Ocean Plastics In Our Food Chain: The Importance Of Lantern Fish And Night Trawling


5 Gyres founders Anna Cummins and Marcus Eriksen holding a piece of plastic found in a night trawl in the South Pacific. Photo credit: Paula Alvarado

The process of taking samples from the sea goes on 24/7 in our trip through the South Pacific with the 5 Gyres Institute in search of plastic pollution, and the night trawls are an important step to find out what's the impact of this material in the ocean.The reason is a basic component of the marine food chain: the myctophids or lantern fish, that live at least 400 meters deep during the day and come to the surface to feed at night.

Making up 50 to 60 percent of the ocean's fish-mass and serving as food for other fishes like tuna, mahi mahi and squid, to name a few, the ingestion of plastic by this organism is dangerous on two fronts.

On one side, confusing minuscule particles for food can create a false sense of satiation in them, potentially putting their health and existence in danger. On the other, as their stomachs are so small, the plastic ingested by them doesn't leave, presenting the risk that potential toxics from plastics build up in the food chain as they get eaten by larger fish.

Although the main focus of the 5 Gyres Institute is to determine the spacial distribution of plastic in the world's oceans (finding out what's the distribution and concentration of plastics in the sea), in their trawls the scientists extract samples of lantern fish.

During their trip to the North Pacific in 2008, the group collected and dissected about 600 of these fish and found that 35 percent of them had plastic in them. Now, they're collaborating with other scientists, like Chelsea Rochman, to determine whether this fish are accumulating toxins in their tissues due to ingestion of plastic and if this presents in fact a risk to human health.

As we pass the middle point between Valdivia and Easter Island and approach the concentration area of the South Pacific gyre, the samples taken from the ocean are consistently showing an increase of plastic particles.

Which seems to announce the coming of what will possibly be called the South Pacific Garbage Patch: The fifth area of the ocean to present plastic pollution surveyed by 5 Gyres.

We'll keep you posted as the trip continues!

More from TreeHugger's voyage with 5 Gyres
First Evidence of Plastic in the South Pacific: Is This a Different Kind of Garbage Patch?
Aboard with 5 Gyres in the South Pacific: The Trawling Begins
On The Way To The (Possibly) Great South Pacific Garbage Patch
5 Gyres Founders Explain How Plastic Pollution in Oceans Really Works (Video)