreases during the spawning period because they allocate less energy to somatic growth in favor of the production of gametes, with an increase in growth in July. Lastly, daily growth individual trends showed a “spawning pattern” in 28% of medium and large females, suggesting an individual spawning period of one to two months, with 4–5 valleys of narrow daily increments, likely associated to batch release: individual spawning frequency would be 4–5 days. This is the first time that individual spawning frequency in hake is estimated based on individual data. Finally, the spawning pattern is detected only once per year, indicating that a single female participates only in one spawning peak per year, supporting the hypothesis of the existence of two or more spawning components in the stock.Versión del edito

Atlantic Cod Growth History in Flemish Cap Between 1981 and 2016: The Impact of Fishing and Climate on Growth Performance

Flemish Cap cod collapsed in the early 90’s after facing multiple threats due to climate variability and anthropogenic pressures. A master 35-year cod growth chronology was reconstructed in the present study by using sclerochronology techniques. Three additional chronologies were developed to account for the age-dependent effect of maturity and fishing intensity on growth. All chronologies showed that cod growth has decreased over the years and it is currently at the minimum level in the historic of data series. Hierarchical mixed-effects models were applied to the master chronology to identify extrinsic drivers of growth. The master chronology was divided into 3 periods: Premoratorium (1988-1998), Moratorium (1999-2009), and Postmoratorium (2010-2019). Our results showed that drivers of cod growth in the Flemish Cap varied between periods (Premoratorium: bottom temperature and fishing mortality, Moratorium: cod and pandalus abundance, and Postmoratorium: cod abundance and thickness of the cold intermediate layer). Our results suggest that density-dependence processes, food availability, and global warming may be behind the lack of recovery of the Flemish Cap cod stock. The Flemish Cap cod growth chronology shows variations on growth over time and identifies its drivers, having the potential to be included in the NAFO stock assessments or to be used to set dynamic reference points that guarantees the stock sustainability. IntroductionVersión del edito

Larval fish community in the northwestern Iberian upwelling system during the summer period

The Galician shelf (northwestern Iberian Peninsula) is a highly dynamic area with an important multi-species fisheries industry that exploits resources from several habitats, characterized by being not only highly diverse, rich, and productive but also seasonally and interannually variable. Early life stages of different species are distributed throughout the year, with fluctuating abundances and community composition. Likewise, the influence of environmental factors and processes on larval production and survival remains unknown. Sampling was carried out in July 2012, and all the larvae obtained were identified to establish the specific composition of the community in a summer upwelling scenario. The results show no zonation in the species distribution, a consequence of the mixing effects of the upwelling and eddies, with high diversity but low abundance, which render in a slight predominance of a few species. Due to the dependence of planktonic populations on upwelling events, which was not highly pronounced in 2012, we cannot conclude that this was a typical conformation of the Galician summer larval fish community, but it is a first approach to comprehend the community composition.En prens

Growth, age estimation and corroboration of northeast Atlantic chub mackerel (Scomber colias) in northern Iberian waters: a first attempt.

Updated information on growth of Atlantic chub mackerel in several areas of its distribution is required for the first stock assessment. Its growth pattern in Northern Iberian waters (2011-2017) is here analyzed with different approaches: those based on otoliths analyses (direct age estimation-DAE, back-calculation-BC and otolith marginal analyses) and those based on length frequency analyses (Bhattacharya, SLCA and PROJMAT methods). Two main different growth patterns are obtained, a "slow" one based on DAE, BC and LFDA from surveys; and a "fast" one based on Bhattacharya and LFDA from commercial landings. The divergence between both patterns begins to be evident at age 3 and older. Otolith marginal analyses that show an annual periodicity in the formation of the hyaline and opaque edge, the unimodal distribution of the annuli radius and the similarity of the back-calculated mean lengths to those obtained by DAE, support the age estimation criteria used in our analysis. The VBGF growth parameters (L∞=45.34, k=0.28, t0=1.18) obtained by otolith age estimation are available for the upcoming stock assessment process

Advances in the study on sexual maturity of Atlantic chub mackerel (Scomber colias) in Cantabrian Sea.

Atlantic chub mackerel (Scomber colias) is a middle size pelagic species distributed on both sides of the Atlantic Ocean. Landings of this species have increased recently in the Iberian Peninsula, likely associated to the increase of its abundance and expansion northwards, probably related to an increment of the sea temperature. The aim of this study is to improve the knowledge of the reproductive biology of the Atlantic chub mackerel and to present updated information on spawning period and maturity ogives that can be used for analytical stock assessment in ICES and its management

Spatial and temporal variability in the occurrence and abundance of European hake larvae, Merluccius merluccius, on the Galician Shelf (NE Atlantic)

The European hake (Merluccius merluccius) is represented as one of the most valuable fisheries in the Galician shelf. We analyzed the distribution, abundance, and environmental conditions of the southern-stock European hake larvae from the Galician shelf during the two main spawning peaks, winter-spring and summer, based on the data from three ichthyoplankton surveys (March 2012, March 2017, and June 2017). A total of 395 larvae in March 2012, 121 in March 2017, and 69 in June 2017 were captured. The northeast section of the study area, close to Estaca de Bares, primarily between 100 and 200 m isobaths, had the highest presence of the European hake larvae in all surveys. Generalized additive models (GAMs) indicated that the occurrence of larvae was significantly different between the surveys and was associated negatively with the temperature, while the abundance of larvae was significantly different between sampling years and was the highest at a temperature around 13.36°C and at sea surface heights of about −0.48 m. Studies of the distribution of early life stages and their relation to external conditions are essential to the understanding of the complex process of recruitment, especially in the exploited species and in highly dynamic environments like the Galician shelf.En prens