Difference between revisions of "Diving the Cape Peninsula and False Bay/Atlantis Reef"
Revision as of 16:30, 20 October 2011
The dive site Atlantis Reef or Pillars of Hercules is an offshore rocky reef in the Finlay's Point area of the Castle Rocks Restricted area on the False Bay coast of the Cape Peninsula, near Cape Town in the Western Cape province of South Africa.
The first GPS survey of the reef places it on one of the sections identified by the Council for Geoscience side-scan survey of 2011.
This site is in a Marine Protected Area (2004). A permit is required. It is entirely inside the Castle Rocks Restricted Zone, so no fishing of any kind is permitted.
The site name was chosen by the first divers to report diving at the site. It is named after the legendary lost continent of Atlantis from Greek mythology.
Maximum depth is about 29m at the eastern limit of the reef, and the top of the highest pinnacle is about 4m deep. Average depth on the immediately adjacent reef is likely to be about 20 to 25m.
The site is dominated by a pair of massive pinnacles, which rise from a jumbled mass of boulders below 18m to within 5m of the surface. The tops of the pinnacles are relatively small and rounded, and are probably in the order of 3m diameter, but they spread out to 15 to 20m wide with roughly rectangular plan at 12 to 15m depth. On the western and souther sides of the eastern pinnacle there is a large overhang. The granite base between the two pinnacles has a deep crack in it, and to the offshore side of the pinnacles, there is a complex swimthrough formed by jumbled boulders. There is a ledge to the north at about 18m, and a number of very large boulders in the immediate vicinity to the north. A fairly large rock with a pointed top at about 17m known as the "Fang" stands a few metres to the east of the pinnacles. It is shaped a bit like a large canine tooth. There is sand a few metres to the south of the pinnacles at about 24m depth.
To the east of the pinnacles the reef edge comprises medium to large outcrops of granite corestone, with sand between them in the gaps. The reef tends to get lower to the north and more broken to the north west, where large areas are quite low and made up of small boulders and low outcrops.
South east of the pinnacles there is a large outcrop a few metres high which has a dense growth of Sinuous, Flagellar and Palmate gorgonian sea fans.
Geology: Pre-cambrian granite of the Peninsula pluton.
This is a boat access dive site. It is technically possible to dive it from the shore, but there would be a long steep climb down from the road to the shore on a slippery path, followed by a long surface swim. Then you would have to find the site, which in itself is not easy.
At present (October 2011) only Animal Ocean (Steven Benjamin), ☎ 0794885053, . and Blue Flash charters have the exact GPS co-ordinates for the pinnacles.
The site is about 3.2km from Miller's Point slipway.
The marine life is extensive and varied. At the tops of the pinnacles and extending to about 12m is a heavy covering of red bait with both knobbly and false plum anemones living in between them. Descending the pinnacles, the more delicate invertebrates take over and the pinnacles' lower sections are densely covered with bryozoans of at least five different species, and a heavy covering of multicoloured seafans. Between the pinnacles is usually found a school of several species of fishes: blacktails, hottentots, fransmadam and zebras. Nudibranchs such as the black, the crowned and gasflames are common on the pinnacles, with the occasional sighting of smaller nudis such as the orange-eyed nudi and the white-edged nudi. A school of janbruins can be seen in the cracks between the pinnacles as well as truly enormous romans.
As the pinnacles join the sand the more horizontal parts of the reef become covered with red-chested sea cucumbers, strawberry polyp anemones and nippled sea fans. Moving north from the pinnacles and into the section of jumbled boulders is a luxuriant seafan forest, consisting of palmate, sinuous and whip seafans. The usual assortment of invertebrates associated with seafans can also be found: topshell snails, hermit crabs and basket stars in number. Continuing north to a lower profile reef section is more seafan forest but this has been overwhelmed with hairy brittlestars so that it resmbles an afghan rug. The sand at about 29m seems to be a shyshark nursery because many small puffadder shysharks can be seen here. Interestingly, the site also features an unusual number of dark shysharks, more usually seen on the Atlantic side of the peninsula.
Notable features of the site, apart from the Pillars of Hercules include the systems of swimthroughs formed by the jumbled boulders at the base of the site and the site's overall topography. Fang-shaped boulders, vertical cracks, embayments of sand, small drop-offs and overhangs are all worth viewing.
The site has only been dived in conditions of good visibility, and some good wide angle scenic shots were taken. The reef life is diverse and prolific, and there are opportunities for both macro photography of benthic organisms, and wide angle photos of the shoals of small fish.
No special routes are known at this stage, but the pinnacles are the highlight of the site, and the dense gorgonian forests on the edge of the reef slightly to the south east of the pinnacles are well worth a visit. The area near the pinnacles appears to be the most topographically interesting, so explore the area, and let us know what you find.
One route worth trying is to drop in at the southernmost pinnacle, descend vertically to 23m, then to turn north along the reef edge, heading through a small swimthrough and pass the fang-shaped rock towards the seafan forest. Since this is relatively deep (around 26m) depending on your mix, it might be worth while heading back towards the pinnacles either on the inshore side, which has many jumbled boulders to explore, or else on the offshore side until reaching the gap between the pinnacles. Swim inshore through this, under the overhang and then head south. Look out for the vertical crack and janbruin school in it, as well as the resident roman. There are overhangs and swimthroughs to explore and a narrow overhang at about 18m on the inshore side of the southernmost pinnacle which seems to attract many fish. Ascend the wall of the southernmost pinnacle.
No special hazards known.
Certification to dive to the depths found at the site would be expected. Parts of the site are within the depth range appropriate for entry level divers, but because the site is so pristine, it is recommended that entry level divers and others with imperfect buoyancy control avoid diving there.
No special equipment required. Divers who intend to explore beyond the vicinity of the pinnacles are advised to deploy a DSMB at the end of the dive so the boat can see where they will be ascending.