Ecological boost for wetlands
2007-03-05 11:46
Johannesburg - Large numbers of fish, prawn and crab larvae are likely to enter Lake St Lucia with some movement of fish out to sea after the first opening of the lake in five years, the Greater St Lucia Wetland Park Authority said on Sunday.
Wetland Park Authority CEO Andrew Zaloumis said low salinity and sediment levels had been maintained in a current drought due to good December rains and an integrated management approach.
"As a result, this natural breaching of the mouth is positive - ecologically, and for tourism and community livelihoods," he said.
High waves were expected over the next six days due to rough seas and spring tides with significant amounts of sea water and sand continuing to enter the lake.
The water would flow up the lake's tidal portion, the Narrows, through Makakatana and into the main body of Lake St Lucia.
By Sunday, seawater was flowing steadily into Makatana Bay and the main lake which is Africa's largest estuarine system with a surface area of 36 000 hectares.
Mouth open for first time since 2001
The mouth of the lake opened on Friday after having closed in June 2001.
Zaloumis said Zululand experienced severe droughts, each lasting for a few years in a roughly 10 year cycle.
Ezemvelo KZN Wildlife Wetland Park Ecologist Dr Ricky Taylor said the Narrows was expected to reach seawater salinity, achieved at 35 parts salt per thousand.
This would cause the dying back of a submerged water plant which had flourished in the low salinity levels.
Zaloumis said sediment inflows posed some risk but that a sediment trap had proved effective.
"The situation is dynamic and will continue to be monitored closely by park ecologists and managers over the next few weeks."
- SAPA