Sharks! MOOC videos (part I)

I completed the edX-hosted Sharks! MOOC, presented by Cornell University and the University of Queensland, and it was excellent. The content was clear and for me, who stupidly quit high school biology at the age of 14 for the sake of a more classical (less useful) education, filled in a large number of gaps in my understanding of sharks and rays.

The course format was a mix of video lectures and interviews, notes, diagrams and multiple choice questions for grading purposes. The videos are available on youtube – you can check out the channel containing all this year’s videos, or a giant playlist containing all the videos from the 2015 iteration of the course.

I’m going to link to some of the most interesting videos below, so you can get a taster of what the course was like. Please sign up next time it gets offered, if you didn’t do so this time!

Broadnose sevengill cowshark at Shark Alley
Broadnose sevengill cowshark at Shark Alley

Week 1: The Big Shark Picture – Biodiversity and Evolution

Intro – the big shark picture

Shark tracking

Light, depth and landforms

Habitat dive

Hotspots

Origins of taxonomy

Start with the fins

Skeletal anatomy

14 living orders

Species discovery

A walk through deep time

Bear Gulch – a golden age of sharks

Megatooths of Maryland

Week 2: Miracles of Evolution – Functional Morphology and Physiology

Introduction – miracles of evolution

Why a hammerhead?

How shark tails work

Drag

Oil and water

Edged weapons

Blue shark vs white shark

Pursue or ambush?

Manta ray feeding and migration

Shark vs mammal circulation

Breathing water

Countercurrent gas exchange

Osmoregulation in the bull shark

Greenland sharks

Reproduction in the sand tiger (ragged tooth) shark

Modes of reproduction

Week 3 (shark brains and behaviour) and 4 (sharks in the world) videos will follow in a separate post.

A visit to the Blue Planet aquarium in Copenhagen

On our last day in Denmark, after a week-long family visit between Christmas 2015 and new year 2016, we went to Den Blå Planet, Denmark’s national aquarium. (Actually we were wrong about it being our last day in Denmark, but that’s another story involving Turkish Airlines, who seem to innovate in the field of disappointment.) The aquarium is situated in Kastrup, Copenhagen, quite close to the airport, and overlooks the narrow sound called the Øresund, which separates Denmark from Sweden.

The Blue Planet after the mist cleared
The Blue Planet after the mist cleared

We visited on 1 January, after (eventually) sleeping through the sounds of Copenhagen’s residents letting off five hundred metric tons of fireworks, starting at 5.00 pm the day before. We bought tickets online (a small saving in Danish krone that amounted to eleventy million ZAR) and arrived at opening time. The building is surrounded by a reflection pool, and is built in a spiral form inspired by the shape of a vortex. In the larger halls the high ceilings give a tremendous sense of space; at 10,000 square metres, the building is very large. The halls are generally wide and I imagine it could accommodate a very large number of people before feeling crowded.

Layout of The Blue Planet
Layout of The Blue Planet

The aquarium is divided into three sections. The first is focused on the life found in the lakes and ocean of Denmark and northern Europe. I particularly enjoyed this first part of the aquarium. The animals are adapted to the cold water, so some of them were very similar what we find around Cape Town, and the displays were creative and interesting. There was also the obligatory “anchor with fish” tank, which was (as always) mesmerising. One of the pictures in the gallery below is of Tony checking it out.

Two sea otters live at the aquarium, having been rescued as infants and raised by hand. The male and female otters were found in Alaska when they were four months old with a broken jaw and wounds after a boat strike, and as a 1.5 kg abandoned one day old respectively. As usual, seeing such an intelligent animal in captivity stirs up all sorts of conflicting feelings. That said, you are a stronger person than I am if you could have left these two baby otters to their natural fate (that is, death). The otters spend a lot of time (up to six hours per day) grooming, and in between keep very busy, requiring a lot of enrichment from their four keepers. It was magical to see them.

Also in the northern seas and lakes section is the puffin exhibit, mimicking the cliffs of the Faroe Islands, a Danish territory. Here, also, we found a touch pool (which the Danes call a sensing-aquarium), and a terrifying ambulatory mascot.

The second section of the building is devoted to tropical lakes and rivers, with incredible freshwater exhibits. We saw piranhas, terrapins, frogs, little black rays the size of pancakes, with white polka-dots, and electric eels. The rainforest exhibit is kept at a temperature and humidity level that are impressive in the Scandinavian winter, and I can imagine that this part of the aquarium is popular with expats from warmer climates!

The third part of the aquarium is for the rest of the ocean, and although it’s a big ask to cover (or summarise) so much in the remaining space, it does a fabulous job. The Ocean tank holds four million litres of water, and is home to rays and hammerhead sharks, and other warm water fish. Amongst many other things, there are seahorses, leafy seadragons and coral reef fish to see.

Feeding time in the Ocean tank
Feeding time in the Ocean tank

We watched feeding time for a while, which was quite funny – the aquarists row out onto the water in a small inflatable boat, and administer the snacks from on board. Standing in the tunnel, we could see the boat from below, with the oars working frantically against what I imagine was a bit of surface current.

One of the things that Den Blå Planet does really well is to integrate multimedia, virtual reality and interactive technology into the aquarium experience. This reduces the number of animals required to be on display, and – for the most part – probably takes care of itself, requiring no cleaning and feeding. My favourite such exhibit was the bouncy plankton wall in the ocean section of the aquarium. The photo below is pretty terrible because the display moves all the time, but I put a video on instagram which shows how the plankton clear a space for you when you walk along the wall.

Plankton multimedia display
Plankton multimedia display

We finished off our visit with a flæskesteg sandwich at ØST, the restaurant at the back of the aquarium. It was still a bit misty, but the large windows looking out over the sound let in a lot of light. There is a play area outside, and despite the midwinter temperatures, children in snow suits were making the most of it.

The restaurant at the aquarium, ØST
The restaurant at the aquarium, ØST

I did not get the same strong conservation message from my visit to The Blue Planet that I think the Two Oceans Aquarium in Cape Town works so hard to propagate. This could be because of different cultural approaches to living a “green” lifestyle; in Scandinavia the government does a lot of the work for you, providing renewable energy, prioritising  pedestrian and bicycle traffic, and making it ridiculously easy to recycle, for example. In South Africa it is more of a conscious personal choice and effort to reduce one’s environmental footprint, and there is there is thus perhaps more of a requirement for direct conservation messaging.

Anyway, if you’re in Copenhagen, visit! Next time we’re in Denmark, we’ll check out the little Øresund Aquarium at Helsingor, which is entirely focused on local fauna.

Giant short tailed sting rays at Millers Point

Giant short tailed sting ray behind the boat at Millers Point
Giant short tailed sting ray behind the boat at Millers Point

Giant short tailed sting rays reliably appear in the warm, shallow waters of False Bay during the summer months. They are seen frequently at inshore dive sites such as Long Beach, but mostly during the warmest months of the year.

They can be seen fairly reliably year-round, however, near the Millers Point slipway. As with Parrie the ray at Struisbaai harbour, the rays at Millers Point have figured out that the discarded fish guts thrown overboard by the fishermen returning from a day on the bay are a steady source of snacks.

Here’s some fly by traffic coming past the boat one November day near the slipway, where we paused between double tank dives to change cylinders and de-gas.

It is illegal to feed these rays or to bait the water to attract them (or anything, if you don’t have a permit), but a short cruise in amongst the fishing boats queuing for the slipway will cause them to come and investigate. Snorkeling or diving this area is very risky because of the boat traffic, so take care.

Newsletter: Smoke on the water

Hi divers

Weekend dive plans

Sunday: Boat or shore dives, conditions dependent!

We have had terrific conditions all week and have been taking full advantage. False Bay is cleanish and warmish. Visibility has varied from site to site but the bay is full of life. On Tueday we spent our surface interval time photographing sea swallows at Batsata Maze. Wednesday’s surface interval was spent filming giant short tail sting rays at Millers Point, and today we were fortunate enough to have two orcas swim by close inshore whilst the divers were on the SAS Pietermaritzburg this morning. Who knows what we will see tomorrow!

Giant short tailed sting ray behind the boat at Millers Point
Giant short tailed sting ray behind the boat at Millers Point

Sadly the diving today was somewhat overshadowed by the raging fire that descended on Simon’s Town with the westerly wind, despite the best efforts of many firefighters. Watching from the water you could see the speed at which the fire traveled and I doubt anything other than a thundershower was going to slow it down. On the run back into Simon’s Town we went through really thick smoke.

Simon's Town fire
Simon’s Town fire

The weekend, however, does not look too rosy. At cowsharks this afternoon the swell was quite noticeable and although it stays at 3 metres for most of tomorrow, the forecast is for 5-6 metres on Saturday. It seldom reaches the height in the forecast but even at 4-5 metres diving becomes less than great. Surge and low viz are on the cards. I think there will be a better than good chance that Sunday will be semi-decent so I will provisionally schedule diving, either from the boat or perhaps a shore dive or two… Text me if you want to join and I’ll keep you posted.

Diarise

Don’t forget the Shark Spotters fundraiser on Sunday – should be fun!

regards

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

Diving is addictive!

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The stingrays at Struisbaai harbour

Struisbaai the town is a picturesque little settlement, with deep historical roots, on the way to Cape Agulhas. The town is situated at the western end of Struisbaai the bay. (Struispunt marine beacon is situated at the eastern extremity of the same bay.)

Struisbaai harbour
Struisbaai harbour

Struisbaai harbour is home to at least two resident giant short-tail stingrays (Dasyatis brevicaudata). The rays are habituated to the sound of the returning fishing boats’ engines, and come out to investigate whether there are any scraps to be had. We were at the harbour long after the fishing boats had left (and perhaps returned already), and it was quiet, but a sport fishing boat returned while we were there and we saw two large, tell-tale black spots moving across the sandy harbour bottom towards the slip.

Tony stuck his pole camera into the water and got this footage, which is quite lovely. The rays will approach humans on the slipway, but I think some kind of fishy treat (tinned sardines?) is required to get them to come this close. We didn’t give them anything, so they checked out the camera and were on their way.

An information signboard in the harbour
An information signboard in the harbour

One of the rays that lives at the harbour – the largest one – is called Parrie (possibly short for Paris?). Parrie was, according to legend (I cannot verify this with a reliable source), once captured by the Two Oceans Aquarium team and lived in one of their exhibits for a short while. Intense pressure from the Struisbaai community led to his return to the wilds of Struisbaai harbour.

A private fishing boat enters Struisbaai harbour
A private fishing boat enters Struisbaai harbour

You can see a picture of Tony filming the rays from the jetty in the newsletter he sent out when we got home from the trip.

Newsletter: Friday diving

Hi divers

Weekend dive plans

Friday: Launching at 8.30 and 11.30 am from False Bay Yacht Club

We are back from an exploration trip to De Hoop. We took in Infanta, Arniston and Struisbaai as well as Cape Agulhas. Our aim was to gather info for future dive trips up the coast and we checked out the launch sites, accommodation, eating spots and so on. We went armed with a chart of the wrecks and reefs and chatted to some of the locals who use the areas daily. It was a fantastic trip and one of the highlights was filming the giant short tailed stingrays that are resident in the harbour at Struisbaai. We’ll share that video on Youtube in a day or two, and some photos on our facebook page. Instagram already has some highlights from the trip

Filming rays at Struisbaai harbour
Filming rays at Struisbaai harbour

Dive conditions

The weekend weather does not look all that rosy so we will launch tomorrow at 8.30 and 11.30. Saturday looks really messy and Sunday looks a little wet. We will launch on Sunday if the weather tones down from the current forecast. Either way, let me know if you’d like to be notified of possible Sunday dives, or if you’d like to be on the boat tomorrow.

Just a reminder to make sure your permit to dive in a Marine Protected Area is up to date. Also, if you book a dive please let me know in good time if you can’t take the spot on the boat so that I can give it to someone else.

regards

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

Diving is addictive!

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Southern African Shark & Ray Symposium 2015 – second day

View from the top of Red Hill, over Simon's Town
View from the top of Red Hill, over Simon’s Town

Overall impressions from the second day of the Southern African Shark and Ray Symposium, which was held from 7-9 September at the Blue Horizon Estate above Simon’s Town, are these nuggets of sharky goodness:

  • Collaboration between scientists leads to amazing things, like the massive acoustic tracking system that covers the entire south and east coasts of South Africa.
  • You can tell a lot about what an animal is doing, without necessarily being right next to the animal all the time, with some clever technology and mathematics (yay maths!)
  • There are tiger sharks that are partially resident off Ponta do Ouro, Mozambique. They are being tracked and studied. Something to bear in mind next time you visit!
  • Sharks that cross borders (e.g. tiger sharks, great white sharks) are hard to conserve and face huge risks when they move out of protected areas.
  • False Bay’s great white sharks are incredibly well understood (great work has been done in the last 5-10 years), and at the same time the more we know, the more questions there are!
  • We are beginning to get a better understanding of sevengill cowsharks in False Bay and research is ongoing. Plus, did you know there’s a huge sevengill population around Robben Island?
  • Many of the shark and ray populations around South Africa’s talks are not comprised of separate groups of animals (e.g False Bay’s white sharks, Gansbaai’s white sharks and so on), but interbreed all along their range. This means you can’t protect one aggregation site and expect the species to survive and thrive – you have to think about threats along the entire range of the animal. This was a common theme in the genetics talks (which is a difficult subject to explain to peasants like me).
  • Juvenile hammerhead sharks aggregate in Mossel Bay at certain times of year! (This wasn’t the point of what was an excellent talk, but I was excited to hear it.)

You can read a summary of all the day two talks in this quite large pdf – Storify died.

Newsletter: So you think you can dive

Hi divers

Weekend dive plans

Saturday: Launching from Simon’s Town jetty at 10.00 am and 12.00 pm

Dive conditions

Diving has been a little on the lean side the past few weeks but that is all set to change tomorrow. The wind dies, the swell is hammering another beach somewhere else, and the forecast is for day time temperatures above 20 degrees. Okay maybe 20.1 degrees, but still, it’s up there. Saturday is going to be best for diving as Sunday looks wild and windy again, so we will launch from Simon’s Town jetty at 10.00am and 12.00pm. I do know there were reports of 15 metre visibility and 4 metre visibility on the same day in the same bay, so I reckon we will go out and look for some clean water and then decide where we dive.

Shells on the beach near Cape Point
Shells on the beach near Cape Point

Sharks, rays and #LoveFalseBay

Next week the Southern African Shark & Ray Symposium is in town. Clare will be live-tweeting the talks from the official twitter handle, so follow @SHARKandRAY2015 and the #SharkRaySA hashtag for some fascinating shark and ray science. We’ll summarise it all afterwards, too, so watch the blog for details.

On Monday evening there is a public event at the Bluebird Garage in Muizenberg where a number of speakers will give short illustrated talks about the wonder that is False Bay. There are more details on facebook! We’d love to see you there.

There is also an exhibition of photographs of False Bay, on display along the catwalk from Muizenberg to St James, and one of the photographers is Joris van Alphen who spent some time on our boat late last year reporting on reef fishes in the bay. It’s worth checking out, too.

regards

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

Diving is addictive!

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

Documentary: Shark (BBC)

BBC Shark
BBC Shark

There is not much to say about this BBC Earth production, other than that it is excellent, contains shark and ray footage unlike anything you’ve ever seen before, and you must watch it. The DVD is now available in South Africa (and of course in the rest of the known world), so you have no excuse.

It was filmed over two years, and from the thousands of hours of footage, three episodes were distilled. The focus is on elasmobranchs, which is slightly broader than the title suggests (but Shark is more catchy). There is a fourth episode devoted entirely to how the series was filmed, including interviews with the camera operators, which was fascinating. I enjoyed seeing the gear they used – as a scuba diver – as much as I did getting an insight into how they framed their shots and told the stories of the different species. A repeated realisation I had watching this episode was how close one has to get to the animals to obtain the kind of footage required for a broadcast-quality production!

I admit that I was frustrated by the brevity of the series – just when I got into it, it seemed to end – but I understand the desire to show only the very best material, to hold viewers’ attention, and to stay focused on the message (which is essentially that sharks are misunderstood and more important, complex and interesting than you may have thought). The series has a strong scientific bent, explaining how scientists’ work assists with conservation and management measures, and how it illuminates the lives of sharks beyond them simply being a potential threat to beach goers. Individual scientists are interviewed in the field, and are shown taking samples, tagging and observing the animals they study. Not all of those scientists were men, ensuring that the program will inspire a new generation of shark scientists of both genders. Thank you, BBC.

The series does a good job of showing sharks other than (in addition to, really) the large, charismatic ones that we’re familiar with as South Africans. Sarah Fowler, co-author of Sharks of the World, said in a talk we attended some years ago that the “average shark” is not a five metre long behemoth with a multitude of sharp teeth. The vast majority of shark species are smaller – say half a metre long – and very unassuming. The catsharks, pyjama sharks and shysharks are the everyday, many times more numerous sharks who get far less press, good or bad, than their larger compadres.

The BBC’s Shark was apparently a welcome addition to Discovery’s Shark Week 2015 – a complete departure from the made-up, mendacious fluff that has been served up on that channel in previous years. Long may it last!

Get the DVD here (South Africa) otherwise here or here.

100th anniversary of the wreck of the Clan Stuart

Clan Stuart sticking out of a glossy sea
Clan Stuart sticking out of a glossy sea

Yesterday, 21 November 2014, marked 100 years since the SS Clan Stuart, a British turret steamer of 3 594 tons, ran aground in a south easterly gale off Glencairn at two o’clock in the morning. She was on her way from St Helena island with a cargo of coal, and dragged her anchor in the gale. Fittingly, the anniversary of her foundering was also marked by a strong south easterly wind!

The entire crew was rescued, but returned to the ship during efforts to refloat her. She was pumped out and pulled off the rocks by a tug from Table Bay, but permission for her to enter the dry dock at Simon’s Town was refused for fear that she sink and block the entrance to the harbour. Her captain was thus compelled to run her aground at Mackerel Bay, where she now lies, in order to prevent her from sinking.

The Clan Stuart today

She is now a well known landmark to drivers on their way along the coastal road between Simon’s Town and Glencairn, as well as being a popular shore dive site. We’ve had some great dives there, and here’s a round up of some of the material we’ve published about the wreck since starting this blog:

How to find the SS Clan Stuart by road (hint: it is not hard)

What does the Clan Stuart look like underwater?

Getting close to the engine block of the Clan Stuart

On the beach at Mackerel Bay

Marine life on the wreck of the Clan Stuart

The wreck is quite heavily encrusted and there’s usually a lot to see. We’ve seen cuttlefish, small schools of two tone fingerfin, and for some reason I always see a wide variety of worms there! There is kelp growing on and around the wreck, but not so much that it’s hard to move around. On the beach we sometimes see African oystercatchers with their striking red legs and bills, and black bodies. Cormorants and gulls often perch on top of the engine block, too, giving them a convenient platform from which to go fishing.

On our first night dive together (Tony’s first in Cape Town, and my first night dive ever) Tony took a video (grainy) of some seals that joned us on the dive – you can find it in our post about Cape fur seals.

We also spotted a onefin electric ray on a dive on the wreck, whose electric personality seemed to interfere interestingly with Tony’s video camera.

On one memorable dive on the Clan Stuart (I think it was on 1 January one year, in the height of summer), we were surrounded by an agitated school of large white steenbras, who seemed to be trying to take cover behind us and on the wreck, repeatedly changing direction and swirling around us. Tony and I concluded independently that something large and toothy was chasing them, and exited the water by practically tunneling our way to the beach, trying to appear relaxed for the sake of the students accompanying us.

A few years later a group of Russian divers accompanied by two locals – diving off the boat this time – actually came face to face with a great white shark on the Clan Stuart – here is Tony’s story, Christo’s story, Craig’s story, and a short video of the shark taken by one of the Russian visitors. Undaunted by their experience they ended the dive on the beach, where I picked them up, drove them back to the jetty to get back on the boat, and they set out for another dive!

Diving the Clan Stuart

The best time to dive the wreck, in light of the above information and the typical movements of sharks in False Bay’s waters, is in winter. The visibility is likely to be better then, though it’s rarely exceptional (I would be ecstatic with 10 metres, and expect closer to six in the winter months). In summer you can expect 2-5 metre visibility. Don’t underestimate the waves on the beach, and keep your regulator in your mouth until you’re through. Save the chit chat for when you’re back on dry land!

Find out more

A team of film makers has been working on a project about the Clan Stuart for some time. Here’s some of their work so far:

You can read more about the Clan Stuart in Hard Aground, Shipwrecks of the Western Cape, and Shipwrecks and Salvage in South Africa.