Octopuses are sheltering in discarded human trash

A new study published in the Marine Pollution Bulletin has found that octopuses have been increasingly forced to shelter among discarded garbage – including bottles, beer cans, batteries, or rusted metal pipes – as trash replaces seashells on the ocean floors. 

The researchers, led by the Federal University of Rio Grande in Brazil, have analyzed hundreds of underwater photos posted on social media platforms and image databases or collected by marine biologists and underwater divers. They found 24 species of octopus sheltering inside glass bottles, cans, or batteries, or even carrying plastic items while “stilt-walking” on two tentacles in order to conceal themselves from predators. Moreover, they also used such discarded trash as sanctuaries for their eggs.

“The deep-sea records were extremely interesting, because even at great depths these animals are interacting with the litter,” said study senior author Maira Proietti, a professor of Marine Biology and Oceanography at the Federal University of Rio Grande. “They clearly see that there’s a lot of litter around, and it can therefore act as a kind of artificial camouflage. It shows their extreme ability to adapt. They are very intelligent animals, and they will use what they have at their disposal to continue sheltering or walking around with protection.”  

The animals appeared to show a preference for unbroken items and darker or opaque containers that could shelter them from the myriad predators continuously endangering their lives. Professor Proietti warns that, while these interactions may seem positive for the animals since they are lacking natural shelters such as seashells (which have largely been removed by humans for ornamental purposes, driven by tourism), “it is not a good thing to think that the animals may be using litter as shelter because the seashells are gone.”

Moreover, sheltering or laying eggs inside discarded tyres, batteries, or various plastic objects could easily expose the animals to a large variety of harmful compounds, such as heavy metals or the toxic additives usually added to plastic.

“It is possible that the negative impacts of litter on octopuses is underestimated due to the lack of available data, and we therefore emphasize that the problem must be more thoroughly assessed,” the study authors concluded.

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By Andrei Ionescu, Earth.com Staff Writer