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Tracking the movement of black bream in the Yarra and Maribyrnong estuaries

Tracking the movement of black bream in the Yarra and Maribyrnong estuaries

Regional estuaries have received most attention in describing habitat preferences, ecology and biology of fish. The Yarra/Maribyrnong estuaries are among the largest systems in central Victoria and are highly urbanised. Both systems also support rich assemblages of fish. Unfortunately, however, we know virtually nothing of how, when or why habitat preferences and patterns of movement change. Understanding the movement of fish in relation to changes in the environment is a critical first step in managing estuarine ecosystems to support fish, and ultimately forms the basis for future research programs on biodiversity-habitat linkages, spawning and recruitment.

An exciting new partnership between Arthur Rylah Institute (DSE) (external link), Marine and Freshwater Systems (DPI), Melbourne Water (external link) and the University of Melbourne (external link) has provided an opportunity to study the movement patterns of a key estuarine fish species (black bream, Acanthopagrus butcheri).
Photo:  Recovery of Black Bream after tagging
Recovery of Black Bream after tagging

Photo:  Yarra & Maribyrnong estuaries
Black bream caught in the Yarra River estuary
      As we have done in the Gippsland lakes over the past 3 years, we are using acoustic telemetry to track the movements of black bream throughout the Yarra and Maribyrnong estuaries. We have also installed acoustic receivers in the Patterson, Mordialloc and Werribee rivers to assess broad-scale movements.

      In late September we implanted acoustic transmitters (pingers) into 20 black bream caught in the Yarra River. Day-to-day patterns of movement by these fish will be monitored over the next 12 months. Stay tuned for results.

      This project will help to increase understanding of the spatial ecology and behaviour of fish in the Yarra/Maribyrnong estuaries. Specifically, the project will provide information on:
      • the patterns of movement and habitat use in urban estuaries
      • which areas/habitats of the Yarra/Maribyrnong system are used most by fish
      • the residency times in the Yarra/Maribyrnong
      • the degree of connectivity of fish populations among different estuaries entering Port Phillip Bay
      • how fish use natural versus artificial habitats
      • how patterns of movement and habitat use change with environmental change (e.g. freshwater flows, dissolved oxygen), and which environmental attributes are most important in determining fish movement

Photo:  Yarra & Maribyrnong estuaries
Tagged bream before release into the Yarra River estuary
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