Lecture: Kay Weltz on predicting white shark presence at False Bay beaches

On the same evening as Alison Kock delivered an update on the Shark Spotters program, we listened to Masters student Kay Welz speak about her analysis of the reams of data that the Shark Spotters have collected. The range of data under consideration stretched over five years, from 2006 to 2011, and was collected at Muizenberg and Fish Hoek beach by spotters who had done 100 or more shifts each. This set of data was selected for its quality, covering the beaches with the most sightings and the highest risk of a human encountering a shark.

The analysis considered a range of variables, and whether any of these increase the probability of a shark being present during a spotting shift (approximately 4-5 hours long). Presence/absence was used instead of counting sightings per shift, because it’s not always possible to identify whether one shark is repeatedly buzzing the beach, or if it’s multiple individual animals. The variables in the study were:

  • sea surface temperature (SST)
  • lunar phase
  • wind patterns
  • year
  • the spotter

The results are exciting and point to many avenues for future research. Here’s a summary that I jotted down during the talk:

Sea surface temperature

Sea surface temperatures of 16-20 degrees increase the probability of a sighting. The statistical model used spat out a probability of a shark sighting at Muizenberg eight times higher when the water temperature was 18 degrees than when it was 14 degrees.

This warm temperature range corresponds to the preferred temperature range of many of the white shark’s summer prey items, such as steenbras. It follows that when these fish are in the bay, enjoying the warm water, white sharks follow them.

Lunar phase

The study found an increased probability of shark sightings during the time from 3rd quarter (waning) to new moon. The chance of a shark sighting at Fish Hoek is four times higher at new moon than at full moon. This is also probably related to prey activity – perhaps there is more fish activity when there is less light to betray their movements.

Year

The finding was that there have been more sightings since 2009 than in the years prior (2006-2008). Unfortunately the study period is not long enough to be dogmatic about this – it’s quite likely a long term fluctuation. Drawing conclusions on this one is dangerous.

Wind

A drive around the south peninsula on a windy day will help explain why this variable didn’t turn out to be significant. The beaches along the False Bay coast are oriented quite differently to one another, and surrounded by mountains at different angles which can influence wind speed and direction. Future studies should, it was suggested, incorporate factors such as wind direction, speed and duration, but at a lag so that the effect of “one day of light northwesterly wind” can be distinguished from “five days of strong southeaster”.

Kay pointed out that it is vital to bear in mind that this is not the final word on when you will see sharks near the beaches in False Bay. On a day when the moon is new and the water is 18 degrees no sharks might be sighted, while at full moon with 14 degree water you may see a shark. It’s important to think about this probabalistically; none of this research deals with impossibilities or absolutes, but it enables water users to make smart choices about their activities and the potential proximity of sharks.

Here’s an article from Wavescape on the research.

Lecture: Alison Kock on Shark Spotters

The Save Our Seas Shark Centre in Kalk Bay held another marine speaker series this November, and Tony and I attended a couple of the talks. One which we enjoyed was given by Alison Kock, research manager at Shark Spotters. Shark Spotters is a beach safety program that Capetonians are rightly very proud of – there’s more about it on the Shark Spotters website, here and here. Alison’s talk focused on some updates as to the research that is going on in False Bay, and extensions of the spotting program.

Updates on the shark spotting program

Between 2004 and 2012 the shark spotters have made more than 1,400 sightings of white sharks, 60% of which resulted in beach closures. The sharks are either resting, passing by, or searching for prey (other sharks, rays, fish) when they come inshore in summer. For spotting to be effective, at least 40 metres of elevation is required from which to observe the beach. The beaches in False Bay differ, in that sightings at Muizenberg resulted in a beach closure only 30% of the time, while at Fish Hoek the beach was closed 80% of the time. This is because of the nature of the surf and sharks’ behaviour at the different beaches.

At Muizenberg, the backline is some 300 metres off the beach, and the majority of the time sharks are cruising along behind the backline or further off the beach. The beach is only closed when sharks enter the surf zone – 74% of the time they are simply swimming past the beach. When a shark is behind the surf zone, the red flag is raised (for High Shark Alert) but the beach remains open.

At Fish Hoek, 61% of the sharks remain behind the breakers, but this is a mere 50-100 metres from the beach. 68% of the sharks are swimming past, but their proxmity to the beach means that more beach closures take place than at Muizenberg. The lookout location at Fish Hoek is on the mountainside, 110 metres above the beach.

Shark exclusion net at Fish Hoek

Fish Hoek is to be the site of a trial shark exclusion net that will be tested in the next month or two, all going well. It’s important to understand that this is an exclusion net, not a gill net, and the team in charge of the trial have been mandated to design and construct a net that will not lead to bycatch of any marine species. The aim is not to kill sharks and reduce the population, thus reducing the chance of interactions with people (this is what the Durban nets do), but rather to build a “wall” in the sea to keep them out of a specific area of Fish Hoek Bay in order to make it safe for swimming.

The other important thing to remember is that nothing like this has ever been done before.  Owing to the strength of the wind and swells that we experience in Cape Town’s summer, and the presence of large amounts of kelp in False Bay which can foul the net, the net will only be deployed on calm days and will be removed overnight. The net has been designed and is being constructed at the moment, but the process of deploying and removing it (to be handled by the trek fishermen) will be a learning experience initially. If the initial prototype has flaws, the City of Cape Town is determined to iron them out and make it work. It would be courteous and generous of the media and other observers to recognise that this is a world first, and to allow for an initial period of change and possible disruption as the net is tested and refined.

New spotting locations

Earlier this year, Caves at Kogel Bay (on the eastern side of False Bay beyond Gordon’s Bay) was added as a spotting beach. This is a popular surfing location and the water is relatively deep as much of the coastline in that location is rocky cliffs. There have been numerous sightings there since spotting commenced, confirming that this site seems to be on a route that white sharks take in and out of False Bay.

Monwabisi Beach on the northern end of False Bay is the site of up to 10 drownings per year, owing to dangerous rip currents that are, in part, a result of artificial structures constructed for swimming (see the satellite image below). Shark Spotters is adding Monwabisi Beach to the list of regular beaches that have spotters on duty. This is an exciting development and will be particularly important if the proposed oceanfront development along Baden Powell Drive takes place.

SharkShield research

South African researchers collaborated with scientists in Australia to test the effectiveness of SharkShield, a portable device for use by surfers and divers and intended to repel sharks with a magnetic field. The South Africa researchers towed a seal decoy at Seal Island with the SharkShield attached, while the Australians tested it in natural predation situations. They found that the device does not attract sharks (this I imagine would be the absolute minimum functionality required before one even considered using it!). The device repelled some sharks, but not all of them, and its effectiveness depended on the shark’s state of mind. The range of its effectiveness was found to be about 2 metres diameter from the object. The full research study is available here.

Safety tips

Sign at the end of Fish Hoek beach
Sign at the end of Fish Hoek beach

Alison concluded her talk with some shark safety tips, of which it’s good to remind oneself of once in a while (specially in summer):

  • Be aware of your surroundings. The presence of dolphins, bird activity, or fishing may indicate that white sharks will be in the area. Don’t let the cute dolphins distract you and get your guard down!
  • Check out recent sightings. Visit the Shark Spotters facebook page, and make sure you understand the flag system and read the signs at the beaches you visit.
  • Don’t swim at night, in low light (sunrise and sunset), or in murky water (such as at a river mouth) or poor visibility.
  • Stay in shallow water. Three quarters of shark activity at our beaches is behind the backline.
  • Avoid high risk times and areas when you go swimming.
  • Stay in groups – don’t get separated or swim out far beyond the other water users.

Lecture: Ryan Johnson on whether science can save sharks

Tony and I attended a talk by television presenter and shark scientist Ryan Johnson at the Save Our Seas Shark Centre in Kalk Bay one evening in mid-July, as part of their series of marine-related talks. We were very interested to hear this talk because Johnson worked on the recent Ocearch project in South Africa, which tagged 42 great white sharks in South African waters earlier this year and caused intense controversy for a variety of reasons. The sharks were removed from the water for up to 15 minutes, and biological samples (blood, parasites, muscle biopsies) were taken for 12 reasearch projects as well as fitting a satellite tag to the shark’s fin.

The topic Johnson chose to speak about was “can shark science save sharks?” By his account, the three month long Ocearch expedition, and the criticisms levelled at the project, caused him to question some very fundamental aspects of what he was doing as a scientist. If scientists cannot help sharks, then of what use is their work? Johnson listed some of the criticisms that were levelled at the Ocearch project, and responded to them one by one.

  • Why must Americans come and do this work? Why can’t South Africans do it themselves? There were 30 South African and 12 international scientists on the project, showing that we do certainly have the scientific capacity to do research on this scale. Funding, however, was never going to be found from local sources.
  • The scientists weren’t using the best methods. Alternative tagging methods for large marine creatures include the pop-up archival tags (PAT) tags used by the Breede River bull shark project, and acoustic tags, which have been used in False Bay and involve placing transponders on the ocean floor which record a signal when a tagged shark swims past. PAT tags have a life of only three months in Southern African waters because of the rate of algae growth, so no multi-year data would be obtained. They also are only accurate to within 300 kilometres, so no fine scale data would be available either. Acoustic tags require a network of transponders to be placed at locations past which the shark is likely to swim (and at this stage we don’t know what those locations are, for white sharks), and provide no detailed directional information unless the transponders are very close together. Satellite tags (SPOT tags) are by far the best option as they have a life of about five years, and work all over the world.
  • White sharks are already protected in South Africa, so what’s the point of doing research on them? This is true, but as Johnson later pointed out, they are not protected in any neighbouring countries other than Namibia, and certainly not on the high seas.
  • It was all done for television sensationalism. I can’t actually remember what Johnson said about this one (I wrote nothing down, so he may have pooh-poohed it briefly and moved on), but I can say that while the visuals of a white shark being wrestled by a fisherman and hoisted onto a platform may be arresting, there was no other way to get the biological samples and apply the satellite tags on an animal this size. Johnson acknowledged that this aspect of the research was not pretty, but that the alternative – no more sharks – is far worse. In response to a question he also acknowledged that deformity of the tagged sharks’ dorsal fins will take place, but that improvements in the positioning of the tags (higher up) and the anti fouling substance used to prevent algae growth will hopefully reduce the deformities from the levels observed during similar research in 2003-2004. The tags will fall off after about five years.Again, it is a trade off between being able to better protect sharks with the knowledge gained from harming a minority of them, or simply not being able to protect any sharks at all. I haven’t seen the show yet, so I’m not sure how much “ocean posturing” went on (it was probably too cold to get the speedos and bikinis out), but there’s no escaping the fact that a lot of science was taking place at the same time. Perhaps we must overlook the human frailty that causes some of us to seek the limelight, and focus on the very exciting research that is taking place now, long after the cameras have stopped rolling.
  • The idea of a “caring fisherman” is an oxymoron. According to Johnson, the professional fishermen working with Chris Fischer to hook the sharks and bring them on board the Ocearch boat have for years been adherents of the “only keep what you’re going to eat” viewpoint. (I’m not sure you should even take it out the water if you’re not going to eat or tag it, though, but we’ll let that one go.)
  • There was no public participation or information provided. Shark cage diving operators in Mossel Bay were only informed two hours before the Ocearch crew started work in the area that they were going to be operating nearby, and we are all familiar with the complete PR debacle that took place when the project came to Cape Town. Johnson admitted several times that they “dropped the ball significantly” on this, and said that while public participation is not necessary (I agree – it’s a ridiculous idea to ask a generally uninformed public whether they think science should be done), keeping the public informed absolutely is both courteous and necessary.
  • The participants took part in the research for financial gain. According to Johnson, none of the scientists got paid a cent, and Chris Fischer himself is not very financially flush either. There is no way for me to know anything about this, and I have no opinion on it.
  • The government has no ability to enforce whatever recommendations the scientists make based on the research, so why do it? This is a poor argument – the mandate of science is to provide research regardless of whether the will or means to act on it exists. At some future time the government may remove its head from the sand on these issues, and at that time scientists will be ready with data and analysis.
  • The project had no academic credibility. There were 30 local shark scientists involved (the majority of the community), and during the course of several workshops and discussions the project was discussed with academics in order to determine whether everyone would be involved. The consensus was a fairly resounding yes, by all accounts.

Johnson acknowledged that several of the criticisms of the project, especially regarding the complete absence of communication on what was planned and what the scientists were doing, were valid, but reiterated that the opportunity to do research like this, with funding provided by the History Channel (over $5 million), is simply a once in a lifetime event. It seems that everyone has learned something about bridging the apparent disconnect between scientists and the general public in South Africa. Hopefully these lessons are taken to heart!

As pointed out earlier, the criticism that bothered Johnson the most was that the research was purely academic and couldn’t contribute to the conservation of the animal. This prompted him to ask several questions, which he shared with us.

White sharks have been protected in South Africa since 1991 on the basis of a “precautionary principle”. What can this research add apart from simply satisfying academic curiosity? Will it have tangible benefits to the conservation status of white sharks in South Africa?

White shark capture rates in the KZN “bather protection” nets between 1978 and 2008 suggest that the population is stable. The average size of captured sharks, however, is dropping significantly, indicating that the breeding stock is being depleted. Female white sharks take 15 years to reach sexual maturity (the age at which they will start to breed), and a rapid, sudden population decline is possible if these mature females have mostly been fished out (by whatever means).

Dorien
Dorien

Moreover, while white sharks are protected here and in neighbouring Namibia, protection simply on a national scale is not effective. Dorien and Lyla Grace are examples of tagged sharks that have ventured far out of South Africa’s EEZ (territorial waters) and are thus exposed to uncontrolled fishing, longlining and finning by foreign vessels. Perseverance, another of the Ocearch sharks, has ventured to the edge of the continental shelf into waters patrolled by longliners.

Luis Antonio
Luis Antonio

Regarding the question of whether white sharks are targeted in South Africa, Johnson observed that the KZN nets take about 30 white sharks per year. (Stop and think about that number. It’s enormous.) Three tagged sharks have already extensively utilised this coast: Edna, Nico, and Luis Antonio, who spent almost three months chilling just off Richard’s Bay in what might be an as yet unidentified aggregation area. Very large white sharks have been caught in the shark nets there (over 4 metres in length), and this has potential consequences for the entire white shark population.

The role of the recreational fishing community was raised in the question of whether white sharks are captured incidentally in South Africa, but I think also ought to be examined in terms of whether it targets white sharks deliberately. Fisherman Leon Bekker of George, who was photographed (by Ryan Johnson, in fact) hauling a white shark out of the water by the gills and posing for photos with it for 15 minutes claimed he had caught the fish by accident and it was washed ashore, but much evidence indicates that a minority of recreational anglers deliberately seek out white sharks, using heavy tackle and special hooks, in order to feel more manly by subjugating another living creature, one presumes. Classy guys.

Johnson did point out (and Meaghen McCord has echoed this point in talks I’ve heard her give) that the majority of recreational anglers are keen to be legal and to operate on the side of the law and of conservation data. I hope this is true and that the local fishermen who use the internet and post in angling forums are a minority. That’s all I’m saying.

Regarding incidental capture of white sharks, in the last 10 years there have been about five white sharks voluntarily surrendered to authorities after accidental capture by fishermen. No one is under any illusion that these are the only sharks that have been captured by accident in the past decade – fishermen are generally afraid to hand over a protected species if it’s caught by accident and most will toss it overboard, or the fins and jaws are valuable enough to tempt many people to hang onto their catch. We have no idea of the impact of long lining, purse seine fishing and trawling, and accidental entanglement. The white shark killed by whelk farming gear (warning – horrible photo) earlier this year is a case in point.

Johnson also questioned whether our Marine Protected Areas (MPAs) are effective. He showed a map of the De Hoop MPA, with a large white shark aggregation area stradding the boundary as these creatures took advantage of the massive fish stocks in the area. Clearly the MPAs are of benefit to fish that don’t range very far (as Colin Attwood pointed out), but white sharks have enormous migratory paths and may spend very little time in protected waters.

Towards the end of his talk, Johnson touched on something that has bothered me about shark conservation in South Africa, but also internationally. There seems to be a disproportionate amount of rivalry, posturing, jockeying for media coverage, and misguided competition between individuals who SUPPOSEDLY have only sharks’ best interests at heart. Johnson observed sadly that this type of infighting “makes shark killers smile”.

In response to questions Johnson shared a bit of insight around the tension that existed between cage diving operators (some of whom bizarrely objected to television coverage of the very “product” they are selling – at high prices – to visitors from around the globe, and have failed to recognise what a boon the real-time tracks of the tagged sharks are to their presentations to guests prior to embarking on a trip), the conditions attached to the permit granted by the Department of Environmental Affairs (DEA), the presence of very professional government observers and vets on board the Ocearch vessel, and the ridiculous controversy over the “five tons of chum“, which was drummed up by an uninformed (or deliberately obstructive) local cage diving operator.

We found this interesting, as it provided much colour and understanding about the events of the torrid couple of weeks when the DEA revoked and then reinstated the Ocearch permit, but at the same time I must observe how saddening and disappointing it is to find such a complete lack of co-operation and open communication between all parties concerned: the DEA, Ocearch, conservationists, scientists, and eco-tourism operators. What is it about sharks that seems to bring out the worst, most self-interested aspects of the personalities involved?

Having depressed myself thinking about this topic again, I’ll close with a quote from an Ocearch press release in which the names of the scientists working on the project were released for the first time (only after a fire storm of controversy erupted when a bodyboarder was bitten by a white shark in False Bay):

Knowledge generated in this way can capacitate resource managers to effectively mitigate threats to this species by developing effective conservation and management measures. Such knowledge may, for example, include identification of areas where white sharks are vulnerable to exploitation, identification of habitats that are critical for mating, birthing, and feeding, and insight as to whether our white shark stock can adequately be conserved locally or whether regional or international cooperation will be necessary.

Let’s obtain that knowledge, analyse it, and act on it. Please, thank you.

Lecture: Colin Attwood on the effectiveness of South Africa’s Marine Protected Areas

Colin Attwood is a professor in the zoology department at the University of Cape Town with a special interest in Marine Protected Areas. Tony and I attended a talk by him at the Save Our Seas Foundation Shark Centre on the same evening as the talk about Baited Remote Underwater Video Stations (BRUVS) in False Bay. The two talks dovetailed nicely, since the aim of the BRUVS project is to enable more effective monitoring of our Marine Protected Areas.

The South African coastal waters are under threat from a number of directions. Resource extraction (mining, oil drilling and the like) carries a danger of catastrophic pollution and spills, and the craft used for these activities are often vectors for alien species. Aquaculture, which may seem like a good idea, also threatens to introduce alien species to sensitive areas of the coast, and generates huge amounts of pollution too. Municipal failures such as sewerage spills, plastic pollution, and most of all fishing are the other big threats to the integrity of the ocean habitat. A future threat to our coastline is phosphate mining (the phosphate would be shipped to China and Australia to rehabilitate farmland), and demersal trawl fishing is a constant threat to large areas of the coastline.

The scale of fishing in South Africa’s coastal waters is terrifying: 800,000 tonnes of marine life is harvested annually. About 300 species (including invertebrates such as abalone and rock lobster) are targeted, but about 550 are impacted, many as bycatch. To put that in perspective, there are about 2,200 fish species found around our coastline.

South Africa has a fairly extensive network of MPAs, covering 19% of our coastline. 9% of the coast falls within no-take zones, where nothing is to be removed by fishing or other methods. If one rather measures the extent of our MPAs as a percentage of our exclusive economic zone (EEZ) which extends 200 nautical miles off our coastline, they cover only 0.4% of South Africa’s territorial waters, and only 0.16% of our EEZ is a no-take zone. The west coast of the country is largely neglected, but other than that the MPAs are distributed quite evenly around the coastline.

Marine protected areas protect habitats and ecosystems, as well as commercially important fish populations. They do this by preventing fishing in nursery areas and locations where spawning takes place, as well as by preserving the genetic structure of the population. They allow research into the effects of fishing to take place by providing areas that aren’t fished to compare with areas that are. They also enable non-consumptive activities such as scuba diving, whale, seal and seabird viewing, and coastal tourism to take place.

One interesting aspect of MPAs that Prof Attwood pointed out is that they are used for crowd control. Anyone who has seen the number of vehicles on the beach at Sodwana during high season might think that this is terribly destructive and not what an MPA should look like. What is in fact taking place is that 95% of the people are being funnelled through 5% of the MPA, constraining the damage done by human activities to a very restricted area.

Redundancy in Marine Protected Areas, as in engineering, is a good thing. If a species exists in more than one MPA, it is less vulnerable to habitat destruction and catastrophic events such as oil spills. One of Prof Attwood’s students has done work on whether all our marine species are adequately protected (i.e. appear in at least one, and preferably more than one MPA). The results are sobering – of the 225 shore species surveyed, 26% of them do not live in any of our MPAs and 85 species only exist in one MPA. Of the inshore species surveyed (230), 33% are not in an MPA. 25% of the 145 estuarine species surveyed do not live in any of our MPAs, and of the 446 species found out in up to 500 metres on the deep continental shelf, 78% of them are not in an MPA. Only two MPAs (Pondoland is one) cover any of these species at all!

Prof Attwood then gave us a rapid tour through the important scientific studies that have been conducted in South African MPAS. It was only in the last 20 years that the scientific community shook off its skepticism that Marine Protected Areas – underwater, without fences – would actually work. The results are very heartening, and numerous studies have confirmed MPAs efficacy. Fish are more abundant, and populations of heavily exploited fish recover remarkably rapidly and thoroughly when fishing pressure is removed. I first read about this in Charles Clover’s book End of the Line, where he describes an MPA in New Zealand, at Goat Island, and what a delight and amazement it is to the locals and tourists who get to encounter abundant fish in knee deep water.

Giant roman at Photographer's Reef
Giant roman at Photographer’s Reef

Roman inside the Goukamma MPA (8 x 1 nautical miles in dimension, along the coast near Knysna) are on average larger, and change sex later. Roman change from female to male at a certain age, but fishing pressure outside the MPA has forced a physiological change in the fish: their sex-change takes place at age 8 instead of the usual 10 years. The roman inside the MPA are thinner and in poorer condition than those outside the reserve, where fewer fish means less competition for prey. This is at first blush a strange result, but makes complete sense given the higher density of fish inside the MPA – and perhaps these “thinner” roman are fit, compared to the chubby, overfed ones outside the MPA! Prof Attwood pointed out that MPAs are not good for all species – the example here is the crinoids (feather stars) that romans love to eat. Inside the MPA there is a significantly lower density of feather stars than outside, where fewer roman prey on them.

The talk concluded with a map showing analysis of where South Africa’s next MPA should be located. It’s possible to identify critical locations where species that are not widespread live or breed, and these are the areas that should be protected. Tony and I both found this talk extremely inspiring and encouraging, as Prof Attwood does not do the kind of science that gets shelved somewhere and forgotten about. The results of his work are useful in policy making, legislation and decisions about the protection and use of our common marine resource, and he is active and willing to participate in that aspect of marine conservation.

Lecture: Baited Remote Underwater Video Stations (BRUVS) in False Bay

One of the projects currently sponsored by the Save Our Seas Foundation is Baited Remote Underwater Video Stations (BRUVS) in False Bay. The project involves deploying cheap video cameras in underwater housings mounted on specially constructed tripods, with a bait container filled with 800g-1kg of sardines nearby. The camera and bait are positioned so that anything that comes to investigate the bait is captured on camera. If two cameras are used to get a stereo image, the dimensions of the fish and other marine life can be calculated. The camera films for one hour, and then is retrieved back onto the boat and deployed elsewhere.

The idea for these cameras and the initial development work took place at the Australian Institute of Marine Science, where BRUVS have been used for biodiversity surveys on the Great Barrier Reef, and have several advantages over the traditional methods used for surveying marine life. Transects swum by scuba divers are limited by diving safety margins, weather conditions, availability of divers, and the fish identification skills of the divers involved. Moreover, the bubbles released by the exhalations of the divers attracts some species and repels others. Controlled angling surveys – partnerships between specially trained fishermen and scientists – can harm species that are fished out from the deep ocean (their swim bladders expand as they are pulled up through the water column, and this necessitates treatment on the surface if the fish is to survive), are not suitable for large creatures, and can be destructive.

Tony and I attended a talk at the Save Our Seas Shark Centre in Kalk Bay by Lauren de Vos of the University of Cape Town, one of the researchers on the project. She explained that the relative cost-effectiveness of the BRUVS makes them an ideal monitoring tool for South Africa’s marine protected areas. The weight of the rig is such that it is easy to retrieve and deploy, and the cost is well within the budgetary constraints faced by the managers of our MPAs.

The data collected is visual, accessible, and can be subjected to rigorous analysis to obtain relative abundance measures for all the creatures that appear on film. It can also be archived, and sent around the world. It is also very useful for educating the public about marine conservation, and “brings our MPAs to shore” in a very real sense.

The BRUVS are being piloted in False Bay, which is an important region for several reasons. There is great diversity of habitat (several kinds of reef, covering 17% of the bay, sand, etc.), it is on the doorstep of a growing urban community, and has a long history of both consumptive and non-consumptive human activity. We know that our bay has incredible diversity of species, but it is important to monitor whether the MPAs are working, and to keep an eye on areas that are vulnerable and potentially over-exploited.

Lauren showed us some of the footage collected so far, and it was wonderful to see shysharks and catsharks nosing at the bait cannister, an octopus sailing in to take a look, sevengill cowsharks rubbing themselves against the camera housing, and a spearnose skate headbutting the rig. I hope that this tool can be well-used by those managing our marine protected areas!

There is another article about the project here with some photos of the rigs underwater. There are some videos on the project here. I recommend “Foiled by an Octopus”!

Lecture: Biomimicry

Tony and I attended a talk at the Two Oceans Aquarium in June, given by two staff members of Biomimicry South Africa. We’re crazy like that.

Biomimicry is the practice of learning from nature, and then attempting to emulate nature’s solutions in solving problems that humans face. The biomimic can imitate (in increasing order of sophistication) form or shape, a natural process, or an entire ecosystem.

The talk made me feel as though I was attending my first meeting at a cult – the woman who “founded” the modern biomimicry movement, Janine Benyus, was repeatedly and reverently referred to as “our teacher”, and there is clearly a shared vocabulary and phraseology that goes beyond mere scientific convenience. Excessive devotion aside, the talk was mostly concerned with explaining biomimicry by means of examples, some of which are very exciting. My favourite examples are those inspired by water and the creatures that live in it.

Humpback whales

When feeding, humpback whales use a technique called bubble curtains to concentrate their food in a small area. To achieve this, they somehow manage to turn their double-decker bus sized bodies in ever decreasing circles. They are able to do this because of the tubercules – knobbly bumps – on the leading edges of their very long pectoral fins. The tubercules influence the water flow over the fin, allowing their fins to function at a steeper angle than a straight-edged fin would. They provided increased lift and decrease the amount of drag experienced by the whale.

WInd farm off the coast of Denmark
WInd farm off the coast of Denmark

Wind turbine blades manufactured with tubercules on their leading edges are able to operate in both higher and lower speed winds than conventional turbines. Industrial fan blades and aircraft wings have also been constructed using this insight.

Boxfish

You wouldn’t say so, but the humble boxfish is a miracle of streamlining. Taking the shape of the boxfish’s body as a template, engineers at Daimler (well, Mercedes Benz) designed an incredibly fuel-efficient concept car that happens also to be quite cute to look at. Furthermore, the hexagonal bony plates that hold the boxfish in a stable shape were also transferred to the car’s design, resulting in a weight reduction without loss of safety and strength.

Boxy, yes? (This isn't the concept car, it's the A180)
Boxy, yes? (This isn't the concept car, it's the A180)

Shark skin (I)

Speedo’s Fastskin LZR racing swimsuits first came to the attention of the general public at the 2008 Beijing Olympics, where a large number of the swimming records were toppled by athletes wearing these suits. Inspired by sharks’ skin, which is covered in enamel-plated denticles that actively push water away from the surface of the skin, these suits use different kinds of fabric over different parts of the body, just as a shark’s skin varies over its body.

Airbus is working on incorporating shark skin-inspired coatings with their airplane fuselages, to reduce fuel consumption.

Shark skin (II)

Sharks are the only slow-moving ocean creatures that don’t foul (i.e. get barnacles, algae and other small passengers adhering to them). Not only does shark skin have impressive streamlining qualities, but the configuration of the ridges on the denticles is such that bacteria and algae are discouraged from settling and breeding. Imitating the roughness qualities of sharks’ skin led to a coating that is used on high-touch surfaces such as in hospitals, restaurants and restrooms, thus reducing bacteria build-up by as much as 80%. The coating can also be used on boats. All of this reduces the need for toxic chemicals to remove bacteria and other fouling organisms, which is kinder to the environment, too. Sharklet Technologies is one of the companies working on this.

Aquaporins

Aquaporins are proteins embedded in cell membranes that regulate water flow. Aquaporins allow only water molecules to pass through, resulting in totally pure water. Instead of requiring high pressure and energy to treat water (desalination, for example), aquaporins use the properties of the water molecules to restrict the types of molecules they permit to pass through. This technology has medical applications, for example in conditions that result in fluid build up in parts of the body, and can reduce the energy required to desalinate water by up to 70%.

Lotus leaves

Lotus leaves exhibit superhydrophobicity – they’re very afraid of water. Water does not dissipate on their surface, owing to the microtopography (essentially the texture) of the leaves. Airbus, a leader in biomimetic design, has been incorporating material based on lotus leaves on their airline seats, carpets, and on bathroom surfaces. This makes the surfaces easier to clean and more hygienic.

Also working with this principle, Stocorp makes building exterior coatings that repel rain and are easy to clean.

Kelp plants

BioPower Systems develop devices to extract clean energy from ocean waves and tidal currents. These devices are anchored to the ocean floor using a mechanism inspired by the holdfasts of kelp plants.

Water vortices

If you’ve ever run and then emptied your own bath – and I assume, unless Queen Elizabeth II is reading this blog, that you have – you’ll be aware that water likes to travel in vortices. These are swirling pathways that are typically logarithmic spirals (i.e. the ratio between successive spirals is constant). Inspired by natural water flow and the golden ratio, the Pax Group “froze” a vortex shape and used it to create an impeller (to the untrained eye – me – it looks just like a PROpeller, except it apparently pulls rather than pushes water). The uses of this design are many, but the one I liked the most was to mix huge tanks of liquid. A self-reinforcing pattern of fluid flow is set up, and because of the golden ratio encapsulated in the impeller blades, all interference is constructive. A tiny handbag-sized impeller can do the same job as a propeller the size of a compact car. The design can also be used to replace fans of all shapes and sizes.

Water bears/tardigrades

Water bears look like polar bears, except with too many legs. They’re also called tardigrades and moss piglets, and apart from being cute (some think), they have incredible powers of survival, if you will. They can be frozen to near absolute zero (-273.15 degrees celcius), heated to 150 degrees celcius, dessicated so that only 3% of their water content remains and left in that state for over 10 years, be exposed to 1000 times the amount of radiation that a human can withstand, and survive the vacuum of space. You could do all those things to me… and I’d die – but if you do them to a waterbear, and then drop it into a glass of water when you’re done, it’ll simply reanimate and toddle away.

Imitating the ways in which waterbears do all these things enables us to create vaccines that don’t need to be refrigerated constantly (a huge issue in the third world)

Venus flower basket

The venus flower basket is a deep ocean sponge that manufactures its own magnificent glass-like silica structure from silicic acid that it extracts from sea water. It’s 1000 times stronger than glass and endures pressure of up to 300 times atmospheric pressure on the ocean floor. It exists at temperatures below 4 degrees celcius. Even the most basic knowledge of how the glass we use in our windows and other objects is made will convince you that the feats performed by this sponge are something quite special. The sponge is of interest in fibre optic research, because man-made fibre optics are brittle and require high temperatures to be forged.

Wired Magazine has a slideshow of some of these examples, plus a few more, that can be found here.

Lecture: Mark Meekan on whale sharks

The Save Our Seas Shark Centre in Kalk Bay has been a hotbed of activity in recent weeks, with a double-whammy of shark-related talks in one week. The “brains trust” of Save Our Seas about – scientists Sarah Fowler, Alison Kock and Mark Meekan, as well as co-CEOs Peter Verhoog and Georgina Wiersma – were all in town and Sarah Fowler and Mark Meekan gave talks on their respective areas of interest. You can find a report on Sarah Fowler’s talk here.

According to Christopher Neff, who introduced Mark Meekan, Dr Meekan describes himself as a “fish biologist”. The rest of the world knows him as the world’s foremost whale shark researcher. He is a researcher at the Australian Institute of Marine Science, on the research team of the ARC Centre of Excellence for Coral Reef Studies. He is a scientist at Save Our Seas and also a member of the National Shark Recovery Group convened by the Australian government department of the environment.

Dr Meekan is involved in several research projects, but the one he spoke about at Save Our Seas was the natural history of whale sharks, and his study of the whale sharks at Ningaloo Reef in western Australia.

A whale shark photographed at Kev's Ledge off Ponta do Ouro
A whale shark photographed at Kev's Ledge off Ponta do Ouro

Natural history

The whale shark, Rhincodon typus, is the largest fish in the sea, and one of three filter feeding sharks, the others being the megamouth and the basking shark. Basking sharks frequent cooler, temperate waters, whereas whale sharks are commonly seen in tropical oceans. The megamouth is a very rare, deep water species. The Mozambique channel is a hotspot for whale sharks, and they are seasonally seen of KwaZulu-Natal and at Mozambique dive sites. The sharks are able to be identified using the pattern of spots and stripes on their bodies.

Whale shark markings
Whale shark markings

Whale sharks have about 3,000 tiny teeth, but feed using a method called ram filter feeding – they swim forwards with their mouths gaping open, or gulp at aggregations of food. Water entering the mouth passes over the gills, allowing them to breathe, and a bolus of food forms which they swallow all in one go. Sometimes their gill rakers get clogged when they are swimming through a particularly dense food aggregation, and the sharks cough in order to expel the excess food. Tony and a group of divers witnessed this once in Ponta do Ouro, Mozambique, and he says that one lady was convinced that the brownish-red substance coming out of the whale shark’s mouth as it coughed was microscopic remains of a scuba diver that the shark had just eaten. The substance was, in fact, plankton and not scuba diver mincemeat, and a whale shark couldn’t eat a diver if he tried!

The first identified whale shark was seen in Cape Town in 1828, after being harpooned in Table Bay. Until 1988 there had only been a total of about 35 sightings of these massive fish (they can grow to up to 20 metres in length), but since then the discovery of various locations (such as off South Africa’s east coast, Belize, Honduras, Ningaloo Reef off Australia, Madagascar, Mozambique, Mexico and the Galapagos Islands), where they gather to breed and feed has occurred, and sightings – and our scientific knowledge of the creature – have ballooned.

Whale sharks have a varied diet, including coral spawn, copepods, sardines, squid, anchovies, mackerel, tuna, albacore, and spawning aggregations of red crabs (such as the one that occurs at Christmas Island), snapper and lantern fish. This video of a whale shark being fed at Okinawa Aquarium shows their gulping behaviour; a bag of plankton is being released at the surface for the shark to eat.

Reproduction

Only one pregnant female has ever been examined, after being fished in the late 1980s. She had (read this carefully – it’s mind boggling!) 300 pups in her uterus, of various ages. Subsequent genetic studies performed on fifteen of the pups (in 2010 – the pups had been frozen for storage in a solid block of ice referred to by Dr Meekan as “the pupsicle”) indicated that they all had the same father, despite being of various sizes. This indicates that female whale sharks are able to store sperm after a fertilisation event, and exhibit aplacental viviparity (apparently a replacement term for what I learned at school, ovovivipary), meaning that they deliver live young. Massive, pregnant females are apparently often seen in the aggregations that occur in the Galapagos Islands.

Whale shark pups have been seen off Pakistan, in markets in the Philippines, and off the Azores. It is presumed that these sharks deliver their young in productive (green! like our local seas in the Cape) waters. When the sharks reach 2-3 metres they head to one of the inshore feeding aggregations mentioned above. Once they’ve grown some more, they simply vanish… into the open ocean. Very large specimens are almost never seen.

4 metre long whale shark in Mozambique
4 metre long whale shark in Mozambique

Threats

Whale shark meat sells for US$13 per kilogram in Taiwan, which means that a 36 tonne shark would be worth about US$200,000. They are known as the “tofu fish” because of the texture of their meat. There is a picture here (scroll down) of a cross-section of a whale shark that shows how dense its muscle is. Dr Meekan showed us this image and pointed out how little of its muscle is dark red (think of a tuna fish), fast twitch muscle. The top speed of a whale shark is only about 5 kilometres per hour.

Whale sharks are protected in the Maldives (1995), the Philippines (1998), Honduras (1999), Belize (2000), Australia (2001), India (2001), and by CITES. Not yet in South Africa. Whale shark fins are used as signage – giant banners or displays – outside Asian restaurants that serve shark fin soup. The organisation Traffic got whale shark fishing stopped in Taiwan (I may have misheard this – it sounds unlikely given east Asian predilections for eating fish regardless of its conservation status, and I can’t verify it), and the Indian whale shark fishery has also been shut down. Many other fisheries remain, however, in small coastal villages such as the ones on Pamilacal Island, where villagers exploit the seasonal whale shark migrations. Dr Meekan believes that with a bit of effort and education, these fisheries can be replaced by profitable (to the villagers) eco-tourism ventures, which will value the whale sharks while they are alive.

The Ningaloo project

The whale sharks observed at Ningaloo – a population of about 500 – are mostly (80%) juvenile males about 5-7 metres long. 10% are females, and the remaining fraction can’t be identified quickly enough (one has to get underneath the shark to tell if it’s male or female). There is a thriving eco-tourist business that charges visitors about $350 for a swim with the whale sharks. A highly significant decline in the size of the sharks observed by tourist boats (from an average of 7 metres in 1995 to a current 5.5 metres) has been observed, which seems to indicate that larger individuals are still being fished elsewhere.

The research team at Ningaloo have used pop-up archival tags (like the ones used locally on bull sharks) to track the movements of the local whale sharks. These tags, which cost about $5000 each, measure light intensity, temperature, depth and other data. They have an onboard clock, and a timed burn wire causes the tag to pop free of the shark after a predetermined time. When it surfaces, it transmits its location to a satellite. The rest of the data on the tag must be recovered directly from the tag, so the team must get hold of the tag in order to download it. Using the light and time data, clever software is able to determine where in the world the shark was when it was on the surface.

The other kind of tag used is called a splash tag, which broadcasts its location to a satellite every time the shark surfaces. Using a light plane to spot the sharks, and a small boat, about 30 sharks have been tagged. From Ningaloo the sharks move in one of three directions: towards Sri Lanka (Indian Ocean), into south east Asia, or towards Indonesia. During the day the sharks frequently dive to upwards of 400 metres, but spend a lot of time on the surface. In the evening they spend a lot of time at about 100 metres, probably feeding on the plankton that migrates upwards in the water column at night.

There are many mysteries, which always delight (and frustrate) me. One is the staggered surfacing technique that some of the whales display on dives. They descend to several hundred metres’ depth, but then ascend some distance, descend again a little bit, and repeat the process, giving a jagged dive profile that would give a divemaster a serious headache!

Whale shark in Mozambique
Whale shark in Mozambique

The largest creatures on earth – whales, whale sharks, basking sharks (second largest fish) eat the smallest prey. How do they survive? One of the questions that the Ningaloo researchers seek to answer is to explain this apparent paradox, with reference to whale sharks. Survival for them is an acute problem. They live in oligotrophic waters – clean, clear water with little nourishment available. Their metabolic rate is regulated by the temperature of the water they are in, and since they’re in warm seas most of the time, it’s high – meaning they need to eat a lot. Their ram filtration and gulping method of feeding uses a lot of energy.

With this question in mind, the researchers have used a bio-logging approach, with a video/data recorder that is attached to the whale shark and pops off after 24 hours. They found that the whale shark spends up to 20% of its time gliding, compared with active swimming (i.e. using the momentum from prior fin strokes). Its dives are asymmetric, with steep ascents and lazy, slow descents that allow it more time to search for food and consume it while expending very little energy. They also conserve energy by swimming at a slow, constant rate rather than executing many sharp, sudden changes of velocity.

Here’s a news story on Dr Meekan and his research.

Dr Meekan hopes that the findings at Ningaloo and elsewhere will indicate a resident population of whale sharks. He is not very positive about the chances of the species should they migrate anywhere near the eastern or western parts of the African continent, and a resident population that doesn’t move about too much on the coast of a first world country would improve their chances of survival. I hope that South Africa is soon able to formally institute measures to protect whale sharks, as an example to the rest of the continent.

Newsletter: Spring diving

Hi divers

The spring conditions have been living up to expectations with some really good diving. We explored a new dive site last weekend and many people are calling this the best dive site in Cape Town. Personally I think the title of best dive site in Cape Town will always be tightly contested as there are just too many stunning sites to choose from. This new site, Atlantis, most certainly has more fish than I have ever seen in Cape Town, but the Fleur – when dived in clean water – still tops the leader board in my mind. Atlantis is however a stunning site with pinnacles, small swim-throughs and overhangs, nice walls and the tops of the pinnacles are at 5-6 metres so a safety stop can be done while cruising around the top of the reef where there is lots to see. The site also drops off to 29 metres on the sand so it is suitable for both Open Water divers and Advanced divers.

One of the pinnacles of Atlantis Reef rises to near the surface
One of the pinnacles of Atlantis Reef rises to near the surface

Very few would rate Long Beach very high but I have yet to dive a site that has surprised me as often as Long Beach has, with wonderful and weird creatures. I have seen devil rays, sharks, a John Dory, giant short tail stingrays, a snakelet, pipefish, cuttlefish, bobtail squid, toadfish, horsefish, seals, whales and dolphins to name but a few and sure I have seen many of these creatures elsewhere, but never all of them in one place. Then again I do dive there more often than other sites…

A knobbly anemone among sea fans, sea cucumbers and other invertebrate bounty
A knobbly anemone among sea fans, sea cucumbers and other invertebrate bounty

Last weekend we dived at Windmill Beach and had really good conditions, so we want to return there this weekend if the conditions hold. After the Atlantis and Windmill dives we went to Long Beach to complete Marc’s first ocean dive – well done Marc on a good dive exploring the barge wreck and fishing boat wreck! Congratulations are also due to Cecil, who successfully completed his Cavern and Introduction to Cave Diving courses with Buks Potgieter at Komati Springs.

Massive school of hottentot, fransmadam and other fish
Massive school of hottentot, fransmadam and other fish

Weekend diving

A cold front cruises in this weekend, late Saturday, bringing with it some swell. Saturday will be better for shore dives as the wind is more a northwester but too strong for boating. Sunday looks better for the boat and Grant plans to explore two new sites he has found. Please let me know if you’d like to join any of the dives.

Box sea jellies at Windmill Beach
Box sea jellies at Windmill Beach

Talks and stuff

Clare and I attended two talks last week at the Save Our Seas Shark Centre. One was by Sarah Fowler, on the challenges of shark conservation, and the other was by Mark Meekan and was about whale sharks. Both talks were fascinating and we are so enjoying expanding our minds this way. Tonight we are attending a talk at OMSAC about the WWF South African Sustainable Seafood Initiative (SASSI) program. The SASSI program empowers consumers to make responsible choices about the seafood they eat – there’s a bit more information here.

Setting off in good visibility at Windmill
Setting off in good visibility at Windmill

We all like to know what dive conditions are like when planning to go in the water – sometimes it’s a no-brainer, based on the weather, but other times it helps if someone actually gets in the water to have a look! With this in mind, two divers from the Somerset West/Gordon’s Bay area established a facebook group called Scuba Diving the Cape Peninsula, to promote diving in the Cape and provide a forum for sharing news and updates on current dive conditions. Clare is now helping them administer the group, and they’d appreciate some help getting off the ground! A moment’s thought (or, even less spent time reading facebook updates from dive operators!) will convince you that claims about dive conditions from someone who has a financial interest in you getting in the water should be taken with a pinch of salt. Please go and visit the group on facebook, click “Like”, and, when you’ve been diving, let everyone know where and what it was like! This can benefit all local divers and hopefully squeeze out some of the fairy tales about 10 metre visibility after a raging southeaster and 5 metre swell that get circulated daily!

Kelp forest at Windmill Beach
Kelp forest at Windmill Beach

See you in the water!

regards

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

Diving is addictive!

Lecture: Sarah Fowler on the challenges & opportunities of shark conservation

Last week Tony and I attended a talk at the Kalk Bay Save Our Seas Shark Centre by Sarah Fowler. Sarah was introduced by Christoper Neff (back in town following the recent shark bite incident in Fish Hoek) and is one of those people who has had such a busy and productive working life that it’s almost futile to try and summarise her qualifications and experience… But she’s a co-author of the fantastic Sharks of the World field guide, founded the European Elasmobranch Society, is a founding trustee of the Shark Trust and has worked in advisory positions to government agencies as well as in an independent capacity as an environmental consultant. She is also the Vice-Chair of International Treaties at the Shark Specialist Group. There’s a better biography of her here – it’s incredibly impressive, and really comforting to know that there are individuals of this calibre involved with shark conservation internationally. Apart from Save Our Seas, our experience of shark conservationists locally has been somewhat dispiriting.

Challenges of shark conservation

Sharks are intrinsically vulnerable animals, perched as they are on the top of the food chain. They are late maturing, long-lived creatures that undergo long (9-18 months – can you imagine!) gestation periods and usually give birth to small litters of well-developed young. They thus have a low population growth rate, and a low resilience to onslaughts by fisheries. Many species of sharks return over and over to the same locations to breed, making them vulnerable to specific habitat threats. Shark populations are also slow to recover, in light of their reproductive characteristics described above.

There is a lack of management of shark fisheries – in many instances, sharks are not the target species but are often bycatch or a byproduct of what the fishery is actually trying to catch. Shark fisheries are low volume, and low value (but the trade in sharks and shark products is high value). From a management perspective, other fisheries have a higher priority to governments and in management treaties.

The IUCN Red List evaluates the global conservation status of plant and animal species. The Shark Specialist Group is responsible for preparing species assessments for elasmobranchs (sharks and rays) for the Red List. There are about 1,040 such species listed on the Red List, of which more than 17% are threatened. The most threatened species are

  • large bodied coastal species such as sawfish, hammerhead and porbeagle sharks, skates, and spiny dogfish
  • deep water benthic (bottom-dwelling) species targeted by fisheries or taken as bycatch
  • freshwater species
  • oceanic pelagics, which are an unregulated target of bycatch fisheries.

Funnily enough, the white shark is not a typical shark (nor is the whale shark). Both are actually fairly well protected, but they differ from the “average” shark in several other ways. The typical shark – if one were to average across all shark species – is small (about 1 metre long), flat (batoid), with uncertain distrubition, unknown population trends, and largely unknown life history. It is probably endemic to a particular region, making it vulnerable to habitat loss. It is utilised bycatch if not actually targeted by fisheries (in other words, if they’re caught by accident, they are used rather than thrown back into the sea). Its fisheries are unregulated and unrecognised. There is no fisheries management or biodiversity conservation attention being paid to the average shark. The species is probably on the IUCN Redlist as critically endangered, or there is insufficient data on it.

What needs to be done

Urgent conservation and management actions are required. Fisheries management (quotas and Total Allowable Catch or TAC) at a regional and national level is required. Shark finning must be banned.

Since some shark species (such as great whites and bull sharks) are highly migratory and regularly cross international borders, countries must co-operate in the conservation of such species. The Convention on Conservation of Migratory Species (CMS) is one means of cementing co-operation. The CMS Shark Memorandum of Understanding is intended to improve the conservation status of several species of sharks listed in the CMS appendices. South Africa signed this treaty in May 2011, and is one of seven African signatories out of a total of 16 countries.

Who should take action?

How we can take action?

These aren’t complicated, time-consuming or difficult things to do. Most of them require a keyboard and a word processing program, a pen and paper, or firing off an email.

  • follow codes of conduct for diving and angling
  • write to elected representatives and government ministers (and shadow ministers)
  • ask them to follow scientific advice (this is VITAL – scientists are the only ones with no financial or status-related interests in the game) for national fisheries management and biodiversity conservation measures
  • ask what your government is doing to implement international biodiversity conventions
  • get yourself photographed hanging onto a shark’s dorsal fin, while wearing a bikini

(Regarding that last point, if you’ve read my post on the proliferation of ridiculous “shark activists” and conservationists that seem to bedevil us, you’ll be well aware of my views of that sort of exploitative, self-promotional behaviour.) Sarah was extremely diplomatic when I asked her about the sheer number of organisations that claim to be saving sharks, and whether this represents an unneccesary division of labour. Perhaps better results could be achieved by one or two organisations that envelop all the others? In reply, Sarah said that there is a role for every kind of organisation, from pure scientific research groups to those who are in favour of more direct (not illegal) action. She wryly observed that some groups’ only role seems to be to make everyone else look good!

This was a fascinating talk from someone who has been actively involved in shark conservation for many years. It confirmed my long-held suspicions that shark conservation is not glamorous work, and anyone who claims that it is – or is constantly getting themselves photographed with no other outputs in evidence – is not doing what they’re claiming to be doing.

Here’s a video of Sarah Fowler discussing a similar subject (at an event covered here).

I actually don’t know too well what the status of South Africa’s shark conservation action plan is (if there is one), and will do my best to find out and report back when I do.

Lecture: George Branch on evolution

The fourth in the Save Our Seas Shark Centre in Kalk Bay’s series of talks was presented by George Branch, who (in my eyes at least) has achieved near-legendary status as a marine biologist and author. He is one of the authors of Two Oceans, the invaluable reference guide to South African sea life, and also wrote the classic reference The Living Shores of Southern Africa in the 1980’s with his wife Margo. The topic of his talk was The Myths and Magic of Evolution, a subject that interests me enormously but until a couple of years ago it was not part of my education (formal or self-taught) at all. Unfortunately, at this stage in my life, I am so ignorant on the subject that I simply cannot judge where to start learning about it.

Enter the Save Our Seas Shark Centre! Prof Branch turned out to be a wise, patient (I asked several stupid questions) and fascinating teacher – clearly he is not only passionate about his areas of specialisation, but also about communicating the subject matter to others, at both beginner and expert level. Several times in his talk he indicated that he’d changed his mind and learned new things in the past two years – which impressed me enormously. I spent a good part of my young adulthood in the presence of frighteningly dogmatic individuals, to whom an idea such as the one espoused by John Maynard Keynes when he said, “When the facts change, I change my mind – what do you do, sir?” would be anathema. Fortunately Prof Branch is not dogmatic – he is gracious, curious, and thorough.

The subject of evolution is controversial in some circles, and Prof Branch started his talk by stating that no science is any use (in fact, I wouldn’t even call it science) if you can’t test the ideas. An untestable hypothesis is doomed to remain just that – a hypothesis, or a belief. Beliefs are only good for and useful to their holder. The talk was divided into five sections –

  1. The basics of evolution
  2. Tests of evolutionary theory
  3. New advances
  4. Controversy
  5. Guidelines

We found the basics of evolution, as set out by Charles Darwin helpful:

  • more individuals are born than survive to reproduce (this is obvious – I am one of those individuals)
  • variety exists among individuals of a species (also obvious – compare my freckles to Tony’s easily-tanned skin)
  • fitter individuals are more likely to reproduce (“survival of the fittest” – a runty little shark who can’t swim fast isn’t going to find himself a sharky girlfriend – and the definition of “fitter” will vary among species)
  • if characteristics are inherited, species slowly evolve, through either adaptation/microevolution (small changes), or speciation/macroevolution (splitting off into a new species)

The first two points listed above were obvious in Darwin’s time. According to Prof Branch, today we have evidence of all four processes.

It annoys and frustrates me that a discussion of science must mention religion, but unfortunately a lot of the objections to evolutionary studies have come from the religious right. One of the common difficulties is reconciling a seemingly random process (evolution) with the idea of a creator characterised by order. With this in mind, Prof Branch (who has spiritual convictions of his own and is apparently occasionally challenged about evolution at church by those less well versed in the sciences) pointed out that evolution is not a random process. The mutations that add variety to populations are random, but the selection process is not random.

The second part of the “basics” was an explanation of sexual selection, also observed by Darwin. To summarise it as far as one safely can, sexual selection occurs as one gender (I think usually the female of the species!) “likes” something in the other gender, that characteristic will be favoured (i.e. lead to more reproductive opportunities in those carrying it) EVEN if it’s a DARN NUISANCE. Just think about birds of paradise, or peacocks as an example.

There are as many as fourteen different tests or lines of evidence one can follow to test whether the predictions made by evolutionary theory are correct. Some of these are survival rates (clearly not every creature that has ever lived has survived to reproduce – if they had, the universe would be completely filled with bacteria, the population of which would be expanding outwards at the speed of light), and the evidence of the fossil record (increasing complexity diversity, and size in newer fossils, and also the existence of intermediate forms). Another line of evidence for evolution is the vestigial organs that occur in many creatures, such as the eye remnants in blind cave fish, the pelvis and femur remnants that exist in dolphins, and remnants in some microbes of the ability to photosynthesise. One can also observe “evolution in action”: speciation in plants, fast evolution of diseases such as flu and HIV, and many other examples.

I’m not going to go into the recent discoveries that Prof Branch covered, but suffice it to say there is enough material for several conferences. He also passed quickly over several new ideas that are being studied – we were running out of time!

In closing, Prof Branch discussed what many perceive as the conflicting forces of religion and science. Science provides us with facts, and through testing of ideas and experiments, it tells us what is true. Religion tells us how to employ those facts in our lives. The example of the different spheres of influence held by science and religion that he gave was of the atomic bomb – a stunning use of science, but a wholesale failure of ethics.

Two of the myths about evolution that Prof Branch dispelled at the end of his talk were particularly interesting to me. First, evolution cannot explain the origin of life. It can explain how life developed and increased in complexity, but not how it started. Second (I knew this already but it’s a stupid and oft-repeated objection to evolution by people who are too intellectually lazy to come up with anything more cogent) evolution is not “just a theory”. I encourage you to look up theory in the dictionary. When scientists talk about the “theory of relativity”, “theory of gravity”, “atomic theory” and “theory of evolution”, they are meaning it in the first sense.

In closing, I’ll list the guidelines Prof Branch gave us for handling the subject:

  • Respect the views of others
  • Recognise the different goals and limits of science and religion – they can be complementary
  • Be frank about ignorance, both personal and scientific
  • Insist on the testability of ideas and opposing ideas

I’ll leave you with a quote from Billy Graham that Prof Branch used towards the end of his talk:

I don’t think that there’s any conflict at all between science today and the Scriptures. I think that we have misinterpreted the Scriptures many times and we’ve tried to make the Scriptures say things they weren’t meant to say, I think that we have made a mistake by thinking the Bible is a scientific book. The Bible is not a book of science. The Bible is a book of Redemption, and of course I accept the Creation story. I believe that God did create the universe. I believe that God created man, and whether it came by an evolutionary process and at a certain point He took this person or being and made him a living soul or not, does not change the fact that God did create man. … whichever way God did it makes no difference as to what man is and man’s relationship to God.

Billy Graham: Personal Thoughts of a Public Man, 1997. p. 72-74

I am sorry that religious discourse has to intrude on a discussion of science. Many of those objecting to the theory of evolution on the basis of their personal beliefs are unfamiliar with the scientific method, the peer review process, and the language of science. Hopefully if, like me, your ability to comprehend this material was (or is) impaired by religious dogma and pseudo-science, you will be able to read the mainstream scientific literature that discusses the subject and gain more factual information in order to make an informed judgment on the topic.

For further reading, you can try Darwin’s Origin of Species (may be a bit dense – I haven’t read it), The Greatest Show on Earth by Richard Dawkins (be warned, he is an angry little man, but a good scientist), Guns, Germs and Steel by Jared Diamond (one of my most favourite books and authors), or The Structure of Evolutionary Theory by Stephen Jay Gould. Gould and Dawkins have both written a lot on the subject and may be a good place to start.

[Given my relative ignorance on this subject, if anything I’ve said here is inaccurate, you can be sure it was an error of transcription or comprehension on my part, and not an error of fact by Prof Branch!]