In the previous post, we’ve talked about how plastics end up in the ocean. Today, we’ll take a closer look on how marine animals are affected by plastic debris in the ocean.
- Entanglement and Ghost Fishing (Laist, 1997)
Laist (1997) identified over 250 marine species that are known to be impacted by entanglement and ingestion. Some of these animals include (but are not limited to) turtles, penguins, albatrosses, dolphins, seal and sea lions. Nowadays, rope and cordage made using nylon and other synthetic plastic materials are often used in marine activities and discarded in the sea. These plastics nets are generally buoyant and durable, entangling many marine animals by accident. These animals are doomed to drown or die from injury and starvation.
In addition to causing entanglements, lost, abandoned or derelict trawl net retain the ability to continue capturing target first and other species for lengthy periods of time (ghost-fishing).
- Ingestion (M.R Gregory, 2009)
As mentioned previously, plastics in the seas tend to undergo mechanical degradation (a result of photo-degradation and exposure to wind and waves) and thus break up into numerous tiny fragments. Once ingested by the marine animals, these plastics fragments are known to cause internal wounds, skin lesions, blockage of digestive tract (induced starvation) and often death. Seabirds and Turtles are known to ‘feed on’ these plastics fragments (especially those that are brightly coloured) as they resemble jellyfish and shrimps.
In summary, this week’s post teaches us how plastics pose as a serious threat to the well-being of marine animals. In the next post, we’ll discuss more about the impact of marine plastic pollution on human society.
For more information,
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 of London B: Biological Sciences, 364(1526), 2013-2025.
Laist, D. W. 1996 Marine debris entanglement and ghost fishing: a cryptic and significant type of bycatch. Alaska Sea Grant College Progarm Report no. 96-03. pp. 33–39, University of Alaska, Fairbanks, AK.