Newsletter: Electric sea

Hi divers

Weekend dive plans

No diving

We won’t be diving this weekend, and there won’t be a newsletter (or diving) next week, but we’ll be back in business after the public holiday on Heritage Day (24 September). This weekend, Saturday looks good, and Sunday ok for diving.

I launched for divers on Tuesday, and they had fairly good conditions (5-6 metre visibility at Sherwood Forest and Castle Pinnacles) but the surface conditions deteriorated as the day progressed and the wind picked up.

Bioluminescence at Fish Hoek beach
Bioluminescence at Fish Hoek beach

This past weekend, helped by the south easter and then the heat, a thick red tide got caught in Fish Hoek bay and as a result we were treated to some incredible bioluminescence (caused by a type of plankton that fluoresces when disturbed by wave action) on Saturday evening.

This occurs at least a couple of times a year, usually in spring and autumn, on this side of False Bay (and it often makes its way around to the Kogel Bay area on the eastern shore). It is an incredible sight to see. There’s a little video here (pardon the screaming – the beach was packed and the people were excited).

Anyway – see you in 10 days.

regards

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

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Bookshelf: Beachcombing in South Africa

Beachcombing in South Africa – Rudy van der Elst

Beachcombing in South Africa
Beachcombing in South Africa

Why so quiet? What have we been doing? Working, mostly. Trying to stay alive. And a bit of reading, and some beachcombing. Enter this is marvellous little book from fish fundi Rudy van der Elst (A Field Guide to the Common Sea Fishes of South Africa).

Chapter by chapter, van der Elst describes the types of debris that one might find on a beach. After a brief orientation chapter covering the ocean current regime around South Africa, relevant regulations, safety, beach ecology, tides, pollution and more, we launch into a tour of washed-up treasures.

Predictably, many of the items to be found are organic in nature – plants, invertebrates of various types, eggs and egg cases, fishes, birds, and shells. There are also items such as oceanographic devices, tags from marine animals, fishing equipment, cyalumes, buoys – some of these (such as tags) should be returned to their owners, and others should be removed from the vicinity of the ocean (such as discarded fishing nets and lines).

The chapter on marine animals (resting, nesting and stranded) is exceptionally useful and it is almost for this alone that I’d like to put a copy of this book in every home in every coastal town in the country. Seals, whales, turtles and seabirds can end up on the beach, sometimes in difficulty and at other times not. It can be hard to tell, and well-meaning members of the public can unwittingly cause great harm while trying to assist. A list of useful contacts in this regard appears at the end of the book, such as the Two Oceans Aquarium and the SPCA (region-specific).

The final two chapters cover miscellaneous “treasures” such as fossilised sharks teeth, sea glass, logs, and actual treasure, as well as beachcombing through the ages in South Africa. Here we learn about tidal fish traps, coastal caves, and other historical coastal dwellers who made their living from the sea.

We’ve found some awesome things on the beach, from shipwrecks to goose barnacles to rare crabs. Beachcombing is an accessible hobby that requires nothing but time, observation skills, curiosity, and a beach to stroll on.

This is a beautifully illustrated, comprehensive little volume that deserves to come with you on your beach holiday. It’ll prompt more careful examination of the flotsam and jetsam on your local beach, and, probably, more early morning low-tide visits to find the best pickings!

Wild Card magazine featured this book when it was published. Get it online here if you’re in South Africa, or here for your Kindle.

Bookshelf: Seaweed Chronicles

Seaweed Chronicles: A World at the Water’s Edge – Susan Hand Shetterly

Seaweed Chronicles
Seaweed Chronicles

This is one of the best kinds of popular science book. It reads so easily that by the time you’ve absorbed enough material to attain a diploma in phycology (the study of seaweed), you also feel as though you’ve met and befriended a varied cast of individuals whose lives revolve – in various ways – around slippery marine algae.

It’s written by an American author, and the book centres squarely on the coast of Maine in the United States, obviously much loved by the author. It’s not clear initially that the geographical focus of the book is so narrow; some readers may want to know this in advance. While reading, I was grateful for the perspective that a Veld and Sea seaweed foraging course gave me on our local seaweeds.

Vignettes of seaweed-centred lives, from foragers turned businesspeople, to scientists, to shepherds whose flocks feast on seaweed during their coastal sojourns, introduce us to a cast of characters illustrating the many uses and commercial possibilities of seaweed, as well as the management and conservation challenges associated with its harvest. Seaweeds are pivotal in coastal ecosystems, providing vital habitat and sustenance. This isn’t just a science book (which some may find frustrating). It’s as much about the people as about the seaweed – but you will learn some science from it!

There’s a good review here at the New York Journal of Books.

Get the book here if you’re in South Africa, otherwise here.

 

Bookshelf: Sea Change

Sea Change: Primal Joy and the Art of Underwater Tracking – Craig Foster & Ross Frylinck

Sea Change
Sea Change

The Sea Change project may be familiar to you from their large format photographic displays, one of which was for a time along the promenade in Sea Point, and is currently in Lamberts Bay. You may have read about the project, or seen its members – ocean-loving filmmakers, journalists, scientists – diving in the cold water of False Bay year round, without wetsuits. You may even have seen the BBC’s Blue Planet II series, in which the filmmakers, guided by Craig Foster and his fellows, captured an incredible octopus sequence filmed on our doorstep in False Bay.

The Sea-Change book has been a long time in the making, and is the product of hours upon hours upon hours spent in the water, observing the animals that call the kelp forests home. The book contains a story of loss and discovery – that of Ross Frylinck – interwoven with large-format photographs of scenes from the kelp forest, taken by filmmaker and naturalist Craig Foster, a co-founder of the Sea-Change project. Foster also provides the captions.

As a diver, it was immediately clear to me that a great deal of patience and close observation was required to gain the deep understanding that Foster has of the smallest creatures living among the kelp. There is no substitute for time in the water. There is no substitute for swimming slowly, deliberately, and for spending extended time looking at one place. The marks that animals leave on rocks, kelp stipes, the sand, and even on each other’s shells, can tell a story.

I learned a huge amount about animal behaviour from this book, and about the interconnectedness of all the elements of the watery, beautiful world around the Cape Peninsula. The photographs are beautiful and striking, capturing moments that one would be extremely lucky to see during the normal course of things. Diving for more than an hour a day, every day of the year, however, makes such things more commonplace.

Sea Change presents a beautiful opportunity for the wider community of ocean lovers to learn from the unique approach taken by the Sea-Change team (this article gives a good sense of it), and to learn how to understand and observe the animals that surround us when we look beneath the surface of the inshore kelp forests. The project also has something to say about how science happens, and the vital connection between science and storytelling. Identifying animals is fun, but – as any veteran twitcher will tell you – the next level is understanding behaviour. This is a challenge I’m happy to take up.

Get a copy here, or directly from the Sea Change team.

Newsletter: The joy of kelp

Hi divers

Weekend dive plans

No diving The forecasts vary wildly this weekend. Windy says howling south easter everywhere, whilst other sites say mild wind suitable for some Atlantic diving. The mountain will break some of the wind so I am sure Table Bay sites will be good, and Hout Bay much the same. I have students for the pool this weekend so there are no launches planned.

Kelp forest near Pyramid Rock
Kelp forest near Pyramid Rock

Kelp night

Learn all about kelp at the Two Oceans Aquarium next Thursday evening, 31 January. There will be talks on kelp science, kelp as a habitat, and kelp as a snack. Read more here, and book tickets at Quicket.

Camera housing

Clare is selling her Sony underwater housing that fits the Sony RX100 range of cameras. If you’re interested, drop me a mail and I’ll put you in touch with her.

regards

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

Diving is addictive!

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Newsletter: Batten down the hatches

Hi divers

Weekend dive plans

No diving

Fish Hoek Beach on a stormy evening
Fish Hoek Beach on a stormy evening

We have not had that much in the way of proper stormy weather this winter, however, that seems set to change for the weekend. Strong winds, big swell and lots of rain don’t bode well for any diving activities… Unless it is in the aquarium.

regards

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

Diving is addictive!

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Newsletter: Signs of summer

Hi divers

Weekend dive plans

Saturday: Boat dives from False Bay Yacht Club

Sunday: Boat dives from False Bay Yacht Club

The Admiral's Waterfall after heavy rains
The Admiral’s Waterfall after heavy rains

We are certainly seeing some strange signs of summer despite the fact that this time of year is supposed to be wet and cold. While the warm weather this month does make surface intervals pleasant, they do also mean we’re not having the rain we need, and they encourage plankton blooms, which reduce the visibility.

There are some large patches of algae blooming around but I think there will be clean conditions by Saturday if the current north westerly winds hold. I am keen to launch on Saturday and Sunday but will decide tomorrow on where and when. Let me know if you want to dive!

regards

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

Diving is addictive!

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Newsletter: Signs of winter

Hi divers

Weekend dive plans

No launches planned – diving on Tuesday and Wednesday next week!

The weekend has typical winter conditions. A long period swell of around 5-6 metres with 30 – 40 kilometre/hour winds means really rough and bumpy surface conditions, not the kind of conditions I enjoy diving in. We have no planned launches. Go flower hunting instead. (The flower in the picture, Hessea cinnamomea, only blooms the winter after a fire, and then goes dormant, sometimes for decades, until the next burn.)

Hessea cinnamomea at Cape Point
Hessea cinnamomea at Cape Point

The visibility is decent and that won’t change too soon. Tuesday and Wednesday have less swell and very little wind so we will launch then. Download a leave form and complete it, and send it in to whoever will miss you if you don’t turn up at work… And join us for some aquatic therapy.

regards

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

Diving is addictive!

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Goose barnacles in motion

Ok, so there had to be a video. Here are some of the goose barnacles (Lepas testudinata) that I found on Noordhoek beach last month. Bear in mind that they are out of their natural habitat (which is sea water) and were struggling in the sun. (I did try to drag some of the kelp back to the sea, but the pieces were huge and high up on the sand.) This group of barnacles was quite frisky, and shows you what a raft of kelp colonised by goose barnacles might look like if you swam underneath it.

For more on goose barnacles, visit this post.

Goose barnacles on the beach

A (lovely, rain-bringing) onshore wind left great rafts of kelp all over Noordhoek beach one weekend in mid May. Finding anything of substance on this beach is unusual; it’s on an exposed piece of coastline and all but the most robust objects are dashed to pieces before they arrive on the sand. Seeing all the washed up kelp also reminded me that frequenting the beaches inside False Bay, that are daily cleaned of washed up kelp by the City of Cape Town, is liable to give one a skewed idea of just how much kelp naturally washes up on the sand.

Kelp stipe covered in goose barnacles
Kelp stipe covered in goose barnacles

This time, there was kelp, and lots of it. Several of the pieces of kelp had been colonised by goose barnacles. There are several species of goose barnacle that occur off South Africa’s coast, but these ones are Lepas testudinata. They are incredibly strange looking animals, and some of them were still alive and writhing slowly in the drying sun.

In parts of the world (I’m looking at you, Iberian peninsula), goose barnacles are an expensive delicacy. I have nothing to say about that.

Goose barnacles, with my paw for scale
Goose barnacles, with my paw for scale

Lepas testudinata larvae most often attach to free-floating pieces of kelp (Ecklonia maxima) and plastic debris, which is why you have probably never seen these mesmerisingly gross-looking creatures while on a dive. In the picture below, you can see that they’re attached to the bottom of a kelp holdfast, where it would ordinarily attach to the rock. This shows that they attached after the kelp broke off.

A kelp holdfast encrusted with goose barnacles
A kelp holdfast encrusted with goose barnacles

Each barnacle is possessed of a long fleshy peduncle, or stalk, which attaches to the kelp holdfast, stipe or fronds. On the end of the peduncle is a carapace (shell) made up of five separate pieces. The large part of the barnacle on the end of the peduncle (what you’d think of as its body), covered by the carapace, is called the capitulum. The apparatus that the barnacle uses for feeding – essentially six pairs of hairy legs – reside inside the carapace, along with the mouth. There’s some more detail and a nice diagram at this link. If you are familiar with other kinds of barnacles – the volcano-shaped ones that live on rocks, ships, whales and piers for example, then most of this (except the peduncle) should sound familiar to you.

Lepas testudinata goose barnacles
Lepas testudinata goose barnacles

Research done around South Africa’s coast (published here) by Otto Whitehead, Aiden Biccard and Charles Griffiths, identified the marked preference of Lepas testudinata for attaching to kelp. The researchers surveyed a selection of beaches around South Africa’s coast, from the west coast of the Cape Peninsula up to northern KwaZulu Natal, between June and October 2009. When they found goose barnacles washed up, they recorded the species of barnacle, the type of material they were attached to, the dimensions of the object, and its location. They also estimated the number of barnacles in each colony they found.

Lepas testudinata was the species they found most commonly, of the six species in total that they identified along the area of coast that was surveyed. (There’s a nice picture of the six species in their paper, which I used to identify the ones I found.)  This species of goose barnacle was found to prefer kelp, as mentioned, and also tended to colonise large objects compared to the other species (this could, of course, be because pieces of kelp are usually larger than items such as bits of plastic, glass, feathers, and shells that some other species prefer).

Kelp fronds with goose barnacles
Kelp fronds with goose barnacles

Lepas testudinata was the only species of goose barnacle that the researchers regularly found to form colonies comprising more than 1,000 individuals. It is also the only species of goose barnacle recorded by the survey that is only found in temperate (cooler) waters, which happens to be where kelp is found, too.

The researchers note that the goose barnacles of the Lepas testudinata species that they found on kelp seemed to have exceptionally long peduncles, some more than 25 centimetres long, and that this seems to differ from what has been previously known about them (which is that they have “short, spiny” peduncles). They suggest that perhaps the variety of Lepas testudinata that colonises kelp may even be a separate species from the one previously described (more research obviously required to ascertain this). You can see from my photographs that the peduncles of the washed up Noordhoek beach goose barnacle colonies are also quite long, some easily 20 centimetres in length.

Clusters of goose barnacles on a kelp stipe
Clusters of goose barnacles on a kelp stipe

They also found that the increasing prevalence of long-lasting and buoyant plastic marine debris and other anthropogenic objects around our coastline, which some species of goose barnacles preferentially attach to, gives these weird little creatures increased opportunities to form colonies, and to spread to new places. This is one of those interesting phenomena to keep in mind, as humans inexorably alter the environment. Some creatures will benefit in strange ways from warming oceans, and others will find new homes in the garbage we leave lying around.