Quality assessment of escaping silver eel (Anguilla anguilla L.) to support management and conservation strategies in Mediterranean coastal lagoons

Abstract

Silver eel samples, collected from the lagoons of Fogliano and Caprolace (Italy), were investigated for a broad range of contaminants (29 polychlorinated biphenyls, 9 polybrominated diphenyl ethers, 5 dichlorodiphenyltrichloroethane, 5 chlordanes, hexachlorobenzene, 3 hexachlorocyclohexane, and 5 metals). Concentrations of targeted compounds stand for a general low contamination pattern. Infestation by Anguillicola crassus and virus infections were also examined. No parasite infestation was found, while infected silver eels had a low prevalence for EVEX, and, for the first time in the Mediterranean area, for AngHV-1. Overall, a good quality status of escaping silver eels, for both lagoons, was highlighted by the use of integrative Indexes. A quality assessment of the ecological status of the two lagoons was carried out developing an expert judgment approach, in order to characterize the habitat of eel stocks. A Final Pressure Index was derived, whose values showed an overall limited global anthropogenic impact acting on both lagoons. Results stand for the suitability of an integrated approach to assess lagoon habitats and eel local stocks quality. This could be proposed as a tool to identify sites yielding high quality eel spawners in the Mediterranean region, in order to set up suitable management frameworks, providing elements to appraise and discuss the potential of coastal lagoons in the Mediterranean region towards the recovery of the eel global stock.

Evaluation of Environmental Quality of Mediterranean Coastal Lagoons Using Persistent Organic Pollutants and Metals in Thick-Lipped Grey Mullet

“…The congeners that mostly contributed to the total PCB loads were PCB 153 (18.5% vs. 22.2% respectively for Fogliano and Caprolace) and PCB 138 (12.3% vs. 10.9%). These percentages are in line with those observed in other fish species, such as the eel from Belgium [47,48] and from transitional environments in Italy [39,49,50]. In 1994, in the two coastal lagoons under study, Casini et al [51] found, in muscle tissues of four species of grey mullets (C. aurata, C. saliens, C. ramada, and M. cephalus), similar total PCB concentrations.…”

“…A methodology based on an expert judgement approach [38], developed for the ecological evaluation of transitional waters (WFD, 2000/60) with special reference to lagoon ecosystems in the Mediterranean area has been set to assess the environmental quality of Fogliano and Caprolace lagoons [39]. This method relies on the preliminary selection of several environmental descriptors of both direct and indirect human pressures acting on lagoon ecosystems.…”

“…Hydro-morphology and the quality of water, as well as the use of the lagoon resources and the surrounding landscape, are taken into account and quantified for the calculation of indices. A detailed description of the selection of pressure indicators, their attribution to specific categories and quantification, data sources and methods of calculation of indices are given in Capoccioni et al [39].…”

Monitoring Skeletal Anomalies in Big-Scale Sand Smelt, Atherina boyeri, as a Potential Complementary Tool for Early Detection of Effects of Anthropic Pressure in Coastal Lagoons

“…The lagoons' overall environmental quality was assessed using a method based on expert judgement [64], whose background, rationale and methodology are detailed in [65]. The method relies on the preliminary choice, by subjective expert judgement, of several indicators of direct and indirect human pressure acting on the lagoon ecosystems, which are quantified on a range scale (from 0-not present to 5-very high).…”

“…CPIs scores concur in turn to the calculation of a Final Pressure Index, FPI. For a detailed description of the choice of pressure indicators for the lagoons under study, their attribution to categories and their quantification, data sources, and formulas for the CPIs and FPI calculation, see Section S1 in Supplementary Material file and [65].…”