Catch-per-unit-effort and Biological Data of Nephrops norvegicus from the SW Ireland Spanish Trawl Fishery

Norway lobster Nephrops norvegicus is a burrowing species inhabiting soft bottoms in the NE Atlantic and Mediterranean. In European western waters (SW Ireland) Nephrops is a comercial species of the bottom mixed fishery prosecuted by fletes from Ireland, France, UK and Spain. A comprehensive collection (1980-2000) of Spanish trawl fishery data and sampling of landings is available. Although Nephrops is a by-catch spcies for the Spanish trawl fleet, some vessels target it mainly during the spring and summer seasoon. This study presents a summarized description of that fishery and catch per unit effort trends. Annual Nephrops length composition by sex, length-weight relationship, sex-ratio and proportion of ovigerous females are given for the referenced period.IEO FPI grant (BOE 06.10.2000, No9). DEMICES project

Distribution and abundance of molluscs and decapod crustaceans in trawl samples from the Galician Shelf (NW Spain)

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Morphometry of Norway lobster Nephrops norvegicus (Linnaeus, 1758) from Galicia (northwest Spain)

Se ha estudiado el crecimiento relativo o alométrico de la cigala Nephrops norvegicus (L., 1758) de Galicia (noroeste de España). Las variables analizadas en relación con la longitud del caparazón fueron la longitud total, la anchura y la longitud de los quelípedos, la longitud del primer par de pleópodos de los machos, la anchura abdominal de las hembras y el peso húmedo. En hembras, la longitud total, la longitud y anchura de los quelípedos y la anchura del abdomen presentaron un crecimiento alométrico positivo. En machos, la longitud y anchura de los quelípedos mostraron alometría positiva, mientras que la longitud total y la longitud del primer par de pleópodos presentaron alometría negativa. Se encontraron diferencias entre sexos en las ecuaciones alométricas que relacionan la longitud del caparazón y el peso húmedo. La mayor parte de los individuos de cigala examinados (96 %) mostró heteroquelia, con la quela fina (cortadora) o la gruesa (trituradora) situada indistintamente en el lado izquierdo o el derecho[Abstract] The present study focused on the relative or allometric growth of Norway lobster Nephrops norvegicus (L., 1758) from Galicia (northwest Spain). The variables analysed in relation to the carapace length included total size, length and width of chelipeds, length of first pair of male pleopods, width of female abdomen, and live weight. In females, total length, length and width of chelipeds, and abdominal width showed positive allometry. In males, the length and width of chelipeds also showed positive allometry, whereas the total length and first pair of pleopods’ length showed negative allometry. Differences were found between males and females regarding the relationship of carapace length to live weight. Most of the individuals sampled (96 %) showed handedness, with the cutter or the crusher claw indistinctly placed on the left or right sideInstituto Español de Oceanografí

Exploring long-term variability of Nephrops norvegicus population in the Porcupine Bank (SW Ireland)

PresentationNephrops norvegicus is a commercial species of the bottom fisheries in European western waters which yield has long-term variability. Their distribution is linked to suitable habitats of muddy sediment in which adults construct burrows but the influence of environmental factors on the populations was poorly investigated. Variability in the catch per unit effort (CPUE) of Nephrops norvegicus from Porcupine Bank (Southwest of Ireland) was explored using a time series approach. The CPUE time series (1979-2005) exhibited a seasonal pattern. The seasonal decomposition of the CPUE shows a declining trend in the trend and cycle component from 1982 onwards. ARMA univariate and dynamic regression models were fitted to the CPUE time series. Population (proportion of males, proportion of ovigerous females and recruits) and North Atlantic Oscillation index were tested at different lags to investigate possible factors related to the yield fluctuations

Peces de los fondos de arrastre de la plataforma continental de Galicia

En el presente trabajo se relacionan las especies de peces capturadas en 91 lances efectuados en cuatro campañas de promoción pesquera, realizados a bordo del B/O Cornide de Saavedra, entre 1980 y 1982 en la plataforma de Galicia. Se presenta para cada especie la abundancia en número y la biomasa por tiempo de arrastre, por zona geográfica y estrato de profundidad, Se citan un total de 72 especies de peces.The species of fishes captured along of 91 hauls realized in four surveys earried out with the R/V Cornide de Saavedra between 1980 and 1982 along the Galicia continental shelf are reported. The abundance in number of individuals and biomass per trawling time, for each geographical area and depth stratum are cited for each species. A total of 72 fish species are cited.Versión del editor