Plastics at almost all of world's coral reefs - study

A coral reef restoration ranger brushes an artificial reef structure in the Indian Ocean near Shimoni on June 13, 2022. [AP Photo]

Fishing gear now contributes to the bulk of plastics found in the reefs; a new study has revealed.

The study, published in Nature on July 12, surveyed 84 shallow and deep reefs at 25 locations across the Indian, Pacific, and Atlantic oceans, tracing for pollutants of over 5cms in size.

Of the 84 reefs surveyed, plastics were found in 77.

The study conducted by researchers from the California Academy of Sciences, Nekton and the universities of Sao Paulo, Oxford and Exeter shows that the presence of macroplastics increased in deeper reefs with fishing gear as the main source of plastics in most areas.

Macroplastics represented 88 per cent of pollutants within the coral reefs.

"Plastic pollution is one of the most pressing problems plaguing ocean ecosystems, and coral reefs are no exception.

From plastics that spread coral diseases to fishing lines that entangle and damage the structural complexity of the reef, decreasing both fish abundance and diversity, pollution negatively impacts the entire coral reef ecosystem," said lead author Hudson Pinheiro, PhD, of the University of Sao Paulo.

The study, which is said to be the most comprehensive survey of plastic pollution on coral reefs ever conducted comes even as experts have been raising alarm that coral reefs are losing the capacity to sustain their biological functions as a result of pressures from climate change and overfishing.

Coral reefs provide habitat, feeding, spawning, and nursery grounds for millions of aquatic species, including commercially harvested fish species. To perform these functions effectively, coral reefs need clean water to survive. When polluted, these reefs, they lose the ability to feed, grow and reproduce. They also become susceptible to disease.

And now the study reveals that plastic pollution is one of the emerging biggest threats to coral reefs.

The study reveals that unlike what was previously thought that plastic densities decrease with depth, it was actually found that plastics are found even in Earth's most remote and near-pristine reefs.

"It was surprising to find that debris increased with depth since deeper reefs in general are farther from sources of plastic pollution. We are almost always the first humans to set eyes on these deeper reefs, and yet we see human-produced trash on every dive," Luiz Rocha, PhD, co-director of the Academy's Hope for Reefs initiative said.

"It really puts the effect we have had on the planet into perspective," Rocha added,

The study was aimed at shedding light on the distribution and quantity of plastics trapped in the world's coral reefs, a topic that previously remained uncertain.

Some of the consumer debris found included water bottles and food wrappers. However, they were not the main form of plastic pollution at reefs.

Co-author Lucy Woodall, associate professor at the University of Exeter and principal scientist of marine conservation charity Nekton, highlighted the large amount of fishing gear at deep reefs.

"Unfortunately, fishing gear debris is often not reduced by general waste management interventions. Therefore, specific solutions related to the needs of fishers should be considered, such as no-charge disposing of damaged gear in ports, or individually labelling gear to ensure fishers take responsibility for misplaced equipment," Professor Woodall added.

Even with the stark findings that plastic pollution is becoming a major threat in times when the world is moving towards a global treaty to tackle plastic pollution, Kenya is among the many countries where regulations on the disposal of fishing gear are yet to take root.

According to George Odera, a project manager at Nature Kenya, plastic pollution along the major coastal beaches remains a major challenge. Poor disposal of fishing gear, he said, remains rampant and needs regulations.

"The fact that fishing gears are often disposed of haphazardly means that plastic pollution in the country in the country is still rampant. If the regulations were to be implemented, maybe we would be on the right path," Odera said.

He added that the poor standards of fishing gear also remain a challenge that leads to rampant pollution as such gear cannot be used for a long time.

And while some communities living around the coast - like in Mida Creek, Sabaki and Kipini among many other groups in Kilifi County have formed conservation groups where they volunteer for beach clean-ups to rid the beaches of plastics being swept downstream and those from old fishing gears, lack of proper disposal mechanisms remains a challenge.

"Once collected, most communities burn these plastics as the only way to dispose of them, which still is not a proper way," Odera added.