Long-term (1781-2010) Eel Fishery in the Coastal Lagoon of Comacchio (Northern Italy) and use of a new Index for Fish Evaluation

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The European eel (Anguilla anguilla L.) is an endangered species with an important role in the local economies of coastal lagoons. Evaluation of its health is of crucial interest both for fisheriesʹ managers and for conservationists. In the lagoon of Comacchio, northern Italy, trends in the eel fishery have been noted since 1781. A sharp decline has been registered since the 1950s and habitat loss would appear to be the most important factor in this stock collapse. Furthermore, a decline in the economic importance of the fishery has led to a lack of funds for restocking, which constitutes a further threat for the conservation of eels in this region. The eel fishery in Comacchio is carried out in autumn using the lavoriero, V‐shaped permanent trapping weirs located in the canal connecting the lagoon to the sea. Because lavoriero capture the fish during their reproductive migration, we report a large dominance of mature females. A Sustainable Eel Fishery Index (SEELF) for the evaluation of fish condition has been designed using body indices, internal indices, and blood parameters. The SEELF Index has been calculated for a 5‐year sample (as a synthetic parameter for the analysis of the historical trend), to reveal whether or not good fishery practices are being respected. Furthermore, mature female eels migrating towards the open sea from the Comacchio lagoon are less than 10 years old, are not affected by Anguillicola crassus, and, according to biomarker analyses, are not affected by pollution. Thus, we argue that this lagoon is a suitable environment for restocking and for the application of an efficient eel management plan.