Numerical modelling to the rescue : environmental models as a novel tool in simulating the trajectory of jellyfish blooms within coastal ecosystems – a case study from the Maltese Islands (Central Mediterranean)

Abstract

A numerical tool based on coupled hydrodynamics and environmental models was developed and applied to the coastal areas of the Maltese archipelago, with the aim of implementing a decision-support system for coastal managers. The hydrodynamic component of the system (ROSARIO-SHYFEM) is operational and provides daily a 4 days forecast of the main 3D hydrodynamics fields for the areas covering the Malta-Sicily Channel with a spatial resolution varying between a few km up to 50 m. The main objective of the tool is to predict the trajectory to be assumed by a jellyfish bloom by providing a four-day forecast of the path to be taken by the same bloom. The ROSARIOSHYFEM model was coupled with a particle-tracking Lagrangian model in order to simulate the diffusion of numerical particles, proxy of jellyfish, inside the area of interest, providing a 4-day forecast for the trajectory of a jellyfish bloom. The system was integrated into a Web Application which will allow users to define the position in time and space of a hypothetical bloom found in the Maltese waters, to select the amount of particles to simulate the jellyfish biomass and to choose between blooms of Pelagia noctiluca and Cotylorhiza tuberculata, the two main blooming species in this part of the Mediterranean. The tool is freely available through the MED-JELLYRISK Project website (www.jellyrisk.eu). Full validation of this dispersión forecasting system, through the deployment of water drifters for example, is still ongoing.