Threatened species & ecological communities

Ten Seabird species Issues paper

Department of the Environment and Heritage, May 2005
ISBN 0 6425 5005 0

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Part A: Introduction and Generic Threats and Issues

1. Purpose

The Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act) provides a comprehensive legislative framework to protect Australia's marine environment. A list of threatened species has been established under Part 13 of the EPBC Act. Species on this list are considered extinct in the wild; critically endangered; endangered; vulnerable; or conservation dependent. Listed threatened species are protected to help ensure their long-term survival. The EPBC Act provides for recovery plans to be made for the purposes of the protection, conservation and management of listed threatened species. Recovery plans must set out the recovery objectives and actions required to achieve those objectives, performance indicators, in addition to identifying who is responsible for implementing the actions and the timeframes involved. The seabird species listed in Table 1 all appear on the EPBC Act list of threatened species and therefore require the development of recovery plans.

Table 1: Seabird species requiring recovery plans under the EPBC Act.
Species scientific name Species common name EPBC Status Date of listing
Pterodroma arminjoniana
Pterodroma heraldica		 Round Island petrel
Herald petrel		 Critically endangered
Critically endangered		 2/7/2002
2/7/2002
Sterna vittata bethunei
Sterna vittata vittata
Halobaena caerulea
Pachyptila subantarctica
Phalacrocorax nivalis
Phalacrocorax purpurascens
Pterodroma mollis
Anous tenuirostris melanops		 Antarctic Tern (New Zealand)
Antarctic Tern (Indian Ocean)
Blue Petrel
Fairy Prion (southern)
Heard Shag
Macquarie Shag
Soft-plumaged Petrel
Australian lesser Noddy		 Endangered
Vulnerable
Vulnerable
Vulnerable
Vulnerable
Vulnerable
Vulnerable
Vulnerable		 16/7/2000
16/7/2000
16/7/2000
16/7/2000
16/7/2000
16/7/2000
16/7/2000
16/7/2000

2. Scope and limitations

This document covers all the seabird species and taxa listed in Table 1. It aims to provide a contemporary picture of the biology of these taxa, and to identify the threats to their long-term persistence in the wild. This document is not a recovery plan and hence does not prescribe management actions necessary to address population decreases. A separate recovery plan for the species is being prepared by the Australian Government Department of the Environment and Heritage. However, where appropriate management strategies are evident they have been identified.

The format of this document closely follows that developed by Taylor (2000) who prepared a national seabird conservation strategy for New Zealand seabirds. There are two parts to this report. Part A provides an introduction to the taxa covered by the report and covers issues and threats that are applicable to all seabird species and taxa. Part B assesses the biology and conservation issues specific to each species or taxon. Because some of the taxa addressed share similar biology, they have been arranged into five groupings. The evaluations for each taxon/group have focussed on global populations in general and Australian populations in particular, addressing key information on the population status, distribution and threats for all the listed taxa. The document format has been structured to permit an extension to include other seabird taxa should they become listed under the EPBC Act.

3. Sources of information

This review has been prepared following a review of the literature and subsequent consultation with relevant agencies, individuals, researchers and interested organisations to ensure that the most current information on each species is collected. The main source of information on Australian seabirds is the Handbook of Australian, New Zealand and Antarctic Birds Volume 1 (Marchant and Higgins 1990) and Volume 3 (Higgins and Davies 1996). These were used extensively to collect information about taxonomy, distribution, abundance, biology and ecology.

The Action Plan for Australian Birds 2000 (Garnett and Crowley 2000), Threatened Birds of the World (Birdlife International 2004) and Baker et al. (2002) were used as the main source of information on the conservation status and threats to Australian populations. Other important references included Warham's two volumes on the petrels (Warham 1990; Warham 1996) and the recently published Albatrosses and petrels across the world (Brooke 2004).

Information was also sought from other researchers with experience of some or all of the taxa covered by this document. The assistance of the following experts is gratefully acknowledged Barry Baker (Australian Antarctic Division), Geoff Copson (DPIWE), Wendy Murray (Parks Australia North, DEH) and Martin Schulz.

4. Threats to seabirds

The threats identified below comprise the major threats that currently endanger seabird populations in Australia. Although some of these (e.g. fisheries-related mortality) are not currently thought to threaten the 10 listed seabirds considered in this document, they are included here for completeness.

4.1 Introduction of predators to breeding islands

Although native species can be serious predators of seabirds e.g. pied currawongs Strepera graculina and Australian ravens Corvus coronoides (Priddel and Carlile, 1997), Lord Howe Island woodhen Gallirallus sylvestris (A. Bester unpublished), the major threat of predation to seabirds comes from alien species.

Alien pest species may reduce seabird population sizes by predation of adults and or nest contents (eggs and chicks), nest destruction and habitat modification. Introduced mammals are the foremost land-based threat to seabirds on sub-Antarctic islands (Jouventin and Weimerskirch 1991). Seabirds are especially vulnerable to alien mammalian predation specifically due to their lack of effective anti-predator behaviour; the habit of most species of nesting at ground level and leaving chicks unattended during long-range foraging; and their low annual productivity. Smaller species are particularly at risk from predation since breeding age adults in addition to chicks are killed (Baker et al. 2002).

Three mammal species have posed the most significant conservation problems for Australian seabirds in recent years: - cats, rats and rabbits. Cats and rats directly impact seabirds through predation of eggs, chicks and adults, and rabbits damage vegetation leading to loss of breeding habitat (Baker et al. 2002). Two of these species have been listed as Key Threatening Processes under the EPBC Act and Threat Abatement Plans prepared to manage their impact (Environment Australia 1999a; 1999b).

Many islands that are important breeding sites for seabirds are currently free of predators, and at these sites feral predators would not be considered an immediate threat. However, the risk of alien introductions is always present, particularly where islands are visited regularly by humans. Small populations of seabirds, in particular, could be immediately threatened if the predator-free status of important breeding sites was lost. Appropriate quarantine measures should be put in place at these breeding sites to minimise this threat.

Issues and Recommendations

4.2 Fisheries-related mortality

Each year tens of thousands of seabirds are accidentally killed on longline hooks when birds, attracted to fishing vessels by discards and baits, ingest baited hooks during the setting or, less commonly, hauling of the longline. The hooked birds are subsequently pulled under the water by the weight of the line and drown. The extent of this mortality is such that longline fishing now represents a major threat to many seabirds, causing widespread decreases in breeding populations (Baker et al. 2002).

While this threat is known to impact many seabirds, there is no evidence to suggest that any of the 10 species covered by this issue paper are likely to be caught incidentally in longline fisheries. These birds either do not follow boats (e.g. Soft-Plumaged Petrel, Herald Petrel), do not feed in areas where fisheries operations are undertaken (e.g. shags) or have not been recorded as bycatch in any fishery for which data exists (Environment Australia 1998; Rosemary Gales and Barry Baker unpublished). It is the larger petrel species (body mass >400g) that are able to swallow baited hooks and that habitually follow ships that are recorded as bycatch in longline fisheries (Baker et al. 2002). Longline fishing is unlikely to threaten any of the gadfly petrels or other seabird species addressed in this document.

There is considerable trawl fishing within Australian waters and many sea birds have learnt to scavenge prey caught within the trawl net during the net haul process. Considerable mortality can occur as birds become entangled in the net or trawl gear, or collide with trawl apparatus and monitor cables (Baker et al. 2002). As described for longline fishing, the 10 seabird species covered by this document do not typically overlap with fishery operations in their daily foraging routines, or do not follow boats, and hence are unlikely to be impacted directly by trawl fisheries (Baker et al. 2002). Some species of seabird are potentially affected by competition with commercial fisheries, although this is not currently an issue for any of the species covered by this plan.

Issues and Recommendations

4.3 Marine pollution

Chemical contamination has been clearly implicated in the decline of a number of seabirds. Its relevance to the conservation of albatrosses and petrels has been reviewed recently by Baker et al. (2002), and includes deleterious effects through diminished reproductive success caused by eggshell thinning, embryo inviability and offspring deformities. Elevated levels of chemicals and heavy metals can be found in the plasma of adults, chicks and eggs of seabirds from every continent and virtually all islands across the globe. Organochlorines and heavy metals degrade very slowly in the environment, are retained by organisms and passed along the food chain, becoming increasingly concentrated. Consequently, top order predators, such as seabirds, may accumulate high levels of chemicals in tissues, a problem which is exacerbated because these birds are long-lived and highly mobile species.

Bulk fuel and oil spills also have the potential to affect high numbers of seabirds. Birds coming into contact with oil can become physically smothered, or suffer oiled plumage, which leads to reduced insulation and increased heat loss, loss of waterproofing, reduced ability to forage efficiently, usually resulting in emaciation and death. Birds may also ingest oil, leading to potential toxicity. Since seabirds spend much of their time on the sea surface, they are particularly vulnerable to the hazards of oil or fuel spills and are difficult to rehabilitate. Shipping discharge of oil and other pollutants is regulated by the International Convention for the Prevention of Pollution from Ships (1973) and its Protocol (1978) - MARPOL 73/78. The Australian Maritime Safety Authority (AMSA) administers MARPOL in Australian waters under the Commonwealth Protection of the Sea (Prevention of Pollution from Ships) Act 1983.

Response to marine oil spills are managed by AMSA, with the States and the Northern Territory, through the National Plan to Combat Pollution of the Sea by Oil and Other Noxious and Hazardous Substances (AMSA 1996). The Plan sets out the role and responsibilities for government and industry in the event of an oil spill. The Plan identifies the potential effects on wildlife and the operations and procedures that should be put into place in the event of an oil spill. However, with current resources, when the incident occurs in remote areas, there may be little that can be done when large numbers of birds are affected.

Marine pollution is becoming increasingly apparent in the southern hemisphere and impact on Australian seabirds is likely to increase in the future. Internationally, only a few studies of any seabird species have been undertaken to identify whether marine contaminants (e.g. organochlorines and dichloro-diphenyl-trichloroethane (DDT) affect seabird survival, in particular aspects of their breeding biology (Croxall 1998; Ludwig et al. 1998).

Issues and Recommendations

4.4 Marine debris

Marine debris can affect seabirds either through ingestion or entanglement. Most of the marine debris affecting seabirds are derived from material jettisoned by vessels at sea (Huin and Croxall 1996).

Many species ingest considerable quantities of plastic and other marine debris, which has a wide range of lethal or sub-lethal effects. The debris can cause physical damage, or perforation, mechanical blockage or impairment of the digestive system, resulting in starvation. Chicks appear to be at greater risk than adults because of their high rates of ingestion and low frequency of regurgitative casting of indigestible material. When the plastics are regurgitated to chicks, the physical impaction and internal ulceration are likely to lower survival. In addition, the chick receives less food, lowering its nutrient intake and increasing its chances of starvation (Fry et al. 1987; Sileo et al. 1990).

Some seabirds are also killed after becoming entangled in marine debris (Nel and Nel 1999). Such entanglement can constrict growth and circulation, leading to asphyxiation. Entanglement may also increase the bird's drag coefficient through the water, causing the animal to die due to reduced ability to catch prey or avoid predators. The rate of this source of mortality remains completely unknown for Australian species.

Injury and Fatality Caused by the Ingestion and Entanglement of Marine Life in Marine Debris has been listed a Key Threatening Process under the EPBC Act. It was considered that 20 listed species are adversely affected by marine debris. Of the species covered by this issues paper, the Blue Petrel is among those listed as being adversely affected by marine debris, through the ingestion of floating particles of plastic perceived as food by the birds.

The problems of plastic ingestion and entanglement may affect many Australian breeding petrels, and has been reviewed in Baker et al. (2002). While it is likely that most seabirds ingest plastic debris without it being observed or documented, and birds of any species may become entangled in marine debris from time to time, there is currently no evidence that these are a significant threat to any Australian seabird species, with the possible exception of the flesh-footed shearwater Puffinus carneipes (D.Priddel unpublished). There are recent records of plastic ingestion in 2 of 18 Antarctic prions at Heard Island (Auman et al. in press), although there is no suggestion that the plastic killed the birds.

Issues

4.5 Storms and cyclones

Small populations such as those of Herald petrel and Round Island petrel, Heard Is shag, Macquarie Island shag, and Antarctic terns will always be adversely affected by stochastic events such as storms and cyclones. Storms and cyclones have the potential to have serious effects on the nesting substrate, vegetation and wildlife on remote seabird breeding islands, in addition to impacting seabirds at sea. Such natural factors can place additional pressures on seabird populations adversely affected by anthropogenic influences. However, stochastic events such as storms and cyclones are beyond the control of management authorities and cannot be addressed in species recovery plans.

Issues and Recommendations

4.6 Climate change

Climate change is a threat that impacts many marine organisms including seabirds. This threat was recently assessed for a tropical seabird, Abbott's booby Papasula abbotti (Olsen 2002). The text below has been largely taken from that document - it is entirely relevant to all Australian seabird species.

The 'Loss of climatic habitat caused by anthropogenic emissions of greenhouse gases' has been declared a Key Threatening Process under the EPBC Act. The threat is described as reductions in the bioclimatic range within which a species or ecological community exists due to emissions induced by human activities of greenhouse gases (DEH website). The listing of this threat recognises that the distribution of the process is continental. Non-biological components of the process include: temperature rise; changes in rainfall patterns; changes to the El Niño Southern Oscillation; and sea level rise. The potential consequences to seabirds could include deleterious effects of an increase in extreme weather events, changes in prey abundance and distribution, and alteration to nesting habitat.

A reduction in the emissions of greenhouse gases requires an internationally coordinated effort. Australia is a signatory to the relevant international agreements, and has made a commitment to limit greenhouse gas emissions. In addition, the States and Territories are pursuing additional opportunities to abate greenhouse gas emissions in a cost-effective and environmentally sensitive manner.

Australia has developed a National Greenhouse Strategy (NGS) with the goals: 'to limit net greenhouse gas emissions, in particular to meet international commitments; to foster knowledge and understanding of greenhouse issues; and to lay the foundation for adaptation to climate change'. The Strategy (DEH website) provides: a broad range of actions some of which will be implemented by governments acting individually, some by joint inter-governmental initiatives and some through partnerships between government, various stakeholders and the community. To date, the emphasis of the NGS has been on emission reduction, but the long-term strategy will also address adaptation actions, including the development of a 'framework for progressing adaptation planning for biodiversity conservation, … providing for more detailed plans targeted towards components of biodiversity of conservation significance', including: endangered and vulnerable species and communities; assessment of the capacity of protected areas to sustain their biodiversity in the event of climate change; identification of altitudinal and latitudinal buffers; and adaptation requirements of species and communities that are likely to be subject to a change in conservation status as a result of climate change.

There is very little data on breeding ecology, feeding requirements and distribution at sea for the 10 threatened seabird species. It is therefore difficult to determine the effects of climate change/sea temperature change on these species.

Issues and Recommendations

.7 Biological and ecological information

Management of small populations of any organism requires adequate biological and ecological knowledge to ensure appropriate conservation action. Unfortunately for most threatened Australian seabirds, there is little relevant biological and ecological data available for both Australian and extra-limital (i.e. outside Australia) populations. The summary tables prepared for each of the 10 threatened seabirds highlights these deficiencies. Future research should focus on addressing the following deficiencies:

Collection of biological and demographic information often involves levels of research intensity that can potentially disturb breeding birds. While there may be colony-specific differences in these parameters, it may be preferable that studies to address these deficiencies are initially carried out on the larger extralimital populations, where applicable. This would minimise disturbance to the extremely small Australian populations (Antarctic terns, tropical gadfly petrels), and provide an indication of the sensitivity of each species to research and monitoring protocols. Such an approach will rely either on the fortuitous research activities of the jurisdictions that contain breeding populations of these species, or require a proactive collaborative approach by Australian conservation biologists.

Issues and Recommendations

References

AMSA (1996). National Contingency Plan, National Plan to Combat Pollution of the Sea by Oil. Australian Maritime Safety Authority: Canberra.

Auman HJ, Woehler EJ, Riddle MJ & Burton HR (in press) Plastic debris ingestion by seabirds at subantarctic Heard Island. Marine Ornithology.

Baker, G.B., Gales, R., Hamilton, S. & Wilkinson, V. (2002). Albatrosses and petrels in Australia: a review of their conservation status and management. Emu 102: 71-97

BirdLife International. (2004). Threatened birds of the world 2004. CD-ROM. Cambridge, U.K: BirdLife International.

Brooke, M. de L. (2004). Albatrosses and petrels across the world. Oxford University Press, Oxford.

Croxall, J.P. (1998). Research and Conservation: a future for albatrosses? In Albatross Biology and Conservation. (Eds G. Robertson, and R. Gales.) pp 269-290. Surrey Beatty and Sons: Chipping Norton.

DEH Website. www.deh.gov.au/biodiversity/threatened/ktp/greenhouse.html

Environment Australia (1998). Threat Abatement Plan for the Incidental catch (or bycatch) of seabirds during oceanic longline fishing operations. (Environment Australia Biodiversity Group: Canberra.)

Environment Australia. (1999a). Threat Abatement Plan for Predation by Feral Cats. (Environment Australia: Canberra.)

Environment Australia. (1999b). Threat Abatement Plan for Competition and Land Degradation by Feral Rabbits. (Environment Australia: Canberra.)

Fry, D.M., Fefer, S.I., and Sileo, L. (1987). Ingestion of plastic debris by Laysan Albatrosses and Wedge-tailed Shearwaters in the Hawaiian Islands. Marine Pollution Bulletin 18, 339-343.

Garnett, S.T. & Crowley, G.M. (2000). The Action Plan for Australian Birds 2000. (Environment Australia: Canberra.)

Higgins, P.J. & Davies, S.J.J.F. (eds). (1996). The Handbook of Australian, New Zealand and Antarctic Birds. Volume 3. Oxford University Press, Melbourne.

Huin, N. and Croxall, J.P. (1996). Fishing gear, oil and marine debris associated with seabirds at Bird Island South Georgia, during 1993/94. Marine Ornithology 24, 190-194.

Jouventin, P., and Weimerskirch, H. (1991). Changes in the population size and demography of southern seabirds: management implications. Pp. 297-316 In 'Bird Population Studies: Their Relevance to Conservation and Management.' (Eds. C.M. Perrins, J.D. Lebreton and G.M.Hirons.) pp 297-316). Oxford University Press: Oxford.

Ludwig, J.P., Summer, C.L., Auman, H.J., Gauguer, G., Bromley, D., Giesy, J.P., Rolland, R., and Colborn, T. (1998). The roles of organochlorine contaminants and fisheries bycatch in recent population changes of Black-footed and Laysan Albatrosses in the North Pacific Ocean. In Albatross Biology and Conservation. (Eds G. Robertson, and R. Gales.) pp 225-238. Surrey Beatty and Sons: Chipping Norton.

Marchant, S. and Higgins, P.J. (eds). (1990). The Handbook of Australian, New Zealand and Antarctic Birds. Volume 1. Oxford University Press: Melbourne.

Nel, D.C., and Nel, J.L. (1999). Marine debris and fishing gear associated with seabirds at sub-Antarctic Marion Island, 1996/97 and 1997/98, in relation to longline fishing activity. CCAMLR Science 6, 85-96.

Olsen, P. (2002). Abbott's booby recovery plan Papasula abbotti 2003-2007. Environment Australia: Canberra.

Priddel, D. and Carlile, N. (1997). Conservation of the endangered Gould's Petrel Pterodroma leucoptera leucoptera. Pacific Conservation Biology 3, 322-329.

Sileo, L., Sievert, P.R. and Samuel, M.D. (1990). Causes of mortality of albatross chicks at Midway Atoll. Journal of Wildlife Diseases 26, 329-338.

Taylor, G.A.(2000). The action plan for seabird conservation in New Zealand. Part A: Threatened seabirds. Department of Conservation: Wellington, New Zealand.

Warham J. (1990). The petrels: Their ecology and breeding systems. Academic Press: London.

Warham J. (1996). The behaviour, population biology and physiology of the petrels. Academic Press: London.

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