73% of Deep Water Fish Ingested Microplastics
As part of the study the NUIG scientists participated in a transatlantic crossing onboard the marine institute’s Celtic Explorer vessel. During this research cruise they took dead deep-sea fish from midwater trawls such as the spotted lanternfish, rakery beaconlamp, stout saw-palate and scaly dragonfish.
PhD candidate and lead author Alina Wieczorek said: “Deep-water fish migrate to the surface at night to feed on plankton [microscopic animals] and this is likely when they are exposed to the microplastics.”
One of the inspected spotted lanternfish, which was 4.5cm in size, had 13 microplastics extracted from its stomach contents. The identified microplastics were mostly fibres, commonly blue and black in colour.
In total, 233 fish were examined and 73 per cent had microplastics in their stomachs, “making it one of the highest reported frequencies of microplastic occurrence in fish worldwide”.
Previous studies have shown microplastics can be ingested by numerous marine animals from zooplankton to worms to fish. The ingestion of microplastics may cause internal physical damage, inflammation of intestines, reduced feeding and other effects.
What is also of concern, Ms Wieczorek said, was that many of these ingested microplastics have associated additives, such as colourants and flame retardants that are added to plastics during production process, and/or pollutants that are adsorbed on to the microplastics from the sea.
“There is now evidence that some of these toxins on the microplastics can be transferred to animals that eat them, with potential harmful effects.”
Co-author Dr Tom Doyle of the Ryan institute at NUIG, said: “It’s worrying to think that our daily activities, such as washing our synthetic clothes in our washing machines, results in billions of microplastics entering our oceans through our waste water stream that may eventually end up in these deep sea fishes.”
The fish were sampled from “a warm core eddy”, which is a circular current in the northwest Atlantic Ocean. Similar to what are known as ocean gyres, these currents are now thought to accumulate microplastics and that the sampled fish may have originated from a particularly polluted patch of the Atlantic.
Ms Wieczorek added: “This would explain why we recorded one of the highest abundances of microplastics in fishes so far, and we plan to further investigate the impacts of microplastics on organisms in the open ocean.”
The research was carried out within the Plastox project, a European collaborative effort to investigate impacts of microplastics in the marine environment under the JPI Oceans framework and supported by the iCRAG (Irish Centre for Research in Applied Geoscience) project, funded by Science Foundation Ireland.
Source: The Irish Times
Video source: Bridie Farren
The study can be read at Frontiers in Marine Science