Native fish population models
Tools to assist water management
Native fishes
This project
Native fishes of the Murray-Darling Basin (MDB)
have suffered substantial declines and, overall,
populations are now considered to be at about
10% of those prior to European settlement. Fish of
the MDB are highly valued for their biodiversity,
cultural, social (recreational angling) and economic
values and the rehabilitation of their populations is
an important Natural Resource Management
objective.
Dynamic population models will be developed for
eight different MDB fish species. These species
have been selected to represent a range of
habitats and flow requirements, (e.g. in-channel,
wetland specialists; flow cued spawners) sizes and
different management needs (e.g. threatened
species, angling species):
 Golden perch
 Silver perch
 Murray cod
 Trout cod
 Macquarie perch
 Southern pygmy perch
 Olive perchlet
 Murray hardyhead
Fish and flow management
Delivering allocations of environmental water is a
key rehabilitation action under the Murray-Darling
Basin Plan. Such flows are provided for a range of
biota, including fish. There is a need to
demonstrate the potential benefits of water
management actions, and the use of population
models provides a method by which this can be
undertaken, at least in a theoretical sense.
Modelling a range of flows allows for a comparison
of a series of management options to be made so
that the benefits to fish populations can be
maximised.
Watering objectives, delivery methods and
mechanisms are based on the best available
science, but as environmental watering is a
relatively new management action, our ecological
knowledge is still evolving. Developing new
species population models will ensure that the
best available science, data and knowledge is
incorporated into these management tools. This
project will undertake literature reviews and expert
workshops to collect the very latest ecological
knowledge,
thinking
and
conceptual
representations which will be used to develop
eight new fish population models.
Water managers will be consulted widely from the
very beginning of this project to ensure that likely
water
management
options
can
be
accommodated.
Murray cod (top), a river channel specialist, and Southern
Pygmy perch (bottom), a wetland specialist fish species.
These models will be used to assess how
populations of different species may be affected by
a range of flows, including natural events,
environmental
watering
and
other
water
management actions.
The models will also
incorporate options for assessing the impact of the
range of other threats impacting these species.
A range of flow scenarios will be modelled with
consideration given to in-channel and over-bank
inundation flow events for suitable habitats. This
will include watering options across the whole
MDB; importantly taking into account any regional
ecological differences, especially between the
northern and southern MDB.
Some of the questions being addressed by this
project are:
 What are the likely responses of populations
under differing flow and watering scenarios?
 What is the likely quantity of any population
responses?
across Murray-Darling Basin. The models will help
demonstrate
the
potential
benefits
of
environmental water management to populations
of these fish species to agencies and the wider
public.
These models will be completed by mid-2017.
Project partners
This project is funded by the Murray-Darling Basin
Authority and undertaken by the Arthur Rylah
Institute for Environmental Research (DELWP,
Victoria) in partnership with a wide range of
experts from: South Australian Research and
Development Institute, NSW fisheries, Kingfisher
Research, Murray Local Land Services, Griffith
University, University of Canberra, La Trobe
University/Murray-Darling Freshwater Research
Centre, University of Melbourne, Fisheries
Victoria, University of Canberra Charles Sturt
University and several Consultants.
Tools for water managers
The
project
will
develop
practical
recommendations for water management to
maximise the benefits to a range of fish species.
Water managers will be involved in workshops and
training
to
ensure
that
the
project
recommendations are feasible and practical, and
to familiarise them with these tools so that the best
use of the models can be incorporated into future
management.
It is anticipated that these models will provide
important tools to assist native fish management at
multiple scales: for both annual and longer-term
planning into the future at both individual sites and
© The State of Victoria Department of Environment, Land, Water and
Planning 2015
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