Tuesday, 14 May 2013
by: John Paterson, Albatross Task Force and Walvis Bay Strandings Network
Gray whales, Eschrichtius robustus, live in the high Arctic and northern Pacific Oceans coming as far south as Baja California and Mexico on the west coast of America and the Korean Peninsula to breed in summer. It used to occur in the North Atlantic Ocean, but was hunted to extinction in the 1700’s. It does not venture south of the equator. Or so we thought.
Last Saturday, 04 May 2013, tour boats doing dolphin cruises to Pelican Point saw a strange whale. Several more sightings during the following week seemed to indicate the unlikely fact that a gray whale was visiting Walvis Bay! On Sunday 12 May a member of the Walvis Bay strandings network confirmed the reports that there was a gray whale about. This is the first known record of this species in the Southern Hemisphere. The question is now “what is the origin of this whale?”
In May 2010 a gray whale was seen off Israel in the Mediterranean sea and the same whale was seen 22 days later in Spanish waters, also in the Med. This sighting raised much speculation on the origin of the whale and the reasons for its appearance. It was suggested that the whale originated from the eastern Pacific population and was able to navigate around the northern Canada due to the reduction in size of the Arctic ice cap caused by global warming. This climatic trend would potentially allow these whales to re-colonise their historic range in the north Atlantic. The authors of that report stressed that it was difficult to draw conclusions from a single event and were only proposing likely hypotheses. Three years later a gray whale makes its mysterious appearance in Walvis Bay. Comparing photographs of the Walvis Bay animal with the Mediterranean animal (courtesy of Aviad Scheinin - http://www.hamaarag.org.il ), it seems unlikely that this is the same individual. Is it another individual that has traversed the North West Passage, or perhaps travelled around the southern tip of South America and across the Atlantic? Unfortunately, we’ll never know the route it followed to get here but keen eyes on the water may tell us where it goes next, so please send your reports to the WBSN if you see this animal.
Gray whales grow up to 14 m in length and undertake the longest known migration of any mammal completing a round trip of over 30,000 km between their summer feeding grounds in the high Arctic and winter breeding area off the coast of Mexico returning to the high Arctic again. The whale seen off Israel had completed the longest known stray by any mammal. Though they are baleen whales gray whales are unique in that they feed off the bottom of the sea floor by sucking up mud, usually through the right side of their mouths, and filter out the bottom mud dwelling amphipods on which they feed. This results in the baleen being shorter in one side of their mouths.
This sighting highlights the chances of seeing amazing animals in Namibia and also how important our marine environment is to sea life. Well done to the marine tour operators for locating this whale and operating in a responsible manner and not scaring the whale off. The Walvis Bay Strandings Network would like to thank the tour operators for passing on all sightings of this whale and particularly Mola Mola Tours for making space on their vessel so that we could confirm the identification and get photographs.
Sunday, 28 April 2013
After a very successful series of surveys of the NIMPA in 2012, we are happy to be continuing the work here with the Ministry of Fisheries and Marine Resources.
The forecast held and we had some of the best weather I've ever had at sea on a ship. Day 01 was a bit swelly still (with some associated sea sickness from us all), but day 2 and 3 were glassy flat and lovely. The area we surveyed is just to the south of Luderitz Bay and straddles the heart of the main upwelling cell within the Benguela ecosystem. This upwelling cell is so strong and so fast moving that there is (counterintuitively) remarkably little life there as there hasn't been a chance for the nutrients to get converted into phytoplankton and move up the food chain. Last year, we only got one day in this area and no sightings but it was horrible misty, swell weather, so it was important for us to get into this area again to confirm our findings. Given potential for low sightings, we were thus quite happy to have had 22 dusky dolphin sightings and 5 whale sightings over the 3 days (although they mostly happened close to shore and outside of the upwelling cell) and the hydrophone worked like a bomb the whole time.
A numerical summary:
3 days, 2 nights
842 km surveyed
22 dolphin sightings
5 whale sightings
~500 GIGS of acoustic data collected
Heaviside's dolphins echolocate at a very high frequency (are~120kHz), we have to record up to 250 kHz to cover the entire click's frequency range - this is more than 10X the data density (quality) of a normal 'human' recording. To put it in perspective, we fill a CD with data every 5 minutes.
A WILSON'S STORM PETREL OVER GLASSY FLAT SEAS
A DUSKY DOLPHIN SURFACES UNDER THE BOW OF THE !ANICHAB BEFORE DAWN
Wednesday, 27 March 2013
In addition to the pygmy right whale stranding detailed in the blog post below, we have had several others recently. A quick thanks to all involved in reporting and assisting at the various events including the Walvis Bay Salt Works for access to the pump station and reporting strandings, Naude Dreyer of Sandwich Harbour tours for coordinating and always being available to assist, Neels Dreyer and John Paterson for their role in coordinating communication within the Walvis Bay Strandings Network (WBSN), Levo Tours for reporting the 2nd pygmy right whale in the harbour, Jeanne Meintjies of Eco-Marine Kayak Tours and Jaco Louw who helped with the attempted rescue of the pygmy sperm whale.
Sunday, 17 February 2013
Ruth has done a great story on her West African Cetaceans blog, about the recent rescue of a baby pygmy right whale which stranded at the Walvis Bay pump station - so head over there to read the full story:
For here, just a few pics:
For here, just a few pics:
EYE OF THE WHALE
STRONGLY ARCHED JAW CHARACTERISTIC OF THE SPECIES
THE NARROW ROSTRUM IS QUITE DIFFERENT TO MOST BALEEN WHALES
KEPT COVERED AND WET ALL AFTERNOON WHILE WE WAITED FOR THE TIDE
GETTING IT ON THE STRETCHER
AND OUT TO SEA
Monday, 11 February 2013
By Monica Betts - University of Pretoria MSc student.
On 25th of January 2013 I arrived in Namibia to begin the first part of my Master’s degree under the supervision of Dr Simon Elwen. The main purpose of my visit has been to get some hands on training in order to prepare me for the field work phase of my project. I will be taking over the collection of data for the long term cetacean project currently underway in Mossel Bay, South Africa as well was conducting my Master’s project.
During my Master’s project, I will be working towards establishing some baseline data needed to apply static acoustic monitoring using CPODs (echolocation click detectors) to studying dolphin populations on the east coast of South Africa. I will be looking into measuring the detection distance of animals and also trying to acoustically differentiate my two study two species, the Indo-Pacific bottlenose dolphin and the Indo-Pacific humpback dolphin. If we can get this right, then we’ll be able to use CPODs (which are relatively cheap compared to other types of hydrophone) to improve our understanding of the distributions and behaviour of these species by using CPODs for long term 24-hour monitoring.
When I first arrived in Walvis Bay the terms ‘CPOD’, ‘Databases’,’ Photo-ID’ and ‘Theodolite’ were completely foreign to me. However, over the last few weeks that has changed. I now know that a CPOD is a device used to detect cetacean clicks over a long period of time, photographing and identifying dolphins involves a lot more than just a good camera, databases that are organized and detailed are essential from the start of the project and theodolite work requires patience and attention to detail.
My experience here in Walvis Bay has been incredible. I found I have learnt so much in a very short space of time. The most important lesson I have learnt that is although working with dolphins involves a lot of hard work, if it is done properly it can yield satisfying and sometime very surprising results. I am very grateful to have the opportunity to work with these lovely creatures and look forward to learning more and more about them.
MONICA HAULING HER FIRST CPOD
HANNAH (RATHER CASUALLY) ASSISTING
SOME RATHER IMPRESSIVE DOLPHIN JUMPS SEEN AT THE POINT
Wednesday, 7 November 2012
By Aurora Nastasi:
In early July this year, we put a CPOD hydrophone down at Sandwich Harbour – the goal being to investigate how frequently bottlenose dolphins go into the lagoon there, compared to Walvis Bay where there are far more human impacts. However, it’s a really challenging environment to put in a mooring for this type of instrument, as it’s very shallow, with a sandy bottom and lots of tidal movement.
Two weeks ago when we went back to recover the instrument (a mighty trip in it’s own right – taking 8 hours on the boat and >80L of fuel to cover the ~150km there and back) we discovered the buoy barely peeping above the surface. Over the 2.5 months that we left it down there, the entire mooring had become buried by the flood of sand that is moved every day by the tides. The power of Nanuuq’s 120 horsesbarely managed to pull the rope free, but couldn’t move even a centimeter of the weight or its blanket of sand, no matter what direction, no matter how tight the ropes were. Nanuuq had to surrender to the power of nature.
Mission impossible – Plan B. After much deliberation, we decided that the best way to rescue the CPOD was to drive to Sandwich Harbour along the beach as close as possible to the mooring, and to carry and small boat and diving equipment to dive it out. So last Friday, we (Simon, Nico and I) set off on our ‘mission impossible’ with the precious collaboration of Gert and Andries from Namib Diving and Marine Services.
Two 4x4 cars carrying all the proper equipment and a 4 m aluminum outboard with a 30 Hp engine left Walvis Bay towards the stunning dunes of Sandwich Harbor. Once there, surrounded by hundreds of birds and a couple of lazy seals, we quickly arranged our short sailing trip to the buoy to complete the mission as soon as possible in order to come back before the high tide would have obliterated any trace of the road we drove in on. Unfortunately, once on board we found out that the engine didn’t work properly (40km of bouncy beach driving isn’t great for engines it seems) and had to row all the way to the buoy. Simon dove and Nico snorkeled above him while Gert and Andries remained on board as support. In less than 5 minutes the rope was cut and the barnacle encrusted CPod was set free.
We were very happy to succeed in rescuing the CPod but a surprise which made our day even more special was about to come: on the way back to Walvis Bay, a group of at least 20 bottlenoses was slowly swimming (and maybe feeding) along shore, so close to the beach that we could have touched them if we had wished to. We grabbed the cameras and took as many photos as possible as there were many marked animals as well as moms and calves. The tide was arising fast and we had to go back very pleased for completing the C-Pod mission and to have had a further chance to meet dolphins from land…
LETTING THE TYRES DOWN AT THE OLD SA-NAMIBIA BORDER
BOAT LOOKS SMALLER THAT IT WAS!
PULL START ENGINES & DRY CARBURETTORS = TIRING
HOME AND DRY
AURORA PHOTOGRAPHING THE DOLPHINS JUST NORTH OF SANDWICH
LUNCH BREAK ON WAY HOME - ENJOYING A RARE SUNNY DAY!