New study proves commercial reality

By Geoff Adams

University researchers in Western Australia have proven what Deniliquin people have known for years — pest European carp can make good fertiliser.

Researchers at Curtin University in Western Australia found that dead carp could be used successfully in a range of ways, from fertiliser to feed.

This could help use the large amounts of dead carp, which would be generated if all Australian governments decided to introduce the carp virus to control this pest fish.

The study investigated various utilisation options, which could also be applied more broadly to deal with fish waste, and found that converting carp into compost and liquid hydrolysate fertiliser are both potentially viable routes.

A private company based in Deniliquin, Charlie Carp, has been catching European carp and turning them into fertiliser for years.

The company uses electro fishing and netting to catch the pest fish.

Curtin University lead researcher Janet Howieson said composting trials of up to 40 tonnes showed the dead carp could effectively be used to produce a safe, nutrient-rich compost for application in agriculture and horticulture.

“This is a viable option on both local and large-scale alike,” Dr Howieson said.

“Fermentative hydrolysis for making fertiliser and use of carp as an input for vermiculture have been shown to be technically viable for smaller community based applications, and can be implemented based on the draft methods, protocols and costings in this work,” National Carp Control Plan co-ordinator Jamie Allnutt said.

The study also investigated, at small-scale, the use of decomposing carp as feed for black soldier fly larvae, used to supplement fish feed in small scale aquaculture trials.

Using the nutrient-rich water, which results from carp processing, to act as input for biogas production was also considered.

During the study, it became obvious that commercial operators were open to exploring carp utilisation options.

This research project is an important part of the National Carp Control Plan. The NCCP is a $10.2 million program led by the Fisheries Research and Development Corporation, on behalf of the Federal Government.

It aims to address two questions: Is it feasible to release the carp virus to control carp? If so, what is the most effective way to release and manage the virus?

This project provides some of the science to help answer these questions.

The NCCP will be delivered to the Federal Government in late December. The government will then decide on the next steps.

The NCCP was formed to investigate the feasibility of releasing a virus to control carp in Australian waterways.

Carp (Cyprinus carpio) completely dominate freshwater fish communities in south-eastern Australia.

Carp impacts are felt environmentally, economically and socially. Carp affect water quality, native fish, fishing and irrigation.