Here’s Tony at the safety stop in a notable plankton bloom, at the end of a dive at Justin’s Caves. Fortunately the water was clean at the bottom, and even cleaner inshore on the landward side of the rocks!
A strong south easterly wind that brings clear, nutrient rich water from deep offshore, followed by even a few windless hours of sunshine, will turn the surface waters of the sea on the Atlantic side of the Cape Peninsula to pea soup. Here’s a salutary example from a dive we did where the top 20 metres or so were thick, green sludge.
Mid September, the bilge pump below the deck of our boat became erratic so I lifted one of the deck plates to take a look. Turns out it was a really good idea as the hydraulic hoses for the power steering were rubbing against a bulkhead, and would have leaked sooner or later.
Whilst the area was open I decided to replace the fuel lines from the tank to the filter, and secure the control cables, wiring looms etc as they could also end up being chafed if they floated around loose for too long. The last time I had this panel out was about 18 months ago when I installed the Lowrance Sonar and GPS units. In this time you can see how the fuel lines had become covered with an algae that was really slimy and would most likely have damaged the fuel lines if left unchecked.
Working behind the console
Cleaning out the area
Securing the hoses
I also replaced the wiring to the existing bilge pump and installed a second one as a back-up. The area is now clean, no loose cables or looms and ready to be closed up again.
Hi divers We had really good conditions last weekend with Saturday being the best. We dived Photographer’s Reef and Roman Rock. Sunday was good at Photographer’s Reef and the Brunswick, but you could see signs of red tide coming and by Monday it was all over False Bay. On Tuesday the swell and the red tide messed up the diving. There are still patches of red tide about but it is not widespread, so odds are good for a diving weekend.
Christo at Photographer’s Reef
Long weekend plans
This weekend, Friday and Saturday are the days I believe will be best for diving. Sunday will be too windy. There is not much swell about but there is currently a south easterly wind which comes straight into False Bay. My guess is that we will be better off launching from Hout Bay. The sea temperature in False Bay is around 14 degrees, as is the Atlantic, but the weather buoy off Kommetjie shows a temperature drop which usually indicates improving viz. Either way, the plan is to launch at 10.00am and 12.30pm. Neither days will be dives deeper than 18 metres as I have Open Water students on the boat. If you want to get wet, text me and I’ll put you on the list.
Fiery nudibranchs at Photographer’s Reef
Free dives for ladies on Friday
Being Women’s Day on Friday, our lady divers will be given a free boat dive to say thanks for never understanding that men don’t need veggies! Cake, yes, any time. But no veggies. One free dive per lady, and kit rental is not included. First come first served! All of you, ladies and gentlemen, must have an up to date MPA permit please. Go to the post office and get one, and bring it with you on the boat.
Craig at Roman Rock
Planning ahead
I will be out of action on the weekend of 24-25 August. Luckily for you, if you want to dive, OMSAC are holding a Treasure Hunt, and you can join one of the boats going out on that day. We went two years ago and it was great fun. The event details are here. If you need a heart to heart and some encouragement to be adventurous, let me know!
When the opportunity arises to go aboard a ship, we like to take it. Our most recent ship tour was of the Greenpeace Rainbow Warrior vessel. In celebration of World Oceans Day on 8 June, the Department of Environmental Affairs opened the SA Agulhas IIpolar research vessel to the public, and we popped down to the V&A Waterfront to see her.
The SA Agulhas II replaces the SA Agulhas, now in use as a training vessel by SAMSA. The SA Agulhas has been in service for many years, and was recently chartered by the organisers of The Coldest Journey to transport the personnel and machinery to Antarctica before the winter.
The SA Agulhas II was built in Finland at a cost of R1,3 billion, and is state of the art as far as safety features and redundancy is concerned. She has two completely separate main engines, and is capable of continuing underway if one engine room floods. The decks and outdoor staircases of the ship are heated to prevent ice build up, and her hull is capable of pushing through one metre thick ice at a speed of nearly 10 kilometres per hour. She will service Marion Island, Gough Island, and the SANAE IV base on the Antarctic continent.
Tony on the helicopter pad
The ship’s bell
View from the bridge, showing helicopter pad and cranes on deck
Department of Environmental Affairs headquarters in table Bay Harbour
Table Mountain seen from the rear lower deck of the SA Agulhas II
Penguin on the Antarctic continent adorning the side of the vessel
The stern of the SA Agulhas
The ship has room for two helicopters, with a large helipad and a hangar in which the choppers can be housed with their blades folded down. The hangar’s walls are heavily fire proofed, and look like a couch or quilt. The ship can carry 100 scientists and a crew of 45. The accommodation is lovely, with every cabin having natural light. I was ready to run away to become a polar explorer after seeing the cabins, but when we stepped out on deck into the freezing wind (remember, the ship was still at her berth in Cape Town) I changed my mind.
Accommodation on the SA Agulhas II
One of the life rafts
There are eight permanent laboratories on board, and six containerised ones which can be lifted on and off the ship depending on what experiments are to be performed. Members of the scientific personnel spoke to us about some of the work that is done on board, including sampling the carbon dioxide content of water at various depths and locations (the levels are affected by global warming), and collection of plankton in special devices that enable the scientists to measure the fecundity of a particular part of the ocean. Tony and I kind of hoped that the intern who told us that they give that information to fishing company I&J was joking or wrong, but sadly I suspect he wasn’t.
The hangar for the helicopters
The side of the ship opens up to enable instrumentation to be deployed
Garth the chemist explaining some of the research done on board
Plankton gathering equipment for research
Containers on the dock at the Department of Environmental Affairs building
A CTD water sampler hanging over the moon pool
In the centre of the ship is a moon pool – just like a James Bond movie – through which instrumentation can be lowered into the ocean. It’s essentially a hole all the way through the hull, surrounded by the ship. The advantage of this is that it won’t ice over, and there is no chance of a heavy piece of machinery hung over the side of the ship causing problems of balance. There is a large door in the side of the ship through which instruments can be sent, a feature shared with the old SA Agulhas, but during long experiments it’s possible that the ship gets iced in and the instruments crushed. The device hanging over the moon pool in the photograph above is a CTD, or conductivity, temperature, depth water sampler. It measures those three variables at different depths by taking water into the cylindrical Niskin bottles that make up the array. These close at predefined depths, and the water thus obtained can be analysed on board.
Bridge instrumentation
Radar display (in Cape Town harbour)
Standing on a piece of the bridge that overhangs the edge of the ship
Instrumentation on the bridge
The ship has thrusters and multi-directional propellors that enable her to move in almost any direction, rotate on the spot, and hold a position with incredible accuracy for hours on end, even in unfavourable sea condtions.
I was amazed by this ship, but also worried by her, half waiting for something to go wrong. We have a very sad habit in South Africa of completely dropping the ball environmentally (I’m thinking of the fisheries patrol boats gathering dust at the quay in Simon’s Town while the minister of agriculture, forestry and fisheries goes on fraudulent trips and accepts bribes), and squandering technology that could otherwise be used for great good. My hope is that the recognition from other nations that this is a special, one of a kind ship with capabilities unmatched by many other vessels will apply a form of peer pressure to keep the powers that be from wasting the SA Agulhas II’s capabilities. The scientists and crew who we spoke to on board are passionate, dedicated people. I hope they will be well served by those who set the maintenance budgets, scheduling and priorities of this special ship.
Summer diving in the Atlantic can be incredible, but only after a couple of days of convincing southeasterly wind have pushed the surface water offshore and allowed it to be replaced by crystal clear water from the deep ocean. This process is called upwelling, and on South Africa’s west coast it occurs at a rate of up to 30 metres per day (compared to an average of less than 5-10 metres per day elsewhere in the world).
The powerful upwelling system supports very abundant fisheries, because in the water from the deep sea – which is so clear when it arrives at our coast – are many nutrients (decaying marine debris, for example) that provides abundant food for planktonic micro organisms. These micro organisms are the bottom of a food chain that extends up to the fish that are caught in the west coast fisheries.
Algal bloom in Maori Bay
As soon as the nutrients from the deep are brought up into shallow water, plankton starts to grow and blossom in the light of the sun, feeding on these nutrients. Phytoplankton (plant plankton) or algae blooms can turn the water in the Atlantic into pea soup in a matter of hours. The water feels thick, like cough syrup, and contains strings of algae that can cause irritation to one’s skin. This process of algae blooming starts as soon as the wind stops and the sun shines, which is why there’s such a small window of time during which Atlantic diving is good after a south easterly wind in Cape Town. After a day of hot sun, the algae is having a party.
Spreading foam
Decomposing algal bloom in Maori Bay
Foam in Maori Bay
On this particular occasion there had been a brief south easter – fairly strong but not for more than a day and a half – followed by a hot, sunny day. We decided to take our chances on the SS Maori. When we approached Maori Bay we could see a lot of foam on the water, which is a bad sign. The foam is created from the proteins and carbohydrates released by algal blooms as they break down. It is also these proteins that make the water feel viscous at times.
Christo holding the reel while Craig adjusts his weight belt on the SS Maori
It turned out that the visibility was not, as the foam warned us, that great – perhaps four metres. The water was very green, as you can see in the photo above. While the divers were in the water, I watched the amount of foam in Maori Bay grow and grow. It happens really fast.
We decided to move away from Maori Bay for our second dive, and went across to the base of Chapmans Peak to dive at Die Josie. Clare took this photo from Chapmans Peak (she had to leave early) of Seahorse at the dive site; you can just see the boat as a speck opposite the rocks sticking out in the middle of the photo.
Seahorse at Die Josie beneath Chapmans Peak
We had better visibility at Die Josie, but by the time we left the algal bloom was closing in and the Atlantic diving was finished for the moment.
Readying divers at Die Josie
For a nifty picture of a growing algal bloom taken underwater, check out the photo of me and Christo at the safety stop at Monty’s Pinnacles. The algal bloom starts on the surface and works its way downwards; in this example it had spread through the first five metres. We were half in and half out of the green water. There are some photos of an algal bloom that had spread through the first 20 metres of water in Clare’s post on Sea Point Ridge Pinnacles.
The seasons’ change has had us diving in mixed conditions, clean one day and dirty the next. Last weekend we dived Hout Bay on Saturday (the Maori and Die Josie) and had mediocre viz, but on Sunday diving in False Bay was far better. We visited the cowsharks and seals at Partridge Point.
At three metres my visibility testing tool is all but invisible
This weekend is again a mixed bag as the water colour and temperature are not promising. Hout Bay has green water and the temperature there today was 15 degrees. The temperature in False Bay today was 17 degrees and I went from Simon’s Town to Cape Point and back as well as far out into the centre of the bay (looking for the orcas) and did not find any clean water anywhere. The picture above is of my visibility testing tool (patent pending) three metres underwater near Atlantis Reef. It’s almost invisible.
Leaving Simon’s Town harbour with a navy patrol boat escort
The orcas were most likely terrified by the naval canon firing… I know I was! The navy patrol boats escorted us past the vessel that was firing. Just before taking the boat out of the water I cruised slowly north of Long Beach and when the sonar read 2.5 metres I could barely see the bottom. There is/has been a plankton bloom of some sort and I think that has been a big factor. There is also a surprising amount of garbage in the water. There is a 3-4 metre swell predicted for the weekend.
Having said that its likely to be a good weather weekend as there is little wind and lots of warm sunshine. Luckily I will not have to put my forecasting skills to the test as we are off to Knysna for a spell of houseboating and seahorse hunting (the little ones that live in the lagoon).
Christo holding the reel while Craig adjusts his weight belt on the SS Maori
Our training pool is in and full, not quite crystal clean yet but will be soon and we will run a Discover Scuba Diving special during May so if you have a friend that needs to experience scuba get in touch.
Almost finished swimming pool at home
Travel
We’re off to Durban in June for three days of wreck diving with Calypso at uShaka Marine World. Durban has warm water like Sodwana, a well known balmy climate, and all the coral reef critters as well as some spectacular shipwrecks. Plus there’s lots to do if the weather doesn’t pan out every day. We’re going in the week of 17 June (a Monday, and a public holiday). If you’re interested let me know and I’ll forward the details.
Our Red Sea trip still seems frustratingly far away, but October creeps closer. The Red Sea is a must visit destination for any scuba diver, and what better way to do it with some non-threatening semi-nice people like us? As Gob from Arrested Developmentwould say, come on!
Abalone (or perlemoen, Haliotis midae) is a highly exploited marine resource in South Africa, to the extent that it is currently illegal for individuals to harvest abalone from the ocean. All fishing was suspended in early 2008. Formerly it was possible to get a permit to do so. Limited commercial fishing has been allowed since 2010. The government acknowledged that this would cause further depletion of the wild stock of abalone, but framed the decision as one to protect the livelihood of approximately 1,000 abalone fishermen. When there is no abalone left to fish, I wonder what those fishermen will do?
Ten, twenty and forty year old abalone
The demand for this unprepossessing grey mollusc is almost limitless, primarily from the east, where it is viewed as a status symbol and is highly sought after at banquets and to prove the host’s prestige. Given the huge demand and the fact that South African waters are the natural habitat of this species, abalone farming has flourished in South Africa, with eleven farms in operation. The largest is Abagold, with four farms located in Hermanus. Abagold employs over 350 local people (it is the largest employer after the municipality). Farm tours are offered every week day at 11am (they cost R50), and Tony and I did one on our way back from De Kelders.
The Abagold farming operation is extensive, actually consisting of several separate farms all located close to the (new) harbour in Hermanus. The tanks are supplied with fresh water directly out of the ocean – the temperature (generally 15-18 degrees) and water quality is not adjusted at all, since this is the optimum natural habitat for the creatures. The animals are fed on kelp, sea lettuce, and specially manufactured abfeed, and no chemicals are added to the water. As a result, the farm can pump the water straight back out into the ocean without causing any contamination. There is a constant circulation of millions of litres of water through the farm, keeping the abalone oxygenated.
The holding pens have a beautiful sea view
Breeding stock are kept separately, and range in age from three to 30 years. Pairs are retrieved from the ocean periodically, and returned after a time. Abalone are distinctively male or female, distinguishable by the colour of their gonads, which are nestled under their shell above their large fleshy foot. Abalone spawn between August and November in nature, prompted by increased oxygen levels in the water. To stimulate spawning in captivity, hydrogen peroxide (H2O2) is added to the water containing broodstock, which causes their muscles to contract and release eggs and sperm.
Three to six month old abalone
Spat clinging to an algae-covered plastic sheet
The underside of some spat feeding on specially grown algae
Three to six month old abalone inside a plastic cone
The cones under which 3-6 month old abalone live
The water in the breeding tanks is constantly refreshed
Baby abalone on my hand
Eggs and sperm are mixed in the correct proportions, and fertilised eggs sink to the bottom of the tanks where they are sucked out and placed in tanks where they hatch after several hours. Algae is specially cultivated on large plastic sheets, to which the free swimming larvae attach when they are ready (after about a week). They spend about three months feeding on these algae-covered sheets of plastic. The baby abalone (spat) are beautiful, with blue and turquoise, perfectly formed little shells 3-5 millimetres in size.
In order to remove the fragile abalone from the plastic sheets, they are anaesthetised with an infusion of magnesium sulphate into their water, which enables them to be gently rubbed off the sheets. It is around the age of three months that they develop light-sensitive eyes, which prompts them to seek out darker hiding places. Black plastic cones are supplied under which the young abalone live for another three to four months.
The blue-grey colour of the gonads visible here shows this is a female
At about six months of age the abalone are sorted by size and moved into simple tanks with fittings that are constructed largely of standard irrigation piping and hard plastic sheets. The abalone are quite sensitive to their environment and water has to be kept very clean. They spent the next 3-5 years growing in their tanks.
The fringe, eyes and mouth are visible here
An example of a holding pen
These abalone are close to 30 years old
This abalone is several years old
The underside of an abalone, showing its meaty foot and fringe
Young abalone in the breeding tank
Kelp is collected to feed the abalone at various farms in the Hermanus area
When the abalone are large enough (about 250 grams, I think – a bit bigger than my palm), they are removed from their shells. The gonads, mouth, eyes and other organs are discarded, and the foot is either canned in fresh water and pressure cooked in the tin, or dried, in about a 50-50 split. All the production is exported to Hong Kong, China, Malaysia, and Singapore, with a 440 gram tin of abalone in brine fetching R200 to R450 for Abagold (it obviously costs more to buy it in the shops). The farm produces nearly 500 tons of abalone per year. This is big, big business.
Canned abalone is imported to the east
The finished product: canned abalone
Various abalone species from around the world
We were very excited to see how sustainable this aquaculture model is. Fish farming isn’t a wonderfully clean or sustainable business, but this seems to be an effective way to reduce demand for wild abalone without harming the environment. There is a long way to go, however, before supply of abalone outstrips (or even comes close to matching) demand – according to our tour guide, there are buyers for whatever quantity of abalone the farms can produce. Legally harvested and farmed abalone comprised one ton out of the seven tons of abalone that left South African shores last year. The scale of the poaching problem is massive.
A while ago I posted two photographs of (more or less) the same feature on one of the Smitswinkel Bay wrecks, taken one after the other. On one the flash fired, and for the other I turned the flash off. The idea was to demonstrate what the absence of light at depth does to colour.
Pipe on the Maori, flash not firing
Here’s another example of the same phenomenon, taken on the SS Maori at about 15 metres’ depth. The water was very clear, but the red algae growing on the pipe had lost much colour even at that depth.
To everyone that voted for us in the SA Blog Awards we say thank you very much, but we did not make it to the finals. Oh well.
This time of year most people start winding down in preparation for Christmas; often nothing much happens in the office and you might not even be missed if you slip out and go for a dive. Here’s a secret… Go online and buy all your Christmas presents now! Then every morning you can claim that you’re out shopping for a different member of the family. You will be surprised at how long you can milk this excuse with your boss… Try it!! (I cannot be held liable for dishing out bad advice.)
Use this early morning time for a few very pleasant early morning dives. The first year I was in Cape Town I spent a lot of time learning the dive sites, often ready to go in the water by 6.30 or 7.00 am. You will be pleasantly surprised at how often the wind is absent, no traffic and no people around… Come and try it this summer, you can be in the office by nine.
What we have been up to
Safety stopping in a plankton bloom
Last weekend was very odd. Friday I was stunned by the crystal clear blue water of the Atlantic. Saturday we did two boat dives in pea soup (see above) and the visibility only opened up at 20 odd metres so it was very dark. I was fortunate enough to see a huge sunfish swim slowly by – this was the first time I have ever seen one underwater. Two years ago I spent 10 days in Table Bay driving a boat for a film shoot and we saw several sunfish daily on the surface. Clearly this time of year is their chosen time to visit us so hopefully we will get to see more of them.
Divers descending at Barry’s Pinnacle, North Paw
Divers at Sea Point Pinnacle
The offending algal bloom
Waiting on the surface for the boat
Sunday I had a bunch of new students and we spent the entire day in the clean warm (26 degrees) pool. I dived with these new students on Monday in False Bay with a good 6 -8 metre visibility and on Tuesday, since they were on a tight schedule, they had to brave 2 metre visibility to complete their course. It never ceases to amaze me the speed at which the ocean conditions can change.
Anemones and mussels fighting for space
This weekend
On Saturday we will be in False Bay, where, I can’t say, but I will look for the best site. Given the winds we have had this week it’s a difficult call until we get there; I will also have a look tomorrow to see how the water looks. Either way we will meet at Long Beach at 9.30am and move on from there.
Rutger and Kelly starting a dive at Long Beach
Grant will launch from OPBC on Sunday and I am booking for both launches, the first, a wreck called the Highfields and the second a wreck called the SS Cape Matapan. I have yet to dive from OPBC without seeing the permit checkers drive through or lurking in the vicinity, so make sure you have a valid dive permit. Please also remember that boat dives are now R220 per person, per dive.
Nelly at Long Beach
Please let me know if you would like to join us on any dives this weekend, and I will do my best to make it happen.
