So far, researches focused on the amount of plastic present in the Ocean, but a Swedish study now shows that this scourge is impacting the Baltic Sea fish both at behavioural and physical levels. According to the findings, fishes would become smaller and more stupid. Once again, these alarming results prove that we need to keep on our fight against aquatic waste.
The Baltic Sea, a fragile ecosystem
The Baltic Sea is a small shallow (about 55 meters deep) nearly-enclosed sea neighbouring the Atlantic Ocean. And, knowing that the renewal of the aquatic mass takes approximately 30 years, it can be considered as a lake. Hence, the Baltic Sea is highly sensitive to pollution because its waters are not permanently regenerated and its low temperatures as well as the glaciated areas prevent the chemicals from deteriorating quickly.
Do you really think that waste comes from the Ocean?
Is plastic about to replace plankton ?
It is foreseen that in 2050 there could be more plastic than fish in the Ocean. Thus, because marine animals are exposed to this issue, consequences are more and more tangible. For example, young perch are smaller, slower hence easier to catch for predators.
The study about plastic waste effects on animals shows that the concentration of micro particles of plastic (about 90 micrometers) inhibits the European perch eggs’ hatch, lowers their growth rates, disrupts their food preferences and their behaviours. Similarly, individuals exposed to microplastics do not respond to olfactory signs giving indications on the presence of a predator. This increases their death rate due to predators.
The findings of the study hence prove that microplastics have a chemical and physical impact on the performance and the development of juvenile fish. A stunning result reveals that plastic modifies marine animals’ food preferences. Whereas they have access to plankton, fish prefer eating plastic.
Alarming consequences
When there is no plastic diluted in the water, about 96% of the eggs successfully hatch. Only 81% of them hatch when exposed to high quantities of plastic. A scientist of Uppsala University has even precised that the latter are « smaller, slower and more stupid » and above all, that they are easy preys. This contributes to the species’ decline.
These observations, coupled to overfishing, have direct consequences on fishermen’s incomes and food safety, as well as on the survival of the sea ecosystem. The FAO underlines that «while recovery of depleted stocks is urgent, it is just as important to avoid depleting still-healthy stocks in the first place by matching fishing efforts to what these stocks are capable of supporting».
The Baltic Sea can be considered as an example for the study of the consequences of microplastics on fish. Whereas the conditions are particular (low renewal rate), the odds are good that the same effects can be observed on a greater scale and on other marine species.
The interdiction of plastics microbeads and Q-tips (biodiversity law) is a major step but not the end of the fight against aquatic waste. As citizens, our part is to limit the use of plastic (packaging, bags, etc.), to separate and recycle the waste (a compost heap reduces our trash bin by 40%), to be careful to what we eat and to heighten awareness of our relatives on that issue!
Laura Anty, Environmental Writer
