Indicators 2.6
Indicators
Description
2.6.1
2.6.2
2.6.3
Applicable to
2.6.4
Applicable to
Indicators 2.6.5 – 2.6.14 Scope: Type A waterbodies
Indicators
Description
2.6.5
2.6.6
2.6.7
2.6.8
2.6.9
2.6.10
2.6.11
Applicable to
2.6.12
2.6.13
Applicable to
2.6.14
Indicators 2.6.15 – 2.6.17 Scope: Point source systems
Indicators
Description
2.6.15
2.6.16
2.6.17
Indicators 2.6.18 – 2.6.21 Dissolved oxygen requirements
Indicators
Description
2.6.18
2.6.19
Applicable to
2.6.20
2.6.21
Applicable to
Rationale 2.6
Eutrophication is caused by excessive nutrient inputs (especially nitrogen and phosphorus) to water bodies and is a major environmental issue. It disrupts freshwater and marine ecosystems, contributes to algal blooms and oxygen depletion, and affects the quality of water available to local communities and other resource users.3737Akinnawo, S. O. (2023). Eutrophication: Causes, consequences, physical, chemical and biological techniques for mitigation strategies. Environmental Challenges, 12, 100733.
Nutrient releases from aquaculture in the form of faeces and uneaten feed can lead to eutrophication and negatively impact oxygen availability and other water quality parameters.3838Chislock, M. F., Doster, E., Zitomer, R. A., & Wilson, A. E. (2013). Eutrophication: causes, consequences, and controls in aquatic ecosystems. Nature Education Knowledge, 4(4), 10. The severity of these effects depends on factors like water depth and current velocity, location and sensitivity of the waterbody to nutrient loading.
This Criterion focuses on ASC-certified farms minimising their contribution to eutrophication by monitoring water quality, managing nutrient releases, and engaging in collaborative information sharing in at-risk waterbodies.
Intent – The aquaculture industry minimises its contribution to eutrophication and the trophic status shift of waterbodies.
Criterion 2.6 – Water Quality
Scope – Sites using feed or fertilisers and releasing effluents3636An exemption to this Criterion applies to sites that never release effluents..
Indicators 2.5
Indicators
Description
2.5.1
2.5.2
2.5.3
2.5.4
2.5.5
2.5.6
Rationale 2.5
The benthic zone (‘bottom’) of a waterbody often supports a rich biodiversity and provides critical ecological functions such as assimilation of organic waste (e.g. faeces, uneaten feed), provision of food for species and protection of coastal sediment from erosion. Human activities interacting with the benthic zone can negatively impact the functioning of these ecosystems.
Aquaculture can interact with the benthic zone through deposition of organic waste and release of heavy metals.3131González-Gaya, B., García-Bueno, N., Buelow, E., Marin, A., & Rico, A. (2022). Effects of aquaculture waste feeds and antibiotics on marine benthic ecosystems in the Mediterranean Sea. Science of the Total Environment, 806, 151190. When this deposition exceeds the environment’s ability to handle it, harmful changes to the ecosystem can occur. 3232Hargrave, B. T., Phillips, G. A., Doucette, L. I., White, M. J., Milligan, T. G., Wildish, D. J., & Cranston, R. E. (1997). Assessing benthic impacts of organic enrichment from marine aquaculture. In The Interactions Between Sediments and Water: Proceedings of the 7th International Symposium, Baveno, Italy 22–25 September 1996 (pp. 641-650). Springer Netherlands.The severity of these impacts depends on factors such as the amount of waste released, waterbody characteristics and the ability of the benthic microbial community to break down waste.3333Kalantzi, I., & Karakassis, I. (2006). Benthic impacts of fish farming: meta-analysis of community and geochemical data. Marine Pollution Bulletin, 52(5), 484-493.
This Criterion focuses on effective management by ASC-certified farms to monitor the local benthic zone and limit these impacts by ensuring waste deposition is lower than the natural decomposition rate.
Intent – The aquaculture industry maintains healthy benthic ecosystems.
Criterion 2.5 – Benthic Impact
Scope – Every UoC using cage culture, suspended marine mollusc systems and freshwater systems discharging into rivers.
Indicators 2.4
Indicators
Description
2.4.1
2.4.2
2.4.3
2.4.4
2.4.5
2.4.6
2.4.7
Indicators 2.4.8 – 2.4.13 Additional requirements for fish species with a published ASC EICAT evaluation2828Species-specific EICAT evaluations are published on the ASC Website.
Indicators
Description
2.4.8
2.4.9
2.4.10
2.4.11
2.4.12
2.4.13
Indicators 2.4.14 – 2.4.17 Additional requirements for cage culture sites producing smolts in freshwater
Indicators
Description
2.4.14
2.4.15
2.4.16
2.4.17
Rationale 2.4
The introduction of non-native (or alien) species, often driven by human activities, poses significant concerns for natural ecosystems. Their impacts can vary widely, from negligible effects to severe ecological disruptions. These consequences often emerge after extended periods and can vary significantly based on the biological traits of the species and the characteristics of the receiving ecosystem2626Blackburn, T. M., Essl, F., Evans, T., Hulme, P. E., Jeschke, J. M., Kühn, I., … & Bacher, S. (2014). A unified classification of alien species based on the magnitude of their environmental impacts. PLoS biology, 12(5), e1001850. https://doi.org/10.1371/journal.pbio.1001850.
The global aquaculture industry is a key contributor to the spread of alien species. Many of these species have escaped into the wild, establishing populations that can cause ecological harm. Risks to native biodiversity may also arise where farmed animals become reproductively mature and spawn in culture systems, creating a risk of genetic interaction, hybridisation or introgression with wild populations, even where no physical escape of live animals is confirmed. This underscores the need for effective management strategies and scientifically sound evaluation tools.
To address these challenges, the International Union for Conservation of Nature (IUCN) developed the Environmental Impact Classification for Alien Taxa2727International Union for Conservation of Nature (IUCN). (2020). IUCN EICAT Categories and Criteria. The Environmental Impact Classification for Alien Taxa. Gland, Switzerland and Cambridge, UK: IUCN. https://doi.org/10.2305/IUCN.CH.2020.05.en (EICAT). EICAT is a globally recognised framework that classifies alien species based on the magnitude and mechanisms of their environmental impact. It provides a transparent basis for identifying and prioritising species of concern and for informing appropriate management responses. ASC conducts EICAT assessments and makes the outcomes publicly available.
ASC-certified farms are required to implement robust escape management practices and mitigation measures aligned with the relevant EICAT classification(s), where applicable, to minimise the risks posed by alien species and their impacts.
Intent – The aquaculture industry cultivates species in a manner that poses minimal risk to native biodiversity.
Criterion 2.4 – Escapes and Native Biodiversity
Indicators 2.3
Indicators
Description
2.3.1
2.3.2
2.3.3
2.3.4
Applicable to
2.3.5
2.3.6
Applicable to
2.3.7
Applicable to
2.3.8
Applicable to
2.3.9
Applicable to
2.3.10
2.3.11
Applicable to
2.3.12
2.3.13