News agency, Cape Town, South Africa
Friday November 16th 2018

Sand Prawns evidence of positive anti-pollution efforts paying off

30/05/2012

Sand prawns are making a comeback.

After years of polluted run-off resulting in fish and bird species disappearing, efforts to clean the rivers feeding Milnerton Lagoon is paying off, with some species returning to the water body.

In 2004 pollution severity in the lagoon, a 40ha body of water which flows out to see at Woodbridge Island, resulted in a complete population die-off of several species, particularly Sand Prawns (Callianassa kraussi ) which require clean sediments and unpolluted water for their survival.

The City’s efforts to improve the quality of water in Diep River which feeds the lagoon, is bearing fruit, with Sand Prawns being once again seen in the waters, as well as the return of the birds which feed upon them.

Director of the City’s water and sanitation department, Philemon Mashoko, said since the 2004 Sand Prawns die-off, a slow recovery has been noted.

“Recreational fishermen are now harvesting this bait resource again, but not yet at the same level as previously. The steady return of the sand prawn in the Milnerton Lagoon may well be attributed to improved water and sediment quality,” said Mashoko.

The improvement in the state of water quality in the Lagoon has also been noticed by the Woodbridge Island residents.

The Island’s body corporate chair of environment and waterfront, Richard Rundle, said birds that historically inhabited the Lagoon which disappeared eight-years ago are now returning to feed on fish species and blood worms which had disappeared.

“There has been an increase in birds coming to eat the fish. Bloodworms are recovering as well…fishermen are finding some,” said Rundle.

He said Sand Prawns were making a return but they needed to be given time to multiply.

He specifically cited Pelicans as example of a bird that has returned to the Lagoon, as well as Sea Gulls.

“At one stage in 2004 we had about 39 different species of fish. We lost just about all the fish to pollution. At one stage the pollution went to about 1million E.coli count per 100ml,” he said adding that there had been a “remarkable” improvement in the water quality.

The City’s department of Environmental Resource Management director Ossie Asmal said trends in the water quality test results indicate an improvement in the water quality in the Lagoon.

Asmal said the E-coli levels for tests undertaken in January and April 2012 were less than the maximum permissible safe level of 130 counts per100ml for full water contact sports.

The improvement of the pollution status in the lagoon is as a result of upgrading work at Potsdam Waste Water Treatment Works (WWTW) which started in 2003 and cost the city R280 million.

Mashoko said the upgrading had included increased sewage capacity, sludge handling, ultra-violet disinfection and maturation ponds.

Meanwhile, backyard dwellers in Du Noon and Joe Slovo near Milnerton who  did not have toilets and relieved themselves in buckets or plastic bags which they later threw in the storm water canal, have been blamed for the raw sewerage flowing down the Diep River into the lagoon.

However plans, were “currently under way” to divert polluted low-flow storm water to the sewer reticulation system for part of the Joe Slovo area, said Brett Herron, the City’s Mayoral Committee Member of Transport, Roads and Storm water.

Herron said implementation was scheduled to commence this financial year.

Future diversions and other water quality improvement interventions would be depending on availability of funding,” said Herron. — Peter Luhanga

Tags: Bloodworms, Brett Herron, Diep River, DuNoon, Joe Slovo, Milnerton Lagoon, Ossie Asmal, Pelicans, Philemon Mashoko, Potsdam Waste Water Treatment Works (WWTW), Richard Rundle, Sand Prawns (Callianassa kraussi), Sea Gulls, Woodbridge Island

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2 Responses to “Sand Prawns evidence of positive anti-pollution efforts paying off”

  1. Sean says:

    This such encouraging news, as I have noticed the decline of life in the lagoon over the years and now of late niticed the return of birds and fish to the area. Awesome indeed! Nice to see life in our natural resources again 😉

  2. Juriaan says:

    All the fish died in the lagoon today!!!!!!!!!

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