The quality of water for irrigations is conditioned by salt (amount and type) and the sediment it has. The characteristics of the water destined for irrigation influence the edaphic properties, the ...yield of the crops, the infrastructure of the irrigation systems and the durability of pressurized irrigation systems. The objective of this work was to compare the current data (2014-2017) and those from the historical series (1969-2007) of electrical conductivity (CE), total dissolved solids (TSD) and pH in the Multiple Use System of the Colorado River in 25 de Mayo (La Pampa). These parameters were periodically determined, on the matrix channel, which leads the water to the irrigated area of 25 de Mayo. The annual and inter annual behavior of the parameters in this period was analyzed regarding the monthly average values of the historical series that belong to the Ente Provincial del Río Colorado (Government of La Pampa).The analyzed results indicate that the monthly average of the EC and TSD of the last four years are higher than the monthly historical average. The pH was higher than the monthly historical average during 2014, except for the months of November and December. In 2015 and 2016, the registered values were lower than the historical ones. The changes of the analyzed results, specifically the salinity (EC and TSD), could be due mainly to the decrease in the flow that has been registered in the last years.
La calidad del agua para riego está condicionada por las sales (cantidad y tipo) y sedimentos que la constituyen. Las características del agua destinada al riego influyen en las propiedades edáficas, el rendimiento de los cultivos, las obras del sistema de riego y el funcionamiento de los equipos de riego presurizados.El objetivo de este trabajo fue comparar los datos actuales (2014-2017) y los de la serie histórica (1969-2007) de conductividad eléctrica (CE), total de sólidos disueltos (TSD) y pH en el Sistema de Aprovechamiento Múltiple del Río Colorado en 25 de Mayo (La Pampa). Estos parámetros se determinaron de forma periódica, en el canal matriz, el cual conduce el agua a la zona de regadío de 25 de Mayo. Se analizó el comportamiento anual e interanual de los parámetros en este período respecto a los valores medios mensuales de la serie histórica que pertenecen al Ente Provincial del Río Colorado (Gobierno de La Pampa).Los resultados analizados indican que la CE y el TSD medio mensual de losúltimos tres años son superiores al promedio histórico mensual. El pH resultó superior al promedio histórico mensual durante el año 2014, a excepción de los meses de noviembre y diciembre. En 2015 y 2016 los valores registrados fueron inferiores a los históricos. Del análisis de los cambios observados se infiere que el aumento de la salinidad (CE y TSD) es debido, principalmente, a la disminución del caudal que se viene registrando en los últimos años.
The Grande and Barrancas Rivers watersheds conform the upper basin of the Colorado River. They provide discharge from snow precipitated in the high mountain peaks. Morphometric and functional ...characteristics analysis of a basin is elementary in hydrology and modeling approach. The aim of this work was to analyze and interpret the morphometric parameters and derived indices of the upper basin of the Colorado River, Argentina. Parameters quantification and analysis were based on a digital elevation model and Geographic Information Systems. Length of the Grande River is three times greater than Barrancas River ones, with a drainage area that follows the same relationship. Gravelius coefficients evidenced similarities in watershed shapes, both rectangled-oblongued. Both watersheds have a half of their area between 1500 and 2500 m.a.s.l., with predominant slopes between 0 and 15o. In both cases, 54% of slopes are orientated to south direction, meaning predominantly shady. Barrancas River has a greater difference between the source and the mouth, having a smaller drained area. Results from this study offers an important source of base information to further research and modeling spatio-temporal dynamics of flow of River basin.
Las subcuencas del río Grande y del río Barrancas conforman la cuenca alta del río Colorado y la abastecen de agua a partir de la nieve que precipita en las altas cumbres. Conocer las características morfométricas y funcionales de una cuenca es esencial en estudios de hidrología y modelación del agua. El objetivo fue analizar e interpretar los parámetros e índices morfométricos de la cuenca alta del río Colorado, Argentina. La metodología aplicada se basó en establecer y analizar los parámetros morfométricos mediante el uso de Sistemas de Información Geográfica y planillas de cálculo, a partir de un modelo digital de elevación. La longitud del río Grande es tres veces superior a la del Barrancas, con un área de drenaje que sigue la misma relación. Según el Coeficiente de Gravelius ambas subcuencas son similares en su forma, rectangular oblonga. Además, poseen la mitad de su superficie entre los 1.500 y 2.500 m.s.n.m., con pendientes predominantes de 0 a 15°. En cuanto a la orientación el 54 % de las laderas están orientadas al sur en ambos casos. El río Barrancas posee mayor desnivel entre naciente y desembocadura, en un área drenada menor. Este estudio ofrece importante información de base para posteriores investigaciones de modelado de la dinámica espacio temporal del caudal en la cuenca.
The Grande and Barrancas Rivers watersheds conform the upper basin of the Colorado River. They provide discharge from snow precipitated in the high mountain peaks. Morphometric and functional ...characteristics analysis of a basin is elementary in hydrology and modeling approach. The aim of this work was to analyze and interpret the morphometric parameters and derived indices of the upper basin of the Colorado River, Argentina. Parameters quantification and analysis were based on a digital elevation model and Geographic Information Systems. Length of the Grande River is three times greater than Barrancas River ones, with a drainage area that follows the same relationship. Gravelius coefficients evidenced similarities in watershed shapes, both rectangled-oblongued. Both watersheds have a half of their area between 1500 and 2500 m.a.s.l., with predominant slopes between 0 and 15o. In both cases, 54% of slopes are orientated to south direction, meaning predominantly shady. Barrancas River has a greater difference between the source and the mouth, having a smaller drained area. Results from this study offers an important source of base information to further research and modeling spatio-temporal dynamics of flow of River basin.
Abstract
Sustainable management of living resources must reconcile biodiversity conservation and socioeconomic viability of human activities. In the case of fisheries, sustainable management design ...is made challenging by the complex spatiotemporal interactions between fish and fisheries.
We develop a comprehensive metapopulation framework integrating data on species life‐history traits, connectivity and habitat distribution to identify priority areas for fishing regulation and assess how management impacts are spatially distributed. We trial this approach on European hake fisheries in the north‐western Mediterranean, where we assess area‐based management scenarios in terms of stock status and fishery productivity to prioritize areas for protection.
Model simulations show that local fishery closures have the potential to enhance both spawning stock biomass and landings on a regional scale compared to a status quo scenario, but that improving protection is easier than increasing productivity. Moreover, the interaction between metapopulation dynamics and the redistribution of fishing effort following local closures implies that benefits and drawbacks are heterogeneously distributed in space, the former being concentrated in the proximity of the protected site.
A network analysis shows that priority areas for protection are those with the highest connectivity (as expressed by network metrics) if the objective is to improve the spawning stock, while no significant relationship emerges between connectivity and potential for increased landings.
Synthesis and applications
. Our framework provides a tool for (1) assessing area‐based management measures aimed at improving fisheries outcomes in terms of both conservation and socioeconomic viability and (2) describing the spatial distribution of costs and benefits, which can help guide effective management and gain stakeholder support. Adult dispersal remains the main source of uncertainty that needs to be investigated to effectively apply our model to fisheries regulation.
Riassunto
La gestione delle risorse biologiche deve conciliare la conservazione della biodiversità e la sostenibilità socioeconomica delle attività umane. Nel caso delle risorse alieutiche, l'elaborazione di strategie di gestione sostenibili è resa difficile dalle complesse interazioni spazio‐temporali tra pesci e pesca.
Abbiamo sviluppato un modello di metapopolazione che integra informazioni sui tratti vitali, sulla connettività oceanografica e sulla distribuzione degli habitat per studiare gli impatti spaziali della regolamentazione della pesca. Abbiamo applicato questo approccio alla pesca del nasello comune nel Mediterraneo nord‐occidentale, per il quale abbiamo valutato scenari di gestione spaziale in termini di stato dello stock e produttività della pesca per identificare le aree a massima priorità di protezione.
Le simulazioni del modello dimostrano che attraverso chiusure locali della pesca è possibile aumentare sia la biomassa dello stock riproduttivo sia gli sbarchi a scala regionale rispetto a uno scenario status quo, ma che migliorare la protezione è un obiettivo più facilmente perseguibile che aumentare la produttività. Inoltre, l'interazione tra le dinamiche di metapopolazione e la redistribuzione dello sforzo a seguito della chiusura locale della pesca determina benefici e svantaggi distribuiti in modo eterogeneo nello spazio, con i primi che si concentrano in prossimità delle aree protette.
Un'analisi di rete mostra che le aree a massima priorità di protezione sono quelle con la più alta connettività se l'obiettivo è quello di incrementare lo stock riproduttivo, mentre non emerge alcuna relazione significativa tra connettività e potenziale aumento degli sbarchi.
Sintesi e applicazioni.
L’approccio proposto fornisce uno strumento per (1) valutare misure di protezione spaziale che mirano a migliorare le prestazioni della pesca in termini di conservazione e sostenibilità socioeconomica e (2) descrivere la distribuzione spaziale dei costi e dei benefici, la cui conoscenza può aiutare a guidare una gestione efficace e a ottenere il sostegno delle parti interessate. La dispersione spaziale degli adulti rimane la principale fonte di incertezza del modello, che richiede ulteriori indagini per applicare efficacemente il nostro approccio alla regolamentazione della pesca.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
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.
The presence of plastic waste in the marine environment has driven the scientific community to make significant efforts to study and mitigate its possible effects. One of the critical aspects is to ...determine if and how an increase in ingestion events may occur as a result of the accumulation of plastic waste on the seabed. In this study,
G. melastomus
is examined for its ability to indirectly provide information on the amount of macroplastics accumulating on the seafloor. Plastic ingestion is explored by describing the feeding habits of the species, which have the potential to provide very useful information regarding biological or ecological issues. The diet of
G. melastomus
mainly consisted of cephalopods, bathypelagic fishes, and decapod crustaceans, increasing in diversity during growth. The generalist-opportunistic feeding behaviour of this species leads to the incidental ingestion of plastic particles (
N
= 47, with a mean (± SD) of 1.47 ± 0.28 per specimen) which can be indirectly associated to the presence of macroplastics on the seafloor. Indeed, our results indicate a significant relationship between the amount of macroplastics present on the seabed and the frequency of ingestion of plastic particles by blackmouth catshark. We propose
G. melastomus
as an excellent candidate for developing a valid monitoring strategy for the presence of plastics on the seabed, as requested by the EU Marine Strategy Framework Directive.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Among FAO’s Major Fishing Areas, the Mediterranean and the Black Sea had the highest percentage (62.5%) of stocks fished at unsustainable levels, especially demersal stocks. Spatial-temporal ...restrictions of fishing activities are important measures used for the management of marine stocks. However, sometimes these regulations are not fully implemented due to a lack of effectiveness and compliance, which contributes to their failure. Here, we developed a food-web model approach using the Ecopath with Ecosim (EwE) model representing the Fisheries Restricted Area (FRA) of the Gulf of Lion ecosystem (CoSEGoL model) prior to the establishment of the fisheries restrictions (2006–2008). We characterized the structure and functioning of the ecosystem before and after its establishment. The constructed food-web model was then fitted to the available time series of data from 2008 to 2016 to verify whether this FRA has contributed to the recovery of target demersal species and the demersal community. The fitted model was used to explore alternative future management scenarios to explore feasible management options in order to ensure a full ecosystem recovery under climate change conditions. Our results suggest a failure in the recovery of target species in the restricted area under the current management scenario, potentially revealing a lack of protection efficiency and/or enforcement. Scenarios of management options under plausible climate futures revealed possible recovery of targeted species, especially European hake. The study highlighted the importance of considering trophic interactions between predators and prey to identify trade-offs and synergies in fisheries management outcomes and the need to consider both fishing and climate dynamics.
•Fishing impacts were higher after the establishment of the Fisheries Restricted Area.•Fishing regulations failed to rebuild and protect demersal commercial stocks.•The lack of enforcement in the Fisheries Restricted Area contributed to the failure.•Alternative management can improve demersal community status in this area.•Considering trophic interaction is needed when assessing management options.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
In the Mediterranean Sea, the blackbellied angler, Lophius budegassa Spinola, 1807, represents a relevant fraction of the commercial by-catch of bottom trawling and small-scale fisheries that use ...passive gears (e.g., set nets, bottom longlines, etc.). Despite its importance, there are no comprehensive studies on the population dynamics of this species, and there is still scarce and scattered knowledge of its biology and ecology. Biomass, morphometric, and biological data of the blackbellied angler were collected from 1994 to 2021 by means of the Mediterranean International Bottom Trawl Survey (MEDITS) programme in the Ligurian and northern Tyrrhenian Seas, and in the EU Data Collection Framework during the period of 2006-2021. Furthermore, ageing was performed on specimens collected from 2013 to 2021 during the MEDITS programme. There were high values for the density indices and the spatial distribution of biomass in the central sector of the investigated area (the Tuscan Archipelago), mostly on the continental shelf. The length-weight relationship showed negative allometric growth when considering the sexes together, and no difference between the sexes. The size at first maturity (L50) was estimated at 39.4 cm total length (TL) in females and at 29.2 cm TL in males. The obtained Von Bertalanffy growth parameters were: in females, L∞ = 74.50 cm, k = 0.10 years-1, and t0 = -0.40 years; in males, L∞ = 61.30 cm, k = 0.14 years-1, and t0 = -0.38 years. There were differences in growth between males and females for L∞ (χ2 = 10.04; p < 0.05) and k (χ2 = 6.12; p < 0.05).
Worldwide, states are gazetting new Marine Protected Areas (MPAs) to meet the international commitment of protecting 30% of the seas by 2030. Yet, protection benefits only come into effect when an ...MPA is implemented with activated regulations and actively managed through continuous monitoring and adaptive management. To assess if actively managed MPAs are the rule or the exception, we used the Mediterranean and Black Seas as a case study, and retrieved information on monitoring activities for 878 designated MPAs in ten European Union (EU) countries. We searched for scientific and grey literature that provides information on the following aspects of MPA assessment and monitoring: ecological (e.g., biomass of commercially exploited fish), social (e.g., perceptions of fishers in an MPA), economic (e.g., revenue of fishers) and governance (e.g., type of governance scheme). We also queried MPA authorities on their past and current monitoring activities using a web-based survey through which we collected 123 responses. Combining the literature review and survey results, we found that approximately 16% of the MPA designations (N = 878) have baseline and/or monitoring studies. Most monitoring programs evaluated MPAs based solely on biological/ecological variables and fewer included social, economic and/or governance variables, failing to capture and assess the social-ecological dimension of marine conservation. To increase the capacity of MPAs to design and implement effective social-ecological monitoring programs, we recommend strategies revolving around three pillars: funding, collaboration, and technology. Following the actionable recommendations presented herein, MPA authorities and EU Member States could improve the low level of MPA monitoring to more effectively reach the 30% protection target delivering benefits for biodiversity conservation.
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•Protection benefits occur only when an MPA is implemented and actively managed.•Literature and surveys were used to assess actively managed MPAs in Southern Europe.•Barely 16% of designated MPAs have baseline and/or monitoring studies.•Funding, technology, and collaboration strategies could increase MPAs' efficiency.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Many deep‐water fish populations, being K‐selected species, have little resilience to overexploitation and may be at serious risk of depletion as a consequence. Sea warming represents an additional ...threat. In this study, the condition, or health, of several populations of common ling (Molva molva), blue ling (Molva dypterygia) and Mediterranean or Spanish ling (Molva macrophthalma) inhabiting different areas in the North Atlantic and the Mediterranean was evaluated, to shed light on the challenges these deep‐water species are facing in the context of fishing activity and a warming climate. The data on the condition of Molva populations which are analysed here have been complemented with data on abundance and, for the southernmost species (Mediterranean ling), with two other health indicators (parasitism and hepato‐somatic index). Despite some exceptions (e.g., common ling in Icelandic waters), this study shows that the condition of many populations of Molva species in the northeastern Atlantic and the Mediterranean Sea has worsened, a trend which, in recent decades, has usually been found to be accompanied by a decline in their abundance. In addition, the poor health status of most populations of common ling, blue ling and Mediterranean ling considered in this analysis points to a lower sustainability of these populations in the future. Overall, the health status and abundance of Molva populations in the northeastern Atlantic and the Mediterranean suggest that only some populations located in the North Atlantic may be able to rebuild, whereas the populations in southern North Atlantic and the Mediterranean, which are probably most at risk from sea warming, are facing serious difficulties in doing so. In the context of fisheries and global warming, this study's results strongly indicate that management bodies need to consider the health status of many of the populations of Molva species, particularly in southern European waters, before implementing their decisions.
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