Trends in Spanish catch rates for Northern European hake Merluccius merluccius (L., 1758): Standardizing trawler and longliner fleets in ICES subarea VII

Standardization of catch per unit effort (cpue) series using a generalized linear model (GLM) for Northern European hake Merluccius merluccius (L., 1758) in International Council for the Exploration of the Sea (ICES) subarea VII, based on catch and effort data from the Spanish trawler and longliner fleets from 1986 to 2000, are presented. Data were collected from trawler and longliner fleets targeting hake off the Spanish ports of La Coruña, Burela, and Celeiro. Main factors in the models created include a factor for engine Horse Power, to adjust for characteristics that determine fishing power; Year and Month factors for La Coruña's trawler fleet; and the factors Month, Year, Vessel, and Fishing Days for the Spanish longliner fleet as a whole. Moreover, both models indicate that interactions between the Year and Month factors also had a significant impact on hake catch rates. The total proportions of variance explained by these models were 55% for La Coruña's trawler fleet, and about 48 % for Spanish longliner fleet. The results showed similar patterns comparing nominal and standardized catch rates.Se muestra la aplicación de un modelo lineal generalizado (GLM) para la estandarización de la captura por unidad de esfuerzo (cpue) de la merluza europea Merluccius merluccius (L., 1758) del stock norte en la subárea VII del Consejo Internacional para la Exploración del Mar (CIEM) durante el periodo 1986- 2000. Los datos de esfuerzo y captura proceden de las flotas de arrastre y de palangre de los puertos de A Coruña, Burela y Celeiro (en el noroeste de España) dirigidas a la pesca de merluza del stock norte. En el modelo para la flota arrastrera del puerto de A Coruña se incluyeron los factores año, mes y categoría del barco, que relacionan la potencia del motor con su poder de pesca, y en el modelo para la flota palangrera de los puertos de A Coruña, Burela y Celeiro se incluyeron los factores año, mes, barco y días de pesca. Ambos modelos reflejan interacciones significativas entre los factores año-mes; así, el 55 % de la variación total observada se explica con el modelo para la flota arrastrera del puerto de A Coruña, y el 48 % se explica con el modelo para la flota palangrera. Las dos tipificaciones demuestran, así mismo, tendencias interanuales similares en las tasas de capturas estandarizadas y nominales.Instituto Español de Oceanografí

Feeding Patterns of Greenland halibut (Reinhardtius hippoglossoides) in Flemish Pass (Northwest Atlantic)

A qualitative study of the food composition of Greenland halibut (Reinhardtius hippoglossoides) was made by on-board analysis of commercially caught fish in 1992. The fish were caught east of Newfoundland (NAFO Div. 3LM) in unusually deep waters, with an average of 1 040 m. Variations in feeding according to predator size, depth and month were studied. The annual average percentage of empty stomachs was 69%, increasing through the year for specimens over 60 cm. The frequency of occurrence (FO) of food items was used to evaluate the importance of prey groups. Fish (39%), cephalopods (32%) and decapod crustaceans (22%) were the main items, with cannibalism reaching 2%. An abrupt change in diet composition occurred in fish between 60 and 69 cm, from feeding on decapod crustaceans and cephalopods to fish and factory ship discarded offal. The influence of the fishery itself on the diet of Greenland halibut was observed when an important food component in the largest specimens (>60 cm) consisted of offal discarded after fish processing. This study indicates that the FO of the main prey groups bears more relation to the size of fish than with depth

Using time series methods for completing fisheries historical series

The so-called baca trawl fleet of the port of A Coruña working in the VIIIc ICES Division Area has been used since 1985 as the tuning fleet for the analytical assessment of the southern stock of hake Merluccius merluccius(L., 1758). The historical series of cpue dates from 1983 to 2000 with data missing from 1998. From January 1999, landings were estimated by means of monthly samplings in port. The predictions of the arima model fit the 1983-1997 series, and estimates of the transfer function model from the 1983-2000 series made it possible to complete the series, and to detect errors and possible changes in the orientation of the fleet. The comparison of the two models confirms the series's stability over time, validating the estimates made in the last two years.La flota de baca del puerto de A Coruña que opera en el área VIIIc del CIEM se usa desde 1985 como flota de calibración en la evaluación del stock sur de merluza Merluccius merluccius (L., 1758). Se dispone de una serie histórica mensual de cpue (1983-2000), excepto para 1998, año del que no se posee información. Desde enero de 1999 los desembarcos han sido estimados a partir de muestreos mensuales en lonja. Las predicciones efectuadas por el modelo arima ajustado a la serie 1983-1997 y las estimaciones del modelo de función de transferencia, considerando la serie 1983-2000, han permitido completar la serie, así como detectar errores o cambios en el comportamiento de la flota. La comparación de ambos modelos confirma la estabilidad de la serie, validando las estimaciones efectuadas en los dos últimos años.Instituto Español de Oceanografí

Especies de interés pesquero en Galicia, Asturias y Cantabria

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Feeding of Most Abundant Fish Species in Flemish Cap in Summer 1993

The stomach contents of 4320 fishes comprising 14 species were collected from Flemish Cap Bank (NW Newfoundland) at depths ranging from 130 to 730 m, during summer 1993. The general feeding intensity was high in all species. Three main feeding patterns were evident: the genus Sebastes consume primarily pelagic species, although they also feed on preys which migrate vertically such as shrimps, Euphausids and mysids. The benthic group is made up of American plaice (Hippoglossoides platessoides), witch flounder (Glyptocephalus cygnoglossus), arctic eelpout (Lycodes reticulatus), wolffishes (Anarhichas lupus and Anarhichas minor) and thorny skate (Raja radiata). Lastly, the group of benthopelagic fish remains, longf in hake (Urophycis chesteri), cod (Gadus morhua), grenadiers (Nezumia bairdi and Macrourus berglax) and Greenland halibut (Reinhardtius hippoglossoides). Pelagic and benthopelagic preys are an important food resource for all fish considered, the abundance of Hyperids, P. borealis and Sebastes sp. in summer makes them an important food resource in the diet of fish in Flemish Cap