Durban - Rotting fish lined the banks of the Isipingo River estuary at the weekend after the latest in a series of fish kills in this degraded river system, close to Durban’s largest industrial zone.

North of the city, residents reported that up to 1 000 fish had also been killed by pollution in the uMdloti Lagoon.

Although the exact cause of the deaths at Isipingo has not been confirmed, parts of the estuary were covered in dense mats of green algae and residents reported seeing fish gasping for air last week.

Surveying dozens of dead fish at the river mouth, Isipingo Beach fisherman Haroon Shaik said: “Just look at this stinking mess! I fish at several places along the coastline and many of the other rivers are still clean and healthy. But Isipingo has become a disgrace.”

Shaik said he noticed a strong smell of chemicals in the vicinity of the Reunion Canal just over a week ago.

“We phoned Ezemvelo to come and look at all these dead fish, instead of going after subsistence fishermen who are trying to feed their families. They need to examine the bigger problems in front of their eyes.

“We used to get lovely grunters, mud bream and other big fish in this river, but nowadays all we seem to see is fish gasping for air, or floating belly up,” he said.

Residents Wade Holland and Gerrard Smith estimated that up to 1 000 fish were killed in the uMdloti lagoon.

Holland said paddle-boarders first noticed dead fish on July 3.

The cause of the deaths at eMdloti had also not been confirmed, although water samples were collected for analysis.

Earlier this year, the eThekwini Municipality came under pressure from the Department of Water Affairs to clean up and avoid further pollution of the Isipingo River estuary.

Documents shown to The Mercury suggest that at least 4.8 million litres of sewage, semi-treated beer and potato chip effluent poured into the Isipingo lagoon via a stormwater canal in early January, killing hundreds of fish.

The Water Affairs Department wrote to eThekwini city manager S’bu Sithole in February, noting that there had been several spills in the river mouth since 2006 which appeared to be linked to “failing sewerage infrastructure”.

The department’s regional head, Ashley Starkey, said the estuary was also degraded from high levels of nitrogen and phosphorous, along with litter from the Prospecton Canal.

“The department cannot allow the estuary to be managed at this ecologically unacceptable level,” Starkey said.

Di Dold, the chairwoman of Coastwatch KZN, complained that little had been done to remedy regular pollution of the province’s river estuaries. River scientist Mark Graham has reported previously that several rivers in the eThekwini region have become little more than “open sewers”.

The eThekwini Municipality had not responded to requests for comment sent on Friday.

The Mercury