Estimates of Spanish bottom otter trawl boarfish (Capros aper) discards by area in the Northeast Atlantic area.

Discard estimates for the Spanish bottom otter trawl fleets fishing in the Northeast Atlantic are presented for boarfish (Capros aper). Information was obtained by observers on board under different discard sampling programmes carried out by the Spanish research institute IEO. Raising based on effort (number of trips) was used to estimate total discards in weight and associated coefficients of variation (CV) and number for the fleet. Discards length distributions are presented by year and fishing area. Total estimates indicates different trends in discarding, showing a decreasing trend in north coastal Spanish waters and a increasing trend in western Ireland waters

Discards of Spanish Trawler Fleets Operating in the Bay of Biscay in 2000

A stratified sampling programme by gear and port was carried out by observers on board vessels in 2000 to study the discard behaviour of trawler fleets operating off Spanish North Atlantic coasts. No relationship between discards in weight or numbers and haul duration was found, so the results in weight are presented in kilograms per haul instead of kilograms per hour, as is usual for catches. The data were analysed in order to find groups of ports with a similar behaviour and to reduce the number of strata (30 as a result of the crossing of 10 main ports and 3 types of towed gears). The reduction in the number of strata (from the 30 original strata to the 9 new groups obtained) would mean a high improvement in efficiency for raising purposes, for stock assessment needs and for new Spanish sampling programmes. Significant differences in discards between groups of ports were found. Species composition of discards by stratum is given as a percentage of the total weight, based on data collected by the observers on board vessels. There are also differences in the discarded species composition for the different groups of ports obtained.Para estudiar los descartes de las flotas de arrastre que pescan en las costas Noratlánticas españolas se llevó a cabo, durante el año 2000, un programa de muestreo con observadores a bordo. El tipo de muestreo fue estratificado por arte y puerto. No se ha encontrado relación entre los descartes en peso o en número y la duración del lance, por lo tanto, los resultados se presentan en kilos por lance en lugar de kilos por hora, como es habitual para las capturas. Para reducir el número de estratos (que eran 30 como resultado de cruzar 10 puertos principales con los tres tipos de arte de arrastre considerados) se analizaron los datos en busca de los grupos de puertos con comportamiento similar. La reducción en el número de estratos (de los 30 originales a los 9 nuevos grupos obtenidos) podría aumentar la eficiencia de los muestreos especialmente con vista a la estimación de valores totales útiles en evaluación y futuros programas de muestreo. Las diferencias entre los descartes de los distintos grupos de puertos obtenidos resultaron significativas. Los resultados incluyen la composición específica del descarte por estrato, en porcentaje del peso total, basada en datos recogidos con observadores a bordo. Estos resultados también muestran diferencias entre los diferentes grupos de puertos.Publicado

Results on Northern hake Spanish discard sampling programme

Quarterly discards estimates for the Spanish bottom otter trawl fleet fishing in the Northeast Atlantic ICES Subareas VI and VII are presented for hake (Merluccius merluccius). Information was obtained by observers on board under different discard sampling programmes carried out by the Spanish research institute IEO. Raising based on effort (number of trips) was used to estimate total quarterly discards in weight and number for the fleet. Discards length distributions are also presented. Both in terms of weight and numbers discards present high variation in time, ranging from 0 to 1100 tonnes and from 0 to 12 million fish. Length distributions of discarded hake show that most of the individuals are juvenile fish, although some individuals above the minimum landing size (27 cm) are also discarded. Increases in the number of juveniles discarded are evident after year 2003

Spanish discards estimates of megrim (Lepidorhombus whiffiagonis) in Subarea VII and Divisions VIIIabd

The Spanish discards estimates of the megrim (Lepidorhombus whiffiagonis) stock of ICES Subarea VII and Divisions VIIIabd (mgw-78) are derived from data compiled by the Spanish on-board sampling program, developed by the Spanish institutes IEO and AZTI following the European Data Collection Regulation (DCR, DCF) guidelines since its implementation in 2003. A description of the Spanish fishery and the respective discards sampling program, as well as an analysis of the sampling level and the estimation process of mgw-78 discards are presented

Results of Exploratory Deep-sea Fishing Survey in the Galician Bank: Biological Aspects on Some of Seamount-associated Fish (ICES Division IXb)

Since October 1998 to October 1999 an experimental survey, comprising 12 monthly fishing trips were carried out in Galician Bank (ICES Divisions IXb) by two commercial trawlers of the Spanish fleet. The aims of this survey were to explore the fishing resources of studied area and to know the species community associated to this seamount. A total of 297 valid hauls were made during 309 hours of fishing and yielded a total catch of 45 145 kg in the depth strata studied (650-1200 m). The community of species in the area prospected presented high species richness. A total of 106 species were made up of 70 teleosts, 11 sharks, 3 rays, 2 chimaeras, 11 crustacea, 6 molluscs and 3 equinoderms The most important species captured were teleosts: H. mediterraneus, M.moro, L. eques, A. bairdii, E. telescopus, T. cristulata and L. piscatorius, followed for deep sharks: D. licha, D. calceus and crustacean: Ch affinis. The yields obtained for the whole series of fishing trips were low being the values obtained by order of importance: 30.3, 14.0, 13.1, 11.7, 4.8, 4.2, 2.5 kg/h and 1 kg/h for the teleosts; 2.0, 1.7, kg/h for sharks and 1.2 kg/h for crustacean. The results indicate, in general, there were no differences in depth distribution of the species characterised by the presence or absence of certain species and also, a seasonal variation in the abundance of the most important caught

Discard Pattern of Hake Southern stock from the Spanish Trawl Fleet

Two exploitation units (North and South) of Hake (Merluccius merluccius) are assessed in the ICES Working Group of Hake, Monk and Megrim. In ICES Divisions VIIIc and IXa, Portuguese and Spanish ships captured this species mainly in mixed bottom trawl fisheries, but also in long-liners, gill net or in artesanal fleets. As far now, discard data are not used in the assessment of this species, though they are considered significantly high for younger ages. Discards data are available for Spanish trawlers for 1993, 1994, 1997, and the period from 1999 to 2001.This current paper shows available data of discards for Spanish Southern hake stock (Divisions VIIIc and IXa) as well as to present the sample level for the different periods. Some estimations on discard rate in number and in weight are also showed. Most of the results were obtained by different EU funded research projects. Several problems related to the raising method are discussed. Finally, the possibilities and difficulties to use discard data in stock assessment are numbered

Spanish discards of Small‐spotted catshark (Scyliorhinus canicula) and Blackmouth catshark

This file includes 442 DICOM files of a male Carcharhinus hemiodon specimen housed in the spirit collection of Naturalis Biodiversity Center, Leiden, the Netherlands with registrationnumber RMNH.PISC.34102. The specimen is scanned in a medical CT scanner (Toshiba Aquilion 64) at the Leiden University Medical Center, the Netherlands at 100 kV and 150 mAs with a slice thickness of 0.5 mm