Development of a numerical model to study the dispersion of wastes coming from a marine fish farm in the Ligurian Sea (Western Mediterranean)
Andrea Doglioli ¹ ² , Marcello Magaldi ¹ ² , Luigi Vezzulli ³
¹ INFM - Unità di Ricerca di Genova, via Dodecaneso 33, 16146 Genoa (IT)
² Dipartimento di Fisica - Università di Genova, via Dodecaneso 33, 16146 Genoa (IT)
³ Dipartimento per lo studio del Territtorio e delle sue Risorse - Università di Genova, corso Europa 26, 16132 Genoa (IT)
The lagrangian particles model LAMP3D have been coupled with the hydrodynamical numerical model POM in order to simulate the dispersion of pollutants coming from a marine fish-farm in the Ligurian Sea (Western Mediterranean).
Estimates of the regional dispersion patterns of nitrogen, phosphorous and organic carbon was calculated using a three dimensional mesoscale grid and compare to in situ experimental data. In the numerical simulation the dispersion of different aquaculture wastes (dissolved nutrients, faecal matter and feed waste) was evaluated by changing the sinking rates and the condition of particles release (continuous or periodical).
Result of the simulation clearly showed as dissolved particles tend to spread rapidly and undergoes rapid dilution depending on dominant wind and surface currents direction. In contrast largest particles remain mainly confined in the fish farm area and readily sink to the bottom sediment.
Concentrations of elemental wastes as predicted by the model resulted low in the investigated area in both water column and sediment compartments and never exceed the predicted amounts warned in environmental risk assessments.