There are currently many problems facing the St. Lucia estuary and lake systems, but in my personal opinion the silt levels caused by the closure of the St. Lucia estuary mouth are currently (May 2021 ) the biggest issue that needs to be addressed.
The St. Lucia estuary mouth was closed by the IWPA ( iSimangaliso Wetland Park Authority ) in 2002 following the Jolly Rubino incident. When the #JollyRubino ran around in 2002; there was a very distinct possibility that some chemical polution may occurred in the St. Lucia estuary, and the department of Environmental Affairs instructed the IWPA to MECHANICALY close the St. Lucia estuary mouth as a precautionary measure.
The mouth to the St. Lucia estuary has remained closed ever since, with a 157 day respite in 2007, after cyclone Gumede unleashed huge waves and a storm surge on the KZN coastline. This heavy sea and associated storm surge breached the St. Lucia estuary from the ocean side causing massive and serious long term problems for the functionality of the St. Lucia estuary and lake systems.
The mouth of the St. Lucia estuary system has thus basically been closed to the Indian Ocean since the Jolly Rubino incident, and was MECHANICALY opened on 6 January 2021.
Lake St. Lucia is fed fresh water from 5 major sources, with the Umfolozi River being the largest, and the furthest South. The #UmfoloziRiver is also the biggest exporter of raw silt into the St. Lucia estuary and lake systems. The silt from these rivers has therefore been accumulating within the lake and estuary systems for the last 18 years
Since 2002 there have been many serious rains within the catchment area of the Umfolozi River, and these rains have each added to the silt load within the St. Lucia lake and estuary systems. Both Lake St. Lucia and the St. Lucia estuary have silted up considerably due to these big rain events.
The connecting channel that connects the northern sections of lake St Lucia to the main estuary mouth at Mapelane has silted closed, there after grown over by Reed's, and is now unable to function in a normal manner, then more flooding has dropped deeper silt layers on-top of the Reed's and truly disconnected the northern sections of the lake from the estuary mouth.
This means that the waterflow between the northern sections of the lake and the Indian Ocean is no longer viable, causing great harm to the biodiversity of the entire St. Lucia ecosystem. The fishing industry along the entire South African Coastline has been impacted in a rather negative manner by these silted up waterflow channels.
As discussed in this short YouTube clip by the IWPA, the St. Lucia lake and estuary systems form the core breeding grounds of many marine species. With these breeding and nursery grounds out of commission, due to poor / bad management by the iSimangaliso Wetland Park Authority juvanile recruitment is now a very big issue.
With minimal juvanile recruitment from other esturies our fish stocks are in steady decline. Within the St. Lucia lake system, many of these species are currently locally extinct.
We need to address these issues.
For more info send an email to 4u2fish@info4u.co.za
More coming soon.
