Editing Fish farming (section)

=== Open net pen system ===
The open net pens system is a method that takes place in natural waters, such as rivers, lakes, near the coast or offshore. The breeders rear the fish in large cages floating in the water.<ref>{{Cite web|title=Salmon Aquaculture • Georgia Strait Alliance|url=https://georgiastrait.org/issues/other-issues/salmon-aquaculture/|access-date=2021-12-24|website=Georgia Strait Alliance|language=en}}</ref> The fish are living in natural water but are isolated with a net. Because the only barrier separating the fish from the surrounding environment is a net, this allows the water to flow from the 'natural' surrounding through the fish farms.

The site of the fish farm is crucial for the farm to be a success or not. Before any fish farm is settled, it is highly recommended to be selective with the site location of the farm. The site must be examined on some essential elements. Important conditions on the location are:<ref>{{Cite report |last1=Braaten |first1=Bjørn |last2=Aure |first2=Jan |last3=Ervik |first3=Arne |last4=Boge |first4=Erik |date=1983 |title=Pollution problems in Norwegian fish farming |url=https://imr.brage.unit.no/imr-xmlui/handle/11250/103766}}</ref>

# A good interchange of water and also a high replacement of bottom water.
# At all depths should be a good current condition. This is necessary because the organic particles should be able to be carried away using the current.
# A gravel and sand bottom are qualified for fish farming, although bottoms with silt and mud are not qualified. These should be avoided.
# A net should be at least {{convert|10|m|ft|0}} or more above the bottom, so depth is important.

Despite these important site conditions, the open net pen method was very popular in Norway and China. This is because of the cost friendliness and efficiency of this method.<ref>Upton, H. F., & Buck, E. H. (2010). Open Ocean Culture. Congressional Research Service. Published. https://nationalaglawcenter.org/wp-content/uploads/assets/crs/RL32694.pdf</ref>

==== Negative external effects ====
Because of the ocean's water flow and other reasons, open net pen culture is seen as a high-risk method for the environment.<ref>{{Cite web |title=Aquaculture Methods |url=https://www.seachoice.org/info-centre/aquaculture/aquaculture-methods/ |access-date=2022-08-02 |website=SeaChoice |language=en-CA}}</ref> The flow allows chemicals, parasites, waste and diseases to spread in the enclosed environment, and this is not beneficial for the natural environment. Another negative consequence is the high escape rate of the cultured fish from these open net pens. These escaped fish also pose a high risk to the surrounding ecosystems.

The amount of organic waste produced by fish farms is also alarming. A salmon farm in [[Scotland]], for instance, is estimated to produce as much organic waste as equivalent to a town of people between 10,000 and 20,000 people each year.<ref>{{Cite web |title=Facts {{!}} Seaspiracy Website |url=https://www.seaspiracy.org/facts |access-date=2022-03-12 |website=SEASPIRACY |language=en}}</ref>

Today 50% of the world's seafood is farm-raised.<ref>{{Cite web |title=50% of our seafood is farm raised |url=https://www.carolinacoastonline.com/news_times/opinions/letters_to_editor/article_efe859be-ba70-11e2-b124-001a4bcf887a.html |access-date=2022-07-11 |website=Carolina Coast Online |date=11 May 2013 |language=en}}</ref>