Marine Mammals

Ingesting and entanglement from synthetic plastic in marine mammals is a widespread issue that happens frequently (Sadove, 1989). Used fishing gear is stressed to be a common pollutant that impacts the lives of marine mammals. In one instance in 2008, two sperm whales were found stranded in California with a ruptured stomach and gastric impaction. Between the two whales, 134 nets were inside their stomachs (Jacobsen, 2010). Even though Whales are large animals that can swallow large items, micro plastics make a significant impact on their lives as well.

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Baleen whales are filter feeding whales meaning they suck in plankton filled water and "filter" out water while the plankton remain in their mouths (Marx, 2016). Filter feeding species eat organisms like plankton and krill, species that eat micro plastics (Fossi, 2012).  An example of a filter feeding species would be a Blue whale or a Humpback whale. While filter feeders eat plankton, they are also ingesting the plastic that is inside of them. Traces of phthalates are known to have been found in plankton samples (Fossi, 2012). Filter feeders do not only eat plastic indirectly. When plastic "smog" is present, it is hard to distinguish the difference between what is food and what is plastic particles (Ruxon, 2016). Baleen whales suck in 75,000 liters of water and krill. It can be almost impossible for them to know if plastic is being sucked in as well (Ruxon, 2016). 

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One method that a scientist named Christina Maria Fossi uses to calculate the chemical toxicity in cetaceans is by taking skin samples. The bottlenose dolphin is the most common and polluted species that she does skin biopsies on. She does this by taking a small dart that bounces off with a small skin sample that does not harm the animal. By doing this she has detected that when mammals eat fish that are contaminated with plastic toxins, it stores in the fatty tissues around the body and in vital organs (Ruxon, 2016). These chemicals interfere with growth, metabolism, kidneys and liver function and reproduction (Ruxon, 2016)

 

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References

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Fossi, M. C., Panti, C., Guerranti, C., Coppola, D., Giannetti, M., Marsili, L., & Minutoli, R. (2012). Are baleen whales exposed to the threat of microplastics? A case study of the Mediterranean fin whale (Balaenoptera physalus). Marine Pollution Bulletin, 64(11), 2374-2379.

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Jacobsen, J. K., Massey, L., & Gulland, F. (2010). Fatal ingestion of floating net debris by two sperm whales (Physeter macrocephalus). Marine Pollution Bulletin, 60(5), 765-767.

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(2018). Plastic pollution kills 1m seabirds, 100,000 marine mammals annually. Daily News Egypt (Egypt).

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Ruxon, J. (Producer & Leeson, C. (Director). (2016). A Plastic Ocean [Motion Picture]. Netherlands

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Sadove, S. S., & Morreale, S. J. (1989, April). Marine mammal and sea turtle encounters with marine debris in the New York Bight and the northeast Atlantic. In Proceedings of the Second International Conference on Marine Debris, Honolulu, Hawaii(pp. 2-7).

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