Singapore aims to tackle high fish mortality rate in nascent aquaculture sector with lessons from Australia

“What they have consistently pointed out is that if they have too much dissolved nutrients in the water, it can lead to problems because it means that harmful algae can also grow in there, and that itself can then threaten the fish stock by lowering the oxygen content in the water,” he said.

To ensure the sustainability of a body of water, farmers need to be aware of how much fish are inside and how they feed the fish.

“Some of our farmers use expired bread (and) some put chocolate inside the water to feed the fish as well,” said Dr Koh, adding that some of such products dissipate in the water and end up polluting it with inorganic nutrients.

“It means that actually you don’t have a lot more remaining budget of the water to allow the fish to actually grow in there, because the fish contribute some of this nitrogen into the water as well in their waste production.”

Because one farmer’s feeding practices can affect another sharing the same body of water, legislation may be considered to manage this and level the playing field, forming part of Singapore’s new bill on food safety and security, said Dr Koh.

“Given today’s nascent sector, if we do not have some regulations to guide the proper use of feeding and stocking, it may be difficult for the industry themselves to self-regulate so we would have to think about whether we want to put some enabling legislation as a form of guide to the industry to develop themselves sustainably,” he said.