Are we eating plastic eating fish?

Plastics are one of humans’ most recent ubiquitous and long-lasting changes to Earth’s surface. Due to the durable, inexpensive, lightweight, strong nature of plastics, they are suitable for an immense range of products, including a number of single-use items. Unfortunately, the same properties that make plastics suitable for a variety of applications make them a persistent problem in the natural environment. Due to the increasing abundance of anthropogenic debris in marine systems, species are increasingly likely to interact with it, often to their detriment. Interactions include entanglement, ingestion, and nest incorporation (seabirds). Most plastics do not biodegrade, but instead photodegrade (break into increasingly small pieces under sunlight), and these microplastics (particles smaller than 5mm) are becoming an increasingly large problem. Plastics, and microplastics, at sea are becoming part of fish diets. Unfortunately, yes, we may be eating plastic eating fish. Plastic ingestion by marine fish was first recorded in 1972, and since then the amount of plastic in the world’s oceans has increased dramatically, as has the documentation of fish ingesting plastics. Plastic ingestion can affect fish both physically (by blocking the digestive tract) and chemically (by leaching toxic pollutants which are part of or have been attached to the plastic). Unfortunately, the potential ecological and human health risks regarding microplastics are rather understudied and unknown, as the hazard and exposure levels which determines risk are uncertain. It becomes evident that reducing the amount of plastic litter making its way into the ocean, and removing what is currently out there, is so important! We need to do our part to reduce our use of plastics, re-use those we have, recycle that which we don’t want, and rethink our choices. Single use plastics are terrible, and please do not use cosmetics that contain micro-beads! The ORCA Foundation has started a new project looking at plastic ingestion by game fish in Plettenberg Bay, and it will be interesting to see how our results compare to other areas of South Africa, and the world.

Written by: Minke Tolsma

For further reading:

  • Barnes, D.K.A., Galgani, F., Thompson, R.C., Barlaz, M., 2009. Accumulation and fragmentation of plastic debris in global environments. Philosophical Transactions of the Royal Society B 364: 1985–1998.
  • Derraik, J.G.B., 2002. The pollution of the marine environment by plastic debris: a review. Marine Pollution Bulletin 44: 842–852.
  • 2015. Sources, fate and effects of microplastics in the marine environment: a global assessment. Kershaw, P. J. (ed.). (IMO/FAO/UNESCO-IOC/UNIDO/WMO/

IAEA/UN/UNEP/UNDP Joint Group of Experts on the Scientific Aspects of Marine Environmental Protection). Reports and Studies GESAMP No. 90: 96pp.

  • Gregory, M.R., 2009. Environmental implications of plastic debris in marine settings – entanglement, ingestion, smothering, hangers-on, hitch-hiking and alien invasions. Philosophical Transactions of the Royal Society B 364: 2013–2025.
  • Laist, D.W., 1987. Overview of the biological effects of lost and discarded plastic debris in the marine environment. Marine Pollution Bulletin 18: 319–326.

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