Tracking Alien Marine Species along South Africa’s Coast

Saldanha Bay harbour is an important global shipping route along the coast of South Africa. The Mediterranean mussel is an invasive species that has spread along the south and west coasts displacing native species, damaging infrastructures like pipes, aquaculture equipment and jetties. This invasive species like many others have attached entered waterways due to ballast water or from attaching themselves to the hulls of vessels.

Scientists had recently identified 95 marine alien species known as fouling agents. Fouling organisms such as algae, barnacles and mussels are sedentary. Included are burrow-dwelling worms and isopods and amphipods that cling to surfaces. Starfish and crabs are also included as fouling organisms. Fouling is a threat to biodiversity as it can be costly to clean infrastructure and hulls, which would also increase fuel demand for ships and lower productivity for the aquaculture industry.

To properly evaluate biosecurity protocols for policymakers, a monitoring method was developed to monitor and control bioinvasions.

The study was conducted with a combined effort of governments, academics, and harbour managers to track alien species before they become established.

The method was developed and tested at the Robinson Lab at Stellenbosch University, to monitor alien fouling species at yacht clubs and ports along the South African coast. Small PVC (plastic) panels, about the size of a medium-sized envelope, to buoys close to the harbour and to harbour piers. It is a low-cost method that was left for two months to see what organisms would attach themselves.

Two months is the minimum time necessary to detect and identify invasive species at the harbours in Cape Town, Port Elizabeth, Durban, and Saldanha Bay. 66% of the 21 species detected during the trial were invasive.  The results concluded that long-term standardized surveillance is important and must be established.

Aquaculture companies, shipping companies as well as managers of marinas, ports and yacht clubs could benefit from this monitoring approach as it would decrease future invasions and losses.

Read more about this here!