Heidi Spurrell | 4th May 2021 | 4min read

A fish farm using a network of floating balls to hold the nets together. Credit: HKOrganicaa 



According to the United Nations Food and Agriculture Organization (FAO), roughly 32% of world fish stocks are overexploited, meaning that wild fish stocks don’t have time to be replenished before they are fished again. One solution to this problem is aquaculture, a controlled process of catching, breeding, and raising fish in tanks or enclosures. This method has been rapidly growing in recent years as the fish only need to be caught once before being bred in tanks or enclosures, reducing reliance on the wild-caught resources. However, like all commercial farming, if fish are not farmed responsibly, aquaculture can bring a multitude of unintended consequences, including severely damaging ecosystems by introducing diseases, pollutants and invasive species, and there have been additional concerns over the use of antibiotics and hormones.

For aquaculture to be considered sustainable, farmers must meet strict criteria, showing that they actively minimise their impact on the surrounding natural environment while operating their farm in a socially responsible manner, including treating staff fairly (no slave or child labour) and working with the local community. To ensure that the fish you purchase has been farmed sustainably, you should look out for certifications on the packaging – some of the most well-respected standards include the Aquaculture Stewardship Council (ASC) and Global G.A.P. (Good Agricultural Practices). However, it is not guaranteed that all sustainable fish farms are organic, as although it is implied that sustainable fish farming should limit their use of unnecessary antibiotics and chemicals, there are sometimes exceptions – for example, ASC standards for shrimp accept low levels of antibiotics if found as residue in water systems where medicines have been used.



To be more certain that fish were raised healthily without the use of chemicals, we can look towards organic aquaculture, which guarantees that fish were raised without the use of artificial chemicals. Although there isn’t a universal definition of organic, there are several internationally-recognised standards, such as the International Federation of Organic Agriculture Movements (IFOAM), an international organisation whose principal work is to maintain organic farming standards and provides an organic accreditation and certification service. Unlike other sustainable standards, IFOAM dictates that the fish have to begin life in organic units, meaning they must come from organic sources and must have been caught without using destructive methods. They must also be reproduced by natural spawning and must only be fed organic feed, unless it is of inadequate quantity or quality, in which case other feeds may be used under special permission. Additionally, natural methods or medicines must be used first in case of illness, and synthetic substances may only be used when prescribed by a veterinarian if natural methods fail.


IFOAM logo


IFOAM has around 800 affiliates in 117 countries, including HKORC-Cert, the only independent incorporated third-party organic certification agent in Hong Kong, accredited by IFOAM in 2012. It is managed by Hong Kong Organic Resource Centre (HKORC). As of March 2021, there are 11 fish farms in HK that have been certified organic by HKORC-Cert, which includes both freshwater and mariculture farms.


Empty nets collected at a fish farm. Credit: HKOrganicaa


There are many types of aquaculture, either raising fish in freshwater, man-made ponds or in circular systems but in this article, we will take a deeper dive into mariculture. Mariculture is a specialized branch of aquaculture which involves rearing marine fish in cages suspended by floating rafts in (usually) sheltered coastal areas. In 2018, there was an estimated production of 850 tonnes through mariculture, or 5% of all locally consumed live marine fish. One of these certified mariculture farms is HKOrganicaa.

HKOrganicaa is a fish farm located in O Pui Tong Fish Culture Zone with three products that have been certified by HKORC-Cert as well as the AFFS: Pearl oyster, Noble scallop and Pompano. Prior to applying for certification with HKORC-Cert, HKOrganicaa joined the Accredited Fish Farm Scheme (AFFS), a scheme that promotes the sustainability of the local fisheries industry. Through this voluntary scheme, participating fish farms are required to adopt a set of Good Aquaculture Practices (GAP) and quality assurance tests, including analyses of drug residues and heavy metal in fish, are conducted to ensure all cultured fish meet food safety standards before they are sold. The GAP also sets out recommendations for cleaning the cages every two weeks, which prevents contaminating the natural seawater and also ensures that the fish are thriving in a clean environment.


Net for culturing Pearl oyster at HKOrganicaa farm

The produce of Noble scallop from HKOrganicaa farm

Pompano is being cultured in the fish cage

HKOrganicaa uses seaweed as fish feed. Credit: HKOrganicaa


Another way HKOrganicaa has incorporated sustainability into their operations is by growing seaweed, which is used as feed for many of their products, such as the Mottled spinefoot. Buying organic fish feed can be expensive and the fast-growing seaweed was the perfect solution to lowering transport costs and reducing the cost of buying feed. In addition to these sustainable practices, HKOrganicaa has also adopted special techniques from Japanese fishing, such as using floating balls to keep their nets afloat, using vertical fishing techniques as well as using a shell washing machine to wash their shellfish, which reduces manpower. Additionally, HKOrganicaa limits the use of chemicals as much as possible, only making changes to the water if they need to dilute it to control the salinity or alter the water temperature to remove worms. This results in a higher price per piece, because of the high mortality (thus  fewer stock), since they are unable to use chemicals to kill pests and cure diseases. Additionally, the stocking density must be controlled to a level that doesn’t have a negative impact on fish health and welfare.

Finding the right space for the farm also proved difficult – as a mariculture farm, HKOrganicaa had to find an area that was at least 100 metres from potential sources of contamination. They finally decided on O Pui Tong as there were very few fish farms in the area, so they were less likely to be affected by other elements out of their control.



Getting an organic certification was not an easy task as it took 10 years before any products were certified and it will be another 6-8 months before these products can be sold as “organic” fish – they are currently still in the conversion phase. Mr. Law of HKOrganicaa adds that “although we cannot guarantee that our fish tastes better, as taste and texture is subjective and depends on the species, HKOrganicaa can guarantee that our organic fish is healthier than conventional fish”, which means it is healthier for us too.

Although the certification process takes a lot of time and effort, organic fishing methods are intended to produce high quality, nutritious food that also sustains and enhances the health of ecosystems, which helps to maintain fish stocks. Consumers can also be certain that the fish has been farmed sustainably due to the strict criteria the farm has to follow in order to become certified.

Whether you are in procurement or a consumer of fish, we can all encourage farmers to switch to organic methods by purchasing more organic fish, showing farmers that there is a market and a need for sustainable fish, while managing our own health by eating organic.