Category Archives: Research

Whale Sharks A Plenty in Mafia

We were lucky to meet Matt Potenski who came from Mafia Island to visit us during the expedition. He has sent the following report and pictures showing the work he has done in Mafia. Rachel our scientist from the WCS gave him some receivers and tags to put out so that we can all work together. It is a very exciting start for Mafia as you will read below!! Many thanks for the info Matt – at least we now know where all the sharks are!!!

EAWST Blog – Cooperation with Tanzania

     To all the EAWST friends, greetings from Tanzania.  My name is Matthew D Potenski, and I run a research program on whale sharks in Mafia Island, Tanzania.  Over the last few years, some data has been collected to suggest that whale sharks may use areas of both Kenya and Tanzania.  This year I had the pleasure to come up to Kenya to meet with members of the EAWST and head out into the field with Dr. Rachel Graham.  Upon discussion with both Dr. Graham and the EAWST, we were able to look at some data and agree to collaborate on projects in the future.  In that vein, I have just completed my season of field research at Mafia, and have a number of interesting things to report.

Last year I made observations of a tagged shark off Mafia Island.  This is not remarkable as I tag the sharks there, but this shark had a tag that was not like the ones I put out.  After some effort, I was able to remove enough algae from the tag to decipher a number.  The tag read K001, and I rightly guessed that the tag’s origin was in Kenya.  I contacted members of the EAWST and they confirmed that it was a tag they put out.   In the past few months, I have re-sighted this shark numerous times.  At the last count, I have encountered this shark six times over a span of three weeks.  All the sightings have been made in the waters immediately to the west of Mafia Island.  Shark K001 was seen on January 27th and 29th, and February 1st, 2nd, 9th, and 23rd.  The identification of this shark was confirmed by spot-pattern analysis.  Please see below for a spot ID picture taken of shark K001 on January 27th.


I am also happy to report that in cooperation with the EAWST and Dr. Graham, I have been able to deploy automated telemetry equipment at Mafia Island.


This means that Tanzania has joined with Madagascar, Mozambique, and Kenya in forming acoustic arrays for whale shark detection.  On March 20th-22nd I managed to deploy the eight transmitters I received from Dr. Graham.  Seven male sharks ranging from 3-6.5 meters and one 5m female were fitted with a Vemco V16 acoustic transmitter.


On the 23rd, a small team helped me deploy two Vemco VR2W acoustic receivers.  This involved diving on scuba and pounding iron bars into the sand.  We then attached the units both to the bars and to 150 kg cement blocks as a preventative measure.  There is some net fishing in the area where these receivers are located and the cement block should be heavy enough to keep the units from being pulled up in a net.


The important point is that the deployment of this equipment is completely reciprocal with transmitters and receivers deployed by the EAWST.  This automated telemetry equipment may give further insights into the actual amount of migration by whale sharks between Kenya and Tanzania.  Sharks tagged with transmitters in one location can be detected by receivers in another location.  The actual residence time or amount of time a whale shark spends in a location with each receiver will be measured.  This means that data on both local movements and migrations between receiver arrays can be collected.  The receivers will spend several months in the water before they are retrieved and their data downloaded.  I know I am very excited to see what data we will be able to get with this technology, and I look forward to comparing data with the EAWST so that we can get a more accurate picture of the behavioral patterns of whale sharks in East Africa.

Special thanks to Volker, Nimu, and all the volunteers at the EAWST and to Dr. Rachel Graham of the Wildlife Conservation Society for their friendship and support.   I look forward to more whale sharks in both Kenya and Tanzania in 2010.

Meet Eagle Eye The Whale Shark

Here are some pictures of the whale shark we tagged on Sunday 8 March. It was a small juvenile male of about 4 metres tagged by Rachel Graham of the WCS. This shark has been adopted by London Vision Clinic and is called Eagle Eye.


You can see the tag clearly in the picture just below the dorsal fin.


Rachel has been with us for over a week now and this is the only shark we have seen. We are planning to go out again this weekend and Rachel has extended her stay so that she is here for the last 2 days of the expedition! Her enthusiasm abounds and she is firing up her satellite tags in anticipation of the Saturday expedition even as I write this blog so she is obviously hopeful 🙂

Thanks for reading our blog and we will keep you posted on how the expedition goes.

3rd Acoustic Tag Deployed


After almost 2 weeks with zero sightings, yesterday at almost the end of the expedition Rob our pilot spotted a whale shark opposite the Barclays shopping centre. He said he had to look twice and nearly fell out of his seat he was so surprised! We have searched solidly now for 2 weeks with no joy and Rob was coming in to land when we spotted this shark. Quick as  a flash Rachel tagged it with our 3rd acoustic tag and the boat full of kind expedition members danced with joy!

With sightings so low we have had to keep our researcher and film crew busy. One of the things we did was to put down an acoustic receiver in Nyuli which is a deep site further south with the kind assistance of Harm and Selina from Pili Pippa. Harm and Selina run a fantastic snorkelling and diving dhow trip. They will be in charge of the receiver station and work together with us and with Rachel at the WCS to gather and analyse data. We all got some great footage of the Nyuli receiver being put down and I will put some pictures up soon. I had the opportunity to film it with my new video camera. Filming underwater is not as easy as Volker makes it look that’s for sure!! I really enjoyed it but have a lot to learn!

Another thing we did with the Australian filmcrew is take them up to the Shimba hills – Kenya is one of the only places in the world where you can swim with whale sharks in the morning and have sundowners with elephants in the afternoon! Quite a claim to fame and one that will feature in the documentary being made.

We have also been kept busy with local film crews doing stories on the whale sharks. We have had no less than 3 different crews from Nairobi alone. As always the huge interest in our work is so encouraging even when we don’t see any sharks! The boats have been full every day and people are so supportive of what we are trying to do. When they don’t see sharks they all look on the bright side and we haven’t had a single complaint if they don’t see sharks! People understand that whale sharks are wild and free (thank God) and if they don’t show up there’s nothing much we can do about it. But we have seen hundreds of dolphins each day which is always very special. We are learning more each time we take the boat out and put the plane up. This expedition is one of the longest aerial surveys of Kenya’s south coast ever to be carried out. It’s amazing what you can do with community support and interest from the public – we are acutely conscious of that and very grateful to everyone who has supported us.

This shark we tagged yesterday has been adopted and sponsored by London Vision Clinic and is to be called Eagle Eye. Thank you so much to Professor Dan Reinstein and the London Vision Clinic for their kind and constant support to our project. It is through Professor Dan that we met world renowned concert pianist Katya Grineva who you might remember visited the project last year to do some fund raising concerts. It is also thanks to Professor Dan that Katya, my dad and I all have eagle eye vision!


Pictures of Eagle Eyes to follow 🙂

Whale Shark Expedition Highs and Lows

It is the start of a new week and we hope we will see more sharks than we did last week! The sightings have been very poor with no sharks seen for 6 days. We don’t really know why but we suspect it may be due to the unsettled weather we have been experiencing. The sea is a lot rougher than it should be at this time of year and the wind direction keeps changing. Climate-wise nothing is really as it should be but then isn’t that true of so many parts of the world these days.

Despite the disappointing number of sharks, we remain positive. We will keep trying and the huge numbers of people interested in our work keeps us motivated. We have had full boats every day. The media interest has been immense and we have 4 different film crews in the past few days. Reuters, AP, KTN and The Standard have all covered the expedition.

Last night the film crew from Australia and our lead scientist Dr Rachel Graham arrived. We are set for a good weeks worth of work here in Diani. If we don’t see sharks here, we will move the expedition further north where there have been sightings.

We are carrying out the longest and most coherent aeriel survey ever to be done for whale sharks in Kenya. Whatever happens we will learn something and continue to work hard for whale shark conservation in Kenya.

This week the boat is booked exclusively for the Australian film crew to film for their documentary. We are so excited that they are here! Volker gets the opportunity to work alongside one of the top underwater videographers in the world. From Friday the boat is fully booked over the weekend and the last weekend of the expedition is almost fully booked as well. We continue to be amazed and encouraged by the number of people who come and support our work. We are determined and 110% committed to see it through.

I will keep you posted as the week progresses.

Whaleshark Expedition Pictures

As promised here are some pictures of the whale shark tagging expedition 2009. This is the microlight.


This is the flight crew. Alexis is the pilot and he is in the middle, his girlfriend Emma and Chris the cameraman on either side of him. The team fly for 3 – 4 hours per day and do an amazing job helping us!


This is the boat we used called Melia (daughter of Neptune). It belongs to Southern Cross Scuba. SXS has several dive bases, one of which is at Aqualand Watersports Centre next to Pinewood Village Hotel on Galu Kinondo beach where we meet each morning at 10am.


And here are the lucky people swimming with the biggest fish on the planet! An experience you will never forget 🙂


We have circled the shark for you. They are not as easy to spot as you think! Best is when they are swimming over a sandy patch like in the picture here.


Meet Bumble, adopted by Peter and Philipa Gibbon, Kenya’s first acoustically tagged shark. May he bumble on peacefully for many years to come and enjoy a long and happy life.

Tagging Expedition Day 3

Another cracking day with 3 sightings and 1 tagged. This shark was also adopted and sponsored by Peter and Philipa Gibbon last year. I will let you know what the name is!!

I have wonderful sponsors lined up for our 3rd tag and 4th tag, after which it’s anybodys game so please help us by sponsoring a shark! Professor Dan Reinstein and the London Vision Clinic have sponsored the next tag. Thank you so much Professor Dan! And Camp Kenya and Camps International have sponsored the 4th acoustic tag we put out. Thank you so much Camps!

Pictures to follow when the expedition team returns later and I get a chance to download them 🙂 Wanted to share the good news with you immediately!


Expedition 2009 is off to a flying start. With 15 eager participants, a filmcrew from the Nation and a KWS team on board the anticipation was high as they all set off. Volker and I were both wide awake at 5am too excited to sleep.

I watched them set off wondering how the day would turn out. Whale sharks were spotted yesterday by divers and we have a microlight as air support (I can hear it droning overhead as I write this) so all the signs were good. But you never know! And I can never relax until I get the call from Volker –


Volker has just called me 🙂 Less than an hour into the first expedition they found a whale shark, everyone swam with it and it was tagged with Kenya’s first acoustic tag. This tag was sponsored by Philippa Gibbon (Gwili from the Colobus Trust’s mum). Philippa sponsored our first 2 acoustic tags as presents for Gwili’s dad and uncle.

So a BIG thank you to Philippa – her acoustic tag is finally deployed and well done to Volker and everyone on the expedition team today 🙂

Do you remember this mournful picture of Volker’s fins from the acoustic expedition we did in April last year? No sharks were spotted and Volker didn’t get a chance to even get in the water!


We are already a far cry from that and we’ve only just started!!!!!

Please donate and help us keep the expedition going.


Very exciting news for us here at the project!! The Wildlife Conservation Society has funded 2 satellite tow tags and they are going to put them on 2 Kenyan whale sharks during our expedition later this month! Thank you to Dr Rachel Graham and the WCS!


The satellite tow tags or splash tags are satellite tags attached to the whale sharks with a tether so that everytime the whale shark swims near the surface the tag can transmit data. We are able to track the shark’s movements in close to real time each time the tag breaks the surface. So rather than waiting for months or even years, we can find out where are sharks are going and can track their movements!


Rachel is coming with these tags as well as some acoustic tags in a few weeks. We first met Rachel at the 1st International Whale Shark Conference in Perth in 2005. We have kept in close contact over the years and met again in Mexico at the 2nd International Whale Shark Conference in Holbox in 2008. Rachel is the world wide acoustic tag specialist and has set up the MarineMeganet which will allow us to track our whale sharks world wide through a string of underwater acoustic arrays.

She has done a lot of work all over the world particularly in Belize where she lives and she has recently started along the East African coast in Madagascar. Now she will add Kenya to her list of acoustic tag areas.


This is a picture of some of the delegates at the conference in Mexico. That’s Rachel at the front waving, behind her is her husband Dan and 2nd born son Gabriel both of whom would come tagging with us in Mexico! Other luminaries in the picture include Brad Norman sitting opposit Rachel, Jennifer Smith (geneticist) and Mark Meekan. A very sunburnt Volker is behind Dan.

We are very excited that Rachel will be coming to Kenya in a few weeks to help us put out these tags. As always, any donations will go towards the expenses of the project. If anyone wants to adopt any of the sharks we tag let me know!! The 2 sharks that we tag with the splash tags will be called Obama and Michelle 🙂

Whale Shark Tagging Expedition 2009

Great news! The dates for this year’s first tagging expedition will be 20 February to 15 March. Come and join us and be part of our team. It costs Kenya shillings 12,000/- per person and all the money goes directly to the project in order to fund the expedition. We need your help and support but in return we will give you memories for a lifetime! Please tell everyone you can about the expedition! Thanks! Email me [email protected] to book your place on the boat!

Albino Whale Shark

Check out these pictures of an albino whale shark in the Galapagos islands.


Isn’t that the most amazing sight? I would give my right arm to be the person who took these pictures!


Rumour has it that the Galapagos islands might be a breeding ground for whale sharks. They see a lot of large females there. These pictures of an albino whale shark are incredible. Yet again we are reminded of how mysterious this creature really is!!

Enjoy your weekend.