How ocean plastics impact marine life

The consequences of ocean plastic for marine life are devastating - and often invisible. While viral images of whales dying with bellies full of bags grab public attention, the broader damage runs much deeper. 

Over 100,000 marine mammals die each year due to plastic entanglement or ingestion (WWF 2021). At least 340 species have been recorded entangled in debris, especially fishing gear like nets and ropes. Once trapped, animals can suffocate, drown or suffer debilitating injuries. Marine birds are also found dead with plastic pellets and other fragments in their digestive tracts, and plankton is commonly ingesting microplastics before they even enter the marine food chain.

Plastic ingestion is even more widespread. Over 380 marine fish species  have ingested plastic particles - including 210 species of commercial value. Ingesting plastic reduces stomach capacity, causes blockages and can be fatal. Microplastics accumulate in tissues, impacting reproductive systems, growth and even neurological function. 

Filter feeders like baleen whales and small plankton eaters are especially vulnerable. So are seabirds, which frequently mistake plastic pellets for food. Some birds have been found with stomachs full of plastic shards, pellets and bottle caps, leading to starvation. In extreme cases, parent birds feed plastic to their chicks and make their nests out of plastics. This has caused a newly documented disease to arise - Plasticosis - a fibrosis condition in seabirds caused by ingesting plastic over time (CSIRO 2023).

Even coral reefs are at risk. Floating plastic debris erodes coral surfaces, introduces pathogens and blocks light, weakening reef ecosystems already threatened by warming seas and acidification.

Top predators like orcas suffer from biomagnification - accumulating toxic chemicals through prey that have consumed plastic. These chemicals disrupt hormones, damage organs and have already contributed to declining fertility among orca populations in areas like Scotland.

Ocean plastic and microplastic pollution isn’t just ugly - it’s killing the ocean from the inside out. Its effects are felt throughout the food web, threatening not just ocean ecosystems but people and the economies that depend on them. Plastic degradation at sea is also proven to contribute to climate change through GHG emissions.

Next in Ocean series: 10/10: Plastic and people: from shrimp to the dinner plate 

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For more information contact: info@scarabtrust.org.uk

Images:

white and blue ocean waves - Photo by Matt Paul Catalano (ST ref: 1313)

Gannet using plastics for their nests - Image by Bernhard Bauske / WWF Deutschland (ST ref: 1193)

Thanks to Frédérique Mongodin from Seas at Risk for editorial support.

Edited 6 July 2026