An outlook of the sieving selection of striped venus clam (Chamelea gallina) in the Mediterranean hydraulic dredge fisheries

The infaunal bivalve striped venus clam (Chamelea gallina) is the target of a large fleet of hydraulic dredgers operating in the sandy coastal bottoms of the Northern and Central Adriatic Sea (Mediterranean). Despite the resource is now showing strong signs of depletion and overexploitation relatively little scientific work has been done to assess the selectivity of the hydraulic dredges. Selective process in the hydraulic dredge fisheries mostly occurs on board the vessel during sieving operations rather than at sea while fishing is in progress. We investigated the striped venus clam (C. gallina) selectivity occurring during the sieving process on board the hydraulic dredge in the Adriatic Sea fisheries. The sieving tool consists of sequential holed grids made with holes of different diameters that select clams on the basis of their size. This study was undertaken to analyse both the effect of sieve-diameter and the speed of sieving on the clam selectivity. Selectivity was measured using the same approach followed in the covered codend technique taking into account the between-haul variation in selectivity. The results attained in the present study can assist fisheries managers in the revision of current legislation.