Abstract :
[en] The growing global demand for fish is resulting in a progressive increase of the aquaculture industry, which soon will surpass fisheries as main source of seafood worldwide. At present, approximately 44% of the fish consumed by humans comes from aquaculture, and this percentage is predicted to reach 52% by 2025. Aquaculture provides undoubted economic benefits and diverts part of the fishing pressures exerted on wild stocks. However, it is also at the origin of many impacts on the marine environment and biota due to biological, chemical and physical effects.
Production safety measures to prevent environmental contaminations from mariculture are not required yet. A number of nocive biological effects are therefore occurring such as genetic interactions between escaped and wild fishes, disease transfer or ingestion of waste by wild fishes. Aquaculture further depends on large additions of aquafeed, fertilizers and other additives leading to chemical contamination. As the industry expands, it also requires the use of more drugs, disinfectants and antifouling compounds (biocides) to eliminate microorganisms from aquaculture facilities. These chemicals are known to be harmful to the marine environment because of their toxicity. Although field evidence of, e.g. metal enrichment in sediments due to fish farming is abundant, its environmental risk is still in discussion. However, there has been increasing interest in alternative ecological approaches for improved management of aquaculture with the adoption of new, cleaner production technologies (e.g. organic aquaculture, Integrated multi-trophic aquaculture IMTA...).
Mariculture farms are more or less invasive structures that physically modify and alter the marine environment. In addition, intensive fish farming causes large amounts of organic waste accumulation in the water column and sediments. Main organic waste sources are fish feces, uneaten feed and dead individuals. Their decomposition increases the biological demand in oxygen and causes the deterioration of water and sediment quality. Physical impacts of mariculture indirectly influencing the biota, they must also be taken into account in addition to biological and chemical direct stressors.
The impacts and consequences of mariculture on marine organisms are complex and yet still remain unclear. They depend on a large number of parameters such as: type of organism, species, metabolism, physiological conditions, feeding mechanisms and behavior, size, age, sex, spawning status, parasites, mobility and migration, habitat and so on. Furthermore, it is now generally accepted that climate change is occurring and that this will have significant implications for the marine environment and, consequently, aquaculture. Faced with this complexity and lack of knowledge, this Frontiers Research Topic therefore aims to collect works that demonstrate the impacts of mariculture on the marine biota, in all its manifestations and in any kinds of wild organisms and that propose mitigation measures to reduce their potential negative effects.
