Fish farming trials to improve sustainability and income

Researchers are beginning a project to optimise fish feeding and strategies and fish husbandry to boost inland aquaculture in Papua New Guinea.

Fish farming creates a source of protein and income for often impoverished families in rural areas of PNG.

After many years working with subsistence and small-scale fish farmers, a UNSW-led team has been funded to explore ways to increase yields, develop sustainable practices for commercial sized operations, and find local feed ingredients to reduce dependency on imported materials and formulated fish feeds.

Associate Professor Jes Sammut from the UNSW Faculty of Science has received more than $2.6 million from the Australian Centre for International Agriculture Research for the project.

Sammut has been working with small-scale and subsistence fish farmers for about 13 years. The new project, in partnership with the PNG National Fisheries Authority (NFA), “will develop sustainable farming practices for fish grown in floating cages in reservoirs, and under more intensive pond-based farming systems,” he told Cosmos.

“This builds on the team’s past work but focuses on helping farmers achieve commercial-scale production. The project will continue to assist small-scale farmers whose main goal is to produce much needed protein.

“Most, however, were traditionally  gardeners – they have learned to integrate the fish ponds into their vegetables gardens,” says Sammut.  “We mostly work with villages in remote areas, but also in peri-urban areas,  and with communities interested in farming fish in reservoirs. Through NFA and our NGO partners, we have an extensive knowledge network to share fish farming knowledge.”

He says the number of fish farms is estimated to have increased from 11,000 in 2009 to more than 70,000 farms in 2023.  

The fish are known as Genetically Improved Farmed Tilapia (GIFT). They grow to about 900g in around 5-6 months depending on the climatic zone.  The fastest growth is on the coast due to the warmer water. In the highlands, farmers will harvest them to eat at a smaller size. Their priority is to grow protein.

Fish farming

It’s believed each farm can produce around 150-200kg per year to feed the family, but many struggle due to difficulty accessing formulated fish feeds.

“More advanced farmers produce around 500kg a year but depend on formulated feeds.  Larger farms are scarce – we are going to try and introduce sustainable commercial practices to some of the more advanced farmers; the new project will investigate optimal stocking densities for pond and caged based systems, and determine the carrying capacity of reservoirs to avoid negative environmental impacts.”

Samut says other Pacific nations and Timor-Leste also farm tilapia and are showing interest in the new research: “We need funding to adapt and transfer our technologies to other countries. Many Pacific Islands farm tilapia, but there are some other environmental challenges and higher costs for feeds and feed ingredients.”

The challenge in PNG is to create local feed for the fish, as most subsistence farmers have little  cash for imported fish feed.  Fish feed can account for up to 80% of production cost if fish feeding strategies and fish feed quality are poor.

“On the last project we improved production by increasing natural food sources via fertilising, and testing different fish feeding frequencies to avoid waste.  Fertisilising ponds is fine for low stocking densities. NFA also subsidised imported feeds for cage-based farms but the cost of imported feeds remains very high and eats into farm profits.  During COVID, fish feed costs increased dramatically in PNG.”

“On the new project we will be exploring insect meal and cost-effective feed ingredient replacement using locally-available materials.” 

Jacob Wani, project lead from the NFA, told UNSW media reporter Yolande Hutchinson that “Jes and I share a common goal for PNG – we both want to see more people access protein and to improve their income and livelihoods.

“We have a multi-disciplinary team across the two countries working as equals.  We respect each other and tackle the challenges as a unified team regardless of the agency we work for.”

Wani says “NFA and UNSW have had a very productive collaboration for over a long time. We train UNSW students in PNG, and UNSW trains NFA staff and students at UNSW and ANSTO, as well as on the project in PNG. This capacity building is a two-way process that benefits PNG and Australia.”