Carp study plan on home straight
Anational
project to determine whether the biological release of a speciesspecific virus can tackle noxious carp is on track to finish in December this year.
Researchers are steadily tabling results from more than 19 projects exploring the potential of controlling the pest with the virus.
The National Carp Control Plan is a $10.2-million Federal Government program led by Fisheries Research and Development Corporation.
Wimmera catchment leaders, following the progress of the plan, have previously suggested, depending on research findings, that the landlocked Wimmera River system might offer an ideal pilot area for the release.
One project led by Dr Susan Nichols from the University of Canberra is in its final stage of review.
Dr Nichols’ project has involved collecting and analysing expert views and scientific literature to understand the likely medium to longterm environmental responses to reduced carp populations.
“Longer-term predictions over broader geographic areas are complicated by the diversity of ecosystem types,” she said.
“There are different types of lakes, rivers and wetlands inhabited by carp in Australia, each with unique management histories and conditions.”
Carp, Cyprinus carpio, are the most abundant freshwater fish in many waterways of south eastern Australia, including the Wimmera.
Waterway specialists believe the species has detrimental effects on water quality, native fish populations, fishing and irrigation.
However, they say identifying specific benefits of carp removal is complex, adding that flow history and types of ecosystems influence long-term ecological responses.
Carp-control research focuses on the premise that reducing the number of carp in Australia’s waterways will improve the health of aquatic ecosystems.
This premise is based on experimental and anecdotal evidence from Australia and overseas.
Additional recent research also highlights the potential impact on the broader environment following reductions in carp numbers.
As part of the project, researchers invited experts from a wide range of disciplines to participate in an online survey and workshops to predict how different levels of carp reduction would affect a variety of ecosystems and species such as native fish, water plants, macroinvertebrates including molluscs, water bugs, yabbies and shrimp, water birds, amphibians, algae and zooplankton. They also considered a response to water quality.
Forty-nine experts who responded to the survey were invited to discuss thoughts in two workshops and given the opportunity to review their predictions in light of the discussions.
The experts agreed carp populations needed to be significantly less to provide benefits across most ecosystems.
They emphasised that different ecosystem types would vary in their response to carp and that responses were likely to vary over time.
The expert responders also identified factors they believed would influence ecosystem responses.
One of the predictions was that degraded systems might not return to their original state after the reduction of carp. This could be due to factors such as other alien species including redfin doing better without the presence of carp.