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A narrow relationship between marine resources and local populations always existed in fishing communities of coastal areas. In the Portuguese estuaries bait fishing is a common practice in which gatherers collect intertidal species such as seaworms, shrimps, crabs or clams. In recent Local Natural Reserve of Douro Estuary (RNLED) this activity is fairly entrenched due to the proximity of a great fishing zone, the Afurada, and the abundance of recreational fishermen operating in the area. This study aimed to quantify the impact of bait fishing gathering on the ecology of this estuary benthic community, in order to propose management measures for this activity, ensuring its sustainability, and to verify the influence this activity may have on the conservation of intertidal resources in a protected area. Between June 2010 and May 2011 monthly samples were collected in the intertidal zone, in order to quantify the density of populations of Hediste diversicolor and Scrobicularia plana at two locations in the estuary. During the same time period, weekly interviews were performed to bait fishing gatherers operating in RNLED area. In this area of Douro estuary, (239.7ind/m2) was the most abundant species compared to the clam S. plana (0.3ind/m2). In the area of RNLED the species most collected by bait fishing gatherers was the polychaete , and it is estimated that each year 9.9tons are captured, representing an annual mean catch per bait fishing gatherer of 0.3tons. However, the total annual biomass collected was substantially less than the productivity estimated for the entire intertidal area of RNLED (78.7 to 141.3tons). The number of bait fishing gatherers varied between 0 on December 2010 and 12 in July 2010, showing a decrease in activity in the RNLED, especially during the times when surveillance occurs. The area prospected by each gatherer was estimated to be 10m2/day. Considering both tides and all the effort done by an average of 8 men/day, the prospected area was 80m2/day, corresponding to 0.3% of the intertidal area. This effort was mainly concentrated in about 1/3 of the available intertidal area. Results indicated the sustainable management of bait fishing activity in the referred protected area is possible. However, other aspects must be taken into account, such as the possible conflict of this activity with biodiversity conservation in the reserve. Therefore, we suggest some possible solutions for the sustainability of this activity, along with less disturbance to birds that may feed in the reserve, such as: delimitation of a marginal area within the reserve, smaller than the current one, where the collection of organisms is allowed, as well as the oversight and control of licenses and educational procedures. Moreover, these measures would have a positive impact in the integrated management of the reserve, while enabling an activity with positive economic consequences in an underprivileged population. Also, they will contribute to lower the impact of human presence on the avifauna and on the structure of the sediments. Nas comunidades piscatórias das zonas costeiras sempre existiu uma estreita ligação entre os recursos marinhos e as populações locais. Nos estuários portugueses é comum a presença de mariscadores na apanha de algumas espécies intertidais como as minhocas, os camarões, os caranguejos ou as ameijoas. Na recente criada Reserva Natural Local do Estuário do Douro (RNLED) esta actividade está bastante enraizada pela proximidade de uma forte zona piscatória, a Afurada, e pela abundância de pescadores lúdicos que actuam na zona. Os objectivos deste estudo são quantificar o impacto que esta actividade tem na ecologia desta comunidade bentónica estuarina, propor medidas de gestão para assegurar a sua sustentabilidade, e verificar a influência que esta actividade poderá ter na conservação dos recursos intertidais numa área protegida. Entre Junho de 2010 e Maio de 2011 foram efectuadas amostragens mensais na zona intertidal para quantificação da densidade das populações de Hediste diversicolor e Scrobicularia plana em dois locais do estuário. Durante o mesmo período de tempo foram realizados inquéritos semanais aos apanhadores que efectuavam esta actividade na área da RNLED. Nesta zona do estuário do Douro, a espécie é mais abundante (239.7ind/m2) em relação à ameijoa S. plana (0.3ind/m2). Na área da RNLED a espécie apanhada em maior abundância pelos mariscadores é o poliqueta e estima-se que por ano sejam capturadas 9.9 toneladas, o que representa uma média anual de captura por mariscador de 0.3 toneladas. No entanto a biomassa anual total colectada é bastante inferior à produtividade anual estimada para a totalidade da área intertidal da RNLED (78.7 a 141.3 toneladas). O número de mariscadores por dia variou entre 0 em Dezembro 2010 e 12 em Julho 2010, tendo-se verificando uma diminuição da actividade dentro da RNLED, especialmente nas horas em que existe vigilância. A área revolvida por cada apanhador estima-se em 10m2/dia. Considerando as duas marés por dia e todo o esforço feito por uma média de oito apanhadores/dia, a área prospectada foi de 80m2/dia, correspondendo a 0,3% da área intertidal. Este esforço foi concentrado principalmente em aproximadamente 1/3 da área disponível intertidal. Os resultados indicam que é possível a gestão sustentável da apanha da minhoca na área protegida. No entanto, outros aspectos devem ser tidos em conta para que esta actividade não provoque conflitos com os objectivos de conservação da biodiversidade na reserva. Assim, sugerimos algumas possíveis soluções para a sustentabilidade da actividade, juntamente com menor perturbação para as aves que se alimentam na reserva tais como: delimitação de uma área marginal dentro da reserva, menor que a actual, onde a apanhar é permitida, bem como a fiscalização no controle das licenças e acções de educação ambiental. Por outro lado estas medidas teriam um impacto positivo na gestão integrada da reserva, permitindo simultaneamente uma actividade com reflexos económicos positivos numa população desfavorecida. Também vão contribuir para diminuir o impacte da presença humana na avifauna e sobre a estrutura dos sedimentos.

The Mondego estuary is a mainly polyhaline estuary in central Portugal in which eutrophication increased during the last decades of the 20th century. In 1998 the system hydrology was changed, aiming to reverse the eutrophication process. A long environmental monitoring database showed that the mean concentrations of dissolved inorganic phosphorus (DIP) increased by 50%, due to the increase in winter concentrations, i.e., in periods characterized by lower temperature and lower salinity. Given existing background knowledge, especially on the system hydrodynamics, phosphorus dynamics and phosphorus speciation in the estuary, we framed the hypothesis that the significant increase of DIP could be related to different sorption capacities of the sediments. The results highlighted two scenarios: i) Before 1998 the nutrient-rich freshwater input from the upstream cultivated lands entered the system through the area with the highest PO4-P adsorption capacity (Q* = 657 mu g P g(-1) wwt), thus the PO4-P availability in the water column was mostly dependent on the mineralization processes, which is in agreement with previous findings; ii) After 1998, the water residence time diminished from moderate (weeks) to short (days). This change coincided with a diversion of the water to an area with a much lower PO4-P adsorption capacity (Q* = 410 mu g P g(-1) wwt), which represented a decrease in 7.3% of the system adsorption capacity. This means that sediments were not able to adsorb much of the PO4-P and a higher equilibrium concentration occurred in the water column. The sorption study proved to be a valuable tool in testing our hypothesis and provided essential information on the mobility of PO4-P from soils/sediments to the water column. (C) 2011 Elsevier Ltd. All rights reserved.

Geographic information systems (GIS) are now widely applied in coastal resource management. Their ability to organise and interface information from a large range of public and private data sources, and their ability to combine this information, using management criteria, to develop a comprehensive picture of the system explains the success of GIS in this area. The use of numerical models as a tool to improve coastal management is also widespread. Less usual is a GIS-based management to ol implementing a comprehensive management model and integrating a numerical modelling system into itself. In this paper such a methodology is proposed. A GIS-based management tool based on the DPSIR model is presented. An overview of the MOHID numerical modelling system is given and the method of integrating this model in the management tool is described. This system is applied to the Sado Estuary (Portugal). Some preliminary results of the integration are presented, demonstrating the capabilities of the management system.

The management of french estuaries After a general presentation of three main estuaries (Seine, Loire, Gironde), estuarine hydrology and sedimentological processes inducing a turbidity maximum, are presented ; the part played by hydrodynamic factors (tide, river flow) is explained. Recent studies on these estuaries show relationships between hydrosedimentological processes and estuarine sedimentology (migration of turbidity maximum), biology (primary production) and chemistry (nutrients, organic matter, dissolved oxygen, micro pollutants). The knowledge of these relationships allows to point out the consequences of human activities for estuaries, and finally guidelines for a better management are proposed., RÉSUMÉ Après une présentation générale des trois principaux estuaires français (Seine, Loire, Gironde), on précise le rôle des facteurs hydrodynamiques (marée, débit fluvial) sur l'hydrologie estuarienne et sur les mécanismes sédimentaires qui conduisent notamment à la formation d'un bouchon vaseux. Au vu des derniers résultats des études réalisées sur ces trois estuaires, il est ensuite montré quelles sont les relations entre les mécanismes hydrosédimentaires et les caractéristiques sédimentologiques (déplacement du bouchon vaseux), biologiques (production primaire) et chimiques (sels nutritifs, matière organique, oxygène dissous, micropolluants). La connaissance de ces relations permet enfin de préciser quelles peuvent être les conséquences des activités humaines sur les estuaires, et de définir des lignes directrices pour une meilleure gestion., Guillaud J.-F., Romana A. La gestion des estuaires en France. In: Norois, n°121, Janvier-Mars 1984. La France et la gestion du milieu marin et côtier. pp. 97-112.