Aquaculture is a very diverse industry that encompasses a wide range of cultivation techniques applied to various organisms (see sectors’ characteristics and trend below). It is defined as “the rearing or cultivation of aquatic organisms using techniques designed to increase the production of the organisms in question beyond the natural capacity of the environment, where the organisms remain the property of a natural or legal person throughout the rearing and culture stage, up to and including harvesting” [1].
The combination between different types of aquaculture production can take many forms, such as polyculture, or IMTA (Integrated Multi-Trophic Aquaculture).
These interactions have been specifically designed to enable different kinds of productions to coexist on the same site (shared ponds for example) to enable synergies and even positive impacts (e.g., nutrient recycling) as well as providing potential economic benefits (e.g., diversification of aquaculture businesses).
This fiche sets out the range of interactions to be considered between different types of aquaculture production, and what MSP can do to foster synergetic interactions.
- SECTORS' CHARACTERISTICS
Aquaculture is defined as “the rearing or cultivation of aquatic organisms using techniques designed to increase the production of the organisms in question beyond the natural capacity of the environment” [2]. The EU aquaculture sector is slowly but steadily growing and is ranked the eleventh largest worldwide with a 0.9 % share of the volume of global output in 2021 [3]. At EU level, the activity is framed by the guidelines for sustainable and competitive EU aquaculture. It is a hugely diverse industry [4]: fish farming refers to the growth of fish in controlled aquatic enclosures, farming of shellfish is the cultivation and harvest of molluscs and crustaceans, and algaculture focuses on the farming of algae species. The EU Algae Initiative aims at making a wider use of that resource, that is not sufficiently developed [5].
Physical factors (water temperature and quality, currents, nutrient availability, etc.) have a direct effect on the growth of aquaculture species. Companies are therefore looking for the most suitable locations for their farms, also considering the associated costs of operations such as depth or distance from port that modify transport possibilities as well as construction, and maintenance costs [6]. This makes distant offshore farming more expensive and more exposed to extreme weather hazards. One of the main challenges is therefore the limited availability of inshore sheltered areas.
For more European statistics and data you can also visit the Eurostat website
Related challenges
- Technical complexity
As explained in the introduction, aquaculture is a hugely diverse sector that encompasses a very wide range of rearing techniques applied to a great array of organisms and species.
Properly managing the varying needs of different species is therefore complex as it requires a high level of knowledge and technical sophistication. This is especially true when it comes to the required infrastructure, as different species may need specific types of infrastructure, increasing complexity and costs. The prevailing conditions in the marine environment where these species are farmed adds even more complexity due to the spatial and temporal variability of hydrodynamic conditions but also the water quality characteristics, pelagic primary productivity, etc. [7].
- Economic Viability
Establishing aquaculture developments and especially integrated aquaculture systems can be capital intensive, notably due to the high level of initial costs. Capital investment and maintenance costs represent a major difficulty in the development and implementation of aquaculture facilities and especially more complex integrated systems [8].
- Regulatory and Policy Issues
Although existing documents provide guidance on the regulatory framework and administrative procedures related to aquaculture (such as The Commission Staff Working Document “Regulatory and administrative framework for aquaculture”), navigating the regulatory environment of aquaculture can be challenging for operators, with different rules for different species. Obtaining the necessary licenses for integrated operations can be more complicated than in the case of a single species development. This regulatory and legal challenge is often considered as a significant obstacle to the establishment of IMTA facilities. A 2022 study on the factors affecting IMTA implementation on Atlantic Salmon farms states that “The lack of governmental support and commitment to implementation and innovation were repeatedly referenced among the literature review papers and the industry survey” [9].
- Cross-Species Disease Transmission
Different species cohabiting can lead to the spread of diseases and parasites between them. This is notably due to the fact that “The rapid decomposition of waste deteriorates water quality, affecting cultured fish species and causing diseases and mortality conditions” [10].
However, as detailed below, one of the benefits of integrated multi species systems is precisely that species can be carefully selected to process the waste from one another.
Related enablers
Technical enablers
This first part will detail the main types of combination between different aquaculture productions
- Polyculture
Polyculture refers to the practice of simultaneously cultivating multiple aquatic species such as fish or other aquatic organisms in the same environment. The cultivated species are chosen based on their complementarity, as they interact in ways that optimise resource use and reduce waste. The species are carefully selected with different diets, so as not to compete for food.
This system mimics natural ecosystems and ultimately aims to enhance the productivity of aquaculture operations.
- Integrated Multi-Trophic Aquaculture (IMTA).
IMTA refers to the integrated farming of different species from different trophic levels in close proximity, generating benefits for each other.
It notably offers the potential to limit the impacts of fish farming, by combining it with low-trophic aquaculture (shellfish and algae productions) which will reduce and filter organic waste material. Indeed, in IMTA systems, the byproducts (such as waste) from one cultivated species are used as inputs (fertilizers, food) for another, creating a positive circle.
The ASTRAL (All Atlantic Ocean Sustainable, Profitable and Resilient Aquaculture) EU-funded project contributed to the development of IMTA production chains for the Atlantic markets by bringing together labs in Ireland, Scotland, South Africa, Brazil and Argentina in order to increase circularity compared to monoculture baseline aquaculture and to boost revenue diversification for aquaculture producers.
General enablers
This second part will detail the more general enablers that apply to all types of aquaculture combination.
- Innovation and Technology
As explained in the challenges section, properly managing the varying needs of different species requires a high level of knowledge and technological sophistication, thus creating some kind of technological complexity. Technology and advanced monitoring systems can help manage the complexity of integrated aquaculture systems, ensuring optimal conditions for all species. Additionally, automating processes can reduce labour costs and increase precision in system management.
- Policy Support
The regulatory environment of aquaculture and the combination of different production types such as in IMTA, is challenging as different rules and regulations apply to different species. Appropriate policy support in reducing regulatory complexity to encourage sustainable and integrated aquaculture practices would be a key element in enabling more combined aquaculture developments. Additionally, the availability of financial support such as subsidies and grants, especially dedicated to sustainable aquaculture practices would help to overcome the difficulty linked to the high level of initial investment.
- Economic Advantages
As explained in the challenges section, establishing integrated aquaculture systems such as polyculture or IMTA can prove to be capital intensive, notably due to the high level of initial costs. However, the economic yield of such operations can be higher than mono-culture operations. Operations combining different kinds of production reduce the financial risk and increase financial outputs by increasing the productivity of the exploitation and diversifying their marketable products.
- References
Existing co-existence and multi-use initiatives
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