Researchers say that coastal fish nurseries are filled with an alarming amount of microplastics. When oceanographer Jamison Gove and his colleagues set out to study larval fish congregating in ocean slicks, “ribbons of calm water that form naturally on the ocean’s surface,” he was not thinking about plastics at all. The team was just interested in studying this very early, vulnerable, and important stage of our ocean food chain, and what they discovered is disheartening to say the least.
Published in Proceedings of the National Academy of Sciences (PNAS), the study sampled ocean slicks 100 times between 2016-2018, from the coastal areas surrounding Hawaii. The ocean slicks have higher concentrations of nutrients and plankton, and researchers found large groups of larval fish (millimeters in length), and something else—plastic. And the plastic isn’t simply floating next to these very vulnerable baby fish, much of it is small enough to eat.
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Comparing plastic with larval fish densities in slicks revealed a positive relationship, with plastics outnumbering larval fish by 7:1. In contrast, the plastic-to-larval fish ratio in ambient waters was reversed (1:2) and showed no relationship. Along with higher densities of plastics, we found the size distribution of plastics was skewed toward smaller particles in slicks. Prey-size preference for larval fish broadly scales with their size but is generally less than 1 mm. The relative abundance of prey-size (≤1 mm) plastics was 40.9% higher in slicks compared to ambient waters (41.0% slicks, 29.1% ambient; Fig. 3C).
“Dissections of hundreds of larval fish found that 8.6% of individuals in slicks had ingested plastics, a 2.3-fold higher occurrence than larval fish from ambient waters.”
There is little known about the ramifications on larval fish ingestion, but it isn’t likely going to give us super powers. Jennifer Brandon, an oceanographer told Science News that as distressing as this study is, it may be just the tip of the iceberg. “They used a net that may have missed smaller fragments of plastics, so it could be even worse.”
Our oceans are smothered in plastics. There are the large plastics that we can all easily see—water bottles and “disposable” bags—and there are microplastics, tiny plastics (commonly used in modern clothing materials among other things) that can make their way through filters and into areas where we really shouldn’t have them. There are small glimpses of hope as professional scientists and amateur scientists try to figure out ways to heal our planet, but like climate change, we need to get everyone on board.