Debris from our throwaway society doesn't just ruin seaside aesthetics – it leaches pollutants into the water and sand, gets into whales' stomachs and round seals' necks, entangles propellers and transforms barefoot beach strolls from a carefree into a hazardous activity.
Read: Facial scrubs choking the ocean
Last year, 650 000 volunteers took part in coastal cleanups and removed nearly 6 million kilograms of litter from beaches, making it the world's single biggest volunteer event.
The Ocean Conservancy, which spearheads the Cleanup campaign, counts every litter item retrieved to identify the top offenders.
Last year, cigarette butts topped the list at 2 million, followed by food wrappers (1.6 million) and plastic bottles (almost a million).
Voodoo dolls, handguns and "ghost nets"
In among the more mundane debris, the Ocean Conservancy also reports some bizarre finds, like a voodoo doll, a trampoline, a wedding dress, a treasure map in a bottle, a loaded handgun and, yes, a kitchen sink.
Handguns aside, such items may seem fairly innocuous, but they have no business in the natural environment. Marine animals mistake manmade items like drinking straws for food; when ingested, they block digestive tracts. Curious foragers get plastic containers caught round their muzzles, often leading to starvation.
Ghost gear haunting the oceans
Another serious threat, reports World Animal Protection, is what they term "fishing's phantom menace": nets, lines and hooks lost or discarded from the industry that feeds our voracious appetite for seafood.
This "ghost gear", highly durable and often almost invisible in the water, persists for years, continuing to do what it was designed for - effectively trapping sea life. Among the animals most frequently reported mutilated and killed by ghost gear are fur seals, sea lions and humpback and right whales.
Few animals are as lucky as this dolphin, who seemed to "ask" a diver to free it from ghost gear:
Picking up trash isn't as crucial as stopping it being produced and discarded in the first place, but it helps. To "turn the tide" on trash in ocean, find a Cleanup event at a beach or wetland near you with this interactive map.
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