Entanglement in or ingestion of anthropogenic debris in marine and estuarine environments - key threatening process listing
NSW Scientific Committee - final determination
The Scientific Committee, established by the Threatened Species Conservation Act, has made a Final Determination to list the Entanglement in or ingestion of anthropogenic debris in marine and estuarine environments as a KEY THREATENING PROCESS in Schedule 3 of the Act. Listing of key threatening processes is provided for by Part 2 of the Act.
The Scientific Committee has found that:
1. Anthropogenic debris in marine and estuarine environments (usually known as marine debris) is defined as pollution by human-generated objects (Faris and Hart 1996). Marine debris is mostly comprised of fishing gear, packaging materials, convenience items and raw plastics (Pruter 1987). The major sources of marine debris are from ship waste, recreational activities, aquaculture industry and both urban and rural discharges into rivers, estuaries and coastal areas (Faris and Hart 1996, Frost and Cullen 1997, Herfort 1997).
2. There is an increasing quantity of marine debris entering the marine environment every year (Laist 1987, Jones 1995). In particular, the use of plastics in the fishing industry has become more widespread in the last four decades and this has resulted in large quantities of debris entering marine and estuarine environments (Henderson 2001).
3. Marine debris may be transported long distances by oceanic currents and is concentrated at convergence fronts and in coastal waters (Shaw and Mapes 1979, Carr 1987). These marine areas are also highly productive ecosystems that support high densities of marine species and leads to their exposure to marine debris (Carr 1987).
Marine debris is known to entangle and be ingested by marine, estuarine and pelagic vertebrate species. Entanglement and ingestion may occur either accidentally while feeding or scavenging, or deliberately if marine debris is mistaken for prey items (Laist 1987). It can also be regurgitated by adult birds as food for hatchlings (Cooper 1995, Huin and Croxall 1996). Sub-lethal effects of entanglement or ingestion of marine debris may reduce an individual's fitness and ability to successfully reproduce, catch prey and avoid predation (Ryan 1990, Pemberton et al. 1992).
4. Detrimental effects of entanglement with marine debris include strangulation, increased drag, lacerations, infection and loss of limbs. Ingestion of marine debris may lead to the blockage and/or perforation of an individual's digestive system (Prendergast and Johnson 1996), or potentially, poisoning by polychlorinated biphenyls (PCBs). High levels of PCBs can suppress an individual's immunity or reproductive ability (Hutchinson and Simmonds 1992), and amounts of ingested plastic have been positively correlated with levels of PCBs in seabirds (Ryan et al. 1988).
5. Several studies have investigated the impact of marine debris on seals in Australian waters. A study of the New Zealand Fur-seal, Arctocephalus forsteri, population on Kangaroo Island found 0.8% of the population suffers entanglements each year (Page et al. 2003). In Tasmanian waters between 1989 and 1993, 136 Australian Fur-seals, A. pusillus, were observed with plastic neck collars (Pemberton et al. 1992). Observations of juvenile Australian Fur-seals on Montague Island found entanglement around the neck by rope, strap or portions of trawl net on seven occasions (Shaughnessy et al. 2001).
6. Records of injured and dead marine wildlife are kept by NSW National Parks & Wildlife Service (K. Waples, pers. comm.) and Taronga Zoo (L. Hall, pers. comm.). These databases show a wide variety of marine vertebrates are impacted by entanglement in line, the presence of hooks in the mouth or gut, wounds caused by line or net and gastric impaction by plastic bodies. A study of 173 estuaries along the NSW coast found at least 10% of the Australian Pelican, Pelicanus conspicillatus, population to be suffering from entanglement by fishing line (L. Ferris pers. comm.). Overseas studies show that most albatross and giant-petrel species ingest plastic debris and regurgitate it as food for their offspring (Fry et al. 1987, Ryan 1987, Sileo et al. 1990, Huin and Croxall 1996, Robertson 1998).
7. Cases of entanglement with and ingestion of marine debris have been recorded in the following species and populations that are threatened in NSW:
- Caretta caretta Loggerhead Turtle
- Diomedea exulans Wandering Albatross
- Macronectes giganteus Southern Giant-petrel
- Chelonia mydas Green Turtle
- Dermochelys coriacea Leathery Turtle
- Diomedea gibsoni Gibson's Albatross
- Diomedea melanophris Black-browed Albatross
- Arctocephalus pusillus Australian Fur-seal
- Arctocephalus forsteri New Zealand Fur-seal
- Megaptera novaeangliae Humpback Whale
- Physeter catadon Sperm Whale
- Little Penguin, Eudyptula minor, population in the Manly Point Area.
8. Entanglements with and ingestion of marine debris are likely to affect the following species that are threatened in NSW:
- Sterna albifrons Little Tern
- Thinornis rubricollis Hooded Plover
- Dugong dugong Dugong
- Balaenoptera musculus Blue Whale
- Charadrius leschenaulti Greater Sand-plover
- Charadrius mongolus Lesser Sand-plover
- Diomedea antipodensis Antipodean Albatross
- Diomedea cauta Shy Albatross
- Haematopus fuliginosus Sooty Oystercatcher
- Haematopus longirostris Pied Oystercatcher
- Limosa limosa Black-tailed Godwit
- Pandion haliaetus Osprey
- Phoebetria fusca Sooty Albatross
- Eubalaena australis Southern Right Whale
9. Entanglement with and ingestion of marine debris could cause the following species or populations that are not threatened to become threatened in NSW:
- Numenius madagascariensis Eastern Curlew
- Numenius phaeopus Whimbrel
- Limosa lapponica Bar-tailed Godwit
- Puffinus gavia Fluttering Shearwater
10. In view of the above the Scientific Committee is of the opinion that Entanglement in or ingestion of anthropogenic debris in marine and estuarine environments adversely affects two or more threatened species or populations, or could cause species or populations that are not threatened to become threatened.
Associate Professor Paul Adam
Proposed Gazettal date: 13/2/04
Exhibition period: 13/02/04 - 26/03/04
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Page last updated: 28 February 2011