Microplastics and their presence in the oceans has now become a well studied topic. Countries like Canada, the United States and the UK have banned the usage of plastic micro-beads in personal care and cosmetic products, with many European countries following suit. Filter feeders, which for the most part, feed rather indiscriminately ingesting particles of a given size. However, this only one small part of the problem. What about fish?
Recent evidence suggests that fish are actively seeking out plastic debris as the small bits of plastic may appear to look and smell like their natural prey. Savoca et al. discusses in the journal Proceedings of the Royal Society B, the some fish may be confusing these pieces of plastic debris as an edible substance. This is in part because while suspended in the water, these plastic accumulate a a covering of biological material. This material can come to include algae, bacteria, etc which mimics the smell of food.
To prove fish were actively feeding on the debris schools of wild-caught anchovies were presented with plastic debris taken directly from the oceans and with pieces of clean plastic debris which had never been in the ocean. What they observed were similar responses by the anchovies to the odours of the ocean debris in the same manner as they do to the odours of the prey they choose to consume. Plastic of all shapes and sizes are floating throughout our oceans and has also been found within the guts/intestines of whales and birds, Through the process of biofouling, the plastic debris, which is not readily degradable, is colonized quickly by fouling organisms. Fouling organisms like algae then emit chemicals which act as an attractant to hungry fish.
The next questions that must be attacked are how do we do reduce plastics entering our oceans? What are the long term effects of marine debris on the ecology and behaviour of the fish that consume it
To do your part recycle, avoid unnecessary plastic packaging, do not use personal care products with plastic microbeads and share the knowledge.
Please see the publication: http://rspb.royalsocietypublishing.org/content/284/1860/20171000
Savoca, MS, Tyson, CW, McGill, M. Slager, CJ (2017) Odours from marine plastic debris induce food search behaviours in a forage fish. Proc. R. Soc. B.
https://www.theguardian.com/environment/2017/aug/16/fish-confusing-plastic-debris-in-ocean-for-food-study-finds
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