Lipophilic marine biotoxins in commercial clams harvested along the western Adriatic Sea

In the western Adriatic Sea there are a number of commercially exploited clam species, but the fishery for manila clams (Ruditapes philippinarum) and stripped venus (Chamelea gallina) is by far the most important. In Italy... [ view full abstract ]

In the western Adriatic Sea there are a number of commercially exploited clam species, but the fishery for manila clams (Ruditapes philippinarum) and stripped venus (Chamelea gallina) is by far the most important.

In Italy both species are considered at low risk of contamination by marine biotoxins for the goals of the shellfish monitoring programme organized under Reg. (EC) No 854/2004, since historical data have never shown positivity for any of the regulated compounds. This is reflected in a reduced sampling frequency for both species. However, in May 2012 okaidates were detected for the first time in manila clams from the brackish lagoon of Sacca di Goro (Emilia Romagna). The episode was linked with high abundances of Prorocentrum lima and showed a maximum of 1154 µg OA eq./kg in summer 2013. The phenomenon became endemic and in 2016 shellfish farmers abandoned the areas where prolonged closures prevented a profitable economic exploitation of the resource.

Following this unexpected event, lipophilic marine biotoxin results in clams have been collected to provide new evidences for a review of the current risk assessment. Data produced in the period 2013-2016 were gathered for the western Adriatic Sea. A total of 1535 samples have been analysed using LC-MS/MS. Manila clams accounted for 77% of the analysed shellfish. Only 4% of the samples contained toxin levels higher than the current EU regulatory limit (160 µg/kg of edible part). Most of them belonged to species Ruditapes philippinarum (97%) from transitional waters.