Full Title
Resnagging the Pomona Priority Habitat Reach, Lower Darling River
Contact Person
Todd Wallace
Project Team
Clayton Sharpe, Iain Ellis, Peter Fraser
Funding Body
NSW Department of Primary Industries
Duration
Til December 2009
Outcomes
Report to Lower Murray Darling CMA
Summary
. Background:
The Lower Murray Darling CMA in conjunction with NSW DPI are planning a strategic and targeted investment in aquatic habitat restoration within the LMD Catchment in the Pomona Priority Habitat Reach of the Lower Darling River. One of the key activities that have been identified in the aquatic habitat restoration project is re-snagging works. The project is the second of its type that addresses the Catchment Action Plan target to improve riverine health. The Pomona Priority Habitat Reach is accessed by the public and is a known recreational fishing area. The development and progression of fish habitat restoration activities in this area will directly engage both fishing club affiliated stakeholders and broader catchment community members.
. Project Concept:
Large woody debris, or 'Snags' are extensively utilised by native fish throughout their life-cycle. Snags are considered critical to the ecology of several native species (e.g. Murray cod and golden perch) as they offer shelter from predation, spawning substrate, and enhance predatory fishes encounter rates with their preferred prey, among other ecological functions. Since European settlement, snags have been extensively removed from rivers to improve navigation and flow rate for irrigation supply. It is widely accepted that this activity has been detrimental to native fish populations within de-snagged areas.
Re-snagging works have been undertaken in recent years to restore the ecological function of rivers, especially for native fish. It is anticipated that implementation of a re-snagging project in the Pomona reach will improve habitat quantity and quality for native fish and subsequently enhance the native fish community within the targeted areas. This research proposal aims to provide data on the relationship between snag density/complexity and native fish communities (e.g. total abundance, species diversity, biomass, size class structure) within the Pomona Priority Habitat Reach (PPHR). It is anticipated that this project will provide managers with regionally specific information on the potential benefits of undertaking targeted re-snagging works in the PPHR.
Detailed understanding of relationships between snag density/complexity and native fish communities will substantially enhance the potential for restoration activities such as environmental flows and re-snagging projects to achieve the goal of maintenance of sustainable native fish communities in the Murray-Darling Basin. A specific emphasis on iconic native fish species will assist in demonstrating to the public sector the benefits of site specific habitat rehabilitation (re-snagging) programs.
. Objectives of the Monitoring Program:
1. Establish monitoring reaches with contrasting levels of snag density (low and high) in the weir pool environment of the PPHR
2. Assess the relationship between snag density/complexity and native fish communities (e.g. total abundance, species diversity, biomass, size class structure) in the PPHR
3. Provide scientifically defensible, regionally specific data to inform future re-snagging works in the Lower Murray-Darling region.
