18 April 2004     

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18 April 2004

Sad loss to dolphin science

Beebop was special to us. He was identifiable in a sea of dolphins that we struggle to identify. We first saw him when he was very young and we watched him grow. We couldn't help but become endeared to him. We had hopes and dreams for him and for what he could teach us about his species. We are saddened by the fact that, at the age of three, he died in the shark nets.

On Friday (2004/04/16) the Natal Sharks Board notified us that there had been a humpback dolphin caught in the Richards Bay shark nets. I went to see if I recognised the dolphin. The body was of a young male and it was so fresh that rigor mortis had not yet set in. I recognized the fin as belonging to a dolphin that was in our catalogue as #43, known to us as Beebop. We first saw Beebop on 23 April 2001, a tiny baby alongside his mother #6, LineL. We saw Beebop quite often because LineL is one of Richards Bay's resident dolphins (only two other mothers, Zipper and Venus, have been seen more often than LineL). By age two, Beebop's fin was quite identifiable with two notches and a distinctive fin shape. Most youngsters aren't very identifiable and once they leave their mother's sides we can no longer identify them. This is a pity because it means that we don't know what happens to them - do they stay in the area, do they leave never to return, do they leave but come back sometimes? Because he was distinctive, Beebop was going to help us begin to answer these questions. The literature suggests that humpback dolphins calve about every three years, so we were expecting LineL to have another calf soon and we were very excited to investigate Beebop's reaction to a new arrival. The day after Beebop died we found a group of dolphins that included LineL and, to our surprise, a tiny new baby, probably just days old. Usually when a new baby arrives, the older sibling is forced to leave his mother's side. We presume that without his mother's protection and guidance, Beebop fell victim to the shark nets.

17 January 2004

Dolphins on Tour of the Bay

Despite perfectly windless conditions, the rain on Saturday (17 January 2004) kept us on the hard until about 11:00 when it finally let up and allowed us to head out to look for humpback dolphins. We didn't have to go far; they were right there in the Mzingazi Canal just east of Pelican Island. 

We followed them back, the way we'd just come, to the Zululand Yacht Club and Mzingazi Waterfront. Once there they seemed to chase fish. After we'd spent a little time with them we realized that it was Zipper and her calf, Pip, two Richards Bay residents. Zipper is definitely more than 20 years old. Ben Durham used to see her in Richards Bay in 1991 and she was already an adult because even then she had a calf with her. We were so surprised when, right next to a moored yacht, Free Spirit, Zipper spin-jumped out of the water. We know that the youngsters jump, we suspected that big males may jump sometimes too but we never expected an old lady like Zipper to jump like that!
We were very pleased to see that a crowd of people at the Yacht Club had noticed the two dolphins and came to the edge to watch. The dolphins only stayed for a short while before they turned around and headed up the canal again. We're pretty excited because on the way Pip jumped and Brett took a couple of photographs and we now have on record that he is a young male.
The two of them made a beeline for the end of the North Pier, into view of the people standing on the Dolphin Viewing Platform. Suddenly two new dolphins came from the northeast. We instantly recognized them as Toothbrush and Sinbad. We have photos of Toothbrush dating back to 2000 but last year s/he was recorded quite often, frequently with Zipper and Pip. Sinbad just has two tiny notches and isn't very distinctive, s/he is easy to miss. However, last year we recorded his/her presence relatively frequently as well, mostly with Toothbrush, Zipper and Pip.
The levels of social intensity were high: Toothbrush, Sinbad and Pip circled one another, swam up-side-down, spyhopped and jumped for half an hour just off Richards Bay's main beach, Alkantstrand. All the while, Zipper was close to the end of the North Pier, apparently not interested in the boisterous play.
The play turned into social-travel and the 4 dolphins headed back into the harbour, still circling and spyhopping. They spent the next half hour feeding intensely between Pelican Island and the T-jetty. Shoals of fish surged out the water ahead of the dolphins. On a few occasions, we witnessed dolphins' jaws clamping down on hapless fish, something we don't often see.
After a while, the number of dolphins around us dwindled until there were no dolphins and so we decided to call it a day. We headed back for Mzingazi Canal and on our way, at the tip of Naval Island, we saw the dolphins again. Again we saw large fish jumping out ahead of the dolphins. This time it was quite plain to see that the dolphins were herding the fish into shallow water. This brought them very close to the Naval Island beach and once again attracted human attention.
They then seemed to hurry around Naval Island, on their way to the Small Craft Harbour. They detoured briefly to meet up with another 2 residents: mother-calf pair Ivory and Tusk. The six dolphins fed quite intensely in the Small Craft Harbour in plain view of Naval Island's beach goers and fishermen on the quayside. They did this for another 20 minutes or so before heading out into the main channel, off towards the Coal Terminal. By now it was 15:00 and the wind was really blowing, we were struggling to follow them and this forced the end of a very productive dolphin follow that had been seen by many of Richards Bay's human residents and visitors.

7 May 2003

Pip plays with her food

We found a group of humpback dolphins pretty quickly in the entrance to the harbour. They were on the northern side of the North Pier, sometimes just behind backline, close to Alkantstrand’s surfers. The follow began very nicely with a spyhop that continued until half the dolphin was out of the water and ended with a lazy back-flop. There were just three dolphins in the group, resident Zipper and her calf, Pip, and Toothbrush who we’ve been seeing a lot of lately. Fortunately, their behaviour was really obvious – they were definitely feeding. They were here then there (their dive direction was erratic) but they basically stayed in the same area. Their surfacings were mostly independent of the other dolphins in the group and uncoordinated and they were quite widespread, i.e. not all in a tight-knit group. Their dives were steep and intensity levels were high, they were very obviously chasing something. After about 30 minutes, intensity levels dropped a bit, they were no longer chasing so fiercely.

Over the next 10 minutes we watched something rather unusual. Pip, the juvenile, was playing with his/her food – just like a cat playing with a mouse. She’d come to the surface with the fish in her mouth. 

She tossed the fish around and slapped it against the surface and then she’d dive, only to surface a couple of minutes later to toss the fish around again. She seemed to open her mouth wide, release the fish and then catch it again quickly. We have seen other dolphins “playing with their food” but it was always quite brief. Next thing, we saw Pip clamp her jaws shut a couple of times, she gave a little flukes-up dive and that was the last we saw of them.

10 November 2000

Long distance dolphins
Friday began badly. Then it got good. Then it got better and it ended up extraordinary. The bad beginning bit was when we passed the Natal Sharks Board boat coming in - they had six dead sharks on board. This is rather a lot of dead sharks for one day. I really wish that the Sharks Board would find another method to keep people safe from shark attack other than killing the sharks.
Soon after we left the harbour we found a trio of humpback dolphins and that is when the day got good. The trio consisted of a mother with an infant, and a sub-adult. We couldn't decide if the third was an older calf that was recently displaced by the new calf or if it was a young suitor to the mother. The mother had a very white fin, not just a white patch like White Tip's, the whole fin was very light. We think that an appropriate name for her is Ivory and her calf is to be Tusk. Unfortunately, identifying the third one is difficult since it didn't have noticeable marks on its fin (although there was a scar far down on its back). For about 15 minutes they seem to play a bit while they travelled quite slowly in a north-easterly direction. Then they sped up and moved almost three times the distance in the next 15 minutes. Suddenly they turned and headed offshore for a while before they doubled back and went south-west. Unfortunately we lost them quite close to where we had originally found them, just 200m offshore of the shark nets.

After another short search the day got even better. We found a small group of bottlenose dolphins about a kilometre south of the harbour. Three adults and one large juvenile appeared to be feeding. They move so differently to humpback dolphins, so much quicker. They dart around and come much closer to our boat than humpback dolphins. After about 10 minutes one of the bigger ones came over and rode our bow a couple of times - it is so exciting when they do that! He (?) was very daring, coming up centimetres in front of the boat repeatedly for about 10 minutes. Then he stopped interacting with us and went back to feeding. We admired them for a little while longer and then decided to search for humpback dolphins rather. 

Lucky for us, about 2km south-west was group of humpies that consisted mostly of our usual suspects: White Tip and Spike, LineL and Heffalump, Venus and Fire with a couple of other not-so-easily-identified individuals. They played and socialised while making steady progress in a north-easterly direction, parallel to the coast along the 10m isobath. Suddenly they stopped and swam inverted in circles in typical greeting behaviour. The new arrivals turned out to be Ivory and Tusk. The last time we had seen them was an hour and a half before and 4 km away. They joined the travelling group which seemed to grow quite rapidly to at least 13 dolphins. An hour later we passed the harbour entrance. We were so impressed with ourselves because we managed to follow them through our "Bermuda Triangle" where we always lose them. We went more than a kilometre and a half beyond our Bermuda Triangle, which is probably a record, and then we lost them. Together we had travelled 5km in less than 2 hours in near-perfect sea conditions and it seemed impossible to lose such a large group of dolphins on such a beautifully calm day, but we did.

We looked around for a while and then headed over to the shark nets and sure enough, there were some of the dolphins feeding just 150 m from Net 5. The dolphins were quite widespread but we saw White Tip and Spike and another mother-calf pair that were quite unusual. The baby was very, very light, almost creamy rather than grey. We can't say whether it was just a very light individual, or maybe an albino. Perhaps they are born light and darken with thyme. Anyway, it's been christened Bino and it's mom is Al. After about twenty minutes of feeding the dolphins started heading off in a north-easterly direction again. We followed White Tip and Spike travelling very quickly. They covered 1.85 km in 30 min - pretty fast for humpback dolphins. They joined the large group again amidst a lot of fuss and social interaction and then everyone started travelling again. In the big group were LineL and Heffalump, Venus and Fire, FL (who we hadn't seen earlier), Ivory and Tusk, Al and Bino and more. We suspect that one pair was Sally Slice and Squeak (one of the two brand-new-borns; see the newsletter titled "Two new peas in a pod" April 2000 www.dolphins.org.za/news.htm). They continued to follow the 10m isobath for a while and then went into water more than 15m deep before heading inshore near the Richards Bay Lighthouse. They continued to travel north-east just behind backline, close to the breaking waves but the group was smaller, either they had split up or they were more widespread. We stayed with them for another hour before the belated wind made it difficult to follow the dolphins. And so we ended up, almost 10km north-east of the harbour after following these dolphins for more than 5 hours which is quite a good long follow. It was extraordinary however, because we had covered a distance of about 15 km with the dolphins, the longest distance ever.

One point worth noting is that the Natal Sharks Board is planning to place experimental shark nets and baited hooks near the Richards Bay Lighthouse. They want to work out how many baited hooks they need to kill the same number of sharks that one shark net does. So they will be setting extra (experimental) shark nets (probably for 2 or 3 years) in the Richards Bay area which could result in more deaths of humpback dolphins. Although placing the experimental shark nets near the Lighthouse is better than the Sharks Board's original plan which was to set them just south of the harbour (probably the best place to find humpies in KwaZulu-Natal), it is quite possible that humpback dolphins will die in this experiment. We are also concerned that their proposed alternative to shark nets - baited hooks - still works on the principle of killing the sharks to lower the chance of shark attack. Although the baited hooks are better than shark nets because they shouldn't catch dolphins and turtles, we are disappointed that the NSB still intends killing sharks to protect bathers. Can't they use a more modern way to reduce the chance of shark attack, one that is not lethal to sharks?

07 November 2000

Walking for Wildlife
This update is to let our subscribers know about an amazing Coastal Conservation Hiking Expedition being undertaken by three young men from the Wildlife & Environment Society of South Africa (WESSA). Robbie Dyer, Raymond Ngubane, and Derek Brown are planning to hike South Africa's entire coastline - that is 3300km - in seven months! They are doing this to promote coastal conservation awareness through public participation and media coverage. As they go along the team will also be monitoring local coastal ecological conditions and they will conduct basic research. The result will be an awesome amount of pertinent information on which to base Conservation Action for ecologically threatened sections of the coast. For more information and to keep track of their progress, please visit their impressive website: www.wildlifesociety.org.za/Hike/coastal_hike.htm.

If you would like to support them in this momentous task you can, through:
* Sponsorship
* Any kind of donation (hiking equipment, food funding)
* Becoming a member of the Wildlife & Environment Society of SA (WESSA)
* Joining them for part of their hike
* Attending their presentations at WESSA branches
* Caring for our coast!

They started their walk on 20 Oct 2000 at Kosi Bay, at the SA/Mozambique border and have spent the past two weeks walking along a very wild part of the coastline in all kinds of weather. We knew that they were to arrive at Richards Bay on Sunday 11 November. We launched our boat early on Sunday and luckily found a group of dolphins as we left the harbour. When we found them they were very close to the shark nets, socialising! They didn't stay there for very long and we followed them social-travelling across the harbour entrance. In the group were a few familiar dolphins: White Tip and Spike and LineL and Heffalump and there were a few unfamiliar dolphins. It looked like Spike and Heffalump were having great fun off to one side by themselves, chasing each other, jumping and somersaulting. Unfortunately, we had to leave the two young ones because a big ship was leaving the harbour and we had to get out its way. We caught up with the adults over at the south breakwater. After a short while their behaviour had changed from social travel to fast travel and we could only see 2 mother-calf pairs. hat a pity the wind picked up and made it difficult to follow them because soon they were out of sight. 

Check out one of Spike's cool jumps! 
 
Once we had lost the dolphins we decided to quickly (!) ride up the coast to try to spot the Wildlife Walkers because we wanted to give everyone an update as to where exactly they were. Friday's edition of the Zululand Observer had invited the community to join the hikers at Five-mile Beach. We went all the way to Nhlabane Estuary without spotting them. Eventually we turned around and headed back (quickly!). We finally found them a little south of Five Mile beach, walking along the beach with a small group. 
After we had moored our boat we hurried up the beach to meet them. When we reached them everyone was staring out to sea. They were watching a crocodile! In the surf! At first i thought it was just a log but it was definitely a croc. It disappeared after a while and the group continued walking. 
The Wildlife Walkers arrived at Alkantstrand to the applause of everyone on the beach. Dave Savides of the Zululand Observer, representing the Richards Bay community, welcomed them and Roy Jones of KwaZulu-Natal Nature Conservation Services (www.rhino.org.za) congratulated and encouraged them. We of the Endangered Wildlife Trust's Richards Bay Humpback Dolphin Project (www.dolphins.org.za) told them that Richards Bay is a special part of our coast because it is one of the few places on SA's east coast that the rare humpback dolphin is not so rare! We asked them to please take with them our message that it is time for a new method of protecting bathers, that the old-fashioned method being used at the moment, i.e. the killing of sharks in shark nets, is a threat to our KwaZulu-Natal coastal environment. Then, Sea Rescue (rbay.nsri.org.za) offered them its services and let them know that they could call for help anywhere along the coast and that Sea Rescue would be there to help them. Our Port Captain, Cpt. Brophy offered Portnet's services in the way of a helicopter ride across the harbour entrance.
So we waved good-bye to the three men with an immense mission as they lifted off in Pornet's Augusta. Good luck guys in your adventure with a purpose! And Thank You for caring about our Coast. Thank you also to our Partners in Conservation, the Wildlife and Environment Society of South Africa and Mazda Wildlife Fund for investing in these three conservationists and their very important assignment.

Keep the Ocean Alive!

16 September 2000

Mangrove Cleanup
International Coastal Clean-up day, Saturday 16 September 2000, was the day that all around the world people gathered on beaches and other coastal environments to pick up litter. Richards Bay Humpback Dolphin Project and Sea Rescue (http://rbay.nsri.org.za) got together a tidying team of 13. We crossed the harbour in the Dolphin Research boat with the northerly wind howling! It was perfectly sunny but it was blowing! Everyone was soaking wet before we even got halfway across the bay. We were on our way to an area between the Richards Bay Coal Terminal and 40/43, to a small stand of black mangrove trees.

Black mangroves (Bruguiera gymnorrhiza) are not as common as the white mangroves [(Avicennia marina) which grow in a variety of places in the Richards Bay harbour). What a beautiful and mysterious place, the black mangrove forest. The tide was on its way out and water was rushing and bubbling around the gnarled buttress-roots that keep the trees upright. And, as usual, there were many peculiar sounds, snaps and pops, made by falling enigmas.

We did not see much animal life this time - only a few Littorina snails that climb the trunks of the mangroves and a modest number of crabs in the sand. Previously (perhaps on a rising tide) we have seen many more crabs, as well as the strangest of mangrove creatures - the mudskipper. This little fish spends much of its time out of the water, perched on broken branches that lie across the surface. It can use its pectoral fins as limbs to "walk" across the branches or mud. You might wonder how a fish can breathe air. Apparently it gulps a mouthful of water and can hold this oxygenated water in its gill chambers allowing it to breathe in spite of being in the air. I love to watch them bouncing along the water's surface when they're in a hurry.

We have even seen vervet monkeys in this particular mangrove forest. One day as we were leaving the mangroves along the small waterway, as if they had been waiting for us to leave, this troop of vervets came bounding out from further inside the forest. The youngsters proceeded to play at the forest: water interface while the adults sat and sunned themselves. If you would like to learn more about mangroves, i found a site worth visiting: http://www.env.qld.gov.au/environment/coast/habitats/m.html#What (It is written by an Australian and their common names for mangroves are different to ours: they call our "black" mangroves, "orange" mangroves and our "white" mangroves, "grey.")

Our team moved between the mangrove trees picking up and digging up garbage. Mostly we collected plastic bags, plastic sheeting and plastic bottles as well as lots of polystyrene. Ropes were also a problem, often restraining roots. Plastic bags posed less of a problem to the roots and many had grown through the thin plastic. We found shoes, 5 hard hats and even a toy car. The most peculiar item we found was a rubbish bin. Each and every item that was picked up, had to be categorised and counted and recorded on a data sheet provided by the Center for Marine Conservation. They are the main organising body for the International Coastal Cleanup (what an achievement!) and they will analyse the data collected from all around the world to draft anti pollution legislation. Please visit their site: http://www.cmc-ocean.org/3_pt/3_ptintro.php3. Here in KwaZulu-Natal, the KwaZulu-Natal Nature Conservation Services did all the local organising and they deserve our thanks. Please visit their site: www.rhino.org.za. We would also like to thank Portnet for inviting us to clean up this very special part of South Africa's coast.

All together, we picked up about 22 bags of rubbish off about a 500m2 piece of mangrove forest in three and a half hours. This works out to one bag for every 25m2. Which is a lot of rubbish considering that most of it was flimsy plastic bags!

The mangroves' protruding breathing roots (necessary in waterlogged, oxygen-deficient mud) trap wind-blown litter very well. I used to think that this made it a particularly littered environment but what i noticed this time is that the trees at the harbour's edge had a lot of litter but they seem to act as filters and a little further into the forest is remarkably litter-free.

By the time we had finished, the tide had turned and was on its way in again.

If you would like to see some pictures of the mangroves, please visit our site www.dolphins.org.za and go to the "News" page.

A grateful thanks to all in our team: Bushy O'DonOvan and his sons Darren and Gavin. Maritza and Andre Prinsloo. Steven Burgess. Quinton van Wyk. Arlin Doust and his friend Douglas Brown. Kursten and Cameron Meyer. 

22 June 2000

Black Betty
We had a most extraordinary morning yesterday. Early in the morning we got a call from Graham Barrett to say that they had a melon-headed whale in their swimming pool! It had stranded 60 km south of Richards Bay, at Amatikhulu (29.134S, 031.613E) on Wednesday. A nature conservation officer, Joseph had tended to it and kept it wet until Carol Barrett from ORI/Seaworld had rescued it on Wednesday evening. They put bags of salt into their swimming pool and all through the night Carol and Brendon and friends looked after the melon-headed whale (which looks more like a dolphin than a whale at 2.3m long, dark and slender). With the aid of a life jacket, they supported the whale and walked it around and around the swimming pool. When we arrived, we helped Carol and Brendon to feed it squid but it wouldn't swallow. Perhaps the rest it got while being fed made it feel a bit better because it seemed stronger when we started to walk it again. It was incredible to put my arms around this animal and support her, to be so close, to talk to her. We are used to seeing dolphins at a distance or rotten in the shark nets, not close up and intimate. I could see her blowhole tightly shut, then suddenly opening for a breath. Over most of her body her charcoal skin was smooth but across her back the skin was wrinkled. White lips covered small "peg" teeth. Her eyes were always shut. My arms quickly tired and Brett held Black Betty (as I like to call the little whale) and walked with her. Carol walked her again and then it was my turn again. As we changed over, Black Betty started tailslapping, convulsing and after about 15 seconds of thrashing about, she went limp. Her eyes opened for the first time and she died.

Looking inside her mouth, we could see that her teeth were worn suggesting that she was quite old. According to Cockcroft's Whale Watch and Carwardine's Whales, Dolphins and Porpoises, melon-headed whales seldom venture close to shore. They are not seen very often but seem to occur in deep, warm tropical and subtropical waters. A few have been spotted in the Mozambique Channel. One other stranding has been reported in South Africa, at Hout Bay in the Western Cape (34.036S, 018.348E). Not very much is known about the biology of this species.
Black Betty's body was taken to the Richards Bay Sharks Board base, thanks to Portnet for helping by providing transport. Unfortunately, the Sharks Board freezer was broken. On Vic Peddemors' instruction, the body was left under trees in the shade until today when Vic collected it for dissection. We hope to read a report on what he finds.

Sunday 16/04/2000

Two new peas in a pod

Finally, the weather let up and we didn't have to be landlubbers any more. On Tuesday, we launched the boat at sunrise and checked the pingers (always our first task once we're on the water). Then we headed south. As we rounded the southern breakwater we decided to drop the hydrophone in the water, just in case we could hear any whale sounds. We were very surprised when we heard dolphin whistles instead. We looked up and there were four dolphins! A large male (one of the "White Brothers") with a female that we did not recognise and the tiniest baby we have ever seen. A fourth dolphin was also swimming with them, possibly an older calf. There was some social interaction while they travelled southward. About half an hour after we had found these four, they joined up with another group.

This group had two or three adults with ANOTHER TINY BABY. This new baby still had neo-natal folds which means that it was probably only a few hours old. This baby had two adults flanking it whereas only one adult flanked the first baby. The babies were so funny to watch they really lacked the adult's elegance. When the adults surface it is a very smooth action - nose, head, fin and under the water again. The babies do not judge the surface at all and they come shooting out the water only to belly flop down with the grace of a turkey landing. They'll learn.
We need some help naming these two. Since it is impossible to tell whether they are male or female, the names should be neutral. We've been thinking along the lines of Sugar and Spice or Peaches and Cream. Ifyou think up any good names, mail us at ideas@dolphins.org.za.

On Wednesday, we launched and went looking for them again but we didn't manage to find them. As we were coming back into the harbour we found another two mother-calf pairs, right near the southern breakwater. The babies were pretty young but not nearly as young as the ones we saw the day before. One of the mom's was a dolphin we've seen quite often in the last few months. She has a very noticeable V-shaped notch in her dorsal fin so we called her Venus. They travelled offshore very quickly and the wind was picking up so we didn't stay with them for very long.

On Saturday we launched and found a group, again near the south breakwater. We managed to spend about 50 minutes with them before we lost them. This morning (Sunday) we were out and about for most of the morning in perfect weather conditions. We looked in all the likely spots (two or three times in some of them) but we never found any dolphins. Tomorrow's weather looks promising for another search - hopefully we'll have better luck than today. We'd love to find the small babies again, just so that we know that they're okay. We'll have to wait and see.

It's been raining and blowing in Zululand for ages. We've not been able to launch our boat for 11 days now. That means that we don't have very much news about the dolphins. When it rains like this, lots of people ask: Where do the dolphins go when it storms and the sea is so rough? Have you ever wondered? We don't think that they have too many options, they can't disappear under the sea - they have to come up to breathe. We think that they carry on as normal. The few times that we have been out there in bad weather we have seen them near the Richards Bay harbour. Some of the local paddleskiers have said that they also see them out and about around the harbour in spite of the weather.
Even though the dolphins don't seem to behave differently when the wind blows, our behaviour is quite different. We've been stuck in doors for most of the passed couple of weeks. But that's probably not such a bad thing since we have had lots of time to catch up with work in front of the computer. Three things are worth writing about.
The first is that we've added some new links to our website. Besides the new links to other dolphin sites, there is also a new link to Richards Bay tourism opportunities. We've also added a page with statistics about the shark nets and prompted the questions: Do we have to kill sharks to keep people safe? Can any one come up with ways of protecting bathers and surfers that are not lethal to sharks? These links can be found on our home page www.dolphins.org.za.
The second thing is that we have trying to formalise the results of the pinger experiment for publication, hopefully in Marine Mammal Science. For some of the details of what, why and how we did the experiment, check out the page called "Project Info" on www.dolphins.org.za Here is the briefest summary possible.
We aimed to test the effects of pingers on the behaviour of humpback dolphins. The pingers are acoustic warning devices designed to keep dolphins/porpoises out of fishing nets. The experiment was conducted in the shark nets that are visible from the North Pier, Richards Bay. We tested the effects the pingers had on the dolphins by randomly alternating between pingers and similar, but silent pingers in the shark nets to monitor any difference in behaviour in the two situations. The results of the pinger experiment failed to support the hypothesis that the behaviour of the humpback dolphins would be changed when pingers were actively emitting a signal. The pingers did not appear to have a measurable effect on the behavior of the humpback dolphins. Therefore, we are uncertain whether pingers will reduce humpback dolphin incidental mortality in shark nets. Further study of the behavioural reaction of humpback dolphins to pingers is recommended.
The third thing is that we found a really cool site: SharkFriends@netscape.net. There are all sorts of things to see on this site with lots of information to be found about all sorts of marine creatures. One of the coolest things is the beautiful picture of a humpback dolphin. It's a picture of a pink humpback dolphin mom with her grey calf.
Talking about moms-and-babies, we've got some sad news. Mid-February, we found a fine example of a humpback dolphin, a female with large well-developed hump. Harvey from Sea Rescue (you can visit them at http://rbay.nsri.org.za/) called her Flipper Lady. We knew she was a female because she had a tiny baby. This mother-calf pair came into the harbour with two other mother-calf pairs, White Tip + Spike and Venus + her baby, as well as LineL and another dolphin. We saw Flipper Lady again at the end of March. She was with White Tip + Spike and Venus + her baby and they were in the harbour again. Unfortunately, her baby was nowhere to be seen.

Lastly, a word of welcome to all our new subscribers - "Welcome."
And viva MTN!

We watched these dolphins playing for almost an hour. Then at least two new dolphins joined the group. They were quite big and quite scarred, we think they were males. One had a huge hump and a very distinct fin that looked a lot like a periscope (so we've called him Perry). The arrival of these two changed the whole mood of the group - they stopped playing - no more jumps and spyhops, no more chasing. They were suddenly much more sedate. Any one with any ideas about why the change in behaviour occurred when these males arrived, please write to shanan@dolphins.org.za. We couldn't stay for much longer so we don’t know what happened next.

 On two other occasions during the follow, bottlenose dolphins appeared for a short while before disappearing. About 13 km from where we found them they changed course and started heading due south. Their behaviour also changed and they didn't spend as much time at the surface. This made them more difficult to follow, and we weren't going in the right direction anymore. So we headed back home. Next good dolphin research day we have, we'll try again to get to St Lucia.

10 September 1999

Dolphin Carousel: Humpback Dolphins seen feeding co-operatively

In June (13/06/99) we watched some humpback dolphins feed co-operatively in the harbour mouth. There was a large school of fish (they covered an area of about 100 m², we don't know how deep they went). Nearby we found a much smaller school (+/- 10 m²) of the same kind of fish (tentatively identified as broad-headed mullet) that appeared to have been pinched off from the larger group by the dolphins. These fish were swirling around in a tight circle, apparently trapped by the dolphins. This has been called a "carousel" by other dolphin researchers. The fish went round and round and would suddenly start shivering and almost rising out of the watersometimes even jumping clear out of the water. They seemed to anticipate the arrival of the dolphin, perhaps the dolphins were using sonar bursts to confuse the fish?

When we first found the carousel there were just a few dolphins but soon there were at least 15 of them. White Tip and Spike were there and so were Hope and her baby, in fact there were quite a few mother-offspring pairs.

 Nicodemus was alsothere; he had fresh wounds behind his hump. After an hour the group started getting smaller again. Hope and her baby stayed on after most of the other dolphins left.

Friday 27/08/1999

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