Efecto de la descarga de aguas residuales sobre la dinámica poblacional de Melarhaphe neritoides (Gastropoda: Littorinidae).

The discharges of sewage effluent treatment plants has a major impact on coastal communities. In our study area (western coast of Portugal) Melarhaphe neritoides (L. 1758) is the dominant high-shore gastropod. Two populations of M. neritoides were studied in order to understand the impact of sewage discharges on intertidal communities: one population in an impacted area and the other in a similar but unimpacted area (reference site). Environmental data and abundance, biomass, population structure and annual growth production of M. neritoides were estimated in the two areas. The results showed that M. neritoides density is higher in the impacted area as a result of massive settlement. The sewage discharge increases the nutrient concentrations in the water, which causes more microalgae to grow on the rocky surfaces. This higher availability of food may promote recruitment. However, we found high mortality in the juveniles in the impacted area, which affected density values on the upper shore levels (where we found the adults) of both areas. Moreover, the adults were bigger in the unimpacted area, which suggests that individuals grow more or live longer in this area.Las descargas de aguas residuales de depuradoras son uno de los mayores impactos sobre las comunidades costeras. En nuestra área de estudio (costa oeste de Portugal) Melarhaphe neritoides (L. 1758) es el gasterópodo dominante en la zona supralitoral. Para entender el impacto que estos vertidos tienen sobre las comunidades intermareales, estudiamos dos poblaciones de M. neritoides: una en un área contaminada y otra en una zona similar, pero no impactada (zona de referencia). En ambas áreas se registraron datos medioambientales, datos de abundancia y biomasa de M. neritoides y se estimó la estructura de las poblaciones y la producción anual. Los resultados muestran una mayor densidad de M. neritoides en la zona contaminada, como resultado de una colonización masiva. Las descargas de aguas residuales aumentan la concentración de nutrientes en el agua, provocando un mayor crecimiento de microalgas en la superficie de las rocas, lo que facilita la colonización. Sin embargo, verificamos una elevada mortalidad de juveniles en la zona contaminada que aproximó los valores de la densidad de las poblaciones en las zonas más altas del litoral (donde encontramos los adultos) en ambas zonas. Además, los adultos eran de mayor tamaño en las áreas no contaminadas, lo que sugiere que en esta zona los individuos tienen un mayor crecimiento o viven durante más tiempo

Composición de grupos tróficos funcionales en una comunidad macrobentónica submareal a lo largo de un gradiente de profundidad

The feeding guild composition of a macrobenthic community from southern Portugal was studied along a depth gradient (1.3 to 32 m). This gradient comprised shallow areas with severe physical stress and deeper areas with no significant hydrodynamic impact at the seafloor. The main goal was to determine the influence of the spatial and temporal differences of the hydrodynamic impact at the seafloor on the feeding guild composition of the macrobenthic community. The feeding guild composition changed gradually with depth, which reflects the differences in the hydrodynamics impact at the seafloor. Herbivores and sand-lickers dominated at the shallowest depths with fine sands, which correlated with higher levels of primary production. Scavengers were also distributed in the shallow areas, which was associated with the lower predation impact. Suspension feeders, in accordance with their physiological requirements, were distributed in coarser sands subjected to a physical impact. Carnivores, surface deposit feeders and sub-surface deposit feeders were distributed mainly below 8 m depth, where there was no significant impact from the wave climate. Carnivores were associated with coarser sands and were mainly small polychaetes and nemerteans. Sub-surface and surface deposit feeders were more abundant in the deepest areas of the depth gradient with fine sands and mud deposits with higher organic content. However, surface deposit feeders also occurred at shallower depths. Some seasonal differences related to disturbance impacts were found in the numerical dominance of the feeding guilds.Se han estudiado las categorías tróficas de una comunidad macrobentónica en el sur de Portugal, a lo largo de un gradiente de profundidad (de 1.3 m a 32 m). Este gradiente incluía áreas someras (poco profundas) con un estrés físico severo y áreas más profundas sin impacto hidrodinámico significativo a nivel del fondo marino. El objetivo principal fue determinar la influencia de las diferencias espaciales y temporales del impacto hidrodinámico en el fondo marino sobre la composición de las categorías tróficas de la comunidad macrobentónica. La composición de estas categorías tróficas cambió gradualmente con la profundidad, reflejando las diferencias del impacto hidrodinámico en el lecho marino. Las profundidades más someras, compuestas por arenas finas, estaban dominadas por anfípodos herbívoros y raspadores de arenas, correspondiéndose con elevados niveles de producción primaria. También había en estas áreas someras carnívoros/necrófagos asociados a un menor impacto de predación. Los suspensívoros, fundamentalmente bivalvos, predominaron en zonas con arenas más gruesas y mayor hidrodinamismo, de acuerdo con sus necesidades fisiológicas. Por debajo de los 8 m de profundidad y en zonas donde no se produce impacto del oleaje, dominaban carnívoros, detritívoros de fondo y de sub-fondo. Los carnívoros, asociados a arenas más gruesas, eran principalmente pequeños poliquetos y nemertinos. Los detritívoros de fondo y sub-fondo eran más abundantes en las zonas más profundas del gradiente, donde aparecían arenas finas y depósitos de limo con elevados contenidos en materia orgánica. Sin embargo, también se encontraron detritívoros de fondo en profundidades menores. Se encontraron algunas diferencias en la dominancia numérica de la estructura trófica a lo largo del año, lo que puede estar relacionado con impactos de incidentes en la zona

TARGET SPECIES OF ARTISANAL FISHERIES AND THEIR CONSERVATION STATUS IN TWO FISHING VILLAGES IN THE ATLANTIC: PENICHE (PORTUGAL) AND ARRAIAL DO CABO (BRAZIL)

This study shared the fishers’ local ecological knowledge (LEK) from the two fishing villages (Peniche, Portugal, and Arraial do Cabo, Brazil), based on answers to the following key question: What are the main target species for fishing in Peniche/Arraial do Cabo? A total of 221 semi-structured interviews were conducted in the Atlantic fishing villages during 2016. Fisher´s interviews reported 42 species of marine animals from Peniche fishing community, and 40 species in Arraial do Cabo. The fisheries resources cited by fishers were assessed for vulnerability, according to the issue’s conservation based in IUCN and Brazilian Red List. We have identified the main target species for artisanal fishing in both fishing villages. The species with some degree of vulnerability included in the list of fishers in Peniche were: T. trachurus and P. glauca. In Arraial do Cabo fishing village this list is formed by nine species: P. saltatrix, E. marginatus, M. bonaci, P. glauca, M. canis, H. flavolimbatus, H. niveatus, G. galeus and P. americanus - Brazilian Subpopulation. These data acquired through the artisanal fishers of these communities can be an essential starting point for the design of future additional research on the conservation of local biological resources. Monitoring the artisanal fisheries through the informal data shared in this study can contribute to more appropriate and integrated management of the marine resources.

Ecological indicators performance during a re-colonisation field experiment and its compliance with ecosystem theories

Through a re-colonisation field experiment three main questions were approached: (1) How do different ecological indicators react during the process of recovery? (2) What does grow first during a community succession, biomass or complexity? (3) Can the chosen ecological indicators help in recognising the three proposed forms of growth: biomass, network and information, throughout re-colonisation?http://www.sciencedirect.com/science/article/B6W87-4H7T0S2-1/1/7f791ab537a262948dd71907dec58cc

A Stochastic Dynamic Methodology (SDM) to the modelling of trophic interactions, with a focus on estuarine eutrophication scenarios

In the face of global change, declines in environmental quality are of increasing concern, especially in shallow coastal areas, densely populated and commonly affected by nutrient enrichment. The warm temperate Mondego estuary (Western Portugal), in common with many other shallow estuarine areas, is exhibiting increased macroalgal growth due to nutrient enrichment. The increase of macroalgal biomass and possible shift of other primary producers resulting from eutrophication, may have profound effects on estuarine trophic chain. The present paper examined the performance of a holistic Stochastic Dynamic Methodology (SDM) in predicting the tendencies of three representative trophic levels as a response to the increase of nutrient concentrations. Therefore, the proposed methodology has been developed by focusing on the interactions between conceptually isolated key-components, such as primary producers (macroalgae and seagrass), some relevant benthic macroinvertebrates, wading birds and changes in local physicochemical conditions. The dynamic model developed was preceded by a conventional multivariate statistical procedure (stepwise multiple regression analysis) performed to discriminate the significant relationships between prevailing biological and environmental variables. Since this statistical analysis is static, the dataset recorded from the field included true gradients of habitat changes. The data used in the model construction was sampled between January 1993 and September 1995 in three areas of the estuary mudflats for benthic macroinvertebrates, macroalgae, environmental and physicochemical factors and from October 1993 to October 1994 for wading birds. The model validation was based on independent data collected in two different periods, from January 1996 to January 1997 and from February 1999 to April 2000 for all the variables selected. Overall, the simulation results are encouraging since they seem to demonstrate the model reliability in capturing the trophic dynamics of the studied estuary by predicting the behavioural pattern for the most part of the components selected under a very complex and variable environmental scenario.http://www.sciencedirect.com/science/article/B6W87-4GKW799-1/1/ab5142848de94cfd92f687763783f2a

Multi-scale approach using phytoplankton as a first step towards the definition of the ecological status of reservoirs

The growing need to analyse the present state of ecosystems and predict their rate of change has triggered a demand to explore species environment relationships for assessing alterations under anthropogenic influence. The Water Framework Directive (WFD) requires the definition of different types of water bodies which are of relevance when assessing their ecological status. The main aim of this study was to define of the types of Portuguese reservoirs located in the North and Centre of Portugal and to assess their ecological status using phytoplankton as water quality indicators. In this study, sampling was carried out in 34 reservoirs during four seasons (spring, summer, autumn and winter), through a period of 8 years (1996-2004).http://www.sciencedirect.com/science/article/B6W87-4ST4CF7-1/1/911b46293dcdcf046f40a1c1863a619

Control estacional, lunar y mareal de la dinámica del ictioplancton en la interfaz entre un estuario templado y las aguas costeras adyacentes (oeste de Portugal)

Influence of season, lunar-tide cycle and tide on ichthyoplankton at the interface between Mondego estuary and the adjacent coast and on up-estuary transport was evaluated. Seasonal samples were collected at a fixed station at the mouth of the estuary during diel cycles, at neap and spring tides. Additionally, four sampling stations along the estuary were assessed. Pomatoschistus spp. was the main estuarine taxon, while Sardina pilchardus and Parablennius pilicornis were the most important marine species. Ichthyoplankton entrance and transport along the estuary presented a seasonal pattern with higher densities during summer. Lunar-tide cycle also represented an important influence, structuring communities that reach the estuary and their subsequent distribution. Solea senegalensis and Sardina pilchardus seemed to take advantage of spring tides to enter the estuary. S. pilchardus appear to be using tides to move upstream of the estuary. Ichthyoplankton entrance in the estuary seemed related to species spawning period, while its distribution within the estuary depends on in situ spawning and on the capacity of species to counteract currents and river flow. The present study provides a better understanding of ichthyoplankton dynamics at the interface of two coastal systems, reinforcing knowledge of the lunar-tide cycle influence on ichthyoplankton communities.Se estudió la influencia de la estación, ciclo lunar y mareas entre el estuario del Mondego y las aguas costeras adyacentes sobre el ictioplancton y el transporte de las larvas hasta el estuario. En cada estación del año, el ictioplancton fue muestreado en una estación fija situada en la desembocadura del estuario, realizandose ciclos diarios en mareas muertas y vivas. Además, fueron muestreadas otras cuatro estaciones en el estuario. Pomatoschistus spp. fue la principal especie estuarina mientras que Sardina pilchardus y Parablennius pilicornis fueron las especies marinas más importantes. La entrada de ictioplancton y transporte a lo largo del estuario presentaron un patrón estacional con mayores abundancias en verano. El ciclo lunar tuvo una importante influencia en la estructuración de las comunidades que llegan al estuario y su posterior distribución. Solea senegalensis y Sardina pilchardus parecen tomar ventaja de las mareas vivas para entrar en el estuario. S. pilchardus parece aprovechar las mareas para moverse hacia la parte alta del estuario. La entrada del ictioplancton en el estuario parece estar relacionada con el periodo de desove mientras que su distribución en el estuario depende del desove in situ así como de la capacidad de las especies de contrarrestar las corrientes y el caudal del río. Este estudio proporciona un mejor entendimiento de la dinámica del ictio- plancton en la interfaz de dos sistemas costeros y refuerza el conocimiento de la influencia del ciclo lunar de la marea en las comunidades ictioplanctónicas

Living from the sea: socio-economic characterization of the fishing communities of arte xávega in Portugal

Este artigo visa caracterizar a pesca com arte xávega do ponto de vista socioeconómico. A arte xávega é um método artesanal de pesca praticado em Portugal desde o século XV, tendo conseguido sobreviver até aos dias de hoje. A pesquisa foi feita com recurso a um inquérito por questionário aplicado em 2018 a comunidades piscatórias da arte xávega, em praias das regiões norte, centro e sul de Portugal continental. A partir destes dados, identificam-se perfis sociodemográficos e económicos de pescadores para compreender as diferentes lógicas de relações que estas comunidades mantêm com esta pesca e com o mar, em particular os seus recursos marinhos. Constata-se que as práticas com a arte xávega traduzem configurações sociais, económicas, ambientais e culturais diversificadas e plurais, e mobilizam uma comunidade mais ampla e heterogénea do que aquela que lhe é comummente associada, refletindo diferentes lógicas de relação entre pescadores e ambiente.This paper aims to characterize the arte xávega (Xávega fishing gear) from a socioeconomic point of view. The arte xávega is an artisanal fishing method practiced in Portugal since the 15th century, having been able to survive until today. Based on a survey with fishing communities of arte xávega, carried out in 2018 on beaches in the north, center and south of Portugal, the paper identifies sociodemographic and economic profiles of fishermen to understand the different logics of relationships that they maintain with this traditional fishing and with maritime resources. It appears that arte xávega reflects diverse and plural social, economic, environmental and cultural positions, and mobilizes a broader and more heterogeneous community than that which is commonly associated with it, which reflects different logics of relationship between the fishermen and the environment.RENATUREinfo:eu-repo/semantics/publishedVersio