The supply of aquatic products for human food predominantly relies on aquaculture, which is 65% of the global production. Worldwide, the sector has grown at an annual rate (APR) of 6.6% since 2020, but growth in the Western World has been considerably slower, and in some cases inexistent. As an example, Fig. 1 shows that growth in Europe was mainly driven by Norway (salmon) and Turkey (bass and bream). If the UK is excluded due to Brexit, the EU APR for the period shown is 0.4%, compared with 10.4% for non-EU European nations.
North America fares no better, with a 2008-2022 APR of 0.5% for Canada and 2.3% for the USA. The total production for Europe and North America in 2022 is 4.2 million tonnes, 3% of world production, for 12% of the world population
In addition, the gap between autochthonous supply of aquaculture products in the West and the demand for seafood has widened over the past decades as per capita consumption increases.
In the West, lake and pond aquaculture play a minor role compared to the East, and cultivation is mainly in coastal systems; at the bay scale, aquaculture growth is strongly constrained by sustainability concerns and requires tools that can deal with multi-use challenges. Marine spatial planning (MSP) is a key component in harmonising multiple uses, but there is a need for frameworks that bring together complex models to deal with issues such as sediment organic enrichment and pathogen outbreaks, that occur at very different time and space scales.
The FINS (Farming In Natural Systems) framework (Fig. 2) combines a set of models that address specific issues related to finfish and shellfish aquaculture.
These include near-field deposition and fate of particulate organics, far-field nutrient enrichment, using ammonia as an indicator, together with oxygen reduction, and for bivalves, chlorophyll (as a proxy for food) depletion.
Detailed models for water circulation are the base for understanding the distribution of key performance indicators (KPI) of aquaculture sustainability. Associated with these circulation models are well-tested physiological models for growth of finfish and shellfish species such as salmon, bass, bream, oysters, and mussels.
The location, type, and dimensions of aquaculture structures are user-defined.
The FINS software can represent different types of cages and other types of structures such as rafts or longlines
Results and Discussion
The results presented in this paper illustrate the outputs of FINS for different KPI in selected bays in Nova Scotia, Canada
Fig. 3 shows four layers for Liverpool Bay, Nova Scotia: the bathymetry and residual velocity (from the FVCOM model) are shown for the entire bay, a grid of 30 m diameter salmon cages is shown to the NW of Coffin Island, and the outputs of three models show the effects of salmon cultivation through a 500-day cycle.
The near-field deposition of particulate organics from uneaten and waste feed is simulated, together with the consequences for sediment diagenesis, in this case with respect to sulphide concentration; far-field dispersal of ammonia is also shown—the residual currents transport the dissolved NH4+ plume NE, and the concentrations within this broader, nutrient-enriched area can be used to assess the eutrophication potential of the activity. Pathogen dispersal is also part of the FINS model and allows managers to examine the interaction between existing or potential farms with respect to disease connectivity, promoting animal welfare, natural biodiversity, and ecosystem sustainability.
The relevance of the FINS platform in the context of MSP helps to take spatial planning to the next level. By applying different mathematical models to aquaculture structures placed in suitable areas and examining e.g. the potential effect of pathogen dispersal or eutrophication in adjacent zones, MSP can be leveraged to account for the dynamic nature of coastal ecosystems.
FINS also represents a major technological advance in a platform of this type when compared to conventional desktop solutions. FINS runs in the browser, like any website, and users can access and use it anywhere, from any computer or tablet. In a world that increasingly relies on the Internet of Things (IoT), this is a critical advantage. The option to use the GPU for the graphics primitives in FINS, including design of any type of polygon as an aquaculture structure, animation of residual current flows, and various other features, has led to very significant improvements in speed and functionality.