HiSea aquaculture model used in scientific research assessing seawater temperature predictions

A coastal 3D hydrodynamic model for simulating and predicting seawater temperature, developed in the context of the HiSea Project investigations related to aquaculture in the southern Aegean Sea, was used in recent research on assessing the uncertainty of seawater temperature predictions produced through ensemble simulation.

The research, titled “3D Ensemble Simulation of Seawater Temperature – An Application for Aquaculture Operations”, by Nithin Achutha Shettigar, Lörinc Mészáros, Anna Spinosa and Ghada El Serafy of Deltares and Biswa Bhattacharya of IHE Delft Institute for Water Education, was published in the scientific journal Frontiers in Marine Science. Ghada El Serafy, Lörinc Mészáros and Anna Spinosa are also part of the HiSea team, in addition to being associated with the Delft University of Technology.

The HiSea model was developed using Deltares’ Delft3D Flexible Mesh tool, and simulated seawater temperature predictions were validated against in-situ measurements provided by HiSea aquaculture partner Selonda.

Ensemble mean and ensemble spread of SWT with two aquaculture farms marked – Ortholithi (Green dot) and Ovrios (Magenta dot).

“Water quality variables play a major role in aquaculture operations, specifically seawater temperature has a major impact on the metabolism of the fish species and therefore on the growth rate too. Since the fish farming business relies on the growth rate of the species to plan and operate the farm, seawater temperature becomes crucial information,” the research team explained.

“Present ad hoc measurement of seawater temperature could only provide information for the present state of the sea and could not give information on the harmful events in future. [In this research,] we build on the existing knowledge on a specific fish species and translate that knowledge for aiding decision making using a numerical modelling tool,” they added.

“With the availability of hydrodynamic modelling tools and global ocean information sources such as Copernicus Marine Environment Monitoring Service (CMEMS), seawater temperature can be simulated for practically any coast with a dynamic downscaling approach. However, the simulated data needs to be assessed for uncertainties for enabling informed decision making using such model predictions,” the research team said.

In the study, the researchers applied numerical modelling alongside ensemble simulation to assess uncertainty in the context of aquaculture farms, “which is presently not a common practice”, they noted.

The research successfully demonstrated a modelling tool simulating seawater temperature with satisfactory results, allowing assessment of seawater temperature from an aquacultural perspective in temporal, seasonal and vertical scales, the team declared.

The study demonstrated that information on vertical seawater temperature behaviour is key for aquaculture farms’ operations, with different behaviour in the various regions and seasons, information that the team stressed is “not  always possible to generate from in-situ measurements alone.”

The study extended the data available from larger open seas “to the remote coastal areas where data is required for businesses,” the researchers noted.

Future studies could combine seawater temperature prediction with fish physiology, linking water quality variables (such as temperature, salinity and nutrient concentrations) with fish growth, shedding additional light on factors important for managing aquaculture farms, they concluded.