Merri Estuary Management Plan Summary The Merri estuary is located near Warrnambool in southwest Victoria. The river has two openings to the sea, both artificially modified. In 1859, the course of the Merri River was diverted in an attempt to prevent sedimentation in Lady Bay (Gill 1984). The main channel of the Merri River now discharges into the sea at Stingray Bay east of Pickering Point. The Merri estuary is also linked to the Southern Ocean through the Merri Marine Sanctuary. The sanctuary supports a wide range of marine habitats including sandy beaches, intertidal reefs with rich species diversity, subtidal reefs and associated kelp forests, seagrass beds, and unvegetated soft sediments. The Merri Marine Sanctuary has the highest level of species richness in the Warrnambool region on calcarenite reefs and also surrounds two offshore islands with significant breeding colonies of Little Penguins The Merri estuary has been an important meeting place for the Gundjitmara people for thousands of years. Ceremonies and celebrations took place and the natural resources provided by the river and estuary were and still are an important resource for the indigenous communities. The western section of the estuary forms Saltwater Swamp and Kellys Swamp that drain into the sea at Rutledges Cutting (Mondon et al. 2003). Kellys Swamp is nationally significant with high values for geomorphologic and ecological features. Fifty-three waterbird species have been recorded in these wetlands, with 47 species at Saltwater Swamp and 30 species at Kellys Swamp. They contain significant habitat for rare species such as the Orange Bellied Parrot and are breeding grounds for the Hooded Plover and other ground nesting birds. A total of 14 native fish species have been recorded from the Merri estuary, which also contains at least four introduced species (brown trout, gambusia, tench and redfin). Highly valued recreational species include black bream and estuary perch. The estuary also supports a commercial eel fishery. Some of the significant threats to the Merri estuary’s ongoing health include: • Reduced water quality; • Inadequate environmental flows; • Pest plants and animals; and • Artificial river mouth opening; This management plan has been developed in consultation with members of the local community and government agencies and provides a basis for coordinated and targeted investment in the maintenance and enhancement of the values provided by the estuary for future generations. From March to September 2002, at the request of Glenelg Hopkins CMA, EPA Victoria undertook an environmental audit of the Merri estuary. This examined land uses, activities and their associated impacts on the beneficial uses of the estuary and identified a range of values and threats, which are now addressed in this management plan. The activities and land uses examined pose at least a moderate risk of harm to the beneficial uses of the Merri estuary, while the risks to the following uses are considered high: • the maintenance of the aquatic ecosystem; • recreational use; and • the fishery potential. Development of the management plan has focused on identification of the key assets provided by the estuary and the threats that are degrading, or have potential to degrade, the value of the identified assets. This approach is consistent with the Glenelg Hopkins River Health Strategy. Development of this management plan also fulfils one of the high priorities identified by the South West Estuaries Coastal Action Plan (Western Coastal Board 2002a), and contributes to Regional Management Action Target 83 in the Glenelg Hopkins Regional Catchment Strategy (RMAT 83: Meet aspirational target for coastal areas through developing and implementing individual estuary management plans in accordance with the South West Estuaries Coastal Action Plan .). Development of this estuary management plan also fulfils actions identified in the Glenelg Hopkins CMA River Health Strategy (Glenelg Hopkins CMA 2004). Assessment of the threats posed to assets in the management plan area and determination of practical means to reduce or eliminate these threats has allowed formulation of management actions. Groupings of these management actions form a set of key programs that when implemented, will provide significant benefits in terms of maintenance and enhancement of the values of the estuary. Merri Estuary Management Plan ii Implementation program quick reference guide The following is a quick reference guide to the implementation programs, their objectives and targets, and links to actions identified in the Glenelg Hopkins River Health Strategy (GHRHS). Program Management objective Target GHRHS Links Habitat – aquatic, semi- Maintain and improve the extent and Establish the baseline condition and RH-H13-1 aquatic and terrestrial. condition of estuarine habitats. extent of aquatic, semi-aquatic and terrestrial habitats in the Merri estuary by RH-H13-4 2012. RH-H13-5 RH-H13-10 Fish Maintain and improve native fish Establishment of baseline information on RH-H13-1 diversity and abundance. diversity and abundance of native fish populations within the Merri estuary by RH-H13-2 2012. RH-H13-3 RH-H13-7 Terrestrial fauna Maintain and improve biodiversity of Establishment of baseline information on RH-H13-4 native terrestrial fauna. diversity and abundance of native terrestrial fauna populations within the RH-H13-10 Merri estuary by 2012. Water quality and Maintain and improve water quality Establish estuary specific water quality RH-H13-3 hydrology within the Merri estuary and ensure criteria by 2012 and ensure that estuarine maintenance of key hydrological water quality meets estuary specific RH-H13-5 features required for estuary guidelines 80% of the time by 2012 and RH-H13-7 processes. compliance of environmental flows for the estuary are met by 2012. Social values Minimal impact on the condition of the All necessary infrastructure, management RH-H13-1 estuary as a result of recreational policies and management resources in activities. place by 2012. RH-H13-2 Rh-H13-4 RH-H13-7 Cultural values Protect the Aboriginal and European Documentation of all recorded sites of RH-H13-1 heritage of the Merri estuary. archaeological and heritage significance within the Merri estuary by 2012. RH-H13-4 RH-H13-7 Economic values Development in the estuary and Only environmentally sustainable RG-H13-3 adjacent catchment encompasses the activities encouraged within the Merri social and environmental values of the estuary area. RH-H13-8 area. Estuary entrance and Maintain as close to natural as Protocols developed for mouth opening RH-H13-3 artificial river mouth possible the opening and closing using the EEMSS by 2008 opening process for the Rutledges Cutting and RH-H-13-8 the Merri River mouth. Pathogens and parasites Maintain healthy indigenous flora and Maintain current agency endorsed fauna populations response plans for all reported incidents of pathogens and parasites. Pest plants and animals Long-term control of pest plants and Implementation of a pest plant and animal RH-H13-2 animals in the aquatic, semi-aquatic monitoring program to ensure early and terrestrial estuarine environments detection of any pest plants and animals RH-H13-6 to a level that does not pose a high by 2012. Rh-H13-10 risk to native biodiversity values. Soils, erosion and To reduce sediment loads in Identify all sites of active erosion within RH-H13-9 sedimentation waterways flowing into the Merri the Merri River catchment and estuary by estuary 2012, and commence remedial works. RH-H1311 Climate change Actively manage risk associated with All future planning for urban development predicted climate change within the and maintenance of habitat and Merri estuary and catchment. biodiversity values of the estuary to include consideration of the likely impacts of climate change, including sea level rise. Local government Development occurs within the Adoption of planning policies and overlays planning framework of ecologically sustainable into the Warrnambool City Council and principles and protects the values of Moyne Shire Council Planning Schemes the Merri estuary. that protect and enhance the values of the Merri estuary. Monitoring, evaluation Improved understanding of the Undertake an evaluation of the and reporting response of the estuary to the effectiveness of implementing actions implementation of the Merri Estuary identified in this plan by 2012. Management Plan. Merri Estuary Management Plan iii Acknowledgements Thanks to those people who gave up their time to participate in the community consultation, the comments and input were invaluable in preparing the management plan. Members of the Coast and Marine Technical Working Group Published by: Glenelg Hopkins Catchment Management Authority 79 French Street, Hamilton Victoria 3300 Disclaimer This publication may be of assistance to you but the State of Victoria and the Glenelg Hopkins Catchment Management Authority and its employees do not guarantee that the publication is without flaw of any kind or is wholly appropriate for your particular purposes and therefore disclaims any liability for any error, loss or other consequence that may arise from you relying on the information in this publication ISBN: 978-0-7594-1031-2 Glenelg Hopkins - Copyright Notice © Glenelg Hopkins Management Authority (2008) This work is the subject of copyright. All rights reserved. No part of this work may be reproduced, adapted, published or communicated (made available online or electronically transmitted)