• Problem
  • Harm To Wildlife
  • Harm To People
  • Who Pays?
  • Transporting Invasive Species
• More Information
• Solutions
• One Whale
• Our Oceans
• Reading

We benefit from synthetic materials, such as plastics, because of their durability, low cost, and light weight. Unfortunately, these same properties pose problems for the environment. Being extremely stable, they do not readily breakdown but tend to remain in the marine environment for 3 to 5 years or more. Each year, debris is released into the environment and as time goes on the amount of debris in the marine environment increases. Once in the marine environment, debris harms both Wildlife and People and provides a means of transporation for Invading Species.

Harm To Wildlife

Marine animals such as fish, dolphins, whales, seals, and birds are harmed by marine debris because they become entangled or mistake debris for food. Around the world, people have reported entanglement for at least 143 marine species -including nearly all the world's sea turtles. At least 162 marine species have been reported to have eaten plastics and other debris -including most seabirds.

A number of things can happen when marine life becomes entangled: they can remain permanently entangled; they can injure themselves; their injuries can cause infections; or they can be killed because they cannot escape from predators.

Entanglement occurs because many animals are naturally curious, and will investigate something new in their environment, like a floating packing strap.

In addition to curiosity, a lot of marine debris resembles the foods that many animals eat. A plastic bag from your grocery store floating on the sea resembles the jelly-fish that are eaten by many species of fish, dolphins, and turtles. When debris is eaten by a marine animal instead of food sometimes the debris can pass through the animal without harming it, but animals can be injured by swallowed debris or have a false sense of being full and not eat enough food.

Plastics are often shipped as pellets before they are made into products we can recognise. Small, with a variety of colours and shapes, they are often invisible to most people unless you actually sift through sands to look for them. These pellets are often found in birds' gizzards and stomachs.

The exact extent of these problems and the effects of marine debris on marine life in general are very difficult to determine. The oceans are vast, (this planet is only about 25% land and 75% ocean) and difficult to reach. As well, when animals die in the sea predators and bacteria normally consume the remains before they can be studied. However, we have seen impacts on marine life many times. Citizens have reported tangled animals in British Columbia. Fisheries Observers monitoring the fishing fleet off Canada's Atlantic coast have reported the entanglement of fish, sharks, turtles, seabirds, and seals. A whale entanglement program in Newfoundland found four whale species as well as dolphins and seals were commonly entangled. A four year study off the coast of Newfoundland estimated that over 100,000 animals were killed by entanglement from 1981 to 1984. A "Tail of a Whale" is a real life story about whale entanglement in gulf of St. Lawrence.

Harm To People

People are also affected by marine debris when it fouls boat propellers, clogs water intakes, or blocks pumping systems. Ghost fishing from lost nets and other debris deprives many fishers of their catch. - For example ghost fishing losses in the sablefish trap fishery off British Columbia have been estimated as high as 30 percent of the actual landings. Divers in the sea can find their lives in danger if they become entangled. As well, communities (tax-payers) end up paying more for public maintenance and litter collection. Identifying these costs is sometimes difficult, because they are often hidden in other expenses accepted as a price of "doing business".

Many people fishing and boating have been stranded when the propellers on their boats are fouled with discarded or lost lines and cables. This can mean lost earnings for fishers or real danger to people should this happen while far out at sea or in front of an oncoming storm. One Japanese insurance company estimated marine debris causes $60 million dollars in damage to shipping each year. In beach areas where tourism is important, marine debris washing on shore can wreck havoc. Loss of mere "aesthetics" and perceptions that a location is "dirty" translates into real dollars. The New York State Department of Commerce estimated it lost over 1 billion dollars when medical waste washed ashore along the state's coast in 1988.

Who Pays?

All of us, in one way or another, pay for the problems caused by marine debris. While this has been said for many environmental issues, it is none the less true. As mentioned in Harm to People, most of the costs are hidden and cannot be readily quantified. Here are three hypothetical cases that try to show where these hidden costs may be found. They are not definitive, merely food for thought.

Even in a case where costs may be evident, there are often hidden costs we may not see. For example, when a fishing boat is disabled by a fouled propeller during a fishing season, there is a loss of income for the fishers, costs for repairs (which can be very expensive), and a possible loss of other fisher's income should they have to render assistance. When these people lose income, they reduce spending and other people doing business with them lose income as well. In small communities, this effect can be very significant.

Another example of hidden costs would be beach or park maintenance in municipalities. To prevent accumulated litter from spoiling a park or beach, costs are incurred to collect litter and, once collected, deal with it. Staff to collect litter must be paid, collection trucks need fuel and maintenance, and the collected litter must go somewhere. These costs may be paid by local taxpayers, as the alternative can be loss of tourist income. The impacts of such costs, however, may be passed on to everyone: admission charges to parks, parking fees, and local businesses increasing prices because of higher taxes. Most of these costs are buried within other expenses and are usually not readily evident.

A final example to ponder is what we pay when wildlife is affected. Ghost fishing (when lost or abandoned nets continue to fish) may be an evident cost. Studies in Canada and the US looking at various species have estimated losses to be between seven and thirty percent of the actual catches. In this case, it is potential income that is lost. Impacts on wildlife generally do not affect us in direct economic terms. Rather, it is usually a loss of potential that is suffered. When an invading species is carried by debris to an island and wipes out a native species, it is a loss of potential to biodiversity. When a single seal pup is entangled and dies, that pup's potential contribution to its species is lost. When a greater number die, their potential contribution to the balance of nature is lost. Such loss often does not affect us directly or immediately, but we may pay for this in the future.

A final observation would be that we as individuals have the choice to be part of the solution. These hypothetical cases serve to illustrate not just problems, but opportunities where we may apply solutions.

Transporting Invasive Species

Another major ecological problem to which marine debris may contribute, but of which we know very little, is the movement of invading species. Debris floating in the sea can carry many organisms such as small crustaceans, plankton, algae, bacteria, and fungi. Rafts of debris can even colonise some land-based species. When organisms from one environment are carried to another part of the world, significant problems can arise. The invading organism in its new environment may not have any predators or another species to compete against for food. When this happens, the number of invading organisms grows so fast and gets so big, that other organisms become out-numbered and cannot compete for food. The balance of animals, plants, fungi and bacteria in the invaders new home is altered forever.

Examples of invading species include the Zebra Mussel taking over the Great Lakes and Purple Loosestrife choking out so many wetlands and fields across Canada and the United States. On islands in the high seas, more than 90 percent of extinctions occurred because of humans introducing an invader. The extent that marine debris has contributed to this problem is not clear, and is probably much less than the other ways organisms are carried globally such as on the hulls of ships or in their bilge water. That said, its role cannot be overlooked.