by Alice Mitchell10 April 2015, at 1:00am
AUSTRALIA – Growing prawns and worms in the same integrated system can lead to improved productivity and waste management, recent results from a Queensland Department of Agriculture and Fisheries research project show.
The two-year study is testing the concept of fully recirculating pond water from intensive prawn culture ponds through polychaete-assisted sand filters (PASF), to create sustainable supplies of prawns and marine worms.
Agri-Science Queensland Senior Biologist Dr Paul Palmer announced the successful production of a second crop of black tiger prawns and marine worms using the PASF system.
“The project has recently successfully produced its second crop of black tiger prawns and marine worms on a semi-commercial scale, without water discharge from the system,” Dr Palmer said.
Dr Palmer described the results as very encouraging for consideration by industry. The sand and worms help to clean the water, provide a valuable by-product and have a lower environmental footprint compared with traditional prawn farming methods.
Dr Palmer explained: “The integrated system uses constructed sand beds stocked with marine worms to filter and recirculate treated-prawn-pond wastewater.
“This treatment removes nutrients and provides a range of operationally desirable effects. It helps to stabilise water qualities within the prawn ponds and allows the farm to operate without regular contact with adjacent natural waters.
“This improves on-farm biosecurity and can help to avoid problems during floods when rivers carry unacceptable levels of silt and freshwater.
“The system also provides a valuable by-product in the form of marine worms that can later be harvested from the sand filters.
“Prawn hatcheries use the cleansed worms as feed to improve the quality of their broodstock and they are also finding particular favour in the live bait industry.
“Presently, the prawn farming industry uses settlement ponds to treat its wastewater and this latest development offers improvements to this process.
“It also offers sustainable methods for the widespread industrial production of valuable marine worms into the future.”