Descartes de la pesca de cerco enfocadas en peces pequeños pelágicos en el mar Mediterráneo Oriental

We analysed data collected on board commercial purse seine vessels in the Aegean and Ionian Seas (eastern Mediterranean Sea, Greece) in 13 seasonal sampling periods from 2003 to 2008 in order to describe the composition of the retained and discarded catch and shed light on discarding practices. In each area, five species constituted the majority of the marketable catch (> 97%): sardine (Sardina pilchardus), anchovy (Engraulis encrasicolus), round sardinella (Sardinella aurita), bogue (Boops boops) (in both areas), mackerel (Scomber japonicus; in the Aegean Sea) and picarel (Spicara smaris; in the Ionian Sea). Discarded quantities were on average 4.6% and 2.2% of the total catch in terms of weight in the Aegean and Ionian Seas respectively. Discards on the marketable ratio fluctuated over years and seasons without showing any particular trend. At the species level, sardine and mackerel were seldom discarded while large amounts of anchovy were discarded only during its recruitment period (autumn), when juvenile fish dominate the population. The discarding ratio for bogue, picarel and round sardinella ranged from zero to total discarding because they constitute a supplementary source of income for the fishers. Discarded fish comprised mainly small individuals for all species considered with the exception of round sardinella. However, the lengths at which 50% of the individuals were discarded were generally small, often smaller than the species minimum landing sizes. Geographical coordinates and marketable catch explained part of the variability of the discarded quantities, as revealed by generalized additive models. Discarding practices and implications for management of purse seine fisheries are also discussed.Analizamos datos recogidos a bordo de pesqueros comerciales de cerco en el mar Egeo y el mar Jónico (Mediterráneo Oriental, Grecia) durante 13 estacionales de muestreo desde 2003 hasta 2008, con el objetivo de describir la composición de las capturas conservadas y de las descartadas con el fin de arrojar luz sobre la práctica del descarte. En cada zona, la mayor parte de la captura comercial (> 97%) consistía en cinco especies, a saber: la sardina (Sardina pilchardus), el boquerón (Engraulis encrasicolus), la alacha (Sardinella aurita), la boga (Boops boops) (en ambas zonas), la caballa (Scomber japonicus; en el mar Egeo) y el caramel (Spicara smaris; en el mar Jónico). Las cantidades descartadas representaban un promedio del 4.6% y 2.2% de la captura total en términos de peso, en el mar Egeo y en el Jónico respectivamente. La proporción de la captura descartada sobre la captura comercializable fluctuó mucho en todos los años y estaciones sin mostrar ninguna tendencia particular. Con respecto a las especies, en el caso de la sardina y de la caballa, los descartes ocurrieron raramente e incluso los individuos más pequeños se conservaron, mientras que grandes cantidades de boquerón fueron descartadas solamente durante su temporada de reclutamiento (otoño), cuando la población está dominada por peces jóvenes. La proporción descartada en el caso de la boga, del caramel y de la alacha fluctuó mucho, desde un descarte de cero hasta un descarte total, ya que estas especies representan una fuente de ingresos complementaria para los pescadores. Las coordenadas geográficas y la captura comercial explicaban parte de la variabilidad de las cantidades descartadas, como se demuestra con modelos aditivos generalistas. Asimismo, presentamos una discusión sobre la práctica del descarte así como de las consecuencias sobre la gestión de la pesca de cerco

El boliche en Grecia: Perfiles de descargas e identificación de potenciales artes menores

Although boat seines have a significant share in the total fish landings in Greece, there is little information on boat seine fisheries. The present study aims to identify boat seine métiers on a national level and contribute to a better understanding of their operation in Greece. We used boat seine landings data collected from a large number of ports in the Aegean and east Ionian Sea between 2002 and 2006. The landings profiles were grouped with a two-step procedure: the first step involved a factorial analysis of the log-transformed landings profiles, and the second step was a classification of the factorial coordinates (hierarchical agglomerative clustering). Six métiers were identified in the Aegean Sea, and three in the Ionian Sea. The ‘picarel-bogue’ métier was the most important in both seas, accounting for 54% and 88% of the fishing trips of the sample in the Aegean and Ionian Seas respectively. Apart from picarel and bogue, other important target species were red mullet, European squid, common pandora, chub mackerel, and European pilchard. Varying spatial (within the Aegean and Ionian Seas) and seasonal patterns were evident for the identified métiers.Aunque la flota de boliche contribuya en una cantidad significativa en las descargas totales de pescado en Grecia, la información que trata de la pesca con boliche es escasa. El presente estudio pretende identificar el arte (métier) del boliche en un nivel nacional y contribuir a una mejor comprensión de su operación en Grecia. Se han utilizado los datos de las descargas de la pesca con boliche, recogidos entre 2002 y 2006 en un gran número de puertos en la costa del Mar Egeo y Mar Jónico oriental. Los perfiles de las descargas fueron agrupados siguiendo un procedimiento en dos etapas: el primer paso consistió en un análisis factorial de los perfiles de descargas transformados logarítmicamente, y el segundo paso en una clasificación de las coordenadas factoriales (agrupamiento aglomerativo jerárquico). Se identificaron seis artes menores en el Mar Egeo, y tres en el mar Jónico. El arte menor “caramel-boga” ha sido el principal en ambos mares, alcanzándose valores del 54% y del 88% respecto al número total de las jornadas de pesca muestreadas en el Mar Egeo y Mar Jónico respectivamente. Aparte de caramel y boga, otras especies objetivo de importancia fueron los salmonetes, el calamar, la breca, el estorino y la sardina. Los artes menores identificados han mostrado unos patrones espaciales (dentro de ambos Mar Egeo y Mar Ionio) y estacionales

The “discard problem” in Mediterranean fisheries, in the face of the European Union landing obligation: the case of bottom trawl fishery and implications for management

Since the first introduction of the landing obligation (a.k.a. Discard ban) in 2015, the EU Mediterranean fisheries are facing some unforeseen challenges. The demersal bottom trawl fisheries, being the most significant contributors to the so-called 'discard problem', are confronted with the greatest challenges. Data from the Italian and the Greek fleet, spanning over two decades (1995–2015), were analysed with the intention of revealing the diversity and heterogeneity of the discard problem, especially for regulated species. Species composition of discards, as well as discarding rates, were shown to be irregular, fluctuating among areas, depth strata, seasons and years. Although fish dominated the discarded gross catch in weight, benthic invertebrates (other than commercial cephalopods and crustaceans) were the taxa discarded almost exclusively. The established minimum conservation reference size was largely ignored by fishers. From a management point of view, the present investigation suggests that the recently established Discard Management Plans lack scientific evidence (given the high intrinsic variability of the parameters and confusion regarding the rules) and provide exemptions from the landing obligation that will in practice allow the average Mediterranean bottom trawl vessel to continue business as usual. Moreover, detecting if these rules are actually respected is an almost impossible task for the Mediterranean control and enforcement authorities. Incentivizing the adoption of fishing technologies and practices that reduce pre-harvest mortality and post-harvest discards, while avoiding damage to sensitive marine species and habitats, seems the only way to move forward, rather than dealing with the problem after it has occurred

A Bayesian model of fisheries discards with flexible structure and priors defined by experts

Peer reviewe

Impacts on biodiversity from codend and fisher selection in bottom trawl fishing

Fisheries have important impacts on marine biodiversity. In this work, combined information on the abundance, species richness, diversity indices, species composition, trophic level and vulnerability index were examined for the first-time to detect differences in five units related to trawl fishing: the fish assemblage entering the trawl codend, and the escaping, retained, discarded and landed fractions, derived by the gear and fisher selection practices. The work was based on a case study conducted in the Mediterranean Sea, using three different meshes in the trawl codend (40mm-40D and 50mm-50D diamond meshes, and 40 mm-40S square meshes) and a cover of the codends with small mesh size. In general, trawl fishing produces an escaping fraction that was always lower in abundance, richness, and vulnerability index, similar in diversity indices and trophic level, and different in species composition compared to the fish assemblage entering the codend. In almost all cases, fishers selected as landings a fraction that was the lowest in diversity indices, and the highest in trophic level. In contrast, fishers discarded a fraction that was the highest in diversity and vulnerability index, and the lowest in trophic level. Although the three codends did not differ significantly in the fraction of escapees in terms of diversity indices, trophic level, and vulnerability index, the 40S codend showed a significantly higher percentage in the escaping number of species and individuals, and less differences in the species composition; in addition, lower percentage in abundance of discards and higher of landings in the retained catch (0.6:1) than did the other two codends (0.9:1). It was suggested that an urgent modification of the trawl for the elimination of the discarded highly vulnerable species (e.g. Elasmobranchs) is needed, and that trawl species-selectivity should be improved by allowing escape or avoiding catch of the discarded fraction to minimize biodiversity losses.publishedVersio

Multi-use of the sea:A wide array of opportunities from site-specific cases across Europe

<p><b>Comparison of MU Combinations:</b> (Top) ranked by Drivers—Highest to lowest, and (Bottom) ranked by Added Values—Highest to lowest.</p

Discards of the purse seine fishery targeting small pelagic fish in the eastern Mediterranean Sea

We analysed data collected on board commercial purse seine vessels in the Aegean and Ionian Seas (eastern Mediterranean Sea, Greece) in 13 seasonal sampling periods from 2003 to 2008 in order to describe the composition of the retained and discarded catch and shed light on discarding practices. In each area, five species constituted the majority of the marketable catch (> 97%): sardine (Sardina pilchardus), anchovy (Engraulis encrasicolus), round sardinella (Sardinella aurita), bogue (Boops boops) (in both areas), mackerel (Scomber japonicus; in the Aegean Sea) and picarel (Spicara smaris; in the Ionian Sea). Discarded quantities were on average 4.6% and 2.2% of the total catch in terms of weight in the Aegean and Ionian Seas respectively. Discards on the marketable ratio fluctuated over years and seasons without showing any particular trend. At the species level, sardine and mackerel were seldom discarded while large amounts of anchovy were discarded only during its recruitment period (autumn), when juvenile fish dominate the population. The discarding ratio for bogue, picarel and round sardinella ranged from zero to total discarding because they constitute a supplementary source of income for the fishers. Discarded fish comprised mainly small individuals for all species considered with the exception of round sardinella. However, the lengths at which 50% of the individuals were discarded were generally small, often smaller than the species minimum landing sizes. Geographical coordinates and marketable catch explained part of the variability of the discarded quantities, as revealed by generalized additive models. Discarding practices and implications for management of purse seine fisheries are also discussed

Multi-use of the sea as a sustainable development instrument in five eu sea basins

This paper examines the concept of maritime multi-use as a territorial/SPATIAL governance instrument for the enhancement of sustainable development in five EU sea basins. Multi-use (MU) is expected to enhance the productivity of blue economy sectors, as well as deliver additional socio-economic benefits related to the environmental and social dimensions of sustainable development. The paper provides a definition of maritime multi-use and identifies the multi-uses with the highest potential in EU sea basins. In each sea basin, multi-use plays a different role as concerns sustainable development. For the Eastern Baltic Sea, the Mediterranean Sea and the Black Sea, the MU focus should remain on the environmental pillar of sustainable development. In the North Sea, North Atlantic and Western Baltic Sea, addressing social sustainability seems a key precondition for success of MU in enhancement of sustainable spatial development at sea. Moreover, it has been suggested to introduce MU key global strategies such as SDGs or Macroregional strategies and action plans and to supplement maritime spatial planning with sectoral incentives and educational efforts as key vehicles supporting MU. The paper concludes by identifying aspects which, in order to inform maritime spatial planning and maritime governance regarding a more conscious application of the aforementioned concept, require further investigation. Key tasks are related to: more profound evaluation of performance of policies supporting MUs, researching the impact of MU on societal goals and on the MU costs and benefits, including external ones, and finally identifying the impact of MU on the development of various sectors and regions on land