Larval flying fish (top) and triggerfish (bottom) with magnified plastics that fish ingested (left). Dime shown for scale. Credit: NOAA Fisheries/Jonathan Whitney.
Recent evidence shows that adult fish ingest plastic. This is the first study to show that larval coral reef fish and pelagic species are also consuming plastic, as early as days after they are spawned.
“Larval fish are foundational for ecosystem function and represent the future of adult fish populations,” said Dr. Jamison Gove, a research oceanographer for NOAA and co-lead of the study. “The fact that larval fish are surrounded by and ingesting non-nutritious toxin-laden plastics, at their most vulnerable life-history stage, is cause for alarm.”
Researchers are unsure of how harmful plastic ingestion is to larval fish. In adult fish, plastics can cause gut blockage, malnutrition, and toxicant accumulation. Larval fish are highly sensitive to changes in their environment and food. Prey-size plastics could impact development and even reduce survivorship of larval fish that ingest them.
The researchers measured the size and distribution of the surface slicks using satellites. Even when viewed from space, surface slicks are distinct from the rest of the ocean. The researchers found that surface slicks comprise less than 10 percent of ocean surface habitat. However, they are estimated to contain about 42 percent of all surface dwelling larval fish and nearly 92 percent of all floating plastics.
“Surface slicks had never been mapped before, but we knew it would be vital to scaling up the field-based study. Our new method developed for this study can be applied anywhere in the world,” noted co-author Dr. Greg Asner of Arizona State University’s Center for Global Discovery and Conservation Science.
“Biodiversity and fisheries production are currently threatened by a variety of human-induced stressors such as climate change, habitat loss, and overfishing. Our research suggests we can likely now add plastic ingestion by larval fish to that list of threats,” said Dr. Gove.
Some scientists criticize the attention on plastic pollution. They say that it is distracting society from tackling more known and severe threats to global fisheries.
“We agree that curbing carbon emissions and finding more sustainable ways to fish must be a priority, but our findings suggest further investigation is needed to understand the effects of plastic ingestion by larval fish on individuals and populations,” said Dr. Gareth Williams, Associate Professor in Marine Biology at Bangor University (U.K.) and co-author of the study. “We as a society have the ability to make changes that would alleviate the stress on ecosystems imposed by our activities. We can and should start making those changes now, to limit stress to already severely threatened marine life.”