Basin Theme: Fish

Rivers and wetlands of the Murray-Darling Basin historically supported unique and vibrant fish communities, but since European settlement, the distribution and abundance of our native fish has markedly declined. Water for the environment, along with complementary actions like putting logs back into rivers, are key to recovering fish like the iconic Murray cod and beautiful Purple spotted gudgeons. Work in the Fish Theme will evaluate the benefits Commonwealth environmental water provided to our native fish populations, and improve our understanding of the flow-relate ecology and population dynamics of native fish to ultimately inform environmental water management for fish outcomes in the future.

Image: Murray cod.  Photo credit: Arthur Rylah Institute

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Why focus on fish?

Many of the critical life-history processes for Murray-Darling Basin (MDB) fish (growth, spawning, recruitment, survival, migration and dispersal) are intrinsically linked to hydrology (flow) and habitats. Alterations to natural flow regimes have resulted in major changes to riverine ecosystems, including alterations to the magnitude, timing, frequency and duration of flows, as well as modifications to food, habitat quality and availability, and water quality.

The Fish Theme Team have a wealth of existing data to draw upon from the seven Selected Area focus sites, as well as knowledge from other Basin Themes and State Agency research data. Our approach will be to use these integrated data to build statistical models that will ask questions about the benefits of water for the environment to native fish populations. This will include population modelling of fish survival – with and without watering – as well as their movement and spawning response to different environmental flow regimes. This is information that is urgently required to improve native fish communities across the MDB.

A major outcome for the Fish Theme is an improved understanding of how Commonwealth environmental water contributes to flow regimes designed to protect and restore native fish populations. These outcomes will be highly transferable across different river systems, and will be presented as a series of summary report cards.

Releasing a Murray cod during a fish survey. Photo credit: Gwydir Research Team
Sampling a range of different sites suitable for native fish translocation. Photo credit: Scott Raymond

Our approach

The foundational data upon which the Fish Theme will build cutting-edge models, is the past work by the Long Term Intervention Monitoring (LTIM) Project and the Environmental Water Knowledge and Research (EWKR) Project, as well as other relevant data from within the Fish team. By individually examining and aggregating Selected Area data, we will be able to determine benefits of water for the environment for fish at local, regional and valley scales.

One exciting example of this work is the fish ear bone (i.e. otoliths) samples collected during the EWKR and LTIM projects. The age of fish can be determined from the otoliths which informs the statistical models of exactly which flow regime contributed to ‘recruitment’ or survival of native fish. The unique chemical signatures of fish otoliths can be analysed and matched to water chemistry data from across the Murray-Darling Basin. This enables us to determine where and when fish spawn and which components of the Commonwealth’s environmental flows were crucial in these processes.

Current activities

The Fish Theme incorporates three new projects, which build on past LTIM and EWKR work:

Fish population models

This work will involve model development for Murray cod, Golden perch and Bony herring to determine the benefits of Commonwealth environmental water at local and regional scales.

Image: Example of fish population model output. Photo credit: Arthur Rylah Institute

Flow, movement and fish population dynamics

Our focus here will be to examine existing otolith microchemistry and fish movement dataset (from acoustic tags) to build a sophisticated statistical model which will determine fish movement, spawning and survival rates in relation to environmental watering.

Image: Fish earbone (otolith). Photo credit: Arthur Rylah Institute

Scott Raymond holding a metre long Murray cod in the Goulburn River, Vic
Photo credit: Arthur Rylah Institute

Our team

Dr Ivor Stuart

Ivor is the Theme Leader for the CEWO FLow-MER Fish Theme, and a freshwater fisheries biologist – with over 25 years industry experience in environmental flow planning, river management, fish passage and fish ecology. Ivor has worked in the tropical north, the semi-arid western rivers of NSW/Qld and in the temperate rivers of Victoria.

Dr Zeb Tonkin

Zeb is the Co-Project Leader for Flow-MER Fish population abundance and diversity project, and a senior scientist at the Arthur Rylah Institute. He currently manages a wide variety of projects relating to recruitment dynamics and migratory behaviour of freshwater fish, environmental flows, floodplain fish assemblages and habitat restoration.

Dr Charles Todd

Charles is the Project Leader for FLOW-MER Population models project. He develops software to assist with managing native freshwater fish and created the Murray Cod management model, as well as undertaking a comprehensive scoping study for applying the template of the Murray Cod management model to other fish species in the MDB.

Dr Jarod Lyon

Jarod is the Principal Scientist and Section Leader of the Applied Aquatic Ecology Section at the Arthur Rylah Institute for Environmental Research. Jarod is particularly interested in undertaking research which has direct applicability to management, and as such has strong links with organisations such as the MDBA, Catchment Management Authorities, Fisheries Victoria and Government agencies.

Dr Wayne Koster

Wayne Koster is a fish ecologist at the Arthur Rylah Institute and the focus of much of his work is assessing the responses of native fish to environmental flows. Wayne is leading the native fish component of the Goulburn Selected Area Intervention Monitoring 5-year program to evaluate the effectiveness of environmental water use in the Murray-Darling.

Dr Chris Bice

Chris is the Fish and Integrated Research Task Leader, and his research focuses on the fish movement, fish passage, threatened species ecology and the response of fishes to changing in flow regimes.

Dr Brenton Zampatti

Brenton is the co-Project Leader for the Flows, Movement and Fish Population Dynamics research project, and a Principal Research Scientist with CSIRO. He has worked for 25 years on the ecology of freshwater and estuarine fish across south-eastern Australia, including flow-related ecology and population dynamics, habitat requirements, and fish movement and passage. He works closely with managers and the community to transfer knowledge and research outcomes to the conservation of freshwater ecosystems.

Dr Jason Thiem

Jason is a Fisheries Scientist with the NSW Department of Primary Industries and co-Project Leader for the Flows, Movement and Fish Population Dynamics research project. Jason’s current research program is focussed on the abiotic drivers of fish movement, spawning and recruitment within the Murray-Darling Basin, with a strong focus on riverine connectivity.

Dr Gavin Butler

Fisheries leader. I oversee and direct the fish sampling, analysis and reporting for the project. I even get my feet wet sampling from time to time.

Professor Lee Baumgartner

Lee is a Freshwater Fish Ecologist who designs, supervises and undertakes into various aspects of the biology and ecology of freshwater fish. His research has been in several broad areas, including fish passage and fish migration, dietary interactions among native fish species, the impact of human disturbance on aquatic ecosystems and, more recently, the effectiveness of native fish stocking.

Assoc Professor Qifeng Ye

Qifeng is a fish ecologist with special interest in environmental water requirements of native fish and ecological impacts of river regulation.

Sally Hladyz

Sally is a community and ecosystem freshwater ecologist based at the Arthur Rylah Institute. Her research focus is on linking biodiversity, ecosystem function and food webs in an applied context to help improve the management of freshwater ecosystems. She has expertise in determining environmental flow benefits for rivers and wetlands in the Murray-Darling Basin.

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