Nobody noticed the threat of plastic waste at sea until the 1970s. Literally, nobody paid attention to it.
But today, plastic waste can be found anywhere and everywhere on Earth. People across the world clearly recognize plastic waste as a threat that will not vanish from the Earth for hundreds or even thousands of years (UNEP Newscentre).
The ingestion of plastic waste is one of the most excruciating causes of death for marine animals. The plastics scattered in every part of the sea can be accidentally eaten by marine animals, clogging their digestive tracts and leading to their deaths.
Whales are also victims of plastic waste (Fossi et al. 2016). Among the 80 species of cetacean that still exist today, 47 species of whales, that is 59% of them, have been found to have marine debris in their digestive tracts (Kühn et al. 2015).
Even among toothed whales, such as sperm whales and beaked whales, the accidental ingestion of plastic has been well documented (Laist 1997).
In Norway, more than 30 big plastic bags with a combined size of two cubic meters were found in the stomach of a beaked whale. It was believed that these obstructed its digestive system (REUTERS February 5 2017).
In Northern California, scientists investigated the stomach contents of two sperm whales that had been stranded on the beach. They found plastic rope, fishing nets, fishing buoys, and other pieces of plastic in their stomachs (Jacobsen et al. 2010).
One of these sperm whales had its digestive tract packed with 24 kg of waste, and this was believed to have caused the rupturing of its digestive tract and thus its death.
As for the second one, 74kg of wastes blocked its digestive tract and it likely starved to death (Jacobsen et al. 2010).
Further reports began to emerge. In Mykonos in Greece, a young sperm whale stranded on the beach was found dead after gulping more than 100 plastic bags (Katsanevakis 2008), while in Taiwan, a huge number of plastic bags and fishing nets were found in the stomach of a dead sperm whale (AFP BB NEWS October 2015).
A Spanish research team investigated the stomach contents of a 4.5 ton sperm whale that had been stranded on a beach in Grenada. They concluded that the 7.6kg of packed plastic waste in its stomach had caused the stomach to rupture, leading to its death (de Stephanis et al. 2013).
Surprisingly, in the stomach of this sperm whale, they found a lot of plastic that was originally used in farming, such as the plastic sheets of greenhouses or those used to cover plants’ roots as well as soft plastic flower pots, etc. (de Stephanis et al. 2013).
It mistook them for squid and ate them.
Plastic sheets that are used in farming are often improperly disposed of, meaning they can easily enter the sea and accidentally get eaten by sperm whales.