By Dr Jade Maggs, Marine Scientist…
The Aliwal Shoal Marine Protected Area (MPA) is situated in the South-West Indian Ocean on the east coast of South Africa. More specifically, it is located on the sunny south coast of the KwaZulu-Natal province. Proclaimed in June 2004, the Aliwal Shoal MPA is one of the premier dive destinations of South Africa, second only to Sodwana Bay. It lies within the subtropical Natal Bioregion with warm waters year-round.
Aliwal Shoal Marine Protected Area on the east coast of South Africa
The MPA covers approximately 18 km of coastline between the Mkomazi and Mzimayi rivers. It extends 7 km out to sea and encompasses 147 km2 of ocean. The majority of the MPA is designated as a Controlled Zone. There are also two restricted zones, which are closed to fishing and all forms of extractive exploitation. These are the Crown Area Restricted Zone and the Produce Restricted Zone. The seafloor within the MPA consists mostly of scattered rocky reef and sand habitat.
There are three boat launch sites that are primarily used to access a variety of dive sites within the MPA. These launch sites are located in the seaside towns of Umkomaas, Scottburgh and Park Rynie. Umkomaas is 82 km (52 min) south of the King Shaka International Airport, with Scottburgh and Park Rynie just a few kilometres further south. Diving in the Aliwal Shoal MPA is best done through one of the many experienced and well-equipped dive charter establishments in Umkomaas, Scottburgh or Park Rynie.
Diving the Aliwal Shoal MPA
Most dive sites within the MPA are relatively close to the shore and are therefore vulnerable to dirty water flowing from the Umkomaas River after rain. The best conditions are usually encountered during early winter (May-June), when there are light winds and less rain. Water temperature ranges from about 20° C in the winter to 25° C in the summer.
Remember, South African regulations require that you purchase a “Scuba Diving in MPAs” permit from an Ezemvelo KwaZulu-Natal Wildlife office or a participating post office before diving in the MPA.
The Aliwal Shoal is a structurally complex rocky reef system, affectionately known as the “Shoal” by locals. The reef got its name from the Aliwal – a vessel which narrowly missed running aground on the reef in 1849.
The main attraction of this system is without a doubt the Crown area which is protected by the Crown Area Restricted Zone. The Crown lies parallel to the coast and is roughly 5 km offshore. It is delimited by the 25 m (82 ft) isobath that encircles the primary reef area. Lying in a roughly north-south orientation, the Crown is about 3.1 km long, 360 m wide at the northern end and 950 m wide at its southern end.
A multitude of popular dive sites exists in the Crown with dive options available for all skill levels. In the north are the spectacular Northern Pinnacles rising up to just 6 m below the surface. Slightly offshore is Manta Point and moving south along the outer reef slope you will find Raggie Cave, Shark Alley, Brindle Cave, Spur Reef, Cathedral, South Sands and many more. With strong currents being a fairly regular occurrence, drift diving is the norm and you can often visit more than one site on a dive.
The Aliwal Shoal is, however, part of a much larger reef complex. South of the Crown there is extensive reef area known as the Ridge. This area, which is closer to the town of Scottburgh, is less often dived than the Crown, but offers many exciting diving opportunities.
The Wreck of the Produce
Less than 2 km north of the northern tip of Aliwal Shoal lies the Wreck of the MV Produce. This vessel was a 20 000 ton, 119 m long Norwegian bulk carrier. She was heading southwards from Durban, reportedly carrying molasses when she struck the Aliwal Shoal on 11 August 1974. A rescue operation was initiated and no lives were lost.
She now lies on the sand at a depth of 30 m (100 ft), tilted to her starboard side and broken into two pieces. Her propeller was salvaged but the spare propeller was left behind and can be seen on the bow.
The Produce is surrounded by sand, so is best dived in little or preferably no current. The wreck site lies within a separate restricted zone of the Aliwal Shoal MPA, known as the Produce Restricted Zone. This wreck is therefore also fully protected from fishing as with the Crown.
The Wreck of the Nebo
Another wreck, that of the SS Nebo, also lies within 2 km of the northern tip of Aliwal Shoal and is about 600 m south-west of the Wreck of the Produce. This 2000 ton British steamship was carrying railway material to the Port of Natal (now KwaZulu-Natal). She was on her maiden voyage when disaster struck on the 20 May 1884, reportedly in fair weather.
The official report says that the Nebo hit an uncharted pinnacle. However, this was never substantiated and there has been speculation about what actually caused the vessel to sink. Her cargo, primarily a heavy railway bridge, may have been improperly stowed causing instability. Nevertheless, she now lies on the sand at a depth of 30 m (100 ft) with her hull bottom-up, which supports the claim of improperly stowed cargo.
As with the Produce, the Nebo is surrounded by sand, so is best dived in little or no current. The Nebo falls within the Controlled Zone of the MPA and is therefore open to fishing.
Marine life of the Aliwal Shoal MPA
Grey nurse sharks, known locally as spotted ragged-tooth sharks Carcharias taurus make an annual appearance on the Aliwal Shoal from July to September. Known to locals as “raggies”, these wide-ranging migrants aggregate on the KwaZulu-Natal south coast, presumably for mating. Raggie Cave on Aliwal Shoal seems to be a favourite of theirs, where large aggregations of sharks can make for a thrilling dive, especially with their highly visible and intimidating teeth.
It seems that during their visit to KwaZulu-Natal, raggies are more interested in mating than in feeding. However, while they generally move slowly and appear docile, you should always exercise caution. Raggies are ambush predators, meaning that they move slowly towards unsuspecting prey before launching a short-range attack at lightning speed.
Other large predatory fish stop over at the wrecks during their annual migration. The wrecks are surrounded by a vast expanse of sand and therefore act like a magnet for any passing marine life. Geelbek or Cape Salmon Atractoscion aequidens and dusky kob Argyrosomus japonicus are sometimes seen at the Produce and the Nebo in September and October.
Do keep an eye out for resident brindle bass Epinephelus lanceolatus, which prefer to remain concealed within the wrecks. The brindle bass is the largest member of the rockcod family and may reach over 300 kg (270 cm long)!
Another large member of the rockcod family is the potato bass Epinephelus tukula, which grows up to 110 kg (200 cm). Large resident potato bass are often encountered on the Aliwal Shoal.
Predatory gamefish can sometimes be seen gliding effortlessly overhead when the water is clear. So, don’t forget to look up every now and again. You may just catch a glimpse of a wahoo Acanthocybium solandri, a hammerhead shark or even a school of barracuda hunting baitfish above your head.
The Wreck of the Produce has been on the seafloor for nearly half a century and the Wreck of the Nebo for well over a century. This has allowed sufficient time for the superstructures to break down and create a wide variety of micro-habitats for smaller marine life.
The uncommon harlequin goldie Pseudanthias connelli is known to favour wrecks in the area and is a must-see on the Produce and the Nebo. For those with a very keen eye, ghost pipefish Solenostomus cyanopterus can sometimes be found among the branches of gorgonian corals. Lookout for camouflaged scorpionfish as they patiently wait to ambush passing prey. A variety of stingray and guitarfish species can be seen over the sand near to the wrecks.
Although a little too far south of the equator for reef-building coral to proliferate, there is an abundance of other beautiful coral species inhabiting this area. These include the extremely slow-growing green tree coral Tubastrea micranthus and turret coral Dendrophyllia sp. However, the benthic community is dominated by coralline seaweeds and large sponges.
Other invertebrate species to look out for include the hump-back cleaner shrimp Lysmata amboinensis. Often betrayed by their long white antennae, these delicate red and white shrimp live in small groups under ledges, where they wave their antennae to advertise their cleaning services to passing fish. Also look out for brilliantly coloured nudibranchs.