Sharks – Page 36 – Learn to Dive Today Blog

Diving in the Lagoon Tank at uShaka Marine World

On the first of our two days in Durban after the Sodwana trip, Tony and I did one of our most favourite things: we went for a dive in the aquarium at uShaka Marine World. Tony used to work at Calypso Dive and Adventure Centre, based at uShaka, and it is in this idyllic location – known as the Avis Snorkel Lagoon – that all the confined water skills were taught. How awesome is that?

Longfin batfish in the foreground, hound shark in the background

Tony and I wanted to go somewhere calm and pretty where we could lie on the bottom and play with different camera settings, and a sunny, shallow dive (3 metres maximum) in limitless visibility surrounded by 1,500 tropical fish and hound sharks (only five of those, fortunately) was just the ticket.

Hound shark passing in front of the aquarium window

It is a magnificent dive. Not challenging by any stretch of the imagination, but that is one of its charms. It’s an open air tank accessed by walking into Marine World with a Calypso Divemaster (you can’t do the dive without someone from Calypso accompanying you, even if you’re qualified). There’s an area to kit up, and then you stroll (or waddle, or slide) down some gently sloping rubber mats in shallow water to the drop-off into the tank proper.

The tank has windows looking onto the aquarium (or, the aquarium has windows looking onto it, if you prefer), and a large window looking into the Open Ocean tank, which contains sharks and rays. Most of the tank, however, is your own private paradise, as the windows only cover a fraction of the one side. On the day we went, there were no snorkelers in the water (it gets really busy on weekends and holidays – last time we dived there it was hilarious and somewhat unnerving to look up and see countless pairs of legs in board shorts hanging above us).

Tony in the undercover portion of the Lagoon tank

There is a section of the tank that’s covered over (including the window onto the shark tank), and in this area is a submerged jeep (with licence plates still attached) and some other bits of atmospheric debris such as ropes, crates and wooden packing pallets. It’s a bit dark in there, and I prefer the sunny bits, but it’s really lovely to lie in front of the window to the shark tank (where it IS sunny) and watch the big predators on the other side of the glass. Some of the fish seem to like it, too.

Clown triggerfish — A clown triggerfish emerging from the covered portion of the tank

There are half hour time slots that can be booked with Calypso – either as a Discover Scuba Diving experience if you haven’t dived before (and I think this will spoil you for diving anywhere else!) or for an accompanied dive if you’re qualified. We took the one at 1.45pm and the half hour immediately following it, so we had a blissful hour in the 24 degree water.

Tony and some fish playing with his camera

I took hundreds of photos, and Tony took some fantastic video footage (for another post). The thing that delighted me the most was that many of the fish interact with you – the old woman angelfish and the boxfish in particular are totally unafraid.

Old woman angelfish — An old woman angelfish comes to visit me

There was also a toothy fish who alternated between harrassing me and Tony, and appears in nearly every frame of Tony’s video as he kept passing by the camera to remind us of his toothy presence. This fish and several of the others deserve their own posts, since they were such large personalities!

Many of the fish were fascinated by the video camera lens – perhaps they could see a reflection or movement in the glass – and came really close to inspect and even head butt it. You can get really close to them either by lying or kneeling on the floor of the tank and waiting for curious visitors, or by sneaking up very slowly and quietly while they’re eating.

Lagoon tank at uShaka — Terracotta vases and fish in the lagoon tank

If you’re visiting Durban, this is a wonderful way to pass a couple of hours. If you don’t dive, it’s the most perfect setting in which to try it, and if you do – don’t scoff at how shallow it is and that it’s confined – just go and relax, marvel and enjoy the spectacle. It’s incredibly reasonably priced and afterwards you can do some water rides, chill out on the beach, enjoy an ice cream, or stroll around the retail space at uShaka.

Bookshelf: The World is Blue

The World Is Blue: How Our Fate and the Ocean’s Are One – Sylvia Earle

Sylvia Earle is a legend (I’ve said so before), and this is a book that flowed out of a TED talk she gave about the need to take urgent action on ocean conservation. I gained a huge amount of understanding about why indiscriminate fishing is a problem for ecosystems (she compares it to removing bits from a computer that look useless, and then expecting it to work afterwards). She also explains the extent of our dependency on the ocean – for example, one kind of plankton provides about 20% of the oxygen we breathe, with other kinds making up a further 50%.

Earle has a long history of ocean exploration, and has been scuba diving and driving submersibles since the 1950s. Her anecdotes about things she has seen and people she has spoken to are fascinating. She was part of the very early days of ocean exploration and recreational scuba diving, and has spent thousands of hours underwater (for comparison, I think I’ve spent only 40 hours breathing compressed air!).

Earle is a strong advocate for Marine Protected Areas – proper ones, that don’t allow fishing. She likens a MPA that allows fishing to a game park – say Kruger – that allows hunting! She also supports the initiatives such as SASSI that classify fish species according to the sustainability of the catch process and their level of endangerment. (If you don’t have a SASSI card, you need to get one before your next seafood dinner!)

I was particularly struck by Earle’s account of her response to a question asked of her in the 1990s by the head of the Japanese delegation at the International Whaling Commission: “… What’s the difference between eating a steak from a cow and eating whale meat?”

I tried to respond seriously: Cows are herbivores and go to market in a year or two, have been cultivated by people for food for ages, and require care and an investment of some sort by farmers; while whales are free, wild beings that belong to no one, are typically taken after they have lived for decades, and are relatively few in numbers (or are not “restocked” like cows), leaving an irreversible tear in the ocean’s fabric of life when removed. There are billions of cows, but all whale species are greatly reduced in number, some bordering on extinction owing to whaling. Taking even a few increases the risk of depletion owing to other pressures – storms, disesase, pollution, and fluctuating food sources. The whales of today have ancestral roots 65 million years deep, and nothing in their survival strategies factored in the impact of humans as predators. What might we learn from them as living creatures, able to communicate with sound over long distances, develop close-knit societies, navigate over thousands of miles with no maps, and perform daily deep-diving feats that defy the capacity of even the most athletic humans? If only considering whales as a priceless source of knowledge, we discover that their value alive far exceeds their worth as pounds of meat. In narrowly-defined economic terms, the growing business of whale-watching is lucrative and demonstrably sustainable, while commercial whaling is subsidised, with a consistent record of “management” failure.

The World is Blue, Sylvia A. Earle, National Geographic Press 2009, pp 38-39.

Buy the book here if you’re in South Africa, otherwise click here. If you want to read it on your Kindle, go here. I highly recommend it.

Dive sites (Sodwana): Deep Sponges

I think our dive on Deep Sponges was among my favourites of the five I did in Sodwana. It was to 30 metres, and Tami and Sophie were doing their deep skills for their Advanced course. I descended right on top of a pincushion starfish the size of a birthday cake!

Giant pincushion starfish at Deep Sponges

There was quite a strong current when we reached the bottom, and the rest of us tried to hang around in one spot while the girls filled in their slates. Once they were done, we set off – swimming into the current! This was exhausting and the water at depth feels like honey… Very hard work. Tony had a word with Divemaster Dean, and we turned around and did a fantastic drift dive in the opposite direction.

Another enormous starfish at Deep Sponges - this one had nice green tips on his legs

Deep Sponges is on Two Mile Reef, and characterised by (surprise!) many different sponge formations. Within minutes of starting our dive we spotted a whitetip reef shark swimming past about 20 metres away. This was my first shark sighting (apart from sevengill cowsharks, catsharks, nurse sharks, gully sharks and shysharks!) and I was thrilled. He didn’t seem to care about us at all, and I wanted to chase him so that we could spend more time together. Story of my life… hehe!

I also saw two hawksbill turtles (or the same one, passing by twice). They look so relaxed in the water, crusing along in perfect solitude. This dive site is amazing because it is both deep and a reef, so you have the gorgeous detailed reef life as well as a good chance of spotting pelagic species passing by on their journeys through the open ocean. The reef fish were far more curious and confident than those we saw on the shallower dives, possibly because they are bothered by fewer divers.

My photos from this dive aren’t very good – I think because the current was quite strong, and because I don’t have strobes to illuminate the depths. They just don’t do the experience justice. Because the visibility was so good – almost top to bottom – there was a tremendous sense of space, but also all this magnificent life begging for some macro shots. I haven’t done enough deep dives with the camera (two!) to figure out what works. But I am quite proud of the picture of the soft coral above.

Safety stop at Deep Sponges — Tony (on the right) and the Silver Fox (on the left) help Giraffe and Mariaan, who had descended unexpectedly while arranging some alternate air source breathing

I hardly finned during the dive because we were drifting with the current, which was great, and in all the dive was very relaxing. I had plenty of air – surfaced with the Divemaster and Tony, which was awesome! Felt very proud of myself and got a handshake from Tony at the safety stop. We did a nice long safety stop punctuated by one or two dramatic incidents which were nicely handled by Dean, Tony and the Silver Fox (who is also a Divemaster). Almost everyone seemed to breathe off someone’s octo at one time or another.

Breathing off octos — Tami taking Dean's octo, and Tony telling Justin, who was finishing breathing from (I think) the Silver Fox's octo behind Tami, to continue his ascent

Dive date: 9 October 2010

Air temperature: 23 degrees

Water temperature: 22 degrees

Maximum depth: 31 metres

Visibility: 20 metres

Dive duration: 37 minutes

Who to follow

So I am sick in bed today while Tony enjoys the sea and southeaster with students. In the absence of my diving fix, I have to rely on the Internet to feed my currently short attention span. Enter Twitter.

To me, Twitter incorporates my favourite feature of Facebook – constant stream of bite-sized news and views – and leaves out all the other guff (Farmville, Zombie Vampire Slayers, Are You Feeling Hot Today?).

It’s not all about socialising and keeping up with your online friends… It’s also useful for news, activism, and informative updates from individuals and organisations whose work interests you. If you want to beef up the list of users you’re following, check out our “followees”!

Diving

Learn to Dive Today: @learn2divetoday (of course!)

PADI: @PADI

South Africa

SANCCOB – the organisation that rescues, cleans and protects our coastal birds: @SANCCOB

Two Oceans Aquarium, Cape Town: @2oceansaquarium

Shark Spotters for reports of shark activity in False Bay: @SharkSpotters

World Wildlife Foundation South Africa: @WWFSouthAfrica

Conservation & Agencies

NOAA’s National Ocean Service: @usoceangov

NOAA’s Ocean Explorer educational program: @oceanexplorer

Project Aware – conservation agency by divers: @projectaware

Save Our Seas: @saveourseas

World Wildlife Foundation: @WWF

Whale & Dolphin Conservation Society: @whales_org

NASA (they do ocean exploration too!): @NASA

Ocean Information Center (OCEANIC) at the University of Delaware College of Earth, Ocean and Environment: @oceandata

The Smithsonian Institute: @smithsonian

Smithsonian Ocean Portal: @oceanportal

Sea Shepherd Conservation Society (because everyone can do with a bit of radical extremism to spice things up now and then!): @seashepherd

Ocean Conservancy: @OurOcean

Ocean Institute: @oceaninstitute

Oceana: @oceana

Photography

Bonica Snapper video cameras (the manufacturers of Tony’s newish toy): @bonicahddv

Fiona Ayerst, underwater photographer who offers courses: @Fayerst

Orms (more awesome camera equipment, knowledgeable sales staff and a top-notch D&P facility): @OrmsdDirect

SA Camera (very reasonably priced photographic equipment, including underwater housings): @SAcamera

Scott Kelby, author of fantastic photography books: @scottkelby

Writing & Television

National Geographic: @NatGeoSociety

Urban Times Oceans: @UT_Oceans

The Guardian Environment section: @guardianeco

PBS NOVA will keep you up to date with science news and cool gadgets: @novapbs

Circle of life

Alison Kock, shark researcher at Save Our Seas reports on how the carcass of a Brydes (pronounced “broodahs” – didn’t know that!) whale was towed out to Seal Island by the SA Navy in order to prevent it from running aground just south of Miller’s Point. Over 30 different great whites showed up over a period of just over a week to munch on the carcass. The full article is here, on The Dive Site – fascinating reading.

Pyjama catsharks… in their pyjamas

We’ve seen a handsome pyjama catshark at Long Beach on a night dive before – about 75 centimetres long and gorgeously striped in white and blue. These small sharks are nocturnal, and during the day apparently like to sleep clustered together and even lying on top of each other in rocky gullies.

We often peer into the ends of the pipeline, looking for octopus (or whatever else is interesting). Lately we’ve been seeing the shape of a large fish in there, but it’s been too dark to figure out exactly what we were looking at. On Sunday morning Tony stuck his video light into the pipe, and his small Sony digital still camera, and took a picture. It’s not the most outstanding photograph ever taken, but we’ve clearly discovered where the pyjama catsharks like to hide during the day!

Diving at the Two Oceans Aquarium

For Tony’s birthday in June we spent a Sunday morning at the Two Oceans Aquarium at the Waterfront, diving in the I&J Predator Exhibit and in the Kelp Forest Exhibit. These were two of the best dives I’ve ever done. You need an Open Water or equivalent qualification for the predator tank, though I think you can do a (expensive?) DSD there too. For the kelp forest you need an Advanced qualification, as even though it’s only 6 metres deep, it’s very surgy.

On both these dives, you are on view to the public. It’s fun to wave at the kids through the windows of the displays. They are very excited to see real live SCUBA DIVERS in the water with all the fish. Needless to say, the scuba divers were very excited to be there!

Youtube videos for both dives can be found here.

Kelp Forest Exhibit

We started in the kelp forest – you wind your way up to the roof of the aquarium and drop into the water off a small wooden platform. This exhibit completely is open to the air, since it’s comprised of vegetation and sea creatures found in Cape waters, and because kelp loves sunlight. Kelp also likes water movement, so there are a variety of devices to keep the water moving – dump buckets, a plunger, and some pumps. This makes it quite choppy on the surface and quite surgy below. (Fascinating fact: since kelp cleans the waste products – such as ammonia – out of the seawater by filtering it, a lot of the aquarium’s water is passed through the kelp tank on its way to other exhibits.)

The exhibit has live kelp that is actually growing, which is quite an achievement, but you’re not supposed to hang onto it the way I sometimes do in the open ocean! The tank is packed to the brim with white steenbras (my absolute favourite), red stumpnose, galjoen, zebra, roman, shysharks, fransmadam, and even a gully shark if you can spot him. The fish are huge, many of them much larger than any I’ve seen in the ocean. I was extremely fortunate to be allowed to feed them – I was given a small bag of squid pieces and sardines, and the fish gathered around me as I knelt on the bottom. It was wonderful, so busy and colourful. They weren’t shy, bumping into my legs and BCD once they’d realised I had lunch with me. There’s a hilarious finger-biting episode at around 2:45 minutes in this video:

[youtube=http://www.youtube.com/watch?v=kePTwljhsyo&w=540]

The water is cold, and the tank isn’t actually very big. There are nice swim throughs between the rocks (made of fibreglass) and the kelp. The visibility isn’t perfect as the water is so highly aerated, and there are little bubbles of air everywhere. But it’s a thrilling dive and a very rare opportunity to get so close to so many beautiful fish.

Dive date: 6 June 2010

Air temperature: 18 degrees

Water temperature: 14 degrees

Maximum depth: 5.7 metres

Visibility: 10 metres

Dive duration: 27 minutes

I&J Predator Exhibit

The second dive we did was in the predator tank, which is a lot warmer than the kelp forest. On this dive, the Divemaster was armed with a piece of broomstick to “guide” the sharks away if they were to bother us. There are five ragged toothed sharks in the exhibit, none more than two and a half metres long. I think they’re all female. They cruise round and round in circles, looking completely awesome. I spent a long time just sitting on the floor of the tank watching them.

The other magnificent inhabitants of this tank are the sting rays. There’s Olive, a giant (and I mean GIANT) short-tailed sting ray like we see at Long Beach and Miller’s Point in summer, and a whole host of small (the sort of size that makes you want to take them home as pets) devil rays. Tony spent a significant part of the dive (while I was sitting watching sharks) chasing tiny rays around with his camera set on video.

In the corner of the tank we met the loggerhead turtle. She was lying next to a water vent, with her head in the corner. I was allowed to touch her on her neck (it felt really soft, and I felt lucky). I wasn’t convinced that she was a happy girl – she looked kind of depressed. Our DM said she gets more active when the water temperature increases, and sure enough I saw her swimming happily past the glass in the predator tank two weeks ago, when I went for my Saturday morning training at the aquarium.

The tank also contains musselcrackers, garrick, yellowtail, and (at the moment, but not when we dived in it) the remains of a sardine baitball.

The only moment when I got a bit of a fright was when we were surfacing against the rocks in the middle of the tank, and I omitted to look where I was going: straight into the path of a raggie. And sharks don’t generally get out of the way! Fortunately our DM had seen me behaving like a space cadet and “guided” the shark off to the side (since I wasn’t able to interrupt my ascent quickly enough).

Dive date: 6 June 2010

Air temperature: 16 degrees

Water temperature: 18 degrees

Maximum depth: 5 metres

Visibility: 25 metres

Dive duration: 35 minutes

Shark tale follow-up

After his shark sighting at Long Beach last week, Tony emailed local guru Georgina Jones of SURG – more on SURG (Southern Underwater Research Group), and Georgina’s work in particular, will follow in another post (probably a book review). Tony wanted to find out whether his observation that there was no visible marine life, no fish and no movement at Long Beach on the day he saw the shark had anything to do with the presence of the creature, or whether it was uncorrelated. Georgina passed Tony’s email on to Alison Kock at Save Our Seas, a veteran white shark researcher based in Cape Town.

Alison’s reply – which is filled with fascinating nuggets of information about shark monitoring in Cape Town and great whites in general – is reproduced below:

Thank-you very much for forwarding this encounter. I keep a database of all white shark-human encounters in Cape waters and with your permission would like to add this encounter and your name, Tony and contact numbers to this database. Interestingly another sighting in the same area was recorded on the 23 August, and there were two white shark sightings at Fish Hoek on the 25 Aug, and one on the 24 and one on the 20th (sharkspotters.org.za has sightings recorded at shark spotter beaches).

Tony, regards your observation one would certainly expect that larger fish and seals would be absent from an area temporarily where a white shark is patrolling. However, it’s also conceivable that smaller marine animals could perceive the shark as a threat. A huge misconception is that white sharks only eat these larger animals, but various smaller fish and invertebrates (bivalves, cuttlefish, squids, octopus, pilchards etc) have also been recorded in white shark stomach contents, particularly smaller sharks (Geremy Cliff data). Thus, these animals may also respond to an immediate presence of a white shark if perceived as a threat. However, I wouldn’t expect this behaviour to persist for long periods of time.

We have deployed small animal-borne cameras on white sharks over the years and have been able to get a sharks POV of what happens on a reef when the shark swims over it. Some smaller fish which you wouldn’t think to be on the menu do react by swimming out of harms way. However, the behaviour is usually instantaneous with ‘normal’ behaviour by the fish resuming almost as soon as the shark’s head has moved past. When we observe white sharks around the research boat, we record similar behaviour, the chumming often attracts large groups of various species of ‘bait fish’, these fish almost always respond to the approaching shark by moving out the way temporarily.

Thanks Alison!

Shark tale

As a freelance instructor I dive at Long Beach behind Simon’s Town railway station several times a week. Long Beach is an ideal training site as it offers protection from the weather under most conditions, visibility is almost always 5 metres plus and it is one of the easiest shore entry dive sites around the Cape Peninsula.

On Wednesday 25 August I was on a training dive with three students. I briefed them as usual and off we went. The visibility was around 6–8 metres and I was surprised to find nothing to show them. Around the barge, over the fishing boat, down the inner pipeline, nothing to be seen. I was starting to feel the place was barren, and it was very strange. Suddenly a klipfish came racing across the sand faster than I believed they could swim and I half expected a seal to be close behind as I had seen one on the surface before we started the dive, but nothing. I honestly couldn’t find anything, no shysharks, no pipefish, no crabs, no octopus and I can almost guarantee I will find these creatures there on any dive. Not even the hundreds of busy little hermit crabs were scurrying around and I could not find any movement. I started to think that perhaps the water had been poisoned by some ship or something weird and all signs of life had moved off somewhere else.

We were just reaching the western end of the outer pipeline, about 60 metres offshore and at a depth of around 5 metres when I looked up and less than five metres away was a 2-3 metre great white shark. She was just cruising very, very slowly and must have seen us long before we saw her. I was most awestruck by the shark’s graceful poise and her girth. The other impressive feature was the length of the pectoral fins. She circled slowly around us and them slowly swam away, close above two other divers in the water not too far from us, and disappeared.

What to do when you see a shark?

Well, we all have our own theory and during briefings we always tell divers what we will do and how we will react. But will we react the way we think we will, and how will we deal with divers that panic?

I always brief divers as to what I will do and what they should do, and this is what we did. We all dropped to the sand, me first as I saw it first. I pulled my buddy, the most jumpy student, down and deflated his BC well before he saw it, I then pulled the other pair closer and dumped their air. It was a family and the youngster was 13 years old. He saw the shark but did not know what he was looking at. We then swam slowly back to shore without seeing the shark again. The first thing they said was ”I thought you said you never see great whites here!” so I had egg on my face as I had just said that – honestly – as I had never seen a great white there before! Oh well… I will need to modify my dive briefing slightly now!

In all reality the shark had been watching us for a while, possibly thinking “man, they make a noise.” According to the Introduction to Sharks course offered by SharkLife (it’s free and fantastic – do it now!), sharks are highly sensory creatures. Sharks have eyes on either side of their heads, which means they have a nearly 360 degree visual field (compare that to the approximate 120 degree width of your visual field when wearing a scuba mask). They have a small blind spot directly in front of their snouts – too small for you to hide in! – and another one just behind their heads. They can focus their eyes at a range of distances, and have excellent vision even in low light conditions. Sharks also have excellent hearing, augmented by a “lateral line” which extends along their bodies and provides additional sensory information. Their sense of smell is likewise highly developed. In a great white shark, 18 percent of its brain mass (largest percentage of all sharks) is devoted to the processing of olfactory (smell) information. As if this arsenal of highly developed sensory organs is not enough, sharks also have electroreceptive cells called Ampullae of Lorenzini located around their snout and head area. These cells can detect tiny bioelectrical impulses given off by muscle movement of potential prey (which is why it’s a bad idea, as a spearfisherman, to swim along with dying fish attached to your belt). The Ampullae are sensitive to temperature, and are also used in navigation.

Anyway… the shark swam a circle wondering what on earth we were looking for, and then swam off looking for something to eat. Clearly she did not find our presence worthy of investigating or for that matter munching. This just shows that divers that are slowly swimming along with good buoyancy, looking at the marine life in the ocean are just not on a sharks’ to do list.

Great white shark in Mozambique — A great white shark I photographed in Mozambique

Divers seldom get to see great whites. I have been diving for 18 years and have only seen three on a dive. I have done over 100 dives at Long Beach in the last year without seeing one and numerous dives at other dive sites in Cape Town, including at Sunny Cove where I was sure I would see one. Without a single sighting. So remember: stay calm, stay together and enjoy the moment because it is not something you get to experience too often.

If you want to chat about this, please email me!

FAQ: If I bleed in the water, will I attract sharks?

Hollywood has a lot to answer for!

For the girls

I get asked this question quite often by girls who are worried about diving while menstruating. The short answer, which should make you breathe a sigh of relief, is no – regardless of what feminine hygiene products you prefer to use. (While we’re on the subject – forgive me boys – but tampons are perfectly safe to use while scuba diving and nothing strange or frightening happens to them inside your body on a dive. If you’re really worried, and there’s no reason to be, use a Mooncup – get one at Wellness Warehouse.)

DAN has a useful answer to this question on their international website. The research that has been done indicates that menstruating women are at no greater risk of shark attacks than men, or women who aren’t on their period.

What you should be aware of is that if you’re a woman, you’re more susceptible to dehydration during your period, which in turn increases the risk of decompression sickness. There is also research that indicates that the use of oral contraceptives may marginally increase a woman’s risk of DCS. So be sure to stay hydrated, do your safety stops, dive conservatively – and enjoy your diving!

For the boys (and the girls who are still reading)

Sharks are not interested in human (mammal) blood – they prefer fish! And what’s more, unless you’ve experienced massive trauma (in which case I doubt scuba diving will be the first thing on your mind), only miniscule quantities of blood will be leaking out into the water – whether it’s because you’ve got a cut or scratch on your body, or (if you’re a girl) you’re menstruating.

(To clarify, in case you’re puzzled: I took these photos of the signs on the restroom doors at the Southern Sun Grayston hotel in Johannesburg with my dodgy cellphone camera while I was there for a conference in June. I’ve been itching to use them since, and frankly didn’t have time to organise a photo shoot of a woman in white trousers frolicking alone on a beach!)