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.

 

Newsletter: Signs of the times

Hi divers

Weekend dive plans

Sunday: Shore dives at Windmill or A Frame

Sewage spill at Long Beach
Sewage spill at Long Beach

Wildly different forecasts for this weekend make me inclined to go with the safest option, namely Sunday, as the best dive day. I have students to dive so will be shore diving, most likely from Windmill or A Frame, as when I checked earlier this week, the “stay out of the water” sign remains at Long Beach.

regards

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

Diving is addictive!

To subscribe to receive this newsletter by email, use the form on this page!

Visible shipwrecks: the barge Margaret

One of the most spectacular shipwrecks I’ve ever seen was that of the 100 metre long unmanned barge Margaret, which ran aground at Jacobsbaai on the West Coast on 24 June 2009. Margaret was carrying two halves of a floating dry dock and twelve river barges (positioned atop each other in side by side pairs, with two rows of three at the bottom). She was under tow by the tug Salvaliant from the Chinese shipyard where everything was manufactured, to Rotterdam. The barges were destined to transport cargo up and down the navigable rivers in Europe. During a winter storm, the tow parted, and Margaret and her cargo ran hard aground on the rocky reef just outside Jacobsbaai.

The eight storey pile of barges in December 2009
The eight storey pile of barges in December 2009

Salvaging the barges proved to be an almost intractable problem, so Margaret was still sitting firmly a couple of hundred metres off the beach when Tony and I visited six months after her grounding, in late December 2009. The stack of barges and two halves of a floating dry dock (the blue parts of the structure in the images) was clearly visible from a great distance. The sight was even more incongruous than that of the Eihatsu Maru aground on Clifton beach, which was  a wreck-lover’s dream (but unfortunately not a permanent arrangement).

View of the barge Margaret from atop the sand dunes at Jacobsbaai
View of the barge Margaret from atop the sand dunes at Jacobsbaai

I wish I’d taken a picture of what the wreck looked like as we drove down the hill into Jacobsbaai, but you can see one here if you scroll around a bit. It looked like an office block rising out of the ocean. The wreck was so large that it was visible from almost every point in the sleepy town, and the brain struggled to make sense of the sight. It’s clear from the images what a challenge it must have been to tow the barge in the wind, as the forty to fifty metre high, perfectly flat sides of the stack must have provided tremendous resistance in a gale.

Portion of the barge wreck at Jacobsbaai
Portion of the barge wreck at Jacobsbaai

The owner ran out of money to continue salvage in February 2010, and Margaret was becoming increasingly damaged and unstable as time passed. The risk of the upper barges coming loose during another storm, and drifting away to cause a hazard to other ships or coming ashore on the beach, was great. It was decided by SAMSA to persist with an attempt to reduce the wreck, at taxpayers’ expense. Any money obtained by selling off the salvageable barges would go towards defraying costs.

During the salvage work on the barge Margaret
During the salvage work on the barge Margaret

Salvage

Tony and I visited the wreck again in April 2010, after the demolition that freed six of the topmost barges. The seaward wall of the upper piece of floating dry dock, weighing 91 tonnes, had been cut away to allow the barges to slide off freely.

The remains of the barge Margaret in April 2010
The remains of the barge Margaret in April 2010

Over two tons of explosives were used in total.  Small (125 kilogram) explosive charges were set off one after the other to create a ripple effect that dislodged the top six barges. These were towed to Saldanha, and then sold.

The wreckage of Margaret and her cargo in April 2010
The wreckage of Margaret and her cargo in April 2010

If you like reading court judgments, here’s one in which the owners of the barges attempt to claim damages (massive ones) from the owners of the tug Salvaliant. There’s also a great collection of photos of the wreck in her various incarnations here.

The wreckage of Margaret in late April 2010
The wreckage of Margaret in late April 2010

In late April 2012, Tony snapped this lucky shot of two of the barges leaving Simons Town harbour under tow. They’d been moored against the harbour wall for at least a month, to the consternation and fascination of the local paddling community.

Two of the salvaged barges leaving Simons Town harbour in April 2012
Two of the salvaged barges leaving Simons Town harbour in April 2012

The remains of Margaret and her cargo were further demolished down to sea level and below, and now comprise an artificial reef. Fortunately there was no fuel or other pollutants in the stack of barges, which made the process significantly less polluting than it might otherwise have been.

The barge Margaret today

Tony and I visited Jacobsbaai to check out what remains of Margaret and her cargo in September 2018. The path to the wreck, which was formerly blocked off by hazard tape and “salvage in progress” signs, is wide and easily walkable. One can go right up to the rocks and view the wreckage from reasonably close up. Watch your foothold here, as it can be slippery and the rocks aren’t all firmly packed.

The remains of the barge Margaret and her cargo
The remains of the barge Margaret and her cargo

Look out for a small memorial to one of the salvors, who passed away in an accident on the wreck during the course of the salvage operation.

Sharp wreckage sticking out of the sea
Sharp wreckage sticking out of the sea

Parts of the wreck look like shark fins in the water, and it is possible that even more of it is visible at low tide.

The remains of the barge Margaret in 2018
The remains of the barge Margaret in 2018

You can find the wreck by turning off the R399 towards Jacobsbaai, and continuing towards the coast until the road becomes gravel. Carry on this road, and when you reach a T junction take a right turn to circle around the tiny, sheltered bay in front of you. When you can’t drive any more – there will be a small housing development in front of you – park the car and either walk up the steps on the dune to get onto the beach, or, preferably, through the houses. The paved area will give way to a wide gravel path that the salvors used to access the wreck. Continue straight along it and you’ll soon spot the wreckage on the rocks ahead and to your right. Co-ordinates are approximately -32.964140, 17.881612.

Path to what remains of the barge Margaret
Path to what remains of the barge Margaret

If you’re interested in visible shipwrecks, check out my ebook Cape Town’s Visible Shipwrecks, and 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.

Newsletter: Traditions

Hi divers

Weekend dive plans

Boat dives on Sunday or Monday / Shore dives on Monday (conditions dependent)

Traditionally Easter is a difficult time for diving. Many people are away and the weather does not always play ball. Add to this the traffic congestion from the Two Oceans marathon on Saturday… This weekend we may dive from Hout Bay on Sunday or Monday, or perhaps shore dives from Long Beach, wind dependent.

We are out tomorrow on a full day private charter but I do think Long Beach will be a good option if you feel like shore diving.

We send well wishes to everyone celebrating a religious observance this weekend. For those of you who celebrate Easter, here’s an egg for you:

Catshark egg on a sea fan
Catshark egg on a sea fan

Plastic and Water

On the marathon topic, watch this video and see how the Two Oceans Aquarium and Old Mutual are teaming up to reduce the use and impact of single use plastic, and learn about the aquarium’s turtle rehabilitation program.

This article on how to responsibly stockpile (or just purchase) bottled water, is very helpful if you’re working on water security at home, but don’t want to contribute to an environmental apocalypse.

regards

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

Diving is addictive!

To subscribe to receive this newsletter by email, use the form on this page!

Newsletter: Close call

Hi divers

Weekend dive plans

To be confirmed – let me know if you want to stay in the loop!

The weather forecast, and what’s actually happening, is extremely difficult to call at the moment. I’d like to do boat and/or shore dives this weekend, but it remains to be seen whether the wind will allow it. If you’d like to dive and have a little bit of flexibility, please message me and I’ll keep you informed. I’ll make a call this afternoon on plans for tomorrow.

Festive whale at the airport
Festive whale at the airport

Desalination talk

On Tuesday 5 December at 7.00pm, Dr Ken Hutchings will give a talk on desalination: how it works, and what its effect might be on the marine environment. This is an extremely topical subject given that many of the City of Cape Town’s alleged water crisis relief plans depend on the implementation of small-scale desalination plants around the peninsula, which will discharge salty brine (a byproduct of the reverse osmosis process) back into the ocean. Is this a big problem? Come and bathe your mind in some facts. The facebook event with more detail is here.

regards

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

Diving is addictive!

To subscribe to receive this newsletter by email, use the form on this page!

A new ocean MOOC starting on Monday!

Online learning with SDI
Online learning

This one snuck up on me. Starting on Monday 25 April (yes, this Monday), a massive open online course (MOOC – remember those?) about science-based solutions to challenges facing the world’s oceans becomes available to the curious. It’s a collaboration between Kiel University in Germany, its GEOMAR Hemholtz Centre for Ocean Research and “cluster of excellence” (I don’t know!) The Future Ocean, and the International Ocean Institute.

The course syllabus is comprehensive and spans 10 weeks of online study. You will cover topics from oceanography, marine biology, and geology. The aspects of the course related to humans include ocean governance, human-ocean interactions, changes happening along our coastline, and – most importantly – solutions from marine spatial planning to ecosystem management.

It looks very comprehensive and unmissable if you’re a marine freak. Go to oceanmooc.org to learn more and sign up. For your own privacy, protection and future access (and this applies to every website that offers you the option, not just this one) don’t sign in with your facebook, linkedin or other credentials. Make a new account using your email address, and create a new password.

Get to it.

How to help marine wildlife in distress

 

It’s not uncommon to come across marine wildlife – seabirds, seals, turtles – apparently in distress. This is not always the case, so before you mount a complex and dangerous rescue mission, or try to provide help where none is needed, it may be wise to get an expert on the telephone to help you determine whether it really is necessary. Fortunately there is a range of 24-hour wildlife hotlines to choose from, depending on what species you are dealing with.

Seals

Bull seal with plastic around his neck, in Hout Bay
Bull seal with plastic around his neck, in Hout Bay

Seals with plastic or fishing line around their necks should be reported to the Two Oceans Aquarium (if the seal was spotted around Cape Town harbour or the Waterfront), or, more generally to the SPCA Wildlife Unit on +27 (0) 21 700 4158/4159, or +27 (0) 83 326 1604 after hours and on weekends. Unfortunately the odds are your seal is probably not going to get the help it needs if it isn’t in the port of Cape Town or at the Waterfront; this doesn’t mean you shouldn’t do your darndest to advocate on its behalf.

You can help to deal with this problem at its source by retrieving any loops of plastic that you see floating in the water when you’re on a boat. Hout Bay harbour is a particular cesspit of plastic pollution, and with a nearby seal colony it’s a recipe for disaster. Cutting through any closed loops on plastic items (such as beer can holders) that you recycle or dispose of yourself also ensures that should the plastic end up in the wild, it won’t entangle an animal.

Seals found lying on the beach are usually not in trouble. Juvenile seals may rest for long periods – a couple of days at a time – on shore, and the most important thing to do is not to disturb them. They don’t need to be kept wet, they don’t need to be fed, and they can inflict a nasty bite. Encourage other members of the public to give the animal a wide berth, particularly if they have dogs. Lead by example. If the animal appears visibly unwell (fitting, for example) or is bleeding, then call the SPCA Wildlife Unit for a chat about what course of action is best.

Seabirds

Seabirds are most often found entangled in fishing line or plastic, pierced by fishing hooks, or, in the event of an oil spill, with oiled feathers. It is important to get help if possible, particularly for oiled birds.

SANCCOB has a 24 hour rescue centre which can be reached on +27 (0)21 557 6155 or +27 (0) 78 638 3731 (after hours & weekends). Their website provides the following advice to would-be seabird rescuers:

What to do when you have found an injured/sick/oiled seabird:

  • If you are unable to handle the seabird, SANCCOB will send out a unit to collect the bird.
  • If you approach any seabird, please approach with care. Some seabirds such as Cape Gannets and African Penguins have sharp beaks.
  • Have with you a towel, or blanket and wear protection over your hands and eyes. Use a towel/blanket to throw over the bird to catch it, ensuring that the bird is able to breathe.
  • If you have a large box ensure that there are holes for air before you place the injured/sick marine bird.

More information can be found here.

Turtles

During the autumn and winter months, juvenile and sub-adult sea turtles sometimes strand on Western Cape beaches. These animals are often shocked by the cold and in poor shape – they do not typically occur in Cape waters but are washed down in eddies of the Agulhas current.

Do not put the turtle back in the sea or into water. It is probably weak, dehydrated and hypothermic, and is likely to drown. Keep it dry, and call the Two Oceans Aquarium for further instructions and assistance. The aquarium rehabilitates and releases the turtles in warmer water when they are healthy.

Here’s detailed information from the Two Oceans Aquarium on what to do if you find a stranded turtle. Do the right thing!

Whales and dolphins

The City of Cape Town would like ocean users to report whale carcasses before they end up on the beach. This is mostly for public safety and resource allocation purposes, but if we can do anything to keep a whale carcass out at sea (or on a secluded non-swimming beach), it serves a conservation purpose as well. There’s a phone number you can use to do this – read more here.

If you come across a current or imminent live whale or dolphin stranding, contact the NSRI on +27 (0) 21 449 3500 immediately. They will activate the relevant authorities. Try to bear in mind that these events often do not end well for the animals concerned, as they are often sick or disoriented and impossible to assist. Be a help, not a hindrance, and obey whatever instructions you are given by the NSRI, SanParks, or whoever comes to take charge.

A free-swimming but entangled whale should be immediately reported to the NSRI as well – they will activate the South African Whale Disentanglement Network. Do not attempt to assist the whale yourself – this could be fatal for you (not the whale) – rather make a note of the direction it is swimming, and its precise location, and whatever other helpful information you can provide. Whale entanglements seem to be increasing in frequency around False Bay in particular, as more experimental fisheries are approved. (If this worries you, you could write a letter to DAFF about it.)

Article: Outside on acoustic sanctuaries for whales

Departing dolphins, and Christo
Departing dolphins, and Christo

Whales and dolphins make extensive use of sound to communicate. Some of the purposes of this communication may be to organise during a hunt, to socialise or to co-ordinate group movement.

The predominance of long-distance shipping as a cost-effective and efficient way to transport goods around the world has increased the amount of anthropogenic noise in the ocean to the extent that, in some parts of the world, populations of wild cetaceans struggle to make themselves heard in order to communicate with each other.

Outside Online describes a recent paper that proposes “acoustic sanctuaries” to protect cetacean populations of marine mammals off the coast of British Columbia in Canada. This is a fascinating idea, and need not be difficult to implement:

These quiet areas could be pain-free places for governments to formally institute quiet zones, the paper argues. Ships wouldn’t have to be rerouted, the authors note, they would simply have to continue avoiding sensitive areas.

Read the full article here.

To read more about acoustic communication between cetaceans, try this article, the book Listening to Whales by marine mammal scientist Alexandra Morton, or (for a touch of eccentricity) the book Thousand Mile Song.

Whale carcass reporting in Cape Town

Whale skull near the Thomas T Tucker
Whale skull near the Thomas T Tucker

The Environmental Resource Management Department at the City of Cape Town needs your help:

We would like to try and get to whale carcasses well before they wash ashore on our coastline to deal with them more effectively and efficiently. As ocean users, if you come across a whale carcass floating anywhere in False Bay or from Cape Point north to Silwerstroom Strand we would be most grateful if you could call, whatsapp or sms 083 940 8143 (available 24/7) with an approximate location and time of sighting.

Please could I ask that you also forward/share this email to as many friends, colleagues or groups that you are aware of that use the ocean as we would like as large a network of people as possible that could report sightings.

Save that number in your cellphone contacts, and do your bit for beach safety and, hopefully, for the environment, by reporting sightings of deceased whales before they reach the beach.

Ideally (environmentally speaking) dead whales should be left out at sea to be scavenged upon by marine life and then sink to the bottom and return their nutrients to the ecosystem. Unfortunately the prevailing summer wind direction in Cape Town (south easterly) generally brings any such carcasses onto the beach in False Bay. This is a hazard to human safety because of the co-incident inshore presence of great white sharks during the summer months. A dead whale is a great feeding opportunity for sharks, and its accompanying oil slick will be evident from miles away, potentially bringing in more sharks to investigate. This is why the City wants the opportunity to deal with whale carcasses before they reach your local swimming beach.

It’s timely to remember that while some cetaceans die and end up on the beach because of reasons such as ship strikes, ingesting plastic or other pollutants, or acoustic disturbances related to human activity, some of these animals also die of natural causes or illness unrelated to man’s impact on earth. Many times, scientists will examine the dead animal and be able to state what most likely led to its demise. While it is distressing to see any dead animal, and particularly strange and discomfiting to see a whale on shore, this is not necessarily confirmation that “the ocean is dying” or that we are “killing False Bay.” Sometimes it’s just the circle of life. Dead whales were an important source of nutrients and building materials to Strandloper communities long before industrial shipping plied the world’s seas.

For more on what happens to whales that die at sea (hint: it’s magnificent), check out this video. For more on the collision of dead whales and the urban environment, there’s this post about a whale on the beach in Fish Hoek, this one about a whale on the road in Cape Town, and this one about a stranded whale in the United States.

But I digress. Save this phone number: 083 940 8143, and tell your ocean-loving paddler, surfer, sailor, boater and diver friends to do the same!