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.


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’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.

Lecture: Christopher Neff on the politics of shark attacks

One rainy Thursday in June Tony and I attended the first of what will hopefully be a monthly series of talks at the Save Our Seas Shark Centre in Kalk Bay. The speaker was Christopher Neff, a PhD candidate at the University of Sydney. Chris is doing his doctorate on the politics of shark attacks, and was in South Africa to learn more about our Shark Spotters program (and to meet some great white sharks).

He spoke about his doctoral research, and described how perceptions of risk and other factors influence government responses to shark attacks. I was struck by a couple of things:

It isn’t all Peter Benchley’s fault

Sure, Jaws demonised sharks and I don’t think Peter Benchley is wrong to feel some residual guilt about the ensuing panic and slaughter of creatures assumed to be bloodthirsty maneaters. The phrase “shark attack” – as opposed to the previously popular “shark accident” – was invented in 1929 by Australian surgeon Sir Victor Coppleson. He mounted a one man crusade, alerting people to the dangers of sharks, in response to a fatal shark attack off Sydney that year. He published a book on the subject of shark attacks in 1958, and was considered a world authority on the subject. Shark nets were installed on the beaches of New South Wales in the early 1930s in response to the findings of the Shark Menace Committee appointed to study the issue of human-shark interactions.

Shark spotters is unique

We’ve posted before about Cape Town’s Shark Spotter’s program on this blog, and I consider myself fairly familiar with its workings, but Chris’s talk shed new light on the program’s importance and singular success.

I was particularly struck by the uniqueness of the Shark Spotters program in the world. In response to the fatal 1929 Australian attack mentioned above, a program functionally identical to our Shark Spotters (observers watch for sharks, and warn bathers to exit the water) was proposed. The program never took off, and the reasons for this – chiefly stemming from a lack of agreement by stakeholders and their conflicting aims – form part of Chris Neff’s PhD studies.

In other countries (such as Australia) and even in parts of South Africa (Durban), shark nets are popular and are widely considered to be very successful. Brazil used hooks laid on the ocean bottom near the beaches, and Hawaii has recently taken down all the interventions that could kill sharks in order to protect humans (nets among them, I think).

The Cape Town Shark Spotters program was started in 2004, and since then just under 1 000 sharks have been spotted in the waters around the Cape Peninsula. The proposal to start the program succeeded where the 1929 Australian proposal did not, for several reasons:

Strong backing

The City of Cape Town, surf lifesavers, the trek fishermen, and community groups all backed the proposal. South Africa has a strong history and cultural ethic of wildlife conservation, and the proposal for a shark spotting program dovetailed nicely with this.

Agreement among proponents

It was agreed that any management program should address all the problems raised by human-shark interactions:

  1. altering human behaviour
  2. restoring confidence to enter the water
  3. conserving the sharks

The shark spotting suggestion deals with all of these issues equally well. (Shark nets, for example, answer the first two concerns but not the third one.)


The local trek fishermen have been watching for sharks from the top of Elsie’s Peak for decades. They had thus proved the feasibility and affordability of the solution.

Trek net fishermen at Muizenberg
Trek net fishermen at Muizenberg

(Tony took the picture above from the top of Boyes Drive, next to the Shark Spotter’s hut.)


Shark Spotters answers public concerns about going into the water, as well as environmental concerns, because no sharks are killed as a preventative measure. Shark Spotters use a siren to encourage people to get out of the water when a shark is sighted, and provide them with information when visibility is too poor to identify sharks in the water (via a black flag – see the image below). Hourly water use around shark warnings indicates that the public has developed a high level of trust in the program, as surfers and swimmers return to the water when the all-clear signal is given. (Initially this was not the case – the beach would empty after a shark sighting.)

Cape Town’s topography and ocean conditions make it uniquely suited to this type of effort. There are elevated geographic features such as hills and mountains from which observers can watch for sharks, and the water is clear. Durban installed shark nets over 50 years ago, and while the bycatch is appalling (dolphins, turtles, etc) this seems to satisfy the stakeholders that Durban’s large number of water users, drawn by the warm waters lapping the coast, are protected. What’s more, the tiger and bull sharks common on the KZN coastline are not endangered, whereas the local great white shark is. A shark net solution for Cape Town would fly in the face of all conservation principles.

Black Shark Spotters flag flying at Fish Hoek indicating poor visibility
Black Shark Spotters flag flying at Fish Hoek indicating poor visibility

Tony and I appreciated Chris’s philosophy on information sharing, and particularly his comment in closing that “while my research is independent, the funding is not.” Too much research is conducted using donations from the public, and then kept secret. Unless you paid for the research yourself, it’s not yours to keep! We’re grateful to Chris for sharing.