DWINDLING CATCH

Why fish will continue declining at the Coast

Corals are likely to decline further as global temperatures continue to rise

In Summary

•The report said the 1998 disturbance of corals killed 8 per cent of the world’s coral.

•Coral degradation, therefore, has consequences for those who rely on fishing.

Coral reefs and mangroves provide protection to coastal habitats. They are also critical habitats for diverse marine life.
Coral reefs and mangroves provide protection to coastal habitats. They are also critical habitats for diverse marine life.
Image: WWF

A sharp decline in coral cover is set to be recorded as a result of the rapid changes in sea surface temperatures, a new report has shown.

The report indicates that corals are likely to decline further as global temperatures continue to rise.

It was unveiled during the International Union for Conservation of Nature World Conservation Congress by the International Coral Reef Initiative on September 7.

The report said the 1998 disturbance of corals killed 8 per cent of the world’s coral.

“Subsequent disturbance events, occurring between 2009 and 2018, killed 14 per cent of the world’s coral,” the report said.

It said there were 20 per cent more algae on the world’s coral reefs in 2019 than in 2010.

Increases in the number of algae, a globally recognised indicator of stress on coral reefs, were associated with declines in the amount of hard coral.

Declines in global coral cover were associated with periods of either rapid increase in sea surface temperature anomaly or sustained high sea surface temperature anomaly.

Mass bleaching occurs when corals are stressed by changes in conditions such as temperature, light or nutrients.

They expel the symbiotic algae living in their tissues, causing them to turn completely white.

Experts blame this on climate change and human activities, such as dumping waste, mangrove cutting and sedimentation.

Healthy corals provide shelter for many species of tropical animals that rely on the structure provided by corals for their homes, and others find food that shelters in the crevices of stony corals.

Coral degradation, therefore, has consequences for those who rely on fishing.

Before the bleaching, corals along the coastal waters occurred in shades of olive green, brown, tan and pale yellow.

The more they bleached, the more fish stocks dwindled.

Coral reefs are home to so many species they often are called the rainforests of the seas.

The report said since 2010, almost all regions have exhibited a decline in average coral cover.

Projections of increased sea surface temperatures in the future suggest coral reefs will experience further declines in the coming decades.

The report said increases in global average coral cover between 2002 and 2009, and in 2019 suggest that many of the world’s coral reefs remain resilient and can recover if conditions permit.

High coral cover and diversity may confer a degree of natural resistance to elevated sea surface temperature.

The report said reducing local pressures on coral reefs to maintain their resilience will be critical while global threats posed by climate change are addressed.

“Monitoring data collected in the field are essential to understand the status of, and trends in, coral reef condition,” the report said.

Coral reefs occur in more than 100 countries and territories and whilst they cover only 0.2 per cent of the seafloor.

They support at least 25 per cent of marine species and underpin the safety, coastal protection, wellbeing, food and economic security of hundreds of millions of people.

The value of goods and services provided by coral reefs is estimated at Sh220,629,510,000 ($2.7 trillion) per year, including Sh395,7480,000,000 ($36 billion) in coral reef tourism.

However, coral reefs are among the most vulnerable ecosystems on the planet to anthropogenic pressures, including global threats from climate change and ocean acidification, and local impacts from land-based pollution such as the input of nutrients and sediments from agriculture, marine pollution, and overfishing and destructive fishing practices.

Maintaining the integrity and resilience of coral reef ecosystems is essential for the wellbeing of tropical coastal communities, and a critical part of the solution for achieving the Sustainable Development Goals under the 2030 Agenda for Sustainable Development.

 

Edited by Kiilu Damaris