Deep-water fishing tactics of the Spanish fleet in the Northeast Atlantic. Seasonal and spatial distribution

Abstract

SUMMARY:The classification and identification of all the Spanish fishing activity targeting deep-sea species was conducted using a non-hierarchical classification technique designed for large matrices (CLARA). Otter trawl and set longlines were the main gears used in deep-sea ecosystems. The otter trawl fleet conducted 3 deep-sea fishing tactics. The only otter trawl fishing tactic targeting deep-sea species was that working in the VI ICES Division and targeting Alepocephalus baiirdi. The other 2 otter trawl fishing tactics targeted shallower shelf demersal resources, deep-sea species being secondary (Phycis blennoides). The longline fleet carried out 7 fishing tactics targeting deep-sea species (Molva spp.; deep water sharks; P. blennoides; Pagellus bogaraveo; and Trichiuridae) and 2 fishing tactics targeting Conger conger, which perform as deepsea fishing tactics in the narrow continental shelf area. This classification, together with knowledge regarding their seasonal performance and spatial distribution, may help to design fisheries sampling protocols and to improve the management of these fleets, thus reducing their impact on deep-sea habitats.Keywords: Northeast Atlantic, métiers, fisheries, deep sea, trawl, longline, multivariate. RESUMEN: Pesquerías españolas de gran profundidad en el Atlántico Nordeste. Estacionalidad y distribución espacial. -Para la clasificación e identificación de todas las pesquerías españolas que actúan sobre especies de gran profundidad se ha utilizado una técnica de cluster no jerárquica diseñada para grandes matrices (CLARA). El arrastre con puertas y el palangre de fondo fueron los aparejos más importantes. Solamente la táctica pesquera de arrastre con puertas desarrollada en la División VI del ICES está dirigida a especies de profundidad, siendo la especie objetivo Alepocephalus baiirdi. Las otras dos tácticas pesqueras con arrastre de puertas son mixtas, teniendo como objetivo especies típicas de plataforma, y teniendo las especies de profundidad como secundarias (Phycis blennoides). La flota de palangre desarrolla siete tácticas pesqueras dirigidas a especies de profundidad: Molva spp.; tiburones de profundidad; P. blennoides; Pagellus bogaraveo; Trichiuridae; y dos pesquerías dirigidas a Conger conger, que se comportan como tácticas pesqueras de profundidad en las zonas de plataforma estrecha. Esta clasificación junto con el conocimiento acerca de su comportamiento estacional y espacial, ayudarán al diseño de los protocolos de muestreo de estas pesquerías así como a la mejora de la gestión de estas pesquerías contribuyendo a una reducción de su impacto en los hábitats profundos.

Spatial characterization of the fisheries in the Avilés Canyon System (Cantabrian Sea, Spain)

“…In the case of fishing gears already described in previous studies, the same structure was obtained for the fishing tactics (Castro et al 2010, Punzón et al 2011. Among those identified, mixed gillnet (GNS_MIX) should not be considered a fishing tactic even though it presents a high partial silhouette coefficient value (Table 2).…”

“…Using statistical rectangles to define if a fishery should be considered a deep-water fishery, like LLS_COE, may be problematic in narrow continental shelves (Punzón et al 2011). As we have observed, the activity of this fishery takes place along the entire continental shelf, including the area close to the 500-m contour line, and for that reason it should be considered a deep-sea fishery.…”

“…In the reviews conducted by Piñeiro et al (2001) and Punzón et al (2011), the authors identified 2 deep-water fisheries in the Northeast Atlantic region: GNS_MNZ and OTB_MIX. In the case of GNS_MNZ, the fishing effort was located below 500 m depth, while in the case of OTB_MIX, the fishing effort deeper than 500 m was carried out only in the western region and was not very intense.…”

“…Para las artes de pesca ya descritas en estudios previos, la estructura de las tácticas pesqueras fue igual a la obtenida en este trabajo (Castro et al 2010, Punzón et al 2011. Entre las tácticas pesqueras identificadas, el enmalle mixto (GNS_MIX) no debería ser considerado una táctica pesquera, a pesar de haber presentado un alto coeficiente parcial de silueta (Tabla 2).…”

Identification of métiers based on economic and biological data: The Spanish bottom otter trawl fleet operating in non-Iberian European waters

“…Recent works, focusing on the deep-water species exploited by this fleet, were not able to provide conclusive results due to be based on commercial data without discards (Piñeiro et al, 2001;Punzón et al, 2011). Nevertheless, the consequences of this fishing activity on all the exploited ecological groups make it particularly relevant to develop a comprehensive analysis of the whole fishing activity of this fleet.…”