Evaluating the impact of hydrometeorological conditions on E. coli concentration in farmed mussels and clams: experience in Central Italy.

Highly populated coastal environments receive large quantities of treated and untreated wastewater from human and industrial sources. Bivalve molluscs accumulate and retain contaminants, and their analysis provides evidence of past contamination. Rivers and precipitation are major routes of bacteriological pollution from surface or sub-surface runoff flowing into coastal areas. However, relationships between runoff, precipitation, and bacterial contamination are site-specific and dependent on the physiographical characteristics of each catchment. In this work, we evaluated the influence of precipitation and river discharge on molluscs' Escherichia coli concentrations at three sites in Central Italy, aiming at quantifying how hydrometeorological conditions affect bacteriological contamination of selected bivalve production areas. Rank-order correlation analysis indicated a stronger association between E. coli concentrations and the modelled Pescara River discharge maxima (r = 0.69) than between E. coli concentration and rainfall maxima (r = 0.35). Discharge peaks from the Pescara River caused an increase in E. coli concentration in bivalves in 87% of cases, provided that the runoff peak occurred 1-6 days prior to the sampling date. Precipitation in coastal area was linked to almost 60% of cases of E. coli high concentrations and may enhance bacterial transportation offshore, when associated with a larger-scale weather system, which causes overflow occurrence.

New protocols to improve the deposition and hatching of Sepia officinalis' eggs.

The objective of this study was the development of hatching protocols in controlled conditions to obtain juveniles, in order to restock and increase the resource of Sepia officinalis. The study was divided into the following phases: development and application of artificial surfaces at specific sites of the Molise coast in Italy; induction of eggs hatching and juveniles maintenance under controlled condition; juveniles introduction into specific sites and assessment their increment; experimental data elaboration. The obtained results concerned both the effectiveness of the artificial surfaces tasted during the study and the importance of the recovery of the eggs laid on artificial surfaces (artefacts and fishing gear) for preservation and the management of the Sepia officinalis resource. The induction tests conducted on eggs hatching under controlled conditions confirmed what described in the extant literature. Water salinity was detected as the only limiting factor, with values ≤ 20% related to the absence of hatching. The described practices for harvesting and induction of hatching for the production of juvenile cuttlefish may be endorsed by the operators at relatively low cost and throughout the year, with obvious economic benefits.

Study of the efficacy of a closed cycle depuration system on bivalve molluscs.

The aim of this study was to develop and apply protocols for the microbiological depuration of bivalve molluscs (Chamelea gallina and Mitylus galloprovincialis). The study was divided into the following phases: preparation of two closed-circuit tanks fitted with mechanical, chemical and biological filtration systems for the depuration of bivalve molluscs, mollusc contamination and depuration, analyses of molluscs and depuration waters (biometric and microbiological tests) and statistical processing of the experimental data. The Escherichia coli challenge revealed the high efficacy of the depuration system and thus the possibility of preparing the molluscs for sale in a relatively short period of time. Depuration tests against Salmonella Typhimurium were effective only after 72 h to 84 h. Results for Vibrio parahaemolyticus revealed only a small reduction in the bacterial load during the entire observation period. However, depuration times were shorter in trials with mussels: V. parahaemolyticus was no longer detected after 36 h to 48 h.