X   

Support Us

Animals cannot help themselves – they must depend on people who care to fight for them. HSI represents more than 10 million people around the world who care.

Join them.

PO Box 439 AVALON NSW 2107
(61) (2) 9973 1728
Fact Sheets - Marine Debris      
Marine Conservation

FACT SHEETS - MARINE DEBRIS

HSI has nominated 'Marine Debris' as a Key Threatening Process to marine wildlife for listing on Commonwealth and state environment laws.

Marine debris is defined as the pollution by human generated objects or as anthropomorphic solid matter in the sea.

The International Oceanographic Commission (IOC) has identified marine debris, as one of the five major marine pollutants. The main components of marine debris are plastics and other synthetic waste such as glass and metal. It has been estimated that Australia alone produces almost 1 million tonnes of plastic each year and world wide estimates put the amount of debris entering the world' s oceans annually at 7 billion tonnes.

Marine debris is then subject to the ocean currents and can spend several years at sea before being washed up many thousands of miles away from the source. This makes marine debris a global concern as well as a national one.

A beach survey carried out in 1998 at Groote Eylandt beaches in the western gulf of Carpentaria, Australia, found an overall debris density of 1,098 kilograms of debris per kilometre. This indicates the magnitude of the problem.

The major sources of marine debris are from vessels, recreational uses, and urban and rural coastal and upland discharges. The main source differs from country to country. In Australia the main sources of debris are from fishing, boating and shipping industries.

Most marine debris is non-biodegradable. The most damaging debris includes materials such as fragments of trawl netting; plastic packing straps and man made twine or cord.

A study on Australian fur seals in the Bass Strait in 1992 showed that polyethylene trawl net fragments were responsible for 40% of seal entanglements, polypropylene packing straps, 30% and nylon rope 15%. Trawl netting is thought to be the main cause of entanglement and foreign trawl netting has made the most significant contribution to the total amount of debris found. The origin of debris around Australian water is probably from Indonesian and Taiwanese fishing operations.

Marine wildlife frequently ingests plastic bags, rubber, balloons, confectionery wrappers - practically all waste products, because they confuse the waste with the food they eat. Turtles often ingest plastic bags due to the similarity to their prey of jellyfish. Research indicates that 56 species of sea birds have consumed plastic materials thinking that they are fish eggs and crustaceans. Sea birds suffer from entanglement and ingestion. The incidence of fishing hooks being regurgitated at the nesting sites of wandering Albatrosses has increased six folds in recent years.

Entanglement leaves the visible mark of the so-called ' ˜plastic necklaces' worn by many animals around their flippers, tails and flukes. Young seals are naturally playful and inquisitive, in this case to their detriment. Once the plastic debris has become entangled around the necks of seals it is very hard to remove due to the direction of hair growth. As the young animal grows it dies slowly from strangulation. If the debris is large, it can become difficult for animals to swim, making it hard for them to catch their prey.

Ingestion of marine debris can lead to the physical blocking of the digestive system, causing pain and internal injuries. A false feeling of being well fed can lead to animals not feeding and therefore becoming starved.

Ocean currents and winds can transport debris many thousands of miles, especially when the debris becomes colonised by ephytic biota such as algae, corals and bacteria. It is possible that this could lead to the contamination of distant waters by possibly noxious organisms.

Contamination and poisoning of sea creatures by polychlorinated biphenyls (PCBs) can occur through ingestion of plastics. High levels of PCBs can cause suppression of the immune and reproductive systems. This may be particularly threatening to species with a low reproductive rate.

Entanglement is considered to be a danger to whales and dolphins including the threatened Blue Whale, Humpback Whale, Common Dolphins and Bottlenose Dolphins.

The Australian Fur Seal and the Australian Sea Lion have the highest rate of entanglement observed in Australia. Populations such as the Stellar Sea Lion and Hawaiian Monk Seal are in decline, which is contributed partially to entanglement. Therefore, it is quite possible that entanglement of Australian species may become a threatening process.

Other animals are also affected. The manatee in Florida has been found to have high levels of debris ingestion. Marine wildlife may come into contact with ghost nets that spend hundreds of years circulating the oceans.

HSI has identified several strategies that could be implemented and incorporated into a feasible Threat Abatement Plan. A possible solution to reduce sea-based debris is to reduce the amount of debris dumped over the side of vessels. HSI agrees with the recommendation found in the report of the International Conference on Marine Debris that suggest that Australia needs to increase surveillance of fishing, tourist/recreational vessels to prevent this sea dumping of debris.

HSI believes that fishers should be encouraged to report any cases of entanglement they observe. Entangled carcasses should be kept and cause of death should be determined. This would enable more accurate estimates of plastic entanglement and ingestion casualties.

HSI also sees the benefit in creating a government subsidised buy back scheme for old fishing nets. As fishers are likely to be the ones who find old discarded nets, a buy back scheme would provide an incentive for the fishers to collect these nets. Incorporating degradable escape mechanisms could reduce moralities from ghost fishing nets.

HSI promotes the introduction of joint agreements with other nations, such as Indonesia, to tackle the amount of foreign debris, which ends up on Australian shores.

A global approach is required to decrease the amount of debris entering the oceans. Fishing and shipping industries need to be particularly targeted, as these are mostly responsible for the problem. HSI believes that fishers should be encouraged to report any cases of entanglement they observe. Entangled carcasses should be kept and cause of death should be determined. This would enable more accurate estimates of plastic entanglement and ingestion casualties.

HSI also sees the benefit in creating a government subsidised buy back scheme for old fishing nets. As fishers are likely to be the ones who find old discarded nets, a buy back scheme would provide an incentive for the fishers to collect these nets. Incorporating degradable escape mechanisms could reduce moralities from ghost fishing nets.





Web: AndreasLustig.com