Modeling the environmental impact of mussels? cultivation in the coastal zone of Crimea

To formulate the environmental requirements for sustainable development of the aquaculture industry adequately, we need a comprehensive understanding of the interrelations between a coastal marine ecosystem and embedded artificial objects of aquaculture. Simulation experiments with the models based on this knowledge provide recommendations on sustainable management of aquaculture in coastal zones. We propose a coupled 2D chemical-biological model of marine ecosystem with an embedded mussel farm. This model was constructed using the object-oriented technique. We described the biological components dynamics in the individual-based approach using the dynamic energy balance of an individual organism. The chemical module included dynamical description the 2D fields of nitrates, nitrites, phosphates, dissolved oxygen, suspended and dissolved organic matter. The model was verified by the observations data from the mussel farm located in the Laspi Bay, Black Sea. We estimated the environmental impact of the mussel farm comparing several simulations with different sets of the model components: phytoplankton, bottom seaweeds, and a mussel farm. The length of each simulation covered the period of intensive growth of mussels and their spawning period (early spring - late autumn of the first year of cultivation). For this comparison, averaged concentrations of dissolved and suspended hydrochemical components were used. It was found that the farm functioning leads to an increase of ammonium, nitrites, nitrates and phosphates and decrease of organic matter in water. Bottom seaweeds have significant positive influence on the ecosystem state and can mitigate adverse effects of the mussel cultivation.