Macquarie University
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Abiotic and biotic factors influencing the invasion of Carcinus maenas in southern New South Wales, Australia

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posted on 2022-03-28, 16:49 authored by Clifford J. Garside
Non-indigenous species are among the greatest threats to global biodiversity and collectively cause significant economic damage. The European shore crab Carcinus maenas is a global marine pest that has been present in Australia for over 100 years, but has been little studied in this part of the world. This thesis aimed to enhance our knowledge of the distribution and abundance of C. maenas in New South Wales (NSW) and the role that the unique abiotic and biotic features of the Intermittently Open and Closed Lakes and Lagoons (ICOLLs) that dominate the NSW coastline play in the invasion. ICOLLs can spend periods of days to years disconnected from the ocean by a sand bar, and display high spatio-temporal variability in their abiotic and biotic conditions. Trapping surveys across 14 estuaries (including ICOLLs) and spanning 8 dates found that in NSW the abundance of C. maenas is low and displays considerable spatial variation at the scales of estuaries and habitat. The detection of crabs in estuaries was positively correlated with the proportion of time estuarine entrances were open. Within estuaries, abundances were greater in mangroves than in saltmarsh, seagrass, oyster or bare sediments and were negatively correlated with the abundance of several native predators. Hence the opening and closing of estuarine entrances influenced C. maenas invasion by determining opportunities for recruitment, and possibly by determining the predator and habitat assemblages within these. Recruitment and cohort analyses indicated that C. maenas larvae primarily settle in the late Austral winter to spring, retaining the reproductive phenology of the northern hemisphere. Overall, this study suggests that although C. maenas has been present in Australia for over a century its abundance, and hence impact, remains low along the NSW coast due to a combination of abiotic and biotic factors.


Table of Contents

1. General introduction -- 2. The frequency of connection of coastal water bodies to the ocean predicts Carcinus maenas invasion -- 3. The timing of Carcinus maenas recruitment to a south-east Australian estuary differs to that of native crabs -- 4. The distribution of the European shore crab, Carcinus maenas, with respect to mangrove forests in south-eastern Australia -- 5. Putative predators of Carcinus maenas in eastern Australia -- 6. General discussion.


"Submitted February 2014 Includes bibliographical references This thesis is presented as partial fulfilment to the requirements for the degree of Doctor of Philosophy in the School of Biological Sciences, Macquarie University"

Awarding Institution

Macquarie University

Degree Type

Thesis PhD


PhD, Macquarie University, Faculty of Science and Engineering, Department of Biological Sciences

Department, Centre or School

Department of Biological Sciences

Year of Award


Principal Supervisor

Melanie Bishop

Additional Supervisor 1

Melinda Coleman

Additional Supervisor 2

Tim Glasby


Copyright Clifford J. Garside 2014. Copyright disclaimer:




New South Wales


1 online resource (x, 136 pages) illustrations, maps

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