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Title:

Influence of freshwater flows on growth and abundance of Barramundi and Mud Crab in the Northern Territory

Project Number:

2015-012

Organisation:

Charles Darwin University (CDU)

Principal Investigator:

Alison King

Project Status:

Current

FRDC Expenditure:

$286,000.00

Program(s):

Environment, Industry

Need

The way water is allocated in the future, and how we find a balance between competing industries, is vital to the Northern Territory (NT) and National economies. In order to achieve this, the fishing industry and Government require a more predictive and quantitative understanding of the role of river flows in driving fisheries productivity. This project provides the first rigorous analysis of specific flow components that drive the productivity of the barramundi and mud crab fishery in the NT. We will quantify these relationships, test a range of water extraction scenarios and explore their impact on downstream fish populations and fisheries. This will contribute to informed decision-making about future water allocations and contribute to Government policies and strategies, particularly around the current northern Australia development agenda. This project directly addresses NT FRAB Priority 3. Previous analyses show that barramundi (e.g. Robins et al 2005; Tanimoto et al. 2012) and mud crab catches (Meynecke et al. 2012) are positively related to coarse hydrological metrics (e.g. total wet season flows). However, the mechanisms driving these relationships remain speculative and it is difficult to determine the effects of specific flow management regimes. For example, it is currently unknown if dry season flows affect fisheries production, or if there are thresholds of wet season flows which alter fisheries productivity. This project will use new, innovative biochronological techniques to better quantify the relationship between hydrological variables and the productivity of barramundi and mud crab fisheries in the NT.

Objectives

1. Undertake ageing and biochronological measurement of barramundi otoliths and mud crab ossicles, and collate NT catch and environmental data (e.g. river discharge).

2. Develop rigorous, regionally specific empirical models to quantify the relationships between fisheries productivity and various metrics of freshwater inflow using advanced statistical techniques.

3. Provide research findings to industry and government for a scientifically defensible and robust basis for decisions on the future use of water in northern Australia in relation to fisheries resources.