Four spot megrim (Lepidorhombus boscii) weight-length and weight-weight relationships in northern Iberian waters (stock 8.c, 9.a)

Total weight-length, gutted weight-length and total weight-gutted weight relationships were fitted for the Iberian Atlantic stock of four spot megrim (Lepidorhombus boscii) and their temporal variations were analyzed. The large sample size, size range and timeseries available allowed obtaining robust somatic parameters of combined sexes for the total weight-length relationships (a=0.0043, b=3.2008), for the gutted weight-length relationships (a=0.0055, b=3.1139), and the weight conversion factors (1.062). They are considered to best fit the current biometric relationships and most appropriate to be used in the stock assessment of the status of the stock and they contribute to a deeper knowledge of the life history traits of this species

Megrim (Lepidorhombus whiffiagonis) weight-length relationships in the northern Bay of Biscay and Celtic Sea

The weight-length relationships are of a great interest in fish biology, stock assessment and fishery management, by predicting weight from length information and allowing to estimate the stock biomass. Weight-length relationships of megrim (Lepidorhombus whiffiagonis), an economically relevant flatfish species, are studied for two decades (2001 to 2019) in northern Bay of Biscay and Celtic Sea (ICES stock Div. 7.b-k, 8.abd), two important European fishing areas. More than 22000 specimens collected from commercial landings by AZTI and IEO were sampled. Total fish length, total weight and commercial gutted weight were obtained. Four five-year periods (quinquennium) (2000-04; 2005-09; 2010-14; 2015-19) were defined in the studied time-series. Both the large sample size and time-series available, as well as the collaboration between both institutions collecting complementary information from this stock, allowed obtaining robust somatic parameters and analyzing their temporal variations. A weight-length relationship model was fitted and the quinquennium and semester factors, which are of interest biologically and for assessment purposes, and their interactions were significant in the preliminary model. The weight-length relationships, both for total and gutted weight and for the combined sexes of the most recent quinquennium are presented in this work and considered the most suitable to be used in the oncoming annual assessment process of the status of this stock in northern Bay of Biscay and Celtic Sea in ICES

Una aproximación económica a la demanda de aborto

El objetivo del presente trabajo se concreta en analizar el comportamiento de la demanda de aborto en nuestro país señalando cuáles son los principales aspectos demográficos que lo describen. El análisis se efectuará desde una perspectiva empírica, evitando cualquier implicación de tipo ideológico o religioso. En primer lugar, realizaremos un análisis descriptivo de este fenómeno demográfico, destacando sus rasgos más característicos. Posteriormente, analizaremos desde un punto de vista socioeconómico, el comportamiento de la demanda de aborto, destacando la influencia que las condiciones económicas y sociales ejercen sobre la misma. Mediante el uso de técnicas econométricas, estudiaremos la influencia que ejercen variables como el nivel de formación femenino, renta salarial, situación laboral de la mujer o la disolución de la unión familiar, sobre la decisión de interrumpir, o no, el embaraz

Una aproximación económica a la demanda de aborto

El objetivo del presente trabajo se concreta en analizar el comportamiento de la demanda de aborto en nuestro país señalando cuáles son los principales aspectos demográficos que lo describen. El análisis se efectuará desde una perspectiva empírica, evitando cualquier implicación de tipo ideológico o religioso. En primer lugar, realizaremos un análisis descriptivo de este fenómeno demográfico, destacando sus rasgos más característicos. Posteriormente, analizaremos desde un punto de vista socioeconómico, el comportamiento de la demanda de aborto, destacando la influencia que las condiciones económicas y sociales ejercen sobre la misma. Mediante el uso de técnicas econométricas, estudiaremos la influencia que ejercen variables como el nivel de formación femenino, renta salarial, situación laboral de la mujer o la disolución de la unión familiar, sobre la decisión de interrumpir, o no, el embaraz

La demanda de vivienda en España: una aproximación empírica

Variables económicas, demográficas y urbanísticas son algunos de los factores que con distinta ponderación explican el comportamiento de la variable precio de vivienda. Dicho aspecto ha sido, hasta el momento, objeto de un tratamiento teórico, en gran medida, residual a pesar del peso que el sector de la vivienda ejerce sobre las principales macromagnitudes económicas. Nuestro estudio se centrara en la modelización econométrica de los factores que explican el comportamiento de la función de demanda de vivienda en España para el periodo 1976-1992. Su conocimiento resulta imprescindible, entre otros aspectos, en la adopción de medidas de política económica

Seasonality in the condition of megrim and its somatic growth in Cantabrian Sea and Galician waters

The megrim (Lepidorhombus whiffiagonis) is a bottom-living species, important part of the benthic community in the Cantabrian Sea, and commercially exploited by the European fisheries. Robust and updated biological information of megrim is required for a deeper knowledge of its life history traits and an adequate stock assessment process and management. Condition factor, weight conversion factors and length-weight relationships are analyzed in Cantabrian Sea and Galician waters based on 7458 specimens from a time-series of 22 years (1998-2019) of commercial landings and from a research survey (2017). The influence of factors as the season, year, multi-year period, fish sex and maturity in the Le Cren’s condition factor (K) were analyzed. A clear seasonal pattern in K, more prominent in females was found, with the lowest condition in April (after the spawning period), and a progressive increase to the highest values from November to February, showing the relevance of K as indicator of the nutritional / reproductive status of megrim. The linear weight conversion equation and the power length-weight equations were also estimated and sexual and temporal differences were found. The somatic parameters obtained here are available to be used in the annual assessment of the Atlantic Iberian stock. Our findings will contribute to facilitating better exploitation, management and conservation of this Iberian resource

Weight-length relationships and weight conversion factors in two stocks of megrim (Lepidorhombus whiffiagonis): Celtic Seas - northern Bay of Biscay (7.b-k, 8.abd stock) and northern Iberian waters (8.c, 9.a stock)

BIOBENTON-4Biología de especies bentónicas comerciales (rape blanco, rape negro, gallo del norte, gallo, cigala y cuco) en el área del ICE

Seasonality in the condition and variability in somatic relationships of megrim (Lepidorhombus whiffiagonis) in the northeast Atlantic

Somatic parameters’ estimation of megrim (Lepidorhombus whiffiagonis), an economically important flatfish species and relevant one in the benthic community, is essential in fisheries biology. It helps us to deepen our understanding of the species life history traits and an adequate stock assessment and fishery management. Le Cren’s condition factor (K), weight-length relationships and weight conversion factors were studied in megrim for more than two decades time-series (1998–2019) and wide area with a relevant fishing activity and the species is distributed into two stocks: northern Bay of Biscay-nBB and Celtic Sea-CS stock, and southern Bay of BiscaysBB and Galician waters-Gw stock. Around 30,000 specimens, mostly collected from commercial landings by the research institutions IEO and AZTI, were sampled. Total fish length, total weight and commercial gutted weight were obtained, and five-year periods were defined throughout in the time-series. The influence of several factors, as seasonality, temporality, fish sex, maturity, abundance, and environmental conditions on the megrim condition were analyzed for each stock by GLM, being the season the most relevant factor. A clear seasonal pattern found for K, with the lowest values in spring, was found in both populations for the first time based on a multiyear period analysis. The pattern was more prominent in females and less marked in immature, related to the reproduction process. The lowest condition value was observed in May in nBB-CS and a month earlier in sBB-Gw (both after the spawning period). A progressive increase (favorable feeding conditions) followed to highest values in November–February, showing the relevance of K as indicator of the nutritional/reproductive status of megrim. Temporality (five-year periods) also had a much smaller effect on condition than seasonality. Megrim condition was inversely related to its abundance, and to the NAO index in the nBB-CS stock. Total weight-length, gutted weight-length and total weight-gutted weight relationships were fitted for each megrim stock and their temporal variations were analyzed. The large sample size, size range and time-series available allowed obtaining robust somatic parameters for the total weight-length relationships (a = 0.0049, b = 3.1012; a = 0.0041, b = 3.1682, respectively in nBB-CS stock and sBB-Gw stock), gutted weight-length relationships (a = 0.0046, b = 3.1033; a = 0.0042, b = 3.1510, respectively in nBB-CS and sBB-Gw stock), and weight conversion factors (1.049; 1.056, respectively in nBB-CS and sBB-Gw stock). They were considered the most appropriate to be used in the stock assessment of both stocks. A historical analysis of the temporal variability of the weight-length relationships showed different trends between stocks.European Union through the European Maritime and Fisheries Fund (EMFF)En prensa2,24