The recent mass fish deaths at offshore farms here could be averted in future, Singaporean scientists hope, if farmers use a powerful, lower-cost water quality sensor they are developing.

The sensor, built by scientists from the Singapore-MIT Alliance for Research and Technology (Smart) and funded by the National Research Foundation, will be able to detect more than a hundred types of organic and inorganic substances found in our waters within seconds.

These include chlorophyll, which can be indicative of algae blooms deadly to fish, and low levels of dissolved oxygen in water. These could have caused the recent deaths of 160 tonnes of fish at 39 farms in Singapore's northern waters, the Agri-Food and Veterinary Authority (AVA) has said.

The sensor could, for instance, alert farmers through a text message on their handphones when chlorophyll levels spike or oxygen levels get dangerously low. It could also be configured to automatically trigger an aeration system to add oxygen to the water.

The system is being commercialised by a local start-up company, which Smart research scientist Kelvin Ng declined to name. It is expected to cost in the region of $25,000.

It can also detect other pollutants such as oil and detergents.

The adaptable system can be made mobile by deploying it in marine vessels such as ships or autonomous underwater vehicles (AUVs), said Mr Ng. This way, 3-D maps could be created to show how contaminant levels vary across a body of water and over time, making it easier to determine their source and address the problem.