Issues Paper for the Grey Nurse Shark (Carcharias Taurus)
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Issues Paper for the Grey Nurse Shark (Carcharias taurus) 2014 The recovery plan linked to this issues paper is obtainable from: http://www.environment.gov.au/resource/recovery-plan-grey-nurse-shark-carcharias-taurus © Commonwealth of Australia 2014 This work is copyright. You may download, display, print and reproduce this material in unaltered form only (retaining this notice) for your personal, non-commercial use or use within your organisation. Apart from any use as permitted under the Copyright Act 1968, all other rights are reserved. Requests and enquiries concerning reproduction and rights should be addressed to Department of the Environment, Public Affairs, GPO Box 787 Canberra ACT 2601 or email [email protected]. Disclaimer While reasonable efforts have been made to ensure that the contents of this publication are factually correct, the Commonwealth does not accept responsibility for the accuracy or completeness of the contents, and shall not be liable for any loss or damage that may be occasioned directly or indirectly through the use of, or reliance on, the contents of this publication. Cover images by Justin Gilligan Photography Contents List of figures ii List of tables ii Abbreviations ii 1 Summary 1 2 Introduction 2 2.1 Purpose 2 2.2 Objectives 2 2.3 Scope 3 2.4 Sources of information 3 2.5 Recovery planning process 3 3 Biology and ecology 4 3.1 Species description 4 3.2 Life history 4 3.3 Diet 5 3.4 Distribution 5 3.5 Aggregation sites 8 3.6 Localised movements at aggregation sites 10 3.7 Migratory movements 10 3.8 Natural predators 11 3.9 Abundance 11 4 Conservation 14 4.1 Conservation status worldwide and in Australia 14 4.2 Protection at key aggregation sites in Australian waters 15 5 Threats to the grey nurse shark 17 5.1 Primary threats 17 5.2 Secondary threats 21 6 Research and management priorities 24 7 Acknowledgements 25 8 References 26 9 Appendices 31 Appendix 1: Grey nurse shark sighting locations 31 i List of figures Figure 1: Grey nurse shark sightings 7 List of tables Table 1: Known key aggregation sites critical to the survival of the grey nurse shark in Australian waters 9 Table 2: Current conservation listings for the grey nurse shark in Australia 15 Table 3: List of known sightings of grey nurse sharks along the east coast of Australia, including aggregation sites that are regularly and consistently used (five or more sharks), sites where small aggregations have been observed (less than five sharks) and also sites where single sharks have been recorded on single occasions. Source: NSW DPI, unpublished data, (2002) 31 Abbreviations AFMA Australian Fisheries Management Authority, Commonwealth ASFP Australian Society for Fish Biology CSIRO Commonwealth Scientific and Industrial Research Organisation DoE Department of the Environment EPBC Act Environment Protection and Biodiversity Conservation Act 1999 IUCN International Union for Conservation of Nature NSW DPI New South Wales Department of Primary Industries QDPI&F Queensland Department of Primary Industries and Fisheries SEACAMS Sustainable Expansion of the Applied Coastal and Marine Sectors ii / Issues Paper for the Grey Nurse Shark (Carcharias taurus) 1 Summary The grey nurse shark (Carcharias taurus) is listed as • Since the introduction of the 2002 Recovery Plan two separate populations under the Environment for the Grey Nurse Shark (Carcharias taurus) in Protection and Biodiversity Conservation Act 1999. The Australia, all but one of the 19 key aggregation east coast population is listed as critically endangered sites identified as habitat critical to the survival of and the west coast population is listed as vulnerable. A the species in the 2002 recovery plan have been recovery plan for the species was finalised in 2002. given some level of protection. The remaining site—China Wall off Moreton Island in A review of the 2002 Recovery Plan for the Grey Queensland—was ultimately not considered a key Nurse Shark (Carcharias taurus) in Australia was aggregation site as the sharks were not consistently completed in 2009. The review concluded that while seen there. progress had been made on most of the recovery plan actions, there was not sufficient evidence to indicate • Fishing pressure from the recreational and that the population had recovered sufficiently to be commercial sectors represents the greatest ongoing removed from the list of protected species. The review threat to the grey nurse shark in Australian waters, further concluded that a new recovery plan was followed by mortalities as a result of the required to remove completed actions and include New South Wales and Queensland bather new conservation priorities. The Department of the protection programs (beach meshing/ 1 Environment, with the support of key stakeholders, drumlining ). has developed a new recovery plan for the grey nurse • Despite significant advances over the last decade in shark. the knowledge base concerning the grey nurse shark in Australian waters, continuation of This issues paper has been developed to support the research into their ecology and biology, as well as development of the new recovery plan and includes into causes of anthropogenic mortality, will assist information on the biology and ecology of grey nurse in developing programs to aid the long term sharks, the species’ current conservation status, a recovery of this species. description of the key threats endangering the species’ survival in Australian waters and recommendations The Recovery Plan for the Grey Nurse Shark for future research. Some of the key findings of this (Carcharias taurus) 2014 can be found at: paper are: http://www.environment.gov.au/resource/recovery- plan-grey-nurse-shark-carcharias-taurus • Recent research has obtained a relatively robust population estimate for the east coast grey nurse shark population. Recent studies suggest estimates of population size are above 1131 individuals, with the highest estimate being 2142 individuals. While this number is still very low and does not warrant changing the protected status of the east coast population from critically endangered, it is higher than previous estimates. 1 The drumlines used in Queensland comprise a series of baited shark hooks suspended from an inflatable buoy. 1 2 Introduction 2.1 Purpose 2.2 Objectives The purpose of this paper is to provide a summary of The specific objectives of this paper are to: the biology, population ecology and current threats to • collate the most recent scientific information the grey nurse shark in Australian waters and to make (published and, where appropriate, unpublished) recommendations on the future research necessary to on distribution, abundance and population trends protect this species. This paper has been written to for the grey nurse shark inform the development of a revised recovery plan for the grey nurse shark and is designed to be read in • identify gaps in our knowledge of the biology and conjunction with the Review of the 2002 Recovery threats to the species and make recommendations Plan for the Grey Nurse Shark (Carcharias taurus) in on future research Australia (DEWHA, 2009) and the Recovery Plan for • discuss any natural and anthropogenic factors that the Grey Nurse Shark (Carcharias taurus) 2014 are currently limiting the recovery of the species in (DoE, 2014). Australian waters. Photo by Justin Gilligan 2 / Issues Paper for the Grey Nurse Shark (Carcharias taurus) 2.3 Scope 2.5.2 Objectives of the Grey Nurse Shark Recovery Plan This document provides a contemporary picture of the biology and ecology of the grey nurse shark and The overarching objective of the Recovery Plan for the identifies threats to its long term persistence in the Grey Nurse Shark (Carcharias taurus) 2014 is to assist wild. This document is not a recovery plan and does the recovery of the grey nurse shark in the wild, not prescribe management actions necessary to address throughout its range in Australian waters, with a population declines. view to: • improving the population status leading to the removal of the grey nurse shark from the 2.4 Sources of information threatened species list of the EPBC Act This document has been prepared following a review • ensuring that anthropogenic activities do not of the literature and consultation with key hinder the recovery of the grey nurse shark in the stakeholders including relevant government agencies, near future, or impact on the long term researchers and interested organisations. conservation status of the species. The east coast population of grey nurse shark is considered to be critically endangered and this 2.5 Recovery planning population will be the primary focus of the actions process outlined in the recovery plan, with an emphasis placed on monitoring and compliance. Although the 2.5.1 Purpose of recovery plans proposed actions are still relevant to the west coast population, further information is required to better The Australian Government minister responsible for understand the status of the population in the west the environment may make or adopt recovery plans and the importance of critical habitat sites for that for threatened fauna, threatened flora (other than population. conservation dependent species) and threatened ecological communities listed under the Commonwealth Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act). Recovery plans set out the research and management actions necessary to stop the decline of, and support the recovery of, listed threatened species or threatened ecological communities. The aim of a recovery plan is to maximise the long term survival in the wild of a threatened species or ecological community. 3 3 Biology and ecology 3.1 Species description 3.2 Life history The grey nurse shark Carcharias( taurus) (Rafinesque, 3.2.1 Reproduction 1810) is one of three species belonging to the family The grey nurse shark has a relatively slow development Odontaspididae (Last & Stevens, 2009). It is also and low reproductive rate with a long gestation period known as the sand tiger shark in the north-west and (Bass, et al., 1975; Gilmore, et al., 1983).