A study carried out by marine scientists at NUI Galway found that 73% out of 233 deep water fish from the Northwest Atlantic Ocean had ingested plastic particles. The research was published today in the international peer-reviewed journal Frontiers in Marine Science.
As part of the study, the NUI Galway scientists participated in a transatlantic crossing onboard the Marine Institute’s Celtic Explorer research vessel. During this research cruise, they took dead deep sea fish from midwater trawls in the Northwest Atlantic Ocean, such as the Spotted Lanternfish, Glacier Lanternfish, White-spotted Lanternfish, Rakery Beaconlamp, Stout Sawpalate and Scaly Dragonfish, from a depth of up to 600 metres using large fishing nets. The fish ranged in size from the smallest species, the Glacier Lantern at 3.5 centimetres to the largest species, the Stout Sawpalate at 59 centimetres. Upon return to Galway, the fish were then inspected at the University’s Ryan Institute for microplastics in their stomach contents.
Microplastics are small plastic fragments that commonly originate from the breakdown of larger plastic items entering our oceans. Other sources may be wastewater effluents carrying plastic fibres from clothing and microbeads from personal care products. Due to their low density, most of these microplastics float at the sea surface.
Alina Wieczorek, the lead author of the study and PhD candidate from the School of Natural Sciences and Ryan Institute at NUI Galway, said: “Deepwater fish migrate to the surface at night to feed on plankton (microscope animals) and this is likely when they are exposed to the microplastics. One of the inspected Spotted Lanternfish, which was 4.5 centimetres in size, had 13 microplastics extracted from its stomach contents. The identified microplastics were mostly fibres, commonly blue and black in colour. Some only measured 50 microns in length. In total, 233 fish were examined with 73% of them having microplastics in their stomachs, making it one of the highest reported frequencies of microplastic occurrence in fish worldwide.”
Previous studies have shown that microplastics can be ingested by numerous marine animals from zooplankton to worms and fishes. The ingestion of microplastics by these animals may cause internal physical damage, inflammation of intestines, reduced feeding and other effects. However, what is also of concern is that many of these ingested microplastics have associated additives, such as colourants and flame retardants that are added to plastics during the production process, and/or pollutants that are adsorbed onto 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 potentially harmful effects.
Dr Tom Doyle, a co-author of the study from the Ryan Institute at NUI Galway, said: “While there is clearly a concern that the ingestion of microplastics with associated toxins may have harmful effects on these fishes or even the fishes that feed on them, our study highlights that these seemingly remote fishes located thousands of kilometres from land and 600 metres down in our ocean are not isolated from our pollution. Indeed, 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 wastewater 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 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 Ocean.
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.
To read the study in Frontiers in Marine Science, visit http://bit.ly/2EEmMHI