Bookshelf: Shoreline

Shoreline
Shoreline

Shoreline: Discovering South Africa’s Coast by Jeannie Hayward, Jaco Loubser, Claudio Velásquez Rojas

Sometimes I do things in the wrong order, and reading this book (I think) is an example of that. It’s the companion volume to locally-produced series Shoreline, of which I have only watched one episode while having a raucous conversation with my sister about whether her former junior school rival had aged well.

Like the television series, Shoreline the book is divided into chapters by location, traversing South Africa’s 2,800 kilometres of shoreline from the Orange river to Kosi Bay. Much of the text is taken directly from the television program, for which the script was written by the brilliant Tom Eaton. Magnificent photographs by Claudio Velásquez Rojas, who worked with Thomas Peschak on Currents of Contrast. The aerial photos in particular are incredible – much of South Africa’s coast is dramatically rocky with gorges, cliffs and free-standing formations such as Hole in the Wall at Coffee Bay, and seeing it from an unusual angle is very special.

The book is not solely focused on the marine and coastal wildlife and plants found along our shores, although many species are singled out. There is evidence of extremely early human settlement and family groups along the South African coastline, where the poly-unsaturated fatty acids available from marine species such as limpets would allow large-brained humanoid inhabitants of the sea caves along the southern Cape coast to thrive. There is thus a strong archaeological focus to the volume, and the marriage between natural history and anthropology, geology, oceanography, zoology, botany and archaeology is beautifully achieved. The communities that currently inhabit the shoreline and utilise its resources also feature, and I enjoyed learning of the fish kraals at Kosi Bay, the fish traps built by 19th century farmers along the Wild Coast, and the Thembe-Tonga people, who harvest red bait and other invertebrates from rock pools at full and new moon. The book also touches on subjects such as the KwaZulu Natal shark nets, Knysna seahorses, the diamond industry on the West Coast, and a number of other special interest subjects that apply to different sections of our coast.

As soon as I finished reading this book I made plans for a midweek break at De Kelders for me and Tony later this year (during whale season) and I have been plotting how we can explore some of the Wild Coast without going missing or getting stuck in the mud. The South African coast is compelling and varied, and it seems that one could travel it for a lifetime without getting bored. This beautiful book showcases the beauty, variety and history of our coast in spectacular fashion.

There are some representative photos here. A short review can be found here. I’d recommend it for locals as well as for tourists who want a coffee table volume to take home as a souvenir – this one has substance, as well as the requisite pretty pictures.

You can purchase a copy of the book here.

Bookshelf: The Living Shores of Southern Africa

The Living Shores of Southern Africa – George & Margo Branch

The Living Shores of Southern Africa
The Living Shores of Southern Africa

It took me a while to get my hands on a copy of this classic volume by Margo and George Branch, with photography by Anthony Bannister. It was a staple in the classroom of every biology teacher I ever had, and occupies pride of place behind the microscope display at the Two Oceans Aquarium, where it has helped countless nonplussed volunteers answer sticky questions about jellyfish reproduction or the eating habits of limpets. It was first published in 1983 and is long out of print.

The first half of the book deals with habitats – the rocky shore, beaches, estuaries, the open ocean, coral reefs, and kelp forests. The authors manage to sneak in quite a lot of physical oceanography without one noticing, as it obviously impacts the flora and fauna that can colonise a particular area. Prof Branch has a special interest in limpets, and I was amazed to discover the intricate adaptations that these unassuming little creatures have to life in the highly competitive, high stress intertidal zone. The section on kelp forests was also wonderful to me, as a regular diver in these parts! I found the chapter on estuaries somewhat dispiriting, given that it was written thirty years ago and it seems unlikely that matters have changed since then. Prof Branch used the Richard’s Bay estuary of the Mhlathuze River as an example of how human interference turned a thriving, sensitive ecosystem into a muddy wasteland in a matter of a couple of years. I have not visited Richard’s Bay, and indeed had not heard anything about this particular estuary before encountering it in this book, so I will have to do some research to find out whether it’s still in such a parlous state.

I found the sections on sharks, seals and whales – under the chapter on man and the sea – puzzling and upsetting, but perhaps they are just a reflection on where scientific understanding of ecosystems was in the early 1980s. I would be interested to hear Prof Branch’s views on these three types of animal today.

Sharks

On sharks, the authors mention that the Natal Anti-Shark Measures Board (now renamed to something less obviously brutal, but still with the same ultimate aim of killing sharks) killed 11,700 large sharks in eleven years (presumably the decade to 1980). The authors state that it is not known what the effect of removing so many top predators will be on the ecosystem, but do note that there were an estimated extra 2.8 million dusky sharks – a smaller species that has thrived in the absence of tiger and bull sharks – at the end of the eleven year period in question. I was immediately reminded of the fairly recent shark bite that occurred on a baited dive on Aliwal Shoal a few months ago. The culprit was a dusky shark.

What I found unsettling was that very little concern was expressed about the impact of killing so many sharks – highly migratory creatures, in many cases – along a small region of the coastline. The authors do mention the case of Tasmania, which after a few years of shark nets experienced a population explosion of octopus (traditional shark food), who destroyed the local rock lobster population and the profitable local lobster fishing industry. I know that the authors’ focus has been more on coastal species, but their apparent lack of recognition of the role of sharks in a healthy ocean was strange to me given their obvious awareness of how vital is every link of the food web on the rocky shore (urchins, abalone, kelp, sea otters, rock lobster, etc.).

Seals

The authors describe the economic value of the seal cull (which in the 1980s was a grim reality of South African life, and in Namibia still is the case). Baby seals were (are) valued for their soft pelts and the oil in their bodies, and mature seals just for the oil – their pelts were deemed to be too battle-scarred to make into a fur coat. The method of killing baby seals with a blow to their heads was sanctioned as humane by the NSPCA because their little skulls are still soft when they are young (and, in a happy coincidence, it doesn’t damage the pelts).

Apart from the economic rationale for killing seals, the authors state that seal colonies “attract sharks” – as if this is a reason to destroy them. I found this extremely confusing – why is one creature more important or desirable than another? The fact that fish, limpets, seals and sharks exist in the ocean means that they all have a role to play, and that somehow these populations lived in balance before human intervention.

Another reason provided for the annual seal cull (which at one point left 35 seals on Seal Island, in contrast to the current population of over 75,000 seals) was that their numbers were increasing “unchecked” and threatening the nesting sites of seabirds on the island. Nowhere do the authors acknowledge that the reason for the seal population explosion could be that their natural predator, the white shark, was fished to the brink of disappearance off the South African coast by testosterone-fueled trophy hunters. Fortunately today shark and seal eco-tourism is big business, and I don’t think (I stand to be corrected) that any seals are legally killed in South Africa any more.

Whales

Whaling was an entrenched part of the South African economy from the early 1800s, but was comprehensively banned in 1979, shortly before this book was published. In Blue Water White Death the whaling station in Durban was shown, and whale carcasses were used by the filmmakers to attract sharks. The authors provide a synopsis of the state of whaling in the world’s oceans at the time of writing (depressing – what is the validity of “scientific whaling” when it is conducted by a country that feeds whale meat to school children?) and the population status of various types of whale.

They suggest that, because the small Minke whale competes with blue whales for food, Minke whales should continue to be hunted in order to give blue whales a chance at increasing their numbers. My (admittedly uninformed) view of it is that – what with the population explosion of krill that whaling engendered in the Southern Ocean, the blue whales aren’t even going to notice a few small Minkes dining at the lunch bar with them. Whale populations have been reduced to such a tiny fraction of what they used to be that – for a long time still, everything else being equal – competition for food isn’t going to feature in their population dynamics. My feeling on the matter is that if a Minke whale ever even SEES a blue whale, let alone has the opportunity to argue over a ball of krill with it, it should count itself a lucky little whale and move right along.

The second half of the book deals with specific organisms, their life cycle (beautifully illustrated by Margo Branch), and their habits. The authors focus on invertebrates, as (they say) fishes are extensively dealt with in other volumes. The accompanying photographs were taken by Anthony Bannister, and have not dated at all in terms of quality – they are vivid, clear, and beautiful.

Some of what I learned

I learned a huge amount from this book. It’s clearly provided source material for almost every other South African marine flora and fauna book that has been written, and sentences – that I’ve seen in other books and presentations – kept ringing bells with me (I tend to use my fish ID books quite hard, trying to wring out every last fact from the one-paragraph descriptions accompanying the photos). The authors in fact collaborated on the handy Two Oceans guide, which keeps getting better with each new edition and is indispensible for the travelling South African diver.

  • I learned that the presence of plough shells on a beach generally indicates that it is safe for swimming – these little snails surf in the waves using their large feet as a sail, and if there were rip currents they would be drawn offshore and lost. Their activities on fish Hoek beach are shown to great effect in the BBC’s The Blue Planet series.
  • I loved learning how Rocky Bank protects the western side of False Bay to some extent, slowing down the swells as they enter the bay and causing them to focus their power somewhere near the Steenbras River mouth on the opposite side of the bay.
  • I loved learning about limpets’ “home scars” – the spot on the rock that fits their shell perfectly, and that they somehow return to over and over after foraging for food – and how some species tend little gardens of algae, encouraging its growth by mowing paths in it (and getting fed at the same time). Simple things like the effects of strong or harsh wave action on the slope and sand type of a beach, and as a result the type of life that thrives there, were also fascinating.
  • I learned that 30 years ago (when this book was published) overfishing was already a serious, serious problem.

You can obtain a copy by scouring secondhand book stores, Amazon.com, and Amazon.co.uk.

Lecture: Meaghen McCord on Bull Sharks

A couple of weeks ago Tony and I attended at talk on bull sharks (also called Zambezi sharks by South Africans) given by Meaghen McCord of the South African Shark Conservancy (SASC) based in the Old Harbour in Hermanus. We’ve heard Meaghen talk before at False Bay Underwater Club, but we were particularly keen to attend this talk (held at the Save Our Seas Shark Centre in Kalk Bay) because some exciting things have happened since Meaghen spoke at FBUC. It was the third (we missed the second one because we were in Malta) in a series of talks at the Shark Centre, concerned with sharks and man. The first speaker was Christopher Neff.

Truth and fiction about bull sharks

Bull sharks (Carcharhinus leucas) are one of the species of sharks that are tolerant of brackish and fresh water conditions. They are not the only species that doesn’t mind freshwater – other examples include the Ganges river shark (found in the Ganges in India – surprise!) and a cluster of Australian freshwater shark species all from the genus Glyphis. They are not, as is popularly believed, solitary or territorial, but have been known to form feeding and hunting aggregations. Nor do they have the highest testosterone level of any animal – an often repeated assertion that Meaghen pointed out is false. This idea was based on a 1970s-era study involving only three animals: a male bull shark, and two female sharks.

The internet abounds with misconceptions and pejorative words about bull sharks, calling them “known man eaters” and citing their enthusiasm for attacking humans. As Meaghen noted, even innocent-looking deer are known to attack humans, and the most dangerous creature on earth – measured in terms of deaths it directly causes – is the anopheles mosquito.

Bull sharks have a low value in fisheries as their flesh is full of ammonia and urea (in other words, it tastes gross!), but they are killed for the shark fin trade – particularly in developing nations such as India and Mozambique. They are also favoured by sport fishermen. Until recently there was no limit on how many could be caught by each angler, but they are now restricted to one bull shark per day. Which is still one too many, if you ask me. As a result of the fishing and the finning, the IUCN lists them as globally near threatened.

Some knowledge exists in Africa regarding bull shark distribution patterns, growth, movement and reproductive habits, but there is nothing in the way of relevant management measures for these creatures. As you’ll see shortly, it’s vital that international co-operation takes place on this species, because they cross borders with alacrity!

Bull sharks in South Africa

Prior to 2009, bull sharks had only been recorded as far south as the Sundays River. Some gut instinct, persistence, luck and hard work led Meaghen and her team to catch a bull shark in the Breede River in 2009, representing a 366 kilometre range extension for the species. What’s more, the shark they landed measured 4 metres total length (tip of snout to farthest extent of caudal fins) which was 50 centimetres longer than the largest bull shark EVER recorded anywhere in the world!

The upper reaches of the Breede River (near Swellendam)
The upper reaches of the Breede River (near Swellendam)

The shark they caught was named Nyami Nyami after the Zimbabwe river god, and was tagged and tracked for 13 days, during which time she did not leave the river at all. She went as far as 32 kilometres upriver, but spent most of her time around 11-15 kilometres up the river, eating the bait off the recreational anglers’ hooks. Her movement was mostly tidally driven, and theories for this include energy saving (important for wild animals), and the possiblity that fish are driven off the river banks by the outgoing tide, resulting in a free meal for the passing shark.

The tags in use in the Breede at the moment are acoustic tags that emit a signal that can be detected by a hydrophone. In order to track the shark, the SASC team has to follow it around with a boat, orienting the hydrophone to find the maximum signal strength to figure out which way the shark is moving. If they get too far from the shark, it’s lost.

Pumpkin

Since meeting Nyami Nyami, in January 2010 the team caught, tagged and tracked two males, both three metres long, called Pumpkin and Jeremy respectively. Jeremy was named after Jeremy Wade, the host of Discovery Channel’s River Monsters show and a so-called “extreme angler” who helped in the capture of both sharks (and was filmed during the process for his show, I assume).

Pumpkin was caught again in March 2011, and fitted with a pop-up archival tag (PAT). It was shortly after doing this that Meaghen came to talk at FBUC, and she shared how the tag had been programmed to pop off Pumpkin’s body after 99 days. It records light intensity, depth, temperature, and a range of other measurements, and when it pops to the surface it announces its location (barring any malfunction) to a passing satellite.

Beach on Ilha de Magaruque, one of the Bazaruto islands
Beach on Ilha de Magaruque, one of the Bazaruto islands

Pumpkin’s tag came off after only 53 days, and surfaced somewhere near the Bazaruto Archipelago off Mozambique. The shark had travelled over 2000 kilometres in just under two months – completely rubbishing the commonly-held view that these are sluggish, lazy animals. A reward is offered for the return of the tag itself (just in case you’re heading to Mozambique any time soon) – certain data can only be retrieved with the device in hand.

SASC

SASC’s objective is “promoting understanding of and participation in the management of bull sharks in Southern Africa.” They recieve funding from Save Our Seas, and support from the Department of Agriculture, Forestry and Fisheries (DAFF). Their experience with Pumpkin has led to what Meaghen called “three burning questions” that they’d like to answer:

  1. What is the role of bull sharks in the Breede River?
  2. How do they influence community structure in estuarine systems?
  3. How can this information be used to co-manage estuaries and apex predators?

The bull shark project aims are to determine the genetic structure of the Breede river bull sharks, and determine whether they are a distinct genetic group. They also aim to determine abundance and population structure of these sharks (how many males, females, what ages they are, etc.) and to find out how they utilise their habitat.

A question that I’d love to see answered (and which they plan to) is whether the Breede river is a pupping ground for Zambezi sharks! The St Lucia estuary is the only known pupping area for these sharks in South Africa, but it’s been closed to the sea for the last decade.

The Breede river is also impacted by physical activities and chemical substances brought there by humans, and it’s important to determine how these affect the sharks, their distribution and movement in the river.

Future plans

SASC plans to collect fisheries and eco-tourism data, conservation status, current management strategies, distribution and abundance data for contribution to an online “bull shark atlas” which will facilitate international co-operation and education as regards this species. They’d also like to find out whether these sharks exhibit philopatry (return to their own birthplaces, and possibly breed there too).

An acoustic array is planned, comprising a set of permanently fixed receivers in the river that will record the movements of tagged animals. SASC hopes to tag prey fish such as dusky kob and spotted grunter, as well as sharks. An exciting development in this regard is the Ocean Tracking Network, an international initiative that will be by led locally by the South African Institute for Aquatic Biodiversity. The OTN will comprise a large number of underwater receivers or listening stations that can all read and record data from compatible tags. In this way a fish tagged in South Africa can be tracked all over the world, if it swims near any of the OTN receivers.

The Breede river system is massively impacted by human activity in various ways, and SASC would like to define the role of apex predators in this sort of environment. There are also plans to study niche partitioning (such as concentration on specific food sources by each species in the face of competition) with other large apex predators. Great whites, bronze whalers, ragged tooth sharks and hound sharks are also found around the river mouth.

Bull sharks and people

Unsurprisingly, some of the Breede river residents and holiday home owners have reacted very negatively to the discovery of sharks on their doorstep. The fact that these sharks were there long before the people were, and that no incidents of any kind have been reported, as well as the presence of several other shark species just outside the river mouth (as I mention above), makes this reaction a bit ridiculous. The presence of these sharks also indicates that the Breede river is a healthy ecosystem, which should inspire pride in those who live near it. Meaghen said that SASC receives co-operation and enthusiastic support from many of the locals too – particularly those who have been in the area for a long time. Personally, I’d be thrilled if a shark lived in my front garden!

I particularly liked the thoughts expressed by one of the other members of the audience, who apparently has a boat and house at the Breede river and has offered to help Meaghen with the project. He expressed concern that “Rambo types” will come to try and catch the sharks or prove something about themselves, but he also said that the bull sharks “deserve to be there”, and they don’t come and harrass him in his bed, so he sees no reason to disturb them in their home.

For pictures of bull sharks, check out the SASC website or use the Google – I don’t have any taken by either me or Tony and I hate poaching other people’s pictures! They are very beautiful creatures, with sharply delineated, squared-off faces.