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Palma S.,Instituto Nacional Of Recursos Biologicos Inrb Ipimar | Mourino H.,University of Lisbon | Silva A.,Instituto Nacional Of Recursos Biologicos Inrb Ipimar | Barao M.I.,University of Lisbon | Moita M.T.,Instituto Nacional Of Recursos Biologicos Inrb Ipimar
Harmful Algae | Year: 2010

Marine planktonic diatoms of the genus Pseudo-nitzschia Peragallo have been responsible for amnesic shellfish poisoning (ASP) events worldwide through the production of the neurotoxin domoic acid (DA). In order to better understand the dynamics of the toxic events of Pseudo-nitzschia there is the need to describe their seasonal and spatial patterns. The main goal of this work is to establish the relation between a physical variable easily measured like coastal upwelling and the presence of Pseudo-nitzschia blooms, in Lisbon Bay. Phytoplankton samples were collected once a week from June 2001 to May 2005 and daily upwelling index were calculated based on values of geostrophic winds. Data of sea surface temperature, upwelling index, and Pseudo-nitzschia concentrations were used to construct statistical models to evaluate the seasonal variation and the relation between all parameters. Due to the nature of the time series involved in the study, it was applied the Zero-Inflated Generalized Poisson Regression Model. An initial spectral analysis was applied to the upwelling data in order to accurately understand the characteristics of the coastal upwelling. The results obtained indicate a close relation between upwelling events and Pseudo-nitzschia blooms which occurred during spring and summer. The mathematical model that describes Pseudo-nitzschia blooms in Lisbon Bay shows a lag of 4-6 days between the upwelling events and the presence of Pseudo-nitzschia in the monitoring station. © 2009 Elsevier B.V. All rights reserved.

Marcalo A.,Instituto Nacional Of Recursos Biologicos Inrb Ipimar | Marques T.A.,Center for Research into Ecological and Environmental Modelling | Marques T.A.,University of Lisbon | Araujo J.,Instituto Nacional Of Recursos Biologicos Inrb Ipimar | And 3 more authors.
ICES Journal of Marine Science | Year: 2010

To study the impact of purse-seine fishing on deliberately released sardine, two laboratory experiments were performed to explore the effect of net confinement for 10, 20, 40, and 60 min at 18 and 23°C. A third experiment considered two levels of fish density while confined for 20 and 40 min at 16°C. Analysis of cortisol and haematocrit demonstrated that stress immediately after simulated fishing was milder than in commercial fishing and did not correlate with observed delayed mortality. Scale loss was related to the probability of dying (mean values of 16.3 and 2 for dead fish and survivors, respectively), and fin erosion was a long-term stress response observed in both dead and surviving fish. Time of confinement was an important stressor, with survival rates decreasing significantly with increasing periods in the net, and temperature having an additional negative effect. Density effects were less conclusive, but there was some indication that survival correlated with biological condition (heavier fish were more likely to survive). It seems that delayed mortality after release can be substantial, although death is not certain and appropriately modified fishing operations and favourable environmental conditions may enhance the probability of sardine survival. © 2009 International Council for the Exploration of the Sea. Published by Oxford Journals. All rights reserved.

Rodrigues A.M.,University of Aveiro | Quintino V.,University of Aveiro | Pereira F.,University of Aveiro | Pereira F.,Instituto Nacional Of Recursos Biologicos Inrb Ipimar | Freitas R.,University of Aveiro
Estuarine, Coastal and Shelf Science | Year: 2012

The macroinvertebrate spatial distribution patterns in the Lagoon of óbidos were studied in 1984 and revisited in 2002. The overall surficial sediments and benthic community patterns show consistent similarities in the two sampling periods, but also important differences. The lagoon is relatively shallow, with about 1/3 of the area covered with extensive intertidal sand banks. These are interrupted by a navigation channel bordering the northern margin (1984) and, following dredging operations, a new navigation channel was opened along the southern margin (2002). The sediments in the navigation channels were coarser and with less percentage of fines in 2002 than in 1984.Arthropods dominated the species richness and abundance in 1984, but were much less important in 2002, when the community was dominated by molluscs and annelids, both in species numbers as well as in abundance. In 1984, the structure of the macrofauna communities closely followed a general model proposed for Atlantic and Mediterranean lagoons, with the marine, the transition and the lagoon communities occupying very well defined areas. This gradient was in accordance with an increase in the fines and organic matter content directed inwards allowing for the coexistence of several characteristic lagoon species with others characteristic of organic enriched sediments. In 2002 this spatial pattern is still recognized but the marine and the transition communities are spatially mixed, occupying both the entrance region and the navigation channels, whereas the characteristic lagoon community identified in 1984 was only recognized in a group of sites located along the southern margin in 2002. Several species show very important changes in their distribution extent in the lagoon system. These changes essentially show a generalized inward expansion of the distribution range of the marine species, in agreement with a larger influence of marine conditions toward the inner areas of the lagoon. This study shows how sensitive lagoon systems can be to the regime of water exchange rate with the ocean being possible to induce more or less marine conditions to the system as a response to the flow and exchange rate of water through the communication inlet following dredging interventions. © 2012 Elsevier Ltd.

Carvalho S.,Instituto Nacional Of Recursos Biologicos Inrb Ipimar | Pereira P.,Instituto Nacional Of Recursos Biologicos Inrb Ipimar | Pereira F.,Instituto Nacional Of Recursos Biologicos Inrb Ipimar | de Pablo H.,Instituto Nacional Of Recursos Biologicos Inrb Ipimar | And 2 more authors.
Marine Environmental Research | Year: 2011

The present work aimed to identify the main environmental drivers shaping temporal and spatial dynamics of macrobenthic communities within a eutrophic coastal lagoon. Sediments in the Óbidos lagoon showed a gradient of increasing metal contamination from the inlet area to inner branches. The mid-lower lagoon area exhibited an intermediate contaminated condition between the inlet and upstream areas, suggesting that the effects of the organic loadings into the lagoon may be reflected until this area. This transitional feature was corroborated by biological data, with macrobenthic assemblages displaying characteristics of down- and upstream areas. Macrobenthic abundance peaked in winter, which was associated with a higher nutrient availability (mainly ammonium) and the proliferation of green macroalgae in mid-lower and inner lagoon areas. However, massive macroalgae growth resulted in a sharp decrease of macrobenthic diversity and abundance in spring, particularly where the higher amounts of decaying algae were detected. Higher dissimilarities between assemblages were detected during winter (and spring, for trophic composition), while in summer, differences were highly attenuated. The least contaminated area (close to the sea inlet) experienced smaller temporal variations for environmental variables, as well as the lowest temporal biological variability. This area was dominated by carnivores, which were related with increased salinity. Deposit-feeders were numerically dominant in the lagoon, being generally spread within organically enriched sandy and muddy areas. The high concentration of chlorophyll a and suspended particulate matter in water was reflected in the abundance of deposit-feeders/suspension-feeders, taking benefit of the high primary productivity. On the other hand, deposit-feeders/herbivores responded to the decay of macroalgae mats in the sediment. Biological associations varied with the biological data used (taxonomic versus trophic group composition; abundance versus biomass), highlighting the relevance of the combination of different data analysis' approaches. In general, BIOENV analysis indicated total phosphorus, biomass of Ulva, metals and organic carbon and nitrogen as being significantly influencing benthic patterns. On the other hand, discrepancies in ecological behaviours of some taxa were also detected in the present study stressing the need for additional studies on the relationships between macrobenthic communities and environmental variables. Implications of the present results for monitoring studies are discussed. © 2010 Elsevier Ltd.

Freitas R.,University of Aveiro | Ricardo F.,University of Aveiro | Pereira F.,Instituto Nacional Of Recursos Biologicos Inrb Ipimar | Sampaio L.,University of Aveiro | And 4 more authors.
Estuarine, Coastal and Shelf Science | Year: 2011

Near-shore benthic biotopes, in the 2-30 m depth range, were analyzed and mapped using a combination of biological, sedimentary and acoustic data to interrogate the utility of these methods. The surveyed area covered approximately 270 km2, along 80 km of the Southeast coast of Portugal. The acoustic data were acquired with a single beam ground discrimination system (QTC VIEW, Series V), connected to a dual frequency echo sounder (50 and 200 kHz). Sediment grain size and macrofaunal community data were obtained by grab sampling at 88 sites. The sedimentary and the biological data were subjected to classification and ordination analysis and the acoustic data obtained with the two frequencies were analyzed individually with the QTC IMPACT (v3.4) software and classified into acoustic classes. The affinity groups obtained with the three datasets were mapped using a Geographic Information System. The study area showed an inshore-offshore pattern with sands ranging from very fine to very coarse, revealing a sediment distribution in the near-shore shelf comprised by two main areas; a very fine/fine sand area up to 7-10 m depth and a very coarse/coarse sand area offshore. In turn, the biological data also showed an inshore-offshore pattern, identifying two main biological assemblages: fine/very fine sand and coarse/very coarse sand communities. Furthermore, the biological pattern clearly reflected the hydrodynamic conditions of the area, from highly hydrodynamic shallow depth to the calmer deeper areas. Accordingly, species richness and densities were lower at shallow areas than at deeper depth. The acoustic data identified the prevailing biosedimentary gradients along the inshore-offshore direction. Overall, the results obtained here showed that the acoustic system could identify two main areas based on sediment grain size, which closely related to the two main biological communities (groups A and B). This study indicates the importance of combining several layers of information in order to increase the spatial resolution of the main biotope distribution (validating the acoustic data) and detail their sub-divisions (ground-truth sampling). Furthermore, we show that designing ground-truth samples on the basis of the acoustic diversity data allows the biological data to " speak" for itself. In general, acoustic techniques are used as a means to optimize ground-truth sampling. This will only be valid if acoustics can capture all the essence of biotope heterogeneity. If this is not the case, special attention should be given when using broad scale methods (acoustic remote sensing) devoted to biotope mapping. © 2011 Elsevier Ltd.

Carvalho S.,Instituto Nacional Of Recursos Biologicos Inrb Ipimar | Constantino R.,Instituto Nacional Of Recursos Biologicos Inrb Ipimar | Cerqueira M.,Instituto Nacional Of Recursos Biologicos Inrb Ipimar | Pereira F.,Instituto Nacional Of Recursos Biologicos Inrb Ipimar | And 3 more authors.
Estuarine, Coastal and Shelf Science | Year: 2013

The present study aimed to assess short-term effects of intertidal bait digging on macrobenthic assemblages of two south Iberian Atlantic coastal systems: the Ria Formosa (RF) lagoon and the Bay of Cádiz (BC). Within each system, two different areas were selected. In each area, six plots were randomly located at least 1m apart from each other. Half of the plots were left undisturbed (control) and the other three were dug (disturbed). Three macrobenthic core samples were taken from each plot, immediately before, one, four and seven days after digging. Samples for analyses of grain-size and organic matter content (OM) were also collected from the top 2cm sediment layers in each sampling period. The effects of bait digging were site specific and were related to sediment and biological composition of the areas before disturbance. Macrobenthic assemblages from the area with proportionally less mud content (RF1), which presented the greatest infaunal diversity and evenness values before disturbance, showed minor effects of digging and assemblages generally recovered within 7 days. On the other hand, the areas located in the Bay of Cádiz, which before disturbance presented the greatest mud content and macrobenthic assemblages dominated by only a few species, were the most affected and did not show signs of total recovery within 7 days after digging. The abundance of sedentary polychaetes from families Spionidae, Capitellidae and Cirratulidae decreased after digging. In contrast, in some areas the abundance of the gastropods Bittium spp., Haminoea hydatis and Retusa truncatula increased after bait digging indicating that they are less affected by this activity. Differences were detected in the response of benthic assemblages to the same intensity, frequency and nature of disturbance between and within coastal systems. Therefore, generalizations of the effects of bait digging and in the recovery of macrobenthic assemblages in the south of Iberian Peninsula are not possible. © 2011 .

Pereira P.,Instituto Nacional Of Recursos Biologicos Inrb Ipimar | Pereira P.,University of Aveiro | Carvalho S.,Instituto Nacional Of Recursos Biologicos Inrb Ipimar | Pereira F.,Instituto Nacional Of Recursos Biologicos Inrb Ipimar | And 4 more authors.
Environmental Monitoring and Assessment | Year: 2012

Macroinvertebrate benthic communities are one of the key biological components considered for the assessment of benthic integrity in the context of the Water Framework Directive (WFD). However, under moderate contamination scenarios, the assessment of macrobenthic alterations at community level alone could be insufficient to discriminate the environmental quality of coastal and transitional waters. Keeping this in view, sediment quality of moderately contaminated sites in a coastal lagoon (Obidos lagoon, Portugal) was assessed by the combination of sediment metal levels, Carcinus maenas biomarkers (accumulated metals and oxidative stress responses) andmacrobenthic communities. Two sites were selected in confined inner branches (BS and BB) and a third one in the middle lagoon (ML). The site BB presented slightly higher levels of metals in sediment but biological variables calculated for macrobenthic data were not significantly different between sites. The biotic index M-AMBI that is being applied to assess environmental quality of transitional waters in the scope of theWFD pointed either to high (siteML) or good quality status (BS and BB) in the selected sites. However, crabs from BB site presented significantly higher levels of Ni in hepatopancreas than those from ML and macrobenthic community structure was significantly different between BB and ML. Additionally, spatial differences were obtained for oxidative stress parameters suggesting that BB site presented stressors for crabs (higher GST and lower GSHt at BB site). Factor analysis (PCA) integrating sediment contamination, biomarkers in crabs and macrobenthic data also distinguished BB site as the most environmentally disturbed. On the other hand, at ML site, some macrobenthic variables (equitability and polychaetes' diversity) were found to be enhanced by current environmental conditions, suggesting the existence of a better sediment quality. Current results pointed to the usefulness of integrating macrobenthic community alterations with responses at organism level (bioaccumulation and biochemical endpoints) in order to increase the accuracy of environmental quality assessment in lagoon systems. Moreover, the application of different statistical methods was also found to be recommendable. © Springer Science+Business Media B.V. 2011.

Moita M.T.,Instituto Nacional Of Recursos Biologicos Inrb Ipimar | Silva A.,Instituto Nacional Of Recursos Biologicos Inrb Ipimar | Palma S.,Instituto Nacional Of Recursos Biologicos Inrb Ipimar | Vilarinho M.G.,Instituto Nacional Of Recursos Biologicos Inrb Ipimar
Estuarine, Coastal and Shelf Science | Year: 2010

A study of the mesoscale distribution of phytoplankton communities observed along the Portuguese upwelling coast in 1985-1986 made it possible to identify an assemblage composed by the coccolithophores Helicosphaera carteri, Syracosphaera pulchra and Coronosphaera mediterranea. The assemblage was consistently present in the coast in the following years (1991, 1992, 1994, 2003 and 2005) and from 1992 onwards, Rhabdosphaera clavigera was recognised as being part of it, although in low concentrations During late summer, this group of species showed higher affinities with upwelling waters of subtropical origin (ENACWst) on the SW coast. At the end of the upwelling season, in autumn, the assemblage was advected to the NW shelf due to the intensification of the poleward surface circulation or meridional seasonal changes of environmental conditions. The species maximum abundances were not coincident in space: H. carteri developed at the central part of the western coast while blooms of S. pulchra and C. mediterranea generally occurred further south, such as at the upwelling centre of cape S. Vicente. Syracosphaera pulchra blooms were characterised by lower concentrations of C. mediterranea and vice-versa. The above patterns were recurrent along the years but the relative abundance of each species appeared related to the interannual variability of physical conditions as the upwelling. © 2010 Elsevier Ltd. All rights reserved.

Bernal M.,Spanish Institute of Oceanography | Bernal M.,Rutgers University | Stratoudakis Y.,Instituto Nacional Of Recursos Biologicos Inrb Ipimar | Wood S.,University of Bath | And 4 more authors.
ICES Journal of Marine Science | Year: 2011

Assumptions of daily spawning synchronicity and estimation of egg mortality for Atlanto-Iberian sardine are revised in the context of daily estimators of egg production. An extensive database of ichthyoplankton surveys from 1985 to 2008, aggregated at different levels, is used, a set of mortality models is derived, and a comparison among them is carried out using standard statistical techniques. Analysis of the database shows Atlanto-Iberian sardine to be a late-evening spawner, in agreement with previous knowledge, but suggests a lengthier daily period of spawning. Comparison among the set of mortality models used suggests that estimates of mortality from single surveys for Atlanto-Iberian sardine are often unreliable, and that the mean estimates obtained after aggregating data from various years are statistically significant, more robust, and in line with existing information gathered from the literature. © 2011 International Council for the Exploration of the Sea. Published by Oxford Journals. All rights reserved.

Bernal M.,Spanish Institute of Oceanography | Bernal M.,Rutgers University | Stratoudakis Y.,Instituto Nacional Of Recursos Biologicos Inrb Ipimar | Wood S.,University of Bath | And 3 more authors.
ICES Journal of Marine Science | Year: 2011

A spatially and environmentally explicit egg production model is developed to accommodate a number of assumptions about the relationship between egg production and mortality and associated environmental variables. The general model was tested under different assumptions for Atlanto-Iberian sardine. It provides a flexible estimator of egg production, in which a range of assumptions and hypotheses can be tested in a structured manner within a well-defined statistical framework. Application of the model to Atlanto-Iberian sardine increased the precision of the egg production time-series, and allowed improvements to be made in understanding the spatio-temporal variability in egg production, as well as implications for ecology and stock assessment. © 2011 International Council for the Exploration of the Sea. Published by Oxford Journals. All rights reserved.

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