Reducción de los descartes en la pesca con trasmallo: resultados experimentales utilizando trasmallo con “faldón” en la pesca artesanal del camarón, Penaeus kerathurus, en el mar Ligur (Mediterráneo Occidental)

This study aimed to test the effectiveness of a “guarding net”, a device placed at the bottom of a trammel net, for reducing unwanted catches in the caramote prawn trammel net fishery of the Ligurian Sea. This specialized and profitable fishery is affected by unwanted catches that generate high discard rates and damage to the nets, with environmental impacts and costs for fishermen. The experimental study consisted in comparing the catches of a standard trammel net (STN) with those of two “experimental” trammel nets, e.g. STNs provided with a guarding net of 19 cm (TGN20) and 24 cm height (TGN25), respectively. The guarding net, a strip of gillnet placed at the bottom of the net, can be considered a by-catch reducer device (BRD). Some fishermen of the investigated fishery have been using this device for several years. The results of the 15 experimental fishing trials performed from June to July 2016 indicate that the guarding nets significantly reduce discards (e.g. crabs and other invertebrates); the biomass of the unwanted species caught was 75% lower than that produced by the STN. The catch rates of the target species obtained with TGN20 and TGN25 were also significantly lower than those of the STN, though of a lesser amount. Nonetheless, this economic loss can be compensated by the decrease in sorting time and material and labour costs that can be achieved using the guarding net.El objetivo de este trabajo fue testar los efectos de un “faldón”, una red colocada en la parte inferior de un trasmallo, para reducir los descartes en la pesquería del camarón del mar Ligur. Se trata de una pesquería especializada y rentable, afectada por capturas no deseadas, que generan descartes y daños a las redes, con impacto ambiental y costes para los pescadores. Se llevaron a cabo pescas experimentales, para comparar la captura de un trasmallo estándar (STN) con la de dos trasmallos “experimentales”, construidos a partir de un trasmallo estándar, con el ajuste de un faldón de 19 cm de altura (TGN20), y de un faldón de 24 cm (TGN25). Este faldón, una banda de red de enmalle, se puede considerar como un dispositivo reductor de capturas accesorias (BRD). Algunos pescadores de la pesquería investigada ya utilizan este dispositivo desde hace algunos años. Los resultados de las quince pruebas experimentales, realizadas de junio a julio 2016, muestran que el faldón de red de enmalle contribuye significativamente a reducir los descartes (cangrejos y otros invertebrados), con una reducción de la biomasa de las especies descartadas hasta el 75%, respecto al trasmallo estándar. Al mismo tiempo, también las tasas de captura de las especies objetivo obtenidas con TGN20 y TGN25 fueron significativamente más bajas que las del STN, aunque de menor magnitud. Sin embargo, esta pérdida económica puede ser compensada por la disminución del tiempo de trabajo, de los costes del material y de la mano de obra, que se pueden lograr utilizando un trasmallo con “faldón”

Chemical evidence for the persistence of wine production and trade in Early Medieval Islamic Sicily

As a high-value luxury commodity, wine has been transported across the Mediterranean since the Bronze Age. The wine trade was potentially disrupted during political and religious change brought about by Islamization in the Early Medieval period; wine consumption is prohibited in Islamic scripture. Utilizing a quantitative criterion based on the relative amounts of two fruit acids in transport amphorae, we show that wine was exported from Sicily beyond the arrival of Islam in the ninth century, including to Christian regions of the central Mediterranean. This finding is significant for understanding how regime change affected trade in the Middle Ages. We also outline a robust analytical approach for detecting wine in archaeological ceramics that will be useful elucidating viniculture more broadly.Although wine was unquestionably one of the most important commodities traded in the Mediterranean during the Roman Empire, less is known about wine commerce after its fall and whether the trade continued in regions under Islamic control. To investigate, here we undertook systematic analysis of grapevine products in archaeological ceramics, encompassing the chemical analysis of 109 transport amphorae from the fifth to the eleventh centuries, as well as numerous control samples. By quantifying tartaric acid in relation to malic acid, we were able to distinguish grapevines from other fruit-based products with a high degree of confidence. Using these quantitative criteria, we show beyond doubt that wine continued to be traded through Sicily during the Islamic period. Wine was supplied locally within Sicily but also exported from Palermo to ports under Christian control. Such direct evidence supports the notion that Sicilian merchants continued to capitalize on profitable Mediterranean trade networks during the Islamic period, including the trade in products prohibited by the Islamic hadiths, and that the relationship between wine and the rise of Islam was far from straightforward.All study data are included in the article and/or SI Appendix

Discard composition of the european hake Merluccius merluccius (Linnaeus, 1758) bottom trawl fishery in two areas of the NW Mediterranean Sea, Northern Tyrrhenian Sea and Catalan Sea

1 page, 2 tablesThis study provides data on the discard composition of the European hake bottom trawl fishery in two different areas of the NW Mediterranean, paying special attention to the non-charismatic species. On board sampling was conducted monthly from February to July 2001. The total number of species caught was 189 (163 discarded, 68 commercial) in the northern Tyrrhenian Sea and 246 (207 discarded, 78 commercial) in the Catalan SeaPeer reviewe

Analysis of the impact of the fishery on the adult population of european hake in the Northwestern Mediterranean

2 page, 3 figures, 1 tableThe impact of the fishery on the adult population of Merluccius merlucciuswas studied in two areas of the north-western Mediterranean. From the analysis of the commercial landings and of the corresponding size structures, appreciable differences in the exploitation pattern of the different fishing gears were evidence

Foreword : Discards regulation vs Mediterranean fisheries sustainability

Special issue Discards regulation vs Mediterranean fisheries sustainability.-- 2 pagesResearch on the sustainability of marine commercial fishing has been an important topic of marine science for over a century. One of the well-known emerging results of this research is that incorrect fishing patterns and fleet overcapacity result in a non-optimal exploitation of marine resources and negative impacts on ecosystems. In addition to excessive fishing pressure on target stocks, these practices also produce unnecessary mortality of unwanted catches that are discarded, often dead, at sea. [...]Peer Reviewe

Comparación de las capturas de merluza (Merluccius merluccius, L. 1758) Obtenidas con redes experimentales de enmalle de diferentes tipos de malla, en el norte del Mar Tirreno (Mediterráneo noroccintal)

The impact of the gillnet fishery on Merluccius merluccius (European hake) was investigated in the northern Tyrrhenian Sea, western Mediterranean. Four mesh sizes were tested: 53, 62.5, 70 and 82 mm. Horse mackerel (Trachurus trachurus), hake and tub gurnard (Chelidonichthys lucerna) dominated the catches, from a minimum of 89% (82 mm mesh) to a maximum of 97.8% (70 mm) of the biomass caught. Efficiency of the four meshes was not significantly different with respect to the total hake catches. Selectivity on M. merluccius was assessed by Sechin and SELECT methods. Tangling was an important catch modality for hake, as evidenced by the results of the Sechin model which described only the first mode of the size distributions corresponding to the entangled specimens. SELECT showed that the bi-modal function gave the best adjustment to the length-frequency distributions; the modal catch sizes were 33, 39.2, 43.6 and 51 cm total length respectively for the 53, 62.5, 70 and 82 mm mesh sizes. Taking into account the size of first maturity for females (35.1 cm TL), 62.5 mm is the most adequate mesh for exploiting hake as it gives some protection to both immature specimens and large females.Se estudió el impacto de la pesquería con redes de enmalle sobre la merluza, Merluccius merluccius, (merluza europea) en el norte del mar Tirreno, Mediterráneo noroccidental. Se utilizaron cuatro tamaños de malla: 53, 62.5, 70 y 82 mm. Los peces Trachurus trachurus, M. merluccius y Chelidonichthys lucerna dominaron la biomasa capturada, con un mínimo del 89% (malla de 82 mm) y un máximo del 97.8% (malla de 70 mm). La eficiencia de las cuatro mallas no resultó estadísticamente diferente. La selectividad sobre M. merluccius fue estudiada con los métodos Sechin y SELECT. El enredamiento resultó una importante manera de captura, como evidenció el método Sechin, con un buen ajuste sólo para la primera moda de las distribuciones de talla, correspondiente a ejemplares capturados por enmalle. Con el modelo SELECT la función bimodal fue la mejor para describir las estructuras de talla; las tallas modales de captura fueron 33, 39.2, 43.6 y 51 cm de longitud total, para las mallas de 53, 62.5, 70 y 82 mm respectivamente. Teniendo en cuenta la talla de primera madurez, la malla de 62.5 mm es probablemente la más adecuada para la explotación de la merluza, permitiendo una cierta protección tanto de los inmaduros como de las hembras grandes

Caratterizzazione archeometrica e archeologica della ceramica invetriata di età islamica a Palermo (fine IX-metà XI secolo): nuovi dati e problemi aperti

International audienc

Caratterizzazione archeometrica e archeologica della ceramica invetriata di età islamica a Palermo (fine IX-metà XI secolo): nuovi dati e problemi aperti

International audienc

Caratterizzazione archeometrica e archeologica della ceramica invetriata di età islamica a Palermo (fine IX-metà XI secolo): nuovi dati e problemi aperti

International audienc