The Problem

Solid materials, typically waste, that has found its way to the marine environment is called marine debris. It is probably a common conception that marine debris cardiff_reef_webconsists of just a few pieces of rubbish scattered along the strand line of beaches and is of no harm to anyone. Unfortunately this is not the case. Marine debris has become a pervasive pollution problem affecting all of the world’s oceans. It is known to be the cause of injuries and deaths of numerous marine animals and birds, either because they become entangled in it or they mistake it for food and eat it.

Plastic and synthetic materials are the most common types of marine debris and cause the most problems for marine animals and birds. At least 267 different species are known to have suffered from entanglement or ingestion of marine debris including seabirds, turtles, seals, sea lions, whales and fish. The scale of contamination of the marine environment by plastic debris is vast. It is found floating in all the world’s oceans, everywhere from polar regions to the equator. The seabed, especially near to coastal regions, is also contaminated – predominantly with plastic bags. Plastic is also ubiquitous on beaches everywhere from populous regions to the shores of very remote uninhabited islands.

Attempts to address the problem of marine debris range from international legislation to prevent shipping from dumping plastic at sea and campaigns to prevent losses due to poor industrial practice to beach and seabed clean-up operations and public awareness campaigns. Plastic debris originates from a wide and diverse range of sources. Estimates suggest that much of what is found at sea originates on the land. The effect of coastal littering and dumping is compounded by vectors such as rivers and storm drains discharging litter from inland urban areas. It is the very properties that make plastics so useful, their stability and resistance to degradation, that causes them to be so problematic after they have served their purpose. These materials persist in the environment and are not readily degraded or processed by natural biological mechanisms. However plastics in the ocean are weathered; broken up either mechanically or by the action of sunlight into smaller and smaller fragments. Eventually, fragments are reduced to into tiny pieces the size of grains of sand. These particles have been found suspended in seawater and on the seabed in sediments. Even such tiny particles may be causing harm to the marine environment since they have been shown to be ingested by small sea creatures and may concentrate persistent organic pollutants (POPs) present in the seas.

Harm to Marine Wildlife

Countless marine animals and sea birds become entangled in marine debris or ingest it. This can cause them serious harm and often results in their death.

Ingestion of Marine Debris

Ingestion of marine debris is known to particularly affect sea turtles and seabirds but is also a problem for marine mammals and fish. Ingestion is generally thought to occur because the marine debris is mistaken for food. Most of that erroneously ingested is plastic. Different types of debris are ingested by marine animals including plastic bags, plastic pellets and fragments of plastic that have been broken up from larger items. The biggest threat from ingestion occurs when it blocks the digestive tract, or fills the stomach, resulting in malnutrition, starvation and potentially death.

Studies have shown that a high proportion (about 50 to 80%) of sea turtles found dead are known to have ingested marine debris. This can have a negative impact on turtle populations. In young turtles, a major problem is dietary dilution in which debris takes up some of the gut capacity and threatens their ability to take on necessary quantities of food.

plastic birdFor seabirds, 111 out of 312 species are known to have ingested debris and it can affect a large percentage of a population (up to 80%). Moreover, plastic debris is also known to be passed to the chicks in regurgitated food from their parents. One harmful effect from plastic ingestion in birds is weight loss due for example to a falsely sated appetite and failure to put on adequate fat stores for migration and reproduction.


Potential Invasion of Alien Species

Plastic debris which floats on the oceans can act as rafts for small sea creatures to grow and travel on. Plastic can travel for long distances and therefore there is a possibility that marine animals and plants may travel to areas where they are non-native. Plastic with different sorts of animals and plants have been found in the oceans in areas remote from their source. This represents a potential threat for the marine environment should an alien species become established. It is postulated that the slow speed at which plastic debris crosses oceans makes it an ideal vehicle for this. The organisms have plenty of time to adapt to different water and climatic conditions.


There are a number of global, international and national initiatives in place that are aimed at protecting the oceans from marine debris.The most far reaching of these is the International Convention for the Prevention of Pollution from ships (MARPOL). Annex V of MARPOL was introduced in 1988 with the intention of banning the dumping of most garbage and all plastic materials from ships at sea. A total of 122 countries have ratified the treaty.There is some evidence that the implementation of MARPOL has reduced the marine debris problem but other research shows that it does not appear to have any positive impact. It must also be remembered that an estimated 80% of marine debris originates from sources on land. Even with total global compliance with MARPOL these sources would remain.

San Luis Rey River CleanupThis is where H2O Trash Patrol has become a valuable part of the solution. Our main focus is on marine debris removal from the waterways. By combining paddleboarding, we are able to reach areas not easily accessible by land and remove debris with little to no impact on the environment. Also, by approaching conservation via environmental recreation, we are able to reach people and get them involved in a new and fun way. They have a good time, get a great workout, and take care of the environment. It’s a win all the way around.

Classroom Trash TalksWe also provide environmental education to schools as well as work with municipalities and other organizations to implement recycling programs in schools. All of our focus goes toward waste reduction and diversion in order to alleviate the pressure of debris making its way into watersheds, waterways, and the ocean.
Join us in our efforts! We can always use help with cleanups and program implementations! Visit our Volunteer page.

Excerpt from Greenpeace International report, “Plastic Debris in the World’s Oceans”


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