Tracking Mr White
Yum, carpeted seal for lunch!
Let's be honest, he ain't our favourite friend. But at least now someone's going to start keeping an eye on him and seeing what he gets up to in our bay, and more importantly, whether he's a regular visitor to our stretch of beach. Ironically a white was spotted cruising off the backline at both Hummies and Pipe just yesterday...
Millerslocal caught up with Dr Matt Dicken, marine biologist and shark researcher, after hearing about the Algoa Bay Great White Shark project.
Millerslocal caught up with Dr Matt Dicken, marine biologist and shark researcher, after hearing about the Algoa Bay Great White Shark project.
So Matt, tell us how the project came about?
I was presenting a paper on sharks at a conference in PE about 2 years ago. Beach manager Fernando Cain was in the audience, and approached me afterwards to explain the development of their Beachfront Aquatic Safety Zone (BASZ) plan and how he'd like to understand what the shark risk profile of the bay was and could I help.
So what does the project entail?
Firstly we spent plenty of time out at Bird Island, monitoring the whites out there. Trying to get an idea how many there are, and when they're there. Bird Island is a seal colony about 60km away from PE's main swimming beaches, as the crow flies. We also did aerial surveys along the coast in a chopper to see what we could spot just off the backline. Phase 2 of the project is now underway, which entails setting up 20 listening stations throughout the bay and then tagging 20 whites so that we can monitor them.
Tell us a bit more about Phase 1.
We made regular trips out to Bird Island, and chummed the waters around there from 08h00-14h00 each day we were there. Our project is registered with the South African Environmental Observation Network (SAEON). They kindly sponsor all of our trips to BI on their research boat "uKwabelana", and Trade Motto supply all our sardines....which is a lot!
The most great whites we ever saw on one day was 7. They range in size from about 1.5m up to 4.5m, and are there mainly over the winter, between May & November. This coincides with the seal pups just starting to make their first forays off the island, so a ready food source is available. We're spotted around 25 different whites in the area, but they come and go frequently, often not hanging around for more than 1-2 weeks at a time before they disappear for a while only to turn up again later. We found that over the summer months, December through April, they almost vanish completely from around the island.
Bird Island is a unique place to study whites and their natural behaviour, as it's the only seal colony along our coast that doesn't have any cage diving operations yet.
And what did you pick up on your chopper flights?
We're done 35 flights to date since we started in November last year. We fly the chopper just behind the backline all the way from Cape Recife lighthouse to Hougham Park. It's the same time of day for each flight, 10-12pm, as we're trying to get the best viewing conditions without too much glare. We look for sharks anywhere between the shore and about 300m out.
So, I hate to ask you this cos I might not want to know the answer, but what have you seen!
I've never spotted a white anywhere along the beach from Cape Recife right up til near Smelly Creek (Ed - where the N2 splits to go to JBay and Grahamstown) in any of the flights we've done to date. They seem to hang out near the beach from the New Brighton Pier area and northwards to Hougham Park. Whites have a fairly distinct outline so it's easy to differentiate them from other sharks.
We tend to spot them off the backline over the summer months, and generally they're around 2m long. These tend to be the juveniles who are coming inshore to feed. There are lots of small rays, sharks and fish around at that time of year, so it's a case of being where the food is. The juvenile's teeth haven't developed enough to feed on seal pups yet, so they're stuck with eating fish. Their teeth mature at around 2-3 years old, and then they can join the adults at Bird Island to feed on the seals.
The most we're seen in a day out in the chopper has been 7, whereas there's talk of the guys doing chopper surveys in Cape Town having seen around 40 in a day!
Ok, so what we have is the big 'un's out at Bird Island in winter, and the groms hanging around inshore in the summer. So who goes where in between!
That's what we're hoping the study will tell us. We're hoping to establish the movement patterns of great whites within Algoa Bay over the time. This is what Phase 2 is about.
So tell us about Phase 2 then!
We've deployed 20 listening stations throughout the bay. They're located from Pipe all the way through to Woody Cape, about 500m offshore. They'll pick up any tagged shark within about a 500m radius. We've set them up so that they have created a monitoring "curtain" giving us an almost continuous line of coverage running just offshore. If a tagged shark goes anywhere near the beach we should pick him up.
What are these listening stations?
We anchor them to the seabed using 3 old brake drums per station (kindly donated by Algoa Bus company). This weighs around 150kg's. A 2m pole is attached onto that, on top of which the listening station is fixed. Each listening stations costs around R10 000.
The Nelson Mandela Bay Metro are sponsoring the project, and have funded the listening stations and the tags.
(Ed - props to the NMBM!!! Least our tax money is doing something useful at last!!)
The Ocean Tracking Network will also be setting up a solid line of 30 listening stations just to the east of Bird Island, extending from just behind the surfzone right out for 2km, to the 200m contour line. They'll pick up ANY tagged animal crossing that line, from a shark to a penguin. So it'd be fair to say Algoa Bay is going to be well covered!
I was presenting a paper on sharks at a conference in PE about 2 years ago. Beach manager Fernando Cain was in the audience, and approached me afterwards to explain the development of their Beachfront Aquatic Safety Zone (BASZ) plan and how he'd like to understand what the shark risk profile of the bay was and could I help.
So what does the project entail?
Firstly we spent plenty of time out at Bird Island, monitoring the whites out there. Trying to get an idea how many there are, and when they're there. Bird Island is a seal colony about 60km away from PE's main swimming beaches, as the crow flies. We also did aerial surveys along the coast in a chopper to see what we could spot just off the backline. Phase 2 of the project is now underway, which entails setting up 20 listening stations throughout the bay and then tagging 20 whites so that we can monitor them.
Tell us a bit more about Phase 1.
We made regular trips out to Bird Island, and chummed the waters around there from 08h00-14h00 each day we were there. Our project is registered with the South African Environmental Observation Network (SAEON). They kindly sponsor all of our trips to BI on their research boat "uKwabelana", and Trade Motto supply all our sardines....which is a lot!
The most great whites we ever saw on one day was 7. They range in size from about 1.5m up to 4.5m, and are there mainly over the winter, between May & November. This coincides with the seal pups just starting to make their first forays off the island, so a ready food source is available. We're spotted around 25 different whites in the area, but they come and go frequently, often not hanging around for more than 1-2 weeks at a time before they disappear for a while only to turn up again later. We found that over the summer months, December through April, they almost vanish completely from around the island.
Bird Island is a unique place to study whites and their natural behaviour, as it's the only seal colony along our coast that doesn't have any cage diving operations yet.
And what did you pick up on your chopper flights?
We're done 35 flights to date since we started in November last year. We fly the chopper just behind the backline all the way from Cape Recife lighthouse to Hougham Park. It's the same time of day for each flight, 10-12pm, as we're trying to get the best viewing conditions without too much glare. We look for sharks anywhere between the shore and about 300m out.
So, I hate to ask you this cos I might not want to know the answer, but what have you seen!
I've never spotted a white anywhere along the beach from Cape Recife right up til near Smelly Creek (Ed - where the N2 splits to go to JBay and Grahamstown) in any of the flights we've done to date. They seem to hang out near the beach from the New Brighton Pier area and northwards to Hougham Park. Whites have a fairly distinct outline so it's easy to differentiate them from other sharks.
We tend to spot them off the backline over the summer months, and generally they're around 2m long. These tend to be the juveniles who are coming inshore to feed. There are lots of small rays, sharks and fish around at that time of year, so it's a case of being where the food is. The juvenile's teeth haven't developed enough to feed on seal pups yet, so they're stuck with eating fish. Their teeth mature at around 2-3 years old, and then they can join the adults at Bird Island to feed on the seals.
The most we're seen in a day out in the chopper has been 7, whereas there's talk of the guys doing chopper surveys in Cape Town having seen around 40 in a day!
Ok, so what we have is the big 'un's out at Bird Island in winter, and the groms hanging around inshore in the summer. So who goes where in between!
That's what we're hoping the study will tell us. We're hoping to establish the movement patterns of great whites within Algoa Bay over the time. This is what Phase 2 is about.
So tell us about Phase 2 then!
We've deployed 20 listening stations throughout the bay. They're located from Pipe all the way through to Woody Cape, about 500m offshore. They'll pick up any tagged shark within about a 500m radius. We've set them up so that they have created a monitoring "curtain" giving us an almost continuous line of coverage running just offshore. If a tagged shark goes anywhere near the beach we should pick him up.
What are these listening stations?
We anchor them to the seabed using 3 old brake drums per station (kindly donated by Algoa Bus company). This weighs around 150kg's. A 2m pole is attached onto that, on top of which the listening station is fixed. Each listening stations costs around R10 000.
The Nelson Mandela Bay Metro are sponsoring the project, and have funded the listening stations and the tags.
(Ed - props to the NMBM!!! Least our tax money is doing something useful at last!!)
The Ocean Tracking Network will also be setting up a solid line of 30 listening stations just to the east of Bird Island, extending from just behind the surfzone right out for 2km, to the 200m contour line. They'll pick up ANY tagged animal crossing that line, from a shark to a penguin. So it'd be fair to say Algoa Bay is going to be well covered!
The lil red dots are the listening stations. The blue shaded area is Bird Island
And how does the tagging work?
We're got the budget to tag 10 large sharks and 10 small sharks. The tags cost about R3000 each. Each tag emits a unique coded single, so we know exactly which shark is picked up by the listening stations. We will tag the big sharks externally, which last around 4 years, and the juveniles will have internal tags. This is the first time in South Africa that internal tagging will be done, and it took a huge amount of paperwork to get approved.
The bonus of internal tagging is that the tags can last for 10 years, so we'll have 10 years worth of tracking data on an individual from when they're small through into their adult life (Ed - sharks can live up to 30 years!) The tags are set to ping every 3 minutes, so the sharks will definitely be picked up by the listening stations should they swim anywhere near them.
We're got the budget to tag 10 large sharks and 10 small sharks. The tags cost about R3000 each. Each tag emits a unique coded single, so we know exactly which shark is picked up by the listening stations. We will tag the big sharks externally, which last around 4 years, and the juveniles will have internal tags. This is the first time in South Africa that internal tagging will be done, and it took a huge amount of paperwork to get approved.
The bonus of internal tagging is that the tags can last for 10 years, so we'll have 10 years worth of tracking data on an individual from when they're small through into their adult life (Ed - sharks can live up to 30 years!) The tags are set to ping every 3 minutes, so the sharks will definitely be picked up by the listening stations should they swim anywhere near them.
About to go swim with Mr White at Bird Island
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The base of the listening stations - 'n boer maak 'n plan
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When do you collect the data?
We'll start tagging later this year. We hope to collect data from the listening stations twice a year. It's quite a challenge to go dive these things out in often zero visibility water, and your're having to try trace them with your GPS, and often the currents and the swells have moved them off their original locations a little bit, so it's not a simple, or a quick, process.
And once you have the data, then what?
The Metro's plan is that we develop a "risk profile" for the bay. So the data will start to show us where the sharks are at what times, and we can advise the public accordingly. For instance, not to go plan an open ocean swim near St George's over the summer for instance, as we already know there seem to be more sharks around there that time of year. So it'll allow the metro to make informed decisions about when and where to hold watersports events in the bay.
We also tie in the listening station info to the weather data at the time the sharks were picked up - so we'll be able to start forming a picture as to whether they're more active in a west or an east, what the barometric pressure does to them, the influence of water temperature, water clarity - all those variables.
Ok, but you're only tagging 20 sharks, what about the one's that aren't tagged!
Obviously the more tags we have the better our data is going to be and the more accurate our findings. Individuals and corporates are welcome to sponsor tags! We have a Section 21 company, so get audited twice a year - so there's no concern that if you donate money for tags that it'll go anywhere other than where it's meant to! You'll receive a printout of the movements of your "sponsored" shark every 6 months to see what he's been up to!
(Ed - great idea ou's, sponsor a shark so we can keep track of more of these critters, and hopefully make sure they aren't cruising by us regularly!)
We'll start tagging later this year. We hope to collect data from the listening stations twice a year. It's quite a challenge to go dive these things out in often zero visibility water, and your're having to try trace them with your GPS, and often the currents and the swells have moved them off their original locations a little bit, so it's not a simple, or a quick, process.
And once you have the data, then what?
The Metro's plan is that we develop a "risk profile" for the bay. So the data will start to show us where the sharks are at what times, and we can advise the public accordingly. For instance, not to go plan an open ocean swim near St George's over the summer for instance, as we already know there seem to be more sharks around there that time of year. So it'll allow the metro to make informed decisions about when and where to hold watersports events in the bay.
We also tie in the listening station info to the weather data at the time the sharks were picked up - so we'll be able to start forming a picture as to whether they're more active in a west or an east, what the barometric pressure does to them, the influence of water temperature, water clarity - all those variables.
Ok, but you're only tagging 20 sharks, what about the one's that aren't tagged!
Obviously the more tags we have the better our data is going to be and the more accurate our findings. Individuals and corporates are welcome to sponsor tags! We have a Section 21 company, so get audited twice a year - so there's no concern that if you donate money for tags that it'll go anywhere other than where it's meant to! You'll receive a printout of the movements of your "sponsored" shark every 6 months to see what he's been up to!
(Ed - great idea ou's, sponsor a shark so we can keep track of more of these critters, and hopefully make sure they aren't cruising by us regularly!)
Speargun loaded with tag
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Matt about to tag a Tiger! Reckon we stick to our day jobs, eh!
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So are the sharks in our bay just like those at Mossels and Cape Town?
We think that Algoa Bay is actually a shark nursery, as it has the highest proportion of small great whites compared to elsewhere along the coast. It does fit the ideal characteristics of a shark nursery - the waters warm, aiding growth, there aren't too many big adults about which would be competing with them for food, and there's plenty of food for them to eat here, fish and rays etc.
It's important to note that the sharks swim up and down the coast, with most of them not staying put in one area. There seem to be feeding hotspots, resting hotspots, mating hotspots and so forth. So a False Bay shark can cruise all the way up to Richards Bay and back.
Shew, that's a pretty impressive project you have going there Matt. Can we as concerned surfers/beachgoers get involved in any way?
The more tags, the better the quality of our data because we'll be tracking more sharks. So yes, the public could definitely assist by sponsoring tags.
(Ed - if you'd like to find out more about sponsoring a tag, get hold of Matt using the form at the bottom of the page.)
It would also be useful if when the public see a Great White that they fill in the short form below (see bottom of page), so that we can start collecting a visual record of what's spotted along the beaches, and then see how that ties up with what our listening stations are telling us. Just really basic info, where you spotted it, when, how far out from the beach, have a guess at the size, what were the weather and sea conditions like.
Shot Matt! We're looking forward (nervously) to the results midway through next year!
So there we go guys, the Whites might have been watching us, but now it's our turn to watch them!!!! The more we know about these ou's the better, as we can start to learn when the potentially "high" risk times might be, and where, so can make safer decisions about where we surf (or at least make sure we then take a couple more mates with us......safety in numbers!)
So be proactive, fill in the form if you spot something, and think about making a donation towards a tag, or even buying your own tag. And's let give some credit to Fernando the Beach Manager and the NMBM to being the only municipality along the coast to be sponsoring a proactive project like this. We're quick to bitch about the stuff they get wrong, but let's also pat them on the back when they do something right!
Watch out for my article all about Great Whites in the upcoming issue of the Bomb surf magazine. Interesting stuff lemme tell you!!
