Maria Dulce Subida

Biochemical responses of the shore crab (Carcinus maenas) in a eutrophic and metal-contaminated coastal system (Óbidos lagoon, Portugal)

A eutrophic and metal-contaminated coastal system (Obidos lagoon, Portugal) was monitored combining water/sediment quality parameters and Carcinus maenas biomarkers (accumulated metals, oxidative stress and biotransformation responses). Two confined branches (Barrosa and Bom-Sucesso) were surveyed and compared with a reference area. Both crab genders from Barrosa exhibited activation of hepatopancreas CAT, GPx and GST, pointing out this area as the major impacted in the lagoon. Females captured at Barrosa were more vulnerable to peroxidative damage while only males showed decreased EROD activity, reinforcing gender specificities. In general, responses were not directly attributed to metals in hepatopancreas, as supported by Principal Component Analysis (PCA). However, higher metals (Ni, Cu, Cd) and nutrients levels registered in Barrosa water were associated with the observed oxidative stress responses by PCA. Despite the difficulty to establish cause-effect relationships due to the co-occurrence of various stressors and their interactions, the adopted integrated monitoring strategy appears to be promising.

Multivariate methods and artificial neural networks in the assessment of the response of infaunal assemblages to sediment metal contamination and organic enrichment.

A 4-year annual sediment survey was conducted in an organically enriched tidal channel to compare the performance of univariate community descriptors, traditional multivariate techniques (TM) and artificial neural networks (AANs), in the assessment of infaunal responses to moderate levels of sediment metal contamination. Both TM approaches and the SOM ANN revealed spatiotemporal patterns of environmental and biological variables, suggesting a causal relationship between them and further highlighting subsets of taxa and sediment variables as potential main drivers of those patterns. Namely, high values of non-natural metals and organic content prompted high abundances of opportunists, while high values of natural metals yielded typical tolerant assemblages of organically enriched areas. The two approaches yielded identical final results but ANNs showed the following advantages over TM: ability to generalise results, powerful visualization tools and the ability to account simultaneously for sediment and faunal variables in the same analysis. Therefore, the SOM ANN, combined with the K-means clustering algorithm, is suggested as a promising tool for the assessment of the ecological quality of estuarine infaunal communities, although further work is needed to ensure the accuracy of the method.

On the Occurrence of Afropinnotheres monodi Manning, 1993 (Decapoda: Pinnotheridae) in European Waters

Abstract Heretofore, the pinnotherid crab, Afropinnotheres monodi, had been recorded only from African waters. The range is now extended into European waters with discovery of material in the Gulf of Cádiz. Furthermore, early collections of material had occurred only in open water; now three hosts can be assigned, the clams Scrobicularia plana, Ruditapes decussatus and Cerastoderma glaucum. Further discoveries of this pinnotherid may now be expected, especially along the coast of Portugal.

Nekton response to freshwater inputs in a temperate European Estuary with regulated riverine inflow

The aim of this 12-year study was to assess the nekton (fish, decapod crustaceans) response to freshwater inputs (rainfall, dam discharges) in a temperate estuary with regulated riverine inflow. Although interannual variability in river discharges to the Guadalquivir estuary has been extremely high since the construction of a dam in 1930, a significant decreasing trend in the dams discharges has been observed in the last 80 years. During this study, an alternation of wet, standard and dry years occurred in the estuarine area but no significant long-term trend was observed. River discharge, in turn, showed a considerable interannual variability and a significantly decreasing long-term trend. Freshwater inputs had an immediate effect on estuarine salinity and turbidity, and consequently on prey availability (mysids). Although 124 nektonic species were collected, only 47 of them (adding up to 99.7% of total abundance) were regularly present in the estuary: 32 marine migrants, 13 estuarine species and 2 diadromous species. Well-defined temporal changes in species composition and abundance yielded clear seasonal patterns in the estuarine nektonic community. Considerable intermonth and interannual changes were occasionally observed relating to freshwater inputs, mainly in winter/autumn of wet years. Thus, within each two-month period, some significant interannual differences in the nektonic community were also observed, with marine migrants tending to be more abundant in dry years. However, changes in the studied nektonic community did not show long-term trends. In conclusion, natural and human-controlled freshwater inputs currently play a significant role in determining the physicochemical conditions and the biota of the Guadalquivir estuary. However, although freshwater input seemed to transitorily affect the estuarine nekton, either directly (flushing out) or indirectly (through changes in salinity, turbidity and prey availability), a quick reestablishment of the estuarine nekton (strong resilience) was observed following freshwater inputs together with the recovery of environmental conditions within the estuary.

Correction: Exploitation rates of two benthic resources across management regimes in central Chile: Evidence of illegal fishing in artisanal fisheries operating in open access areas

[This corrects the article DOI: 10.1371/journal.pone.0180012.].