|NOT Ocean Plastic|
(Through my footnotes I am raising a lot of questions which I realize will eventually be answered when the results are properly published. I'll wait patiently until then and then have another say on the matter.)
So is this good news? I don't see it as such. Consumption of plastics by any stomach-containing animal removes the plastic from the larger environment, but always temporarily rather than permanently. Plastic are not digestible and so the plastic is only temporarily stored within the animal swallowing it. Whether the pieces quickly pass through the animal's digestive track or remain trapped within the animal until the animal dies and decomposes, the particles are not permanently removed from the environment. And since lanternfish make up such a large niche in the open water ocean, they are a food source for a number of other species, listed in the Wikipedia article as "whales and dolphins; large pelagic fish such as salmon, tuna and sharks; grenadiers and other deep-sea fish (including other lanternfish); pinnipeds; sea birds, notably penguins; and large squid such as the jumbo squid..." All of this further supports that the sink is temporary, not permanent.
Plastic waste has no business being in the ocean, and lanternfish eating up large quantities of it does nothing to change this perspective.
 How did the researchers arrive at their expected value of plastic waste? Since the waste has been extensively measured elsewhere, why did they feed a need to derive a new value?
 How was this ruled out? Recent research suggests that microbial degradation is more significant than initially thought.
 How? Did they actually see lanternfish eating plastic?