The Two Oceans I&J Predator Tank Dive - Alison Towner

February 21, 2015 by dyertrust

The Two Oceans I&J predator tank dive: an inside perspective on their denizens of the deep.

By Alison Towner,

PhD cand/biologist, Dyer Island Conservation Trust

As a shark researcher based with the Dyer Island Conservation Trust, I talk sharks with people daily. I often get asked about diving with other species. On winter days when the weather is bad in the Western Cape, I often recommend the Raggie dive at Cape towns Two Oceans aquarium. Recently I decided it was time to try this dive out again, so last Saturday my friend Ilze and I arrived at the reception of the aquarium for our 11 am scheduled dive.

We were greeted by Angie Ginsberg our dive master. Angie told us she has worked with Ians Scuba school at the aquarium for three months and loves her work. She walked Ilze and I round to view the I&J predator exhibit and began our dive briefing while we stood in front of the huge tank. The tank has 10 million liters of water in it, thats enough for you to have a bath for the next 10 years she told us. Ilze had dreamed of doing this dive for a long time and to celebrate her birthday we had brought her seven year old daughter Nicole along with us. Nicole is a keen marine biology enthusiast and was beyond excited at the prospect of watching her mum dive with the raggedtooth sharks. Ilze explained to Angie how she too was excited, but rather nervous. Angie reassured Ilze she need not worry about the sharks, infact the only one in there with a grumpy attitude was an old turtle! Within 15 minutes Angie had helped Ilze and I kit up and we were all ready to descend from a platform above the tank.

The dive

Ilze on diveJacques Costeau once said the best way to observe a fish, is to become a fish and this is exactly how one feels while descending on this dive! As we dropped down beneath the water surface our line of sight was immediately consumed by the vast shoals of Yellowtail comrading together like foot soldiers rushing to battle. Cow nose sting rays elegantly swept in and out between them. Impressive Kobaljeu and Spotted Grunter moved stealthily so as not to get in the way, whilst cartoon like Musselcracker or Poenskop hovered in their own little worlds. Every fish had its rank and knew its place. As we looked carefully on the floor, tiny nudibranchs hid themselves perfectly camouflaged amongst boulders. It truly was an enlivening experience. Glancing out the window at the childrens faces was equally as magical, to see their sheer bewilderment- from the perspective of the creatures swimming in front of them. It was a surreal juxtaposition to be the human intertwined in the world of a captive fish which we found very entertaining! Nicole beamed from ear to ear whilst waving excitedly at us through the window. We waved back, and noted her expression change as the silhouettes of two large Ragged tooth sharks approached us.

Raggedtooth shark 2The Ragged tooth shark (Carcharias taurus) is quite different to the Great White. I like to describe them as the Jimmy Nail of the shark world (Jimmy Nail was the guy who sang the 90s hit crocodile shoes. My mum used to say hes so ugly hes attractive!). Raggies have an undue menacing appearance with their small beady eyes and snaggle like teeth. Pre 1990s fishermen targeted the species as they were perceived maneaters throughout much of their distribution.



Raggedtooth 1This was before research confirmed they are very placid and actually extremely vulnerable to exploitation due to their slow reproduction. The two oceans aquarium have supported some of South Africas most critical ragged tooth research including the tagging and releasing of various sharks. Maxine was a large female ragged tooth caught in the KZN shark nets in 2004. She was rehabilitated in the aquarium and migrated far east when released with satellite tags. The species makes incredible large scale migrations from the Western cape to the East coast annually in SA. Maxine became a real ambassador highlighting these movement patterns during the popular public campaign.

Our dive lasted around 45 minutes, then Ilze and I surfaced with huge smiles very contented! Angie even gave Ilze a Raggies tooth which she said was especially for little Nicole. It was quite the luxury dive experience with a clean towel and warm shower waiting for us after- we did not even have to de-kit our SCUBA gear- Angie and the team had it all covered!

Poenskop MusselcrackerThe great thing about the dive in the I&J predator tank is its warm, its crystal clear and theres an absolute 100% guarantee of seeing the sharks and other predators up close and personal! The staff go out of their way to ensure your comfort and safety. I would definitely recommend this as a must do dive in the Western Cape, especially if the Cape of storms is living up to her reputation!

A brand new predator tank is in the process of being built at the Two Oceans, which Im told will undoubtedly impress. As tourism and conservation partners the Two Oceans aquarium, Marine Dynamics and Dyer Island Cruises go back over a decade. It is a simple relationship; each business is geared around the same passion and drive for marine education and conservation. In fact, one of MD and DICS resident skippers Pieter du Toit was a shore angler who helped catch and tag ragged tooth sharks in Struisbaai during Maxines campaign in 2004!

Two weeks ago the Two Oceans donated 100,000 ZAR towards the building of our African Penguin and Seabird Sanctuary (APSS) which was an integral building block towards the development of the facility in Gansbaai. For more information on this see and

Raggie Facts.

Common Name(s): Ragged Tooth shark Carcharius taurus (also known as the Sandtiger and Grey Nurse shark).

Colour: Sandy brown to Grey- darker brown spot patterns

Relatively large stocky looking shark with an often bloated appearance. Long narrow snout with small beady eyes. Mouth often ajar. Soft rounded dorsal fin and no caudal keel. Spotted patterns down each flank.

Distribution: Warm temperate and tropical Atlantic, Mediterranean and Indo-West Pacific.

Depth: Coastal-190m.

Status: Vulnerable (IUCN)

Reproduction: Viviparous. Slow only 1-2 born in a litter. High inter uterine cannibalism.