Saturday, January 24, 2009

Dispatches from Djibouti.... 7. Cheetahs, Lac Assal and farewell to Djibouti

Hitting dry land for the first time was a bit of a shock with several of the team dealing with sea-legs that didn’t seem to work too well on dry land, but there was no time to lose as a visit to a local volunteer group Decan had been organised.

Decan is a non-governmental organisation set up by local vets to provide a sanctuary to local wildlife in particular the big cats such as Cheetahs and Lynx that are losing their natural habitats through urbanisation and grazing by goats and cattle.

Our group was met by Bertrand one of the veterinarians who had set up Decan with Michel Vely several years ago and proudly showed us the reserve that he and local volunteers had created. By simply fencing the area off and stopping the grazers from accessing the site, the whole area had been transformed into a lush savannah with dense brush inhabited by some 16 species of local birds.

But the cats were the high point of the visit and one Cheetah in particular was the star of the sanctuary; Bertrand allowed us to access the staff corridor to visit this grand old lady and she dutifully appeared at the fence to see us! You don’t appreciate how fast Cheetahs are until one suddenly appears at your side at 50 km per hour..... fast doesn’t do it justice!

The big surprise is that these really are big cats... they purr like cats, like being stroked like cats and they lick like cats.... just everything is much bigger, louder and rougher! What a fantastic experience!

After a farewell dinner in Djibouti our last day was filled with a day trip by ‘magic bus’ back past the Ghoubet al Kharab to the totally land locked lake at the end of the Gulf of Tadjourah, Lac Assal, the lowest lake in Africa.

We were aware of the lunar landscape around the Ghoubet, but Lac Assal a flooded volcanic crater was even more bizarre; the lake is filled by hot salt water springs fed from the Gulf making it the saltiest lake on earth, apparently at 40% salinity at 20 m depth it is 6% saltier than the Dead Sea! The shores of the lake are 155 metres below sea level and are marked by vast crystallised salt pans caused by the rapid evaporation of the hot (34’C) super-saline water.

These salt pans are mined by nomadic people who transport the salt to Ethopia by camel train, an ages old tradition that continues to this day.A more recent trade is the sale of curios to tourists but not plastic nic-nacs made in some factory... lots of fantastic crystals and geodes found gleaned from the surrounding countryside with quaint model cars and buses carved from local pumice. One rather odd addition to this array of collectibles are salt crystal structures such as goat skulls that are placed into the lake for several months and recovered and dried to form spectacular if somewhat macabre souvenirs!

And so our time in Djibouti draws to a close, time for a last photo in front of the amazingly decorated ‘magic bus’ before we prepare for what will range from a few hours of flight to up to 38 hours of travel as the team head back to their respective homes...

We have had a fantastic two weeks with many memorable moments; our thanks to Daniel Jouannet for organising the expedition, to the MCSS team for all their hard (and on-going) work with the data collection and compilation and to all the eco-volunteers who joined us to help document what must be one of the most amazing spectacles that many of us have seen.

And so what’s on the board next? Well there is talk of an expedition to the Straits of Hormuz in the Arabian Gulf but otherwise the next main whale shark activity will be the Seychelles programme in August.... David and Daniel are also talking about planning another Djibouti programme for January 2010 so if you are interested do contact us...

Thursday, January 22, 2009

Dispatches from Djibouti.... 6. The last few days at Djibouti...

Well our return to Ras Korali was welcomed with a flurry of sharks feeding off Acacia beach in the late afternoon, a pattern that seems to be the norm on this trip. As the expedition is drawing to a close we are slowly coming to grips with the fact that in a few days time we will be back in our respective homes with many of us returning to the European winter with temperatures of somewhere just above zero if that!

The trip has been a great success as far as data collection is concerned... we have logged over 500 in-water whale shark encounters in the 11 days so far with one day still to go; we have currently 115 new sharks identified and added to the database but this is only based on sightings for the first seven days as the photo matching has had to take a back seat to data collection. We have also resighted a number of sharks from previous years including Shiraz, the shark we fitted with a satellite tag in 2006.

Shiraz in 2006 fitted with a towed satellite tag, photo Simon Rogerson.

The sharks we are seeing have been predominantly small juvenile males with many below 3 metres in length and very few greater than 5 metres, the largest being a 7 metre male; as such this is almost certainly an aggregation of very young juveniles but the lack of large adult sharks and in particular pregnant female sharks raises questions as to the area being a pupping ground for the species as has been suggested.

The environmental monitoring has also gone well with a whole swath of plankton samples being collected for analysis as well as matching CTD profiles of the area, although an initial look at this data has suggested that there is very little temperature change from the surface to 50 metres depth... Gavin from the BBC let us attach the CTD to his ROV to get some deeper profile data but even at 70 metres the temperature remained at 25.3’C.

Both PAT tags have been deployed and the local live-aboard boats have all been told about them and will make sure that they are not disturbed by their clients, in fact all were very interested in the programme and promised to send us additional photos for the photo ID database.

Dan Beecham had been beset with problems with the HD video camera housing developing a leak in the first week but this was cured by a replacement housing being shipped over and he had finally got the footage he was after of the whale sharks feeding at night in the flood light off the stern of the boat. Tom Peschak also seemed quietly happy with the images he had captured although there was always another slightly better shot he just could get if only...

As for the eco-volunteers who had joined us, all seemed to have enjoyed the experience, even if they weren’t sure exactly what they had signed up for at the outset! Everyone had soon worked out what bits of the process they were most interested in and all contributed wholeheartedly and no-one shirked their share of the paperwork... thanks all for a great job well done!

One shark in particular had caught our attention over the weeks and given us cause for concern, a 5.5 metre female shark that had a thick rope tied around her tail... we have no idea how long the rope had been attached but it had cut deeply into the top and bottom of her tail and several attempts to remove it over the course of the trip had failed.

With the satellite tags attached, David set this as a goal and had borrowed a serious pair of wire cutters from Captain Armand to try to remove the offending rope.... and the 13th of January proved to be a lucky day as Katie found the shark and David was able to cut through the rope and remove it carefully from around the shark, his good deed for sharks for the week!

And so it is with mixed feelings that we head back towards Djibouti aboard the Deli: on the one hand the expedition has gone very well and we have largely achieved what we had hoped to, on the other the joys of the Northern hemisphere winter and thoughts of weeks of work completing the photo ID analysis is a bit daunting!

Once in port the Deli is immediately invaded by Captain Armand’s excited young children and soon everything is a flurry of activity as equipment is stowed away for the home-bound flights....

Dan seems to have accumulated even more baggage and knows that somehow everything does indeed fit into the myriad of boxes that are amassing on the quay side...

One day left to visit some of the other sites in Djibouti!

Wednesday, January 21, 2009

Dispatches from Djibouti.... 5. Volcanoes, cracks and the Devil’s Goblet...

The Gulf of Tadjoura owes its existence to the interface between two of the earth’s tectonic plates, the Southern one being the African plate while the northern one is the Arabian plate... where the two meet there is a zone of crustal instability which results in the Gulf of Tadjoura and extends down through Africa as the East African Rift valley. ‘Crustal instability’ is a nice term which includes such things as earth quakes and volcanic eruptions as the two plates move relative to each other... this is where we are!

We weren’t the only ones interested in this area as we soon met up with a BBC Natural History film crew who were going to be filming for an up-coming documentary on the East African rift and were keen to find out more about the whale sharks in the area. And so it was that Deli moved up into the western end of the Gulf into an area that has almost become a land locked lake due to volcanic activity and uplift in the area... this is the Ghoubet al Kharab or Devil’s Goblet and is an almost surreal area bounded by volcanic craters and lava flows.

The wind at this end of the Gulf was relentless, the ‘khamsin’ wind is caused by air on the mountains being in the North and West being heated more quickly than in the lower sea-level area of the Gulf and increase dramatically through the day… in the Devils Goblet they were intense as the walls of the Goblet funneled the winds from off the sea towards the mountain ranges of Ethopia.

We anchored in the lee of Devil’s Island a bizarre volcanic plug that looks like Ayre’s rock dropped into the middle of a large lake! We went out for a first whale shark survey around the island but found conditions on the up-wind side almost impossible and opted to do a plankton tow and CTD profile in the lee of the island instead, followed by a few hours exploring these strange islands.The scenery was very odd and was largely due to the volcanic bed rock of the islands which was then covered in layers of volcanic dust and ash several metres thick.

A landing expedition soon declared the discovery of the islands Apex Predator (a hermit crab) although the team were still convinced that velocoraptors were nesting in the strange round caves carved into the walls of Devils island...So that’s how we came to spend the night anchored in the lee of Devils Island, in the flooded remains of a volcano next to a lava flow that was spawned by the Ardoukoba Volcano in 1978...

Morning arrived and we were still all safe and sound, the Devils Goblet had not swallowed us up in a lava flow and the morning Khamsin wind greeted us as we moved the Deli around the island into the area known simply as ‘the crack’ where the BBC team, Ingrid and Gavin, were filming with an ROV down into the crack between the two tectonic plates.... and apparently there were whale sharks there!

After two hours of luckless searching through the steep sided flooded calderas that are peppered around this area we returned to the Deli and paid a visit to Ingrid and Gavin to see what they were up to with their ROV. The strange contraption was returning from a dive into the crack and we found it bumbling along just above the crack in shallow water, about 25 meters from a young 3.5 m whale shark! This was soon joined by a second shark and shortly a third was seen at some distance from the boat... if the sharks were here then this must be safe after all!

However, three sharks did not a programme make and so it was with some relief that we left the Devil’s Goblet and headed back to Arta and the Ras Korali area to continue our work on the whale shark aggregation... would the sharks be there? We had had a rather disappointing day prior to heading into the Ghoubet and were worried that the massive aggregation may have dispersed for more productive areas.... the evening would tell...

Dispatches from Djibouti.... 4. Satellite tagging, plankton sampling and more

The team is getting the hang of things now and a daily routine has developed that seems to keep everyone happy and to fit in with both the boat’s schedule and the aims of the programme...

Daniel and David are the early-birds with Daniel eager to get out for an early morning whale shark session while David seems welded to the computer, matching spots on big fish... so there is usually a pre-breakfast run for the early morning team followed by two boats on the main morning survey, an extended break over lunch during which time cameras are downloaded and ‘wet’ data-sheets transcribed onto ‘dry’ permanent copies and checked, prior to the afternoon session.

The amount of data being collected is quite phenomenal and making sure it is in order and properly checked has become the priority with Katie and Luke working with each of the recorders to make sure that this side of things does not fall behind. Our new recorders were doing a sterling job with young Morgan finding that shark spotting was equally as taxing as cetacean photo IDs but with Luke and Katie’s help she was keeping the ‘French’ boat’s data in order.

The photo ID has had to take a back seat as it can only be done once the photos have been matched to each encounter record.... also there’s heaps of ID’s to fingerprint and match and this does take time; as we approach the end of the first week we already have in excess of 80 new sharks photo identified and added to the database as well as several resightings of sharks identified from previous years going back to 2003 when the programme first started in Djibouti.

The first satellite tag deployed on a very cooperative 6 m male shark

The first of the satellite tags was also to be deployed at the end of the week and the modified MK 10 PAT tag from Wildlife Computers was made ready to go on its voyage of discovery... the trouble was that David wanted to put it onto a large shark (larger than 5 m) and with eager camera teams waiting to film the process it had to be a very slow moving shark, in fact preferably one that wasn’t moving at all so that everyone could get their photos!

So with this in mind the teams set out in the afternoon to find a shark to meet David’s exacting needs which seemed to be a bit of a tall order as most sharks being found were around 3 metres in length.However, finding slow sharks proved not to be a problem as the afternoon feeding aggregation was kicking off nicely and many sharks were already into vertical feeding mode where they stay stationary for several minutes at a time just gulping in great mouths full of plankton....

Fortune was smiling and a 6 metre male shark was found placidly vertical feeding off Acacia Beach who didn’t even flinch as David attached the tag.... in fact the shark ignored the whole process and just continued gulping which seemed a little ungrateful! So the first tags is out and alive and we hope to start to get regular updates from the tag as well as its full story when it pops off in three months time.

Talking of gulping plankton, the team has been busy trying to find out exactly what the sharks are gulping by running surface plankton tows and conductivity, temperature and depth profiles.... these too had to be modified from the standard five minute tow to a much shorter two minute tow as the volume of plankton being collected was simply too much to process and we had a limited number of plankton sample pots! What was very apparent was the high number of arrow worms (chaetognaths) and sea-butterflies (pteropods) present which are regarded as prime whale shark food in the Seychelles; and while we don’t yet know the species of the arrow worms these guys were huge compared to those found in Seychelles and so it’s no wonder the sharks here seem to be in vertical feeding mode so often.... all will be revealed when the samples get to the lab!

Wednesday, January 7, 2009

Dispatches from Djibouti.... 3. Things that go bump in the night

After the first hectic day everyone was looking forward to a relaxing evening, except the MCSS team who were contemplating what exactly what to do with the reams of data that were being captured..... that was until Dan announced he had brought out a special light for attracting whale sharks at night, he apparently didn’t see enough during the day!

Dan, Tom and the Captain Armand set about mounting the special light on the suspended gangplank off Deli’s back deck and once the 1000 watt monster was powered up it soon attracted a dense cluster of plankton and in a short while a school of small fish, a few larger fish but no whale sharks.... So back to the data entry for an hour or so before a well deserved sleep!

Day three arrived very early for some with Daniel taking his first group out at 06:30 to welcome the sharks at dawn.... the rest of the day followed the same pattern as the previous day with morning and afternoon whale shark monitoring sessions, but this day was less hectic with 21 encounters in the morning and 27 in the afternoon and a total of 17 biopsies taken.

Suction feeding whale shark off Acacia beach, Djibouti, photo Luke Riley

Dan and Tom once again set up the ‘mega-light’ and again managed to attract a healthy cloud of plankton and lots of appreciative small fish.... but nothing larger. Dinner was almost over when someone happened to notice that there was a large shape swimming around in the beam of the flood-light, a young whale shark had appeared to take advantage of the free dinner service!

All thoughts of post dinner relaxing soon evaporated as people scrambled to get masks, fins and cameras as a second whale shark turned up to assist in the clean-up below the light.... Almost everyone got time in the water with one or the other shark and captured some quite unusual images of them. Almost everyone, as it took Dan some time to get his camera and housing organised only to find that as he entered the water the housing alarm sounded indicating the housing was leaking somewhere and so he had to abort his attempt.

A young whale shark vertical feeding on plankton attracted by the Megalight, photo Luke Riley

By this time one shark had departed but Tom and a few of the team spent several hours with the one who remained.... finally the shark tired of the attention and everyone was able to go to sleep!

The war on data was continuing and we were finally able to catch up on some of the photo ID matching and confirmed 29 individual sharks in the second ‘Manic’ session on the previous day including 4 re-sightings from previous years, 1 from 2003, 1 from 2004 and 2 from 2007...

Dispatches from Djibouti.... 2. Whale shark madness!

At 06:30 on the first morning the whole team were up and raring to go as we boarded Deli’s support tenders and headed across Arta Bay towards the French Foreign Legion camp where in 2006 we had regularly encountered whale sharks..... and sharks there were! Between the two boats we achieved some 18 photo ID encounters (later confirmed as 8 individuals) with the characteristically small whale sharks found around Djibouti and so the expedition was off to a very good start.
On returning to Deli for breakfast we were told that another live-aboard was seeing lots of sharks in the next major bay further west and so we felt obliged to move Deli down to this area for the next session. Heading out in the tenders again we were keen to see if the reports of a big feeding aggregation off Acacia beach were true and much to our surprise they were! There were whale shark tails and dorsal fins everywhere....

What is the collective noun for a group of whale sharks? A Shed Load seemed appropriate!

Luke and David were on photo ID duties while Katie drew the short straw of recording by default, she had brought along a UK cold and so was out of the water for a few days.... just as well as the boys notched up a total of 62 in-water photo ID encounters in two and a half hours.... I think the expression used was Manic!! Dan and Tom, the two cameramen from Save Our Seas were suitably impressed but were heard muttering about too much plankton, too many sharks, swimming too fast, not enough time, not enough sun, too much sun etc. etc. While on the other tender Daniel Jouannet from Megaptera with Luis, Flora and their son Germinal were matching David and Luke shark for shark with both photo and video IDs.... The only really unhappy voice was Katie’s as she was forced to sit on the boat and watch but after much pleading she was released to play in what she called a ‘whale shark sandwich’ (take three whale sharks and one Katie and press together)!

After the adrenalin rush of the last two and a half hours, the return to the boat was a somewhat subdued affair with the dawning realisation that writing up the data sheets for 62 encounters was going to take many hours, not to mention working through the photos and running them through the I3S photo ID program. We were going to have to re-think our approach for the afternoon as both Luke and David knew they had multiple encounters with the same sharks although there were obviously many different sharks around.

For the third and final session of the day it was agreed that a combined photo ID and biopsy routine would be run with Luke taking the photo IDs, David taking biopsies and Katie keeping track of everything on the record sheets. So session three in the afternoon was awaited with a mixture of excitement and dread as if the same encounter level was maintained the next two weeks were going to be spent working through the data instead of photographing more sharks! The afternoon session was busy but nowhere near as manic as the previous one... there were lots of sharks around but the feeding frenzy had abated to some extent and the photo ID / biopsy approach slowed down the speed of activities and ensured the maximum amount of data was captured; in total 27 sharks were encountered and 10 biopsies taken.

A daily work-plan was developed so that tasks that needed to be done immediately were taken care of, such as writing up the data sheets and separating out photos for each encounter; the back ground tasks of fingerprinting and photo ID matching would be done on an as and when possible basis...

All photos courtesy Luke Riley

Dispatches from Djibouti.... 1. Arrival

Well we all made it here safe and sound; after journeys which all seemed to include compulsory visits to several African countries to make connections, arrived at the small but efficient airport at Djibouti. Over a three day period, the expedition participants from Australia, France, Seychelles, South Africa and the UK all managed to convene at the correct hotel in Djibouti without having lost any baggage.... well one camera case did pay a fleeting visit to Somalia on its own but found its way to us in time!

Those of you who dread baggage weighing at international flight check in counter would have had nightmares as Katie and David checked in some 80 Kgs for the flight from the UK on Kenya Airways but this was well within the 45 Kgs each they were allowed so that was fine. Save Our Seas H.D. video cameraman Dan Beecham was ‘traveling light’ this time as it was a live-aboard expedition and so he only had 350 Kgs of equipment while Thomas Peshak the Save Our Seas chief photographer had a mere 120 Kgs!

Day one was spent chasing down the material we had not brought with us and we expected to have problems buying Formalin, a listed poison in many countries, which we needed for plankton preservation,..... However, to our surprise the local pharmacy knew exactly what we needed and had stock on the shelf. A quick visit to the local hardware shop secured a suitable rope for plankton tows and CTD casts and so we were all set for the off.

Le Petit camion struggling under Dan and Tom's kit

Loading up the ‘le petite camion’ with the Save Our Seas baggage was interesting, luckily several other 4 x 4s were on hand to handle everyone else and their kit and we were soon aboard the Deli getting settled in and sorting out equipment and eager for the first whale sharks! The crew were confident that we would get loads of sharks but confided that we ‘should have been here two weeks ago’ when they had seen an aggregation of over 40 whale sharks........ as we left the dock we were still in good spirits but blaming the ‘curse of the photographers’ for chasing the sharks away as we motored off towards Arta and Djibouti’s whale sharks!