Numerical modelling services in support of aquaculture management

The Marine Institute (MI), Ireland, runs a suite of operational regional and coastal ocean models focused on the North East Atlantic and Irish coastal waters. In the last decade, several tailored downstream services have been developed to address the key needs of the aquaculture industry in the region. The numerical modelling system set-up will be briefly presented followed by an overview of the aforementioned services. A shellfish model that includes growth and physiological interactions with the ecosystem was developed and fully embedded within the 3D numerical modelling framework. The numerical model consists of a microbial module to predict the level of bacterial contamination (i.e. coliforms) in mussels. The Irish models are used to estimate the carrying capacity, assess impacts of pollution on aquaculture grounds, and to help classify the water quality status of shellfish waters. Further services provided by the models include a 3-day forecast system of shelf water circulation off the southwest and west coasts of Ireland, which are assimilated into a harmful algal bloom (HAB) alert system for a number of stakeholders. The MI also lead a project that is developing a climate service for the aquaculture industry and policy-makers related with HABs in a changing world. To date, a 20 year hindcast of oceanographic conditions is complete and climate simulations are ongoing. Modelled essential ocean variables are being analysed for relationships with historical HAB outbreaks and climate services will be developed based on the findings and future predictions. The authors have developed a model to represent nitrogen cycling at an Integrated Multitrophic Aquaculture farm that is coupled with a numerical biogeochemical model. This approach allows the study of interactions between fish farms and the marine environment. Further useful services include the models that support marine spatial planning efforts e.g. identification of potential sites for offshore aquaculture, and studies on cross-contamination of farms, e.g. dispersal of planktonic larval salmon lice.