3. Threat:
Aquaculture & agriculture

Background

Marine aquaculture (also known as mariculture) is the farming of fish, crustaceans, molluscs, algae and other organisms under controlled conditions in the marine environment. Aquaculture facilities can cause increased levels of nutrient pollution and microorganisms (Becker et al. 2017). Practices such as sea cage farming are often sited close to reefs (Hedberg et al. 2015, Hedberg et al. 2017) and have been associated with reduced coral cover and increased coverage of turf algae (Hedberg et al. 2015).

Land agriculture can lead to nutrient-rich and pesticide-rich run-offs reaching the marine environment through rivers, and negatively impacting coastal areas due to the increase in nutrients such as nitrogen and phosphorous (Falace et al. 2018; Gabric & Bell 1993). These increases in nutrients often lead to diminished water quality and eutrophication events including hypoxia or anoxia, creating “dead zones” (Breitburg et al. 2018).

Much of the conservation effort related to threats from aquaculture and agriculture has been directed at reducing the impacts of pollution and impoverished water quality, as well as reducing the threat from non-native and invasive species. Actions related to these threats are described in Threat: Pollution and Threat: Non-native, invasive and problematic species

Becker C., Hughen K., Mincer T.J., Ossolinski J., Weber L. & Apprill A. (2017) Impact of prawn farming effluent on coral reef water nutrients and microorganisms. Aquaculture Environment Interactions, 9, 331–346. https://doi.org/10.3354/aei00238

Breitburg D., Levin L.A., Oschlies A., Grégoire M., Chavez F.P., Conley D.J., Garçon V., Gilbert D., Gutiérrez D., Isensee K., Jacinto G.S., Limburg K.E., Montes I., Naqvi S.W.A., Pitcher G.C., Rabalais N.N., Roman M.R., Rose K.A., Seibel B.A., Telszewski M., Yasuhara M. & Zhang J. (2018) Declining oxygen in the global ocean and coastal waters. Science, 359. https://doi.org/10.1126/science.aam7240

Falace A., Tamburello L., Guarnieri G., Kaleb, S., Papa L. & Fraschetti S. (2018) Effects of a glyphosate-based herbicide on Fucus virsoides (Fucales, Ochrophyta) photosynthetic efficiency. Environmental Pollution, 243, 912–918. https://doi.org/10.1016/j.envpol.2018.08.053

Gabric A.J. & Bell P.R.F. (1993) Review of the effects of non-point nutrient loading on coastal ecosystems. Marine and Freshwater Research, 44, 261–283. https://doi.org/10.1071/MF9930261

Hedberg N., Kautsky N., Hellström M. & Tedengren M. (2015) Spatial correlation and potential conflicts between sea cage farms and coral reefs in South East Asia. Aquaculture, 448, 418–426. https://doi.org/10.1016/j.aquaculture.2015.06.024

Hedberg N., Stenson I., Kautsky N., Hellström M. & Tedengren M. (2017) Causes and consequences of spatial links between sea cage aquaculture and coral reefs in Vietnam. Aquaculture, 481, 245–254. https://doi.org/10.1016/j.aquaculture.2017.09.009

3. Threat: Aquaculture & agriculture

3. Threat:
Aquaculture & agriculture