Baboons on the beach

Baboon on the beach Baboon on the beach

A recent low tide visit to the beach at Platboom near Cape Point, on the Atlantic coast of the peninsula, enabled us to watch a troop of Chacma baboons (Papio ursinus)  foraging for limpets, mussels and other marine snacks on the rocks at low tide. The baboons bite the tops off the limpets with their formidable incisors, or pry them from the rocks intact to get at the protein-rich flesh. They also eat mussels.

Baboons foraging for seafood at Platboom Baboons foraging for seafood at Platboom

This foraging behaviour is extremely rare among primates. In baboons, it is only observed on the Cape Peninsula and in one other species in Somalia. Matthew Lewis studied this troop of baboons as they foraged around the Cape Point nature reserve, and his thesis makes for fascinating reading. (Wild Card Magazine also featured Matthew’s research.)

Baboon on the beach Baboon on the beach

The amount of time the baboons are able to spend foraging on the shore is largely determined by the height of the tide, and by weather conditions. As a result, the amount of time the baboons spend seeking marine food sources is small compared with the time they spend looking for roots, bulbs, insects, berries, and small animals.

Low tide at Platboom Low tide at Platboom

These baboons are part of the Kanonkop troop which ranges freely in the Cape of Good Hope section of Table Mountain National Park and whose home range does not bring them into conflict with humans (or, as a rule, allow them access to any anthropogenic food sources). They were completely uninterested in us and our vehicle, unlike the baboons we see further up the peninsula around Millers Point, for example.

Concentrating baboon Concentrating baboon

Newsletter: Awesome Autumn

Hi divers

Weekend dive plans

Saturday: Shore dives at Long Beach

Sunday: Boat dives from False Bay Yacht Club

Autumn is a good time for False Bay diving! False Bay is currently pleasant, not too cold and the weekend does look decent after the latest weather updates. My plan is shore dives on Saturday, when it will be a little more windy, and boat diving on Sunday. Let me know if you’d like to get in the water.

Spring low tide at Muizenberg
Spring low tide at Muizenberg

Shark Spotters binocular fundraiser

Don’t forget to donate to the Shark Spotters crowd funding campaign to raise funds for new high powered binoculars for the spotters. Shark Spotters does fantastic work – read more about it here and here. You should also make sure you download their very cool shark safety and beach information app – available for both Android and iOS.

regards

Tony Lindeque
076 817 1099
www.learntodivetoday.co.za
www.learntodivetoday.co.za/blog/

Diving is addictive!

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Bookshelf: Life’s a Beach

Life’s a Beach: Your Round-The-Coast Guide To South African Beaches – Ann Gadd

Compliments of the season. If you’re contemplating which beach to head to for tomorrow’s traditional Boxing Day beach outing, a venerable South African institution, I have just the book for you. The product of a mammoth investment of time (which couldn’t have been all bad) and distance travelled, Life’s a Beach is a handy guide to (possibly, probably, almost) every single beach along South Africa’s coastline.

Life's a Beach
Life’s a Beach

Each pair of facing pages covers a stretch of coast, and beaches are rated for surfing, alongside information about swimming, kiteboarding, wake boarding, kayaking and canoeing, diving, fishing and hiking. The scuba diving information for the sites around the Cape Peninsula, with which I am familiar, is reasonable, but of necessity very abbreviated owing to the book’s format and primary focus. It goes without saying that you should seek out some local knowledge before diving in an area you haven’t visited before.

Unique experiences and best kept secrets (no longer – haha!) are highlighted, as well as the presence of braai and picnic facilities. Tips on where to go for sundowners are also included. Child friendly activities are mentioned where applicable, too.

Access tips, as well as warnings about rips, pollution, sharks (thank you Shark Spotters!) and whether a beach has Blue Flag status round off the comprehensive information that is provided in a handily concise manner. This book will be extremely useful when you’re visiting an unfamiliar stretch of South Africa’s coastline, and particularly invaluable when it’s a little known and less popular beach.

Get a copy of the book here, or here if you’re outside South Africa.

And if you’re going to the beach in Cape Town tomorrow, make sure you’ve downloaded the free Shark Spotters smartphone app. Get it here for your iPhone, and here for Android.

Cape Town’s visible shipwrecks: Update on the Commodore II

Until recently, the last time I specifically went looking for the wreck of the Commodore II was in December last year, when I went to Milnerton lagoon beach to show visiting family the beautiful view of Table Mountain. At that time tides and waves had moved the wreck further away from the lagoon mouth, and she was lying on the sand at a spot that would be partially submerged at high tide.

There has been some community discussion about the future of the wreck since late last year, but nothing changed until winter arrived.

Commodore II in December 2016
Commodore II in December 2016

Next time I went to look for the wreck, just after the Cape storm of 7 June this year, I couldn’t find it. A waiter at the Wang Thai restaurant on the beach told me he’d seen it all the way up at the old Wood Bridge at Woodbridge Island, and that people were removing pieces of the wreck and carrying them away. The storm surge had actually lodged the wreck partially under the old Wood Bridge (a sensitive National Monument constructed in 1901), and there was the potential for it to cause damage. There’s a picture of the wreck in this position on page 28 of this document (pdf).

Commodore II, secure for now
Commodore II, secure for now

A few weeks ago Gerhard Beukes, a Milnerton resident, messaged me to say that he had secured the wreck about half way down the lagoon. It had been winched free of the Wood Bridge by Koos Retief, Area Biodiversity Manager at Table Bay Nature Reserve, and had floated back down the lagoon to settle on a sandbank near Gerhard’s home.

Gerhard estimates that the wreck weighs about 25 tons, and with considerable personal effort and some financial outlay he has attached it to the lagoon bank, resting on the sandy bottom in shallow water, with chains and heavy lifting straps. The chain is secured to bolts attached to metal pipes sunk deep into the bank.

The Commodore II in Milnerton
The Commodore II in Milnerton

The arrangement will prevent the wreck from washing around inside the lagoon and potentially injuring kayakers and other water users. It will also prevent it from washing out into Table Bay and becoming a semi-submerged shipping hazard, potentially lethal to vessels (something like the Seli 1 is when her buoy goes missing).

View towards Woodbridge Island
View towards Woodbridge Island

It’s also quite visible: if you walk or drive down Esplanade Street in Milnerton with Lagoon Beach behind you, you’ll come across the remains of the Commodore II next to the bank of the lagoon on your left. The wreck is over 60 years old, which means that under South African law it is protected and removing pieces of it is an offence. I hope that having many local residents’ eyes on the wreck will ensure it some measure of safety, even in the absence of any enforcement of the relevant laws.

How can you help?

To make sure the wreck does not come loose next time a large volume of water washes down the river and into the lagoon after heavy rains, it needs some further reinforcing in its current location. This could be done with a further 5 metre length of heavy duty chain, or (preferably) two loading slings, 25mm steel cable with rings or eyes on both ends. The harness needs to be capable of holding 25 tons of wood in place even under strain, and are necessary to completely stabilise the wreck.

If you have such items lying around unused at home, or are sufficiently moved and interested by the wonderful history of the Commodore II to make a donation, please comment on this post or use the contact form here, and I’ll connect you with Gerhard, the current guardian of the Commodore II.

Are you interested in shipwrecks that you can visit without going underwater? Read more about Cape Town’s visible shipwrecks here.

A humpback whale on the beach

Humpback whale on the beach
Humpback whale on the beach

Last year the carcass of a smallish – about 8 metre long – humpback whale (Megaptera novaeangliae) washed up on one of the less-frequented beaches around the Cape Peninsula. I am very belatedly sharing some pictures of it, not least because one doesn’t often get an opportunity to examine an animal like this up close. I view these things with a mixture of sadness and awe; I think it’s easier to process objectively when the animal has already died. Strandings of live cetaceans can be extremely distressing.

Baleen plates
Baleen plates

Some pieces of the whale’s baleen, which these animals use to filter their food from the water, were lying nearby on the beach. A large group of whales had been passing by the Atlantic seaboard in the days preceding the carcass washing up, and it may have been one of them.

The whale had been dead for a few days by the time it washed up on shore, but not so long that a lot of its skin had sloughed off (sometimes dead whales look white all over – as this whale’s belly does – for this reason). There was no obvious cause of death visible on the underside of the whale’s body. It was lying upside down so the top of its body wasn’t accessible.

It is possible that an anthropogenic cause (ingesting plastic, or a ship strike for example) could be responsible for this whale’s death. It’s also possible that the whale was sick or otherwise compromised and died of natural causes. Sometimes, when things in the ocean die, they wash ashore, and we find them.

I’m not sure what ultimately happened to the whale’s remains – it was in the surf line when I saw it, being pushed back and forth by the waves. It might have been taken back out to sea with the tide. I would like to think that it was.

If you come across a dead whale – on the beach or out at sea – here’s what to do.

Colour fronts in False Bay

Colour front seen from Sunny Cove on 27 November 2015
Colour front seen from Sunny Cove on 27 November 2015

Perhaps you have wondered what causes the patterns of strange coloured water in False Bay during the summer months. Perhaps you have dived in it, and wondered why sometimes you can’t see your hand in front of your face! Wonder no more – I am here to help.

Colour fronts

Frequent visitors to and residents of the shores of False Bay will observe that at certain times of the year, the ocean is marked by bands and arcs of sharply contrasting coloured water. This phenomenon is known as a colour front. In oceanography, a front is the interface or boundary between two separate masses of water. In this case, the water masses are easy to discern, because they are of different colours. There are usually other characteristics of the water on each side of the front that differ, too. Fronts are either convergent (the water masses are moving towards each other) or divergent. The presence of marine debris (like pieces of kelp) at the front boundary suggests that it is convergent.

Causes of colour fronts in False Bay

Prior to 2005, there was much conjecture about the causes of these fronts (including the usual pollution bugbear), but little evidence to support any of the theories. By sampling, the fronts were found not to be caused by pollution, or by plankton blooms in the surf zone. It was known that a colour front was most likely to occur in False Bay after a period of southerly or south easterly wind lasting a few days. October and November seem to be prime months for the phenomenon.

When a large, obvious colour front arose near Simon’s Town in November 2005 with milky green water on one side, and darker blue-green water on the other, researchers from UCT and IMT sprang into action, sampling the water on each side of the boundary so that they could measure its characteristics. Speed is of the essence in these situations; colour fronts can disappear quickly. The one in the picture below is busy decaying – notice the smudged boundary.

Colour front in north western False Bay on 13 November 2014
Colour front in north western False Bay on 13 November 2014

Measurements revealed that the milky green water overlaid the clearer, bluer water, down to a depth of 11-12 metres (this will vary from front to front). The milky water did not extend to the ocean floor.  Scuba divers around the Cape Peninsula will be familiar with the experience of diving through two or more layers of water, with varying turbidity (clarity) and temperature! (Here is picture of Tony and Christo diving near Oudekraal in the Atlantic that shows what the boundary between two layers of water can look like.)

The researchers found that the milky coloured greenish water was full of fine, almost neutrally buoyant particles of calcium-rich sediment. The green-blue water contained much less calcium, but relatively more silicon, which would suggest the presence of diatoms (a kind of phytoplankton – you can think of them as teeny tiny plant-like organisms) or sand in the water. The origins of the calcium-enriched sediment in the milky water are interesting: one source is from the shallows (less than 30 metres deep) of north western corner of False Bay, where the ocean floor is made up of rocks that are rich in calcium carbonate (such calcrete and limestone), some areas covered by a thin layer of sand.

Milky-white water near Swartklip on 29 November 2014
Milky-white water near Swartklip on 29 November 2014

The second probable origin for the particles of calcium-rich material is the interface between the sea and the land at the northern end of False Bay. The cliffs at Wolfgat/Swartklip at the head of the bay are made of calcrete, and at Swartklip the beach narrows to the extent that the cliffs erode directly into the water when the sea is high. Strong southerly winds create a wide (of the order of one kilometre) surf zone at Muizenberg and Strandfontein; a spring tide also adds to ideal conditions for the generation of a colour front.

The temperature of the milky water was found to be slightly (0.4 degrees Celcius) higher than the green-blue water. This measurement will also vary from front to front. The researchers speculate that the temperature difference could be because the milky water originated in the surf zone, which is shallower and therefore warmer, or because the high concentration of suspended particles in the milky water caused greater absorption of heat from the sun.

Colour front at Smitswinkel Bay on 24 October 2014
Colour front at Smitswinkel Bay on 24 October 2014

Summary

Here’s the tl;dr: strong southerly and/or south easterly winds, perhaps coupled with spring tide conditions, set up a very wide surf zone along the northern end of False Bay, which disturbs the sediment on the ocean bottom and drives the waves further up the beach than usual. Particles of buoyant calcium carbonate from the sea floor and eroded from the cliffs at Swartklip are lifted up into the water column, changing its colour to a milky-green shade. Wind-driven circulation patterns in the bay push the front from its original location in a southerly direction, towards Simon’s Town.

What to do?

Contrary to what your friends on social media may claim, not all colour changes in the ocean around Cape Town can be attributed to a giant sewerage plume. Hardly any of them can, in fact. In summer, the reason for the ocean looking green, red or even brown is likely to do with a plankton bloom of some description, or related to suspended sediments (as in this case) or other naturally arising material in the water. Instead of using this as an opportunity to become hysterical on the internet, how about celebrating the incredibly dynamic system that we can observe, living near the ocean? Drive up a mountain next to the ocean and take in the spectacle from on high. Dip your face in the water and see what it does to the viz. Take some pictures for posterity. And – if you don’t know what’s causing it – try to find and question someone who does know, like a scientist, or consult a good non-fiction book, to find out some facts.

If you’d like to read more about colour fronts in False Bay, take a look at this scientific paper (pdf), which I used as source material for most of this post. The paper is called A Prominent Colour Front in False Bay: Cross-frontal structure, composition and origin

Visible shipwrecks: SS Kadie

The Kadie on the beach, further parts of the wreck in the rockpools

The mouth of the Breede River is a fascinating and beautiful location. There’s a treacherous sandbar (more on that just now). There are wide, natural vistas. There are sleepy holiday villages on each side of the river mouth. There’s an additional little frisson of excitement related to the fact that bull sharks use the Breede River, and must be passing by all the time (right?!).

When Tony and I were in the area for a spring break, we explored the area. I wanted to see whether I could find the remains of SS Kadie, a steaam-assisted sailing ship that is an integral part of the history of the area. The Kadie was built in Scotland in 1859, for the specific purpose of navigating the Breede River and up and down the coast, as a trading vessel. She did venture out to sea on longer voyages, on one occasion carrying a cargo of ostriches to Mauritius. (You can read a lot more about her history, and that of the Barry family who operated her, here.)

On 17 December 1865 the Kadie ran aground and sank while attempting to cross the sandbar at the mouth of the Breede River. She is easy to find, but you should visit at low tide. Take the turnoff to the river mouth from the dirt road to Infanta. It’s a small sign and easy to miss! Descend the wooden staircase onto the beach, and walk right. You will soon see pieces of the Kadie on the beach, in the shallow rockpools, and out in the surf zone. Best to go at low tide, or at least not at the peak of high tide.

Looking down the beach to the Kadie
Looking down the beach to the Kadie

If you’re interested in visible shipwrecks, check out my ebook Cape Town’s Visible Shipwrecks: A Guide for Explorers!

Cape Town’s visible shipwrecks: Antipolis

The Antipolis lies against the shore in a small rocky bay
The Antipolis lies against the shore in a small rocky bay

The oil tanker Antipolis ran aground off Oudekraal during a July storm in 1977. She and the Romelia, which is wrecked near Sandy Bay, were both under tow by the tug Kiyo Maru No. 2 from Greece to be scrapped in Taiwan. The wreck lies pointing shoreward, a couple of hundred metres south of the 12 Apostles Hotel. She can be viewed from a vantage point above a storm water drain between the hotel entrance and a small parking area on the opposite (seaward) side of the road. Walk along the Armco barrier from the parking area, looking to your left (while also looking out for cyclists). The storm water pipe is about twenty metres from the parking area and is marked by a gap in the bushes through which the wreck can be seen.

There is also the option of climbing down an impossibly steep and slippery path onto the rocks adjacent to the wreck. The view from here is slightly better, but it is not a climb for the faint hearted.

She is now a beautiful dive site if you visit in clear, calm conditions. Most divers shore dive off the rocky beach in front of the wreck, after climbing over the traffic barrier and walking over the boulders on the shore.

There are some pictures of the tanker just after she grounded here and here (the comments are also worth reading). Her superstructure was cut off some time later for scrap. The entire shape of the wreck can be discerned on aerial images, as much of her lies just below the waterline.

If you’re interested in visible shipwrecks, check out my ebook Cape Town’s Visible Shipwrecks: A Guide for Explorers!

Cape Town’s visible shipwrecks: Winton and Hermes

Being (in midlife) a creature of the south peninsula, I tend to focus my attentions on False Bay and the Atlantic coast from Hout Bay southwards. But there are rewards for the shipwreck hunter who ventures further north, and even for the shipwreck hunter who doesn’t necessarily want to get their feet wet. A visit to Milnerton beach, and a walk north from Milnerton lighthouse, reveals two shipwrecks in the surf zone. Milnerton beach is surpassingly filthy, but while I was there a beach cleanup was making some headway on the mounds of rubbish tossed off ships in Table Bay that ends up on the beach. The view of the lighthouse from the beach is also far more fetching than the view from the car park, if you can overlook the garbage.

Milnerton lighthouse
Milnerton lighthouse

About one kilometre north of the lighthouse, where the beach is cleaner and pebbles roll euphoniously in the waves, you will come across the massive boilers of the Hermes in the surf. The NSRI gets calls every year from concerned locals worried that a whale is stranded near the beach; the sea spray sometimes pushes through holes in the top of the wreck creating an illusion of a whale’s blow. The Hermes was a liner, built in 1899, on her way to Cape Town with a large cargo of livestock, forage and a few passengers. When she arrived in May 1901 the harbour was full, and she was forced to drop anchor for the night. A north westerly gale came up, she dragged her anchors, and when the captain ordered her engines started, they failed.

Hermes (front) and Winton (back)
Hermes (front) and Winton (back)

Seawards and to the north of Hermes, the engine block of the Winton is visible, in much the same way as the SS Clan Stuart can be seen at Glencairn in False Bay. The Winton came aground in July 1934, carrying a cargo of wheat from Port Lincoln in Australia to Liverpool, England. Her captain was unfamiliar with Table Bay and had mistook the red lights on top of the radio mast at the Klipheuwel Wireless Telegraph Station near Milnerton for the harbour lights. Attempts were made to pull her off the beach and some of her cargo was salvaged, but the wheat ignited and efforts to refloat her were to no avail.

On a calm day, an aerial view of the site reveals the full outline of both vessels surrounding the parts that protrude from the water. When I visited, it was rough after a large swell, but the tide was low. At high tide the view will be considerably less impressive.

The boilers of the Hermes in front of Table Mountain
The boilers of the Hermes in front of Table Mountain

It is possible to scuba dive this site, and Underwater Explorers dives the Winton every year during their summer Table Bay wreck diving jamboree. Obviously very calm, low swell conditions are required because the wreck is so shallow and so close to the beach.

If you’re interested in visible shipwrecks, check out my ebook Cape Town’s Visible Shipwrecks: A Guide for Explorers!

Newsletter: Roll on summer

Hi divers

Weekend dive plans

Saturday: Early double tank dive, weather permitting

Spring is around the corner and we are still waiting for the weeks of crystal clean water we should have in False Bay. There have been very few real winter visibility days this winter. (I may have had this complaint last winter too…)

Buffels Bay at Cape Point
Buffels Bay at Cape Point

The weekend looks to be another let’s wait and see situation. Tomorrow’s wind should improve the visibility, which is currently not that great, for some good diving early on Saturday. By midday on Saturday the wind is strong and on Sunday it will be close to gale force. I hope to launch early on Saturday for a double tank dive but it’s low tide at 9.00 and there is a forecast 3 metre, 14 second swell so deeper sites will be better. I would imagine that the Roman Rock area will be our best bet. Text or mail me if you want to be on the list for Saturday and I will make a call tomorrow afternoon.

The wharf street parking at the Simon’s Town jetty is a paid parking area again from tomorrow. A slip is placed on your car when you arrive… Make sure the time is recorded correctly.

regards

Tony Lindeque
076 817 1099
www.learntodivetoday.co.za
www.learntodivetoday.co.za/blog/

Diving is addictive!

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