Imagem de Naja Bertolt Jensen em Unsplash
27 julho 2021

Plastic Rafting: Invasive Species “Hitchhiker” on Ocean Trash

The tsunami that occurred in Japan in 2011 had serious consequences, including the death of almost 16,000 people, destroying homes and infrastructure and taking more than 5 million tons of debris into the sea [1] . Ten years after the occurrence, sediments washed away by the natural disaster are now found in several areas of the Pacific Ocean, reaching the coasts of Hawaii, Alaska and California. Along with solid waste, several species of fauna were displaced, creating a route for invasive species.

The Smithsonian Center for Environmental Research reported in 2017 that 289 Japanese marine species such as marine snails, sea anemones and isopods, a type of crustacean [2] , were displaced to distant shores after the tsunami, what is called a “mass rafting” event.

According to Professor Bella Galil, curator of the Steinhardt Museum of Natural History, Tel Aviv University, rafting or “ocean dispersion” is a natural phenomenon, previously regarded as a rare and sporadic evolutionary process, which has become everyday since of human action. The tsunami also brought something new: many of the animals survived more than six years adrift, longer than was thought possible.

Marine organisms “hitchhike” on marine debris and travel hundreds of kilometers. In addition to adversely affecting critical habitats, Galil says, some are “harmful, poisonous or poisonous and pose clear threats to human health.” For example, long-spined sea urchins and nomadic jellyfish, both venomous and native to the Indian Ocean, are two species that now cause damage in the Mediterranean [3] .

Furthermore, invasive species can put even more pressure on ecosystems, already stressed by overfishing and pollution. David Barnes, a benthic marine ecologist at the British Antarctic Survey and visiting professor at Cambridge University, said to the British newspaper The Guardian [4] , said that rafting increases the “risk of extinction [while] reducing biodiversity, ecosystem function and resilience ”.

Continuous act, Barnes also claims that he found invasive species even on plastic rafts in the Southern Ocean, contradicting the idea that the freezing temperatures of Antarctica would keep the invaders away. Antarctica may be particularly sensitive to these invasions, with its endemic species evolving almost in isolation and within a very narrow range of environmental conditions.

It is important to ask who is responsible for the problem of plastic in the oceans that has caused rafting and how to mitigate it. There are several answers or attempts to this question. In the context of the Suez Canal, Galil states: “If we adhere to the ‘polluter pays’ principle, Europe will be complicit: the canal serves mainly that continent”. According to her, the most efficient measure would be an immediate reduction in the amount of plastics in the environment and “a strict ban on dumping into the ocean”.

One tool that can help is tracking technology to locate the source of waste, such as the Integrated Marine Debris Observation System (IMDOS). It is a system, which has not yet been implemented, that combines satellite images, trawl surveys, ship observations and data sent to various organizations to track marine debris [5] . Another measure would be to standardize the monitoring of marine plastic, which the Floating Ocean Ecosystems (FloatEco) proposes, which is a multidisciplinary project, partially financed by NASA, “which aims to better describe the physical and biological dynamics of plastics floating in the open ocean and its emerging properties as a new marine ecosystem” [6] .

Important initiatives to monitor waste in the ocean and mitigate its dumping are led by organizations such as Ospar [7] , which brings together 15 governments and the European Union, with the aim of cooperating in the environmental protection of the Northeast Atlantic Ocean. As Eva Blidberg, former Blastic [8] project leader, said for The Guardian [9] , “a global problem like plastic marine litter and all the challenges it creates is impossible to solve without collaboration”.

The problem was compounded by the pandemic. With the increased demand for biomedical plastic products, it is estimated that 1.6 million tons of disposable personal protective equipment have been disposed of daily, some of which end up in the ocean. As Blidberg says, monitoring and collaboration are important, however: “The most important thing is to eliminate marine litter once and for all.”


By  Rayanne Reis Rêgo Cutrim , intern at the Brazilian Institute for the Law of the Sea (IBDMAR), under the supervision of Doctoral Student Luciana Coelho.





Isabella. Invasive species are hitching a ride on ocean trash, threatening the survival of native animals . Ecycle. Available at:<>. Accessed on: June 29, 2021.

KATSANEVAKIS Stylianos Marios; Crocetta Fabio. Pathways of introduction of marine alien species in Europe and the Mediterranean – a possible undermined role of marine litter . CIESM; 2014. p. 61-68. JRC90466. JRC Publications Repository. Available at:<>. Accessed on: June 29, 2021.

KIESSLING, Tim; GUTOW, LARS; THIEL, Martin. Marine Litter as Habitat and Dispersal Vector . Marine Anthropogenic Litter, 141-181. June 2, 2015. Available at:<>. Accessed on: June 28, 2021.

Plastic rafting: the invasive species hitching a ride on ocean litter. The Guardian . June 14, 2021. Available at: <> . Accessed on: June 27, 2021.

SABATINNI, Amadeo. Plastic rafting : invasive species can cross the Pacific sailing over wastes. Cba24n. June 14, 2021. Available at:<–especies-invasoras-pueden-cruzar-el-pacifico-navegando-sobre-deshechos_a60c72fd5a78ebe63d0ba51c7>. Accessed on: June 28, 2021.


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