The sea swallow, Glaucus atlanticus, is a type of pelagic nudibranch. Pelagic means it lives in the open ocean, and being a nudibranch makes it a member of the phylum Mollusca. They are also called blue dragons, blue sea slugs, and a few other similar names. Because of where they live, these striking creatures are not frequently seen, so we were lucky to encounter a few of them after a dive at Batsata Maze in the south western part of False Bay, just south of Smitswinkel Bay.
The blue patterned side of this nudibranch that is visible when viewed from above is actually its underside. The top surface of the animal, which points down, is counter-shaded (like a great white shark). It is a greyish silver colour to blend in with the surface of the sea when viewed from underwater.
Sea swallows suck air into a gas-filled sack inside their bodies, for buoyancy. They prey on blue bottles (also called Portuguese man o’war) and retain and concentrate the blue bottles’ venom in their bodies for use against their own enemies. This makes them extremely venomous with the potential to sting badly.
Luckily the intrepid Carel leaped into the water to scoop one into a cup and we could all take a closer look (don’t touch!) on the boat and get some photographs. Afterwards, our visitor was returned safely to the ocean.
They are widely distributed through many of the world’s oceans, and sometimes wash up on the beaches in False Bay. They are unusual, but not earth-shatteringly rare. If we were more social media savvy we would have managed to use this sighting to manufacture the kind of hysteria generated by that facebook page whose title expresses an intense and profane love for “science“, or a few other media channels. But we’re not, so you get this blog post!
Above the coral reef at Creche, a dive site in southern Mozambique, hang huge and colourful schools of fish. A quiet, calm diver may approach them quite closely. Here’s Tony filming some yellow snapper:
I love this close up of snappers:
And here’s another school of snappers making shapes in the water:
Heinrich learned to scuba dive recently, and on his final Open Water dive at Duiker Island in Hout Bay, he brought along his Go-Pro camera. He edited together some footage from that dive, and is generously allowing us to share it here.
Shark Alley is a special and unusual dive site just south of Millers Point. It is an aggregation site for broadnose sevengill cowsharks, predators who feed on seals and a variety of other animals. They can grow to three metres in length. These sharks seem to use this site as a resting area (though we aren’t sure – research is ongoing) and their behaviour is typically docile and relaxed. For this reason it is a great place to dive, as the sharks come close enough to get a good look at them but do not behave in a threatening manner.
There has never been a serious incident involving a diver and a shark at this site, but there have been a few incidents. Clare has had her pillar valve gnawed on by a feisty young male shark while on a dive here a few years back, and early in May a diver was bitten on the arm by one of the sharks. That latter bite made the newspaper (the shark drew blood and the NSRI was summoned), but I am sure that there have been other more minor incidents here that didn’t get reported.
This got me thinking about a protocol for diving with these animals. Shark dives all over the world are governed by safety protocols and guidelines, usually put in place by dive operators themselves (examples here and here). We do have a set of standards that we adhere to when visiting this site and mention in dive briefings, but I’ve never written them down all together before. I am a firm believer in self regulation, whereby the industry regulates itself so that we don’t end up with a bureaucrat in an office telling us we can’t dive with cowsharks without (for example) a special permit, or (heaven forbid) ever again!
So here’s our protocol – how we choose to regulate ourselves when diving this site. It’s not a set of hard and fast rules that everyone has to follow, but it’s how we choose to approach dives at Shark Alley, a little bit like Underwater Africa’s diver code of conduct, but for cowshark diving. You are welcome to use these principles yourself, and I’d like to hear any suggestions you have to improve them or for points I may not have thought of.
Do a positive entry (i.e. with your BCD fully inflated) if you are diving off the boat, so you do not risk landing on a shark in mid water. If there is a thermocline, the sharks typically swim above it, and may be shallower than you expect.
Descend slowly in a controlled manner, looking below you at all times. Ensure that you are carrying sufficient weight (you should be able to kneel on the sand if necessary).
Do not feed the sharks. Don’t carry anything edible (sardines, for example) in your BCD, and do not chum from the boat. This includes washing the deck off at the dive site if you’ve just been fishing or on a baited shark dive. Chumming is both illegal (you need a permit) and unsafe, especially if there are divers in the water.
If you have students in the water, perform skills away from the sharks (if possible, avoid conducting skills at this site).
Some sharks will show a keen interest in your camera and flash or strobes. Do not antagonise them by putting a camera directly in their face. If a shark is showing undue interest in your photographic equipment, hold off taking pictures for a moment while it swims away.
Move out of the sharks’ way if they swim towards you. (Here’s a video of Tami doing just that.) Cowsharks are confident and curious, and often won’t give way to divers. Respect their space and move far enough away that they won’t rub against you or bump you as they swim by.
Be alert for any strange behaviour by an individual shark or the sharks around you. Be aware of your surroundings and don’t become absorbed with fiddling with your camera or gear. If a shark does become overly familiar (bumping or biting), gather the divers together in a close group and abort the dive in a controlled manner.
Do not dive at this site at night or in low light. This is probably when cowsharks feed (though we aren’t sure), and as ambush predators their behaviour is likely to be quite different in dark water when they’re in hunting mode.
Do not dive at this site alone. When diving in a group, stay with the group and close to your buddy.
I am not writing this protocol down to make people afraid of diving with cowsharks in Cape Town. But I do think it’s important to remember that this is a dive that needs to be taken seriously, with safety as a priority. Because we can visit this site whenever we want to, it’s tempting to become blasé about what an amazing experience it is, and also about the fact that these are sharks that need to be respected.
In conclusion! Unlike great white sharks, cowsharks (and blue sharks, and mako sharks, and and and…) are not protected in South Africa, so it’s not illegal to fish for them in permitted fishing areas (i.e. outside no take zones, etc). One of the cage diving operators in Gansbaai even used to use cowshark livers in his chum… If you want to make a difference in the lives of cowsharks and ensure they’re still here for us to dive with in future decades, consider writing a letter to the relevant government minister (make sure it’s the current one, in the new cabinet) and also to the shadow minister from the opposition party, requesting protection for more shark species in South African waters.
Fooling around with cameras (and phones) is our second calling. We joined Instagram recently and are enjoying sharing pictures of our adventures, and viewing beautiful images from around the world. You can find us here! Please let us know if you’re an instagrammer – we’d love to follow you.
My Sony DSC-TX5 has served me remarkably well, but after three years I was starting to itch for something with a bit more scope for manual control. The TX5 has an underwater mode: you switch it on, turn on the flash, and you’re good to go. It also has a rugged Sony-built housing that is almost neutrally buoyant with the camera inside, can be held and operated with one hand, and supports the addition of an external strobe (which I did). All these things make it incredibly user friendly and eminently suitable for a busy diver who might be doing other things (like grabbing onto other divers who are being wayward, or being a good buddy) and need both hands now and then.
I did a lot of reading and asking, and ended up settling on another Sony camera (my third, and the fourth for our family), the Sony DSC-RX100. It’s a tiny, pocket-sized camera that has many manual control options (aperture and shutter priority modes, manual and program mode, and some built in automatic modes) but isn’t a DSLR. It has received the most effusive reviews that I’ve ever read for an electronic device. Here’s Wired, and here’s the New York Times. Digital Photography Review also said nice things. It has a giant 20.2 megapixel sensor and a fast Carl Zeiss lens capable of a magnificent 3.6x zoom. You can read up about those things elsewhere. It takes HD video, and you can shoot stills at the same time. What sold me on the camera was its reported excellent performance in low light environments (a feature of several of the Sony models I’ve owned), which I figured would make it excellent for Cape Town diving.
There are a couple of options for an underwater housing for the DSC-RX100, but unfortunately nothing made by Sony. I settled on the Ikelite housing because there’s a local Ikelite presence, and because it wasn’t insanely expensive. The housing unfortunately has the hydrodynamics of a house brick and mine needed its clips replaced after less than thirty dives, but the camera is nice enough that I was willing to put up with having a perspex sea-anchor attached to myself in order to get it into the water. Toting the housing around has also thrown my buoyancy for a loop, so I’m having to consciously adjust some things to get my air consumption back where it was in the good old days. (I’ve decided that my next camera will probably have a manufacturer-built housing, or I won’t buy it.)
Anyway. After much debate I also splurged on the Ikelite W-30 wide angle lens, which cost more than the housing and which has been my only recent Ikelite purchase that has worked flawlessly and hasn’t needed replacement or repair, probably because it has no electronic or mechanical parts. It’s magnificent. It screws onto the outside of the housing, and is a wet lens, which means that upon getting into the water you have to make sure that all the air gets out and water fills the space between the lens and the housing, otherwise you get a line across the middle of your photos. Same goes for when you get out of the water – the lens has to drain before you can use it on land.
My most sustained use of the camera so far has been on our Red Sea trip last October – you can see all the underwater photos on flickr in my wreck dives set, reef dives set, and night dives set. I am still using it mostly on the automatic and very simple manual settings, but I expect that playing with the camera on land (which I haven’t had time to do much of) will make me more confident with it underwater. The buttons on the housing are very hard to use with gloves on or cold fingers, and they are extremely close together, which means you have to learn what each one does (or carry a cheat sheet on dives) in order to change settings underwater. Despite these complaints, you can access all the camera’s controls via the housing, which is more than can be said for other housings.
The camera flash is immensely powerful. The housing comes with a diffuser (for photography without an external strobe) and a shield to completely block the flash from the front when the strobe is on. I use the latter when I attach my AF-35 Autoflash, which works like a charm. I have tried using the flash on the camera while underwater, but you have to be quite far away from your subject to avoid blowing out the image.
Apart from the clip issue on the housing, I’ve been very happy with the camera so far and am looking forward to doing some more underwater macro photography, since the DSC-RX100 focuses much closer than the DSC-TX5 (and indeed any other camera we own). I’m also enjoying its very easy to use video function, as you may have noticed from the proliferation of videos on the blog since April 2013! I’ve added a video light that has come in handy for photography on night dives, but that’s another story…
One Tuesday in early December, Tony escorted some members of the media – Murray Williams of the Cape Argus, and Bruce Hong of Cape Talk radio, on a dive along the inside of the shark exclusion net at Fish Hoek beach. It was just before the start of the school holidays, and since the net has been trialledmultiple times by now and is working well, it’s a good time to raise awareness of the additional beach safety and – importantly – peace of mind that the net offers. I tagged along as photographer.
The net at Fish Hoek beach is a world first. It has a fine mesh that is highly visible underwater, and is designed not to catch anything – unlike the shark gill nets in KwaZulu Natal. The net is put out in the morning and retrieved at the end of the day, but only when sea conditions allow it. The south easterly wind can bring huge quantities of kelp into Fish Hoek bay which would foul the net, so when there is a strong south easter the net cannot be deployed.
If you’re a water person, please educate yourself on how the net works, and its intention, and share it with your friends. Even now, nine months after the trial started, I hear uninformed comments from people who have not bothered to do any reading about the net, and assume it’s the same kind of net as the ones in Durban. It’s not. The whole idea is that nothing – no sharks, no humans, no klipfish – gets hurt. Shark Spotters and the City of Cape Town have been very clear on this from the start. I had a bit of a rant about this late last year.
I digress. We went to the beach, got suited up, and went to check out the net. It was spring low tide, so at its southernmost end we were in about 2 metres of water. The net is high enough that when the tide comes in and the yellow floats rise with the water level, it simply unfurls further downwards, making an unbroken curtain. The lower portion of the net rests on the sand, with two parallel weighted lines to ensure that it lies flat. You can see that in the photo above Murray is gripping one of these leaded lines, and that there is a fairly large amount of net waiting on the sand for higher tides.
We stuck close to the net, and didn’t see much marine life on the sandy bottom. I spotted a large sand shark (when I say I “spotted” him, I mean that I almost landed on top of him). We were mutually surprised, and he zipped away into the bay, sliding neatly under the bottom of the net. I also saw a box jelly cruising along the net. Given my recent history with box jellies, I kept clear! The sea floor in the area where the net is deployed is level, sandy and free from rocks. There’s more life on the catwalk side, where beautiful rock pools wait to be snorkelled.
We were accompanied by Monwabisi Sikweyiya, who is the Field Manager of Shark Spotters. He is a hero and I always feel a bit star-struck when I see him (although he has no idea why – he probably just thinks there’s something wrong with me). He swims along the net regularly – someone does each time it is deployed, actually – to make sure that it’s released properly and hanging straight down.
Swimming inside the net is completely voluntary. When a shark is seen in Fish Hoek bay the Shark Spotter still sounds the siren and the flag is raised to clear the water. The Shark Spotters team are still waiting to see how a shark will respond to the net when it swims close enough to be aware of it. So far none of the local sharks have come close to the net, as the summer season when sharks move inshore has only just started. Tony was half hoping that we’d be swimming along inside the net, look out through the mesh – and blammo! – see a great white shark. But we had no such luck, if that is the right word.
You can read the article that Murray Williams from the Argus wrote after the dive, here.
Photographer’s Reef is a lovely little reef quite close to Simon’s Town. It is eminently suitable for Open Water training, as it has a maximum depth of about 15 metres at high tide, and an excellent first boat dive site as it is close enough to land to give a feeling of comfort to new divers. This is a very short clip I took one day in early August, when a group of six of us dived this picturesque reef. You can see that the visibility is good; my camera skills, not so much!
Unfortunately my dive on Bikini – the second one I did in Durban – was really horrible, as my mask kept flooding (I think I had hair caught under the skirt). After a while fighting off the feeling of imminent drowning became too exhausting, and I surfaced early. I didn’t take many photographs, but what I remember of the creatures on view is that they were many and varied – geometric moray eels, lionfish, scorpionfish, nudibranchs, a frogfish and the other usual suspects found on South Africa’s east coast. I took so few photos that I’ve borrowed a lovely one that Maurice took of said eel. Here it is:
The reef structure was much like we see at Sodwana, made of sandstone with potholes and little overhangs. I saw mostly soft corals – none of the big plate corals that are common in southern Mozambique and beyond. This reef is part of the Blood Reef system that stretches along parallel to the Bluff. The reef system got its name because the old whaling station used to pump out blood and offal from slaughtered whales into the ocean, causing the reef to thrive and supporting an impressive population of oceanic white tip sharks. We didn’t see any sharks – I’m sure they were all too busy being killed in the gill nets off the Durban beaches to come and visit divers.
Bikini Reef is small, and covers the good bits (this is allegedly the origin of its name). It’s a regular haunt of pineapplefish, but the current was going in the wrong direction for us to comfortably visit the overhang that many of these fish frequent. We had a pleasant drift dive (mask issues aside) and an easy introduction to the Blood Reef complex.
I should mention that my Durban photos are mostly questionably lit and poorly executed because I am using a new camera, and prior to the Durban trip had only done two dives with it! Hopefully matters will improve so I don’t have to revert back to my trusty Sony DSC-TX5. I’m still using the Ikelite AF-35 strobe, though (not that it’s much in evidence here).