Reduction of diarrhetic shellfish poisoning (DSP) toxins accumulation in cultured mussels by means of rope clustering and hydrodynamic barriers

Abstract

Accumulation of marine toxins in the organisms is one of the most important problems of the bivalve aquaculture. Mitigation methods are difficult to implement especially in species, as the mussel Mytilus galloprovincialis, which have a relatively low commercial value. For this species, one possible way of decreasing the toxin accumulation is to restrict the availability of toxic cells to the mussels by means of the reduction of the water flow around the perimeter of the culture ropes. We have checked the effectivity to decrease the accumulation of DSP toxins (okadaic acid) in mussels of two ways of obtaining that reduction: surrounding the ropes with a fishing net (1cm mesh); and grouping the ropes (groups of four). During a four week period – with relatively high concentrations of particulate matter – those two ways were tested and shown to effectively reduce both, toxin concentration and toxin burden of cultured mussels exposed to toxic populations of Dinophysis acuminata. The observed reductions were important, 41% and 37% for grouping and surrounding with a net, respectively. Both methods can be used for mussel rafts and long lines and it is very likely they could be also effective with other kinds of toxicity and with other environmental conditions. Statement of relevanceIt would allow a substantial reduction of toxin accumulation.