Beginning of Southern right whale season
June 13, 2012 by dyertrust
The first southern right whales have been observed at Pearly Beach, which makes us all very excited!
A lot has happened during the low season of the southern right whales. The great white house is still vibrating from the energy of the 2nd African Marine Mammal Colloquium hosted from the 21st-25th of May. Presentations were given by most of the delegates throughout the 3 days on subjects such as: The South African Blue Whale Project, Diet of humpback dolphins off the KwaZulu-Natal coastline and Whistle vocalizations of Indo-Pacific bottlenose dolphins inhabiting the south-west Indian Ocean.
The atmosphere was buzzing with new ideas and there is a real sense of co-operation within the scientific community. One really exciting new project is the African Mammal Atlas Project. The goal is to update the current distribution records of all African mammal species based on professional scientists, citizen scientists, conservation organisations and wildlife authorities throughout Africa. The project knows no borders and encompasses the entire continent of Africa from the Northern coasts to Cape Agulhas.
Dyer Island Conservation Trust will be a major contributor by providing observations of marine mammals throughout the year. You can also contribute; www.mammalmap.adu.org.za
In addition to the talks, a long list of work shops were conducted. A sampling of topics includes: Establishing a functioning stranding network in South Africa, Humpback dolphin research in South Africa and South African Department of Environmental Affair permitting procedures.
Coincidently, the same day the stranding workshop was held, a Brydes whale calf stranded at De Platt. The animal was dissected the next day by top researchers; Peter B. Best, Meredith Thornton, Gwenith Penry and taxodermist Piet Pretorius It was an amazing learning experience for the delegates as well as a chance to coordinate which samples and measurements are to be taken should additional animals wash up on the beach. The cause of death of the Brydes whale was not determined, but it was clear that it was a very young individual.
There is also a fabulous new addition at the Great White House. A massive southern right whale skeleton is now hanging from the roof. Everyone stops to admire the skeleton upon entering the building and all of the positive comments have been wonderful to hear. The skeleton is from a 14m female who was hit by a ship. The propeller marks are still visible on the skull and vertebrae of the animal. If you havent come to visit us for awhile, you now have a good excuse to return and come dining with a whale and explore the full story!
Katja has been spending the low season of the whales sorting out all the archive data from Dyer Island Cruises whale watching boat. We now have a much better understanding of the spatial movements and seasonal distribution for all of the animals in our area. June is the main month for humpback whales to pass through the area, so be on the lookout.
Volunteers have been sending dedicated applications and team is set for the theodolite tracking. Anita Hansen from Denmark is the first volunteer for the season and she has been taking part in the preparations and re-securing the water tower. The theodolite tracking is now carried out whenever the weather permits it. The first day of tracking, a group of 50 dolphins were followed close to the kelp and coastline at Pearly Beach. The second day the team tracked 2 southern right whales and a group of humpback dolphins.
The coming season will besides the theodolite tracking and publication of at least the first 2 scientific articles, involve sound recordings of the cetaceans.
A pilot study was carried out in co-operation with DCE (Danish centre for Environment and Energy) who provided an underwater recording station and a technician. The aim was to test passive acoustic monitoring equipment. Based on this test an acoustic logger will be placed on the sea floor as soon as the last funding is in place. Cetaceans are highly vocal animals, relying on sound for orientation and communication. Passive acoustic monitoring enables the researchers to monitor an area acoustically. Cetaceans spend the majority of their time submerged. Thus, passive acoustic techniques have the advantage over visual methods in being able to detect animals; with substantial dive time, at night and in poor weather. Detection rates of cetaceans using acoustic methods can be 5 to 8 times higher than visual techniques (Gillespie and Chappell, 1998). When combined, visual and acoustic survey methods maximize the detection probability of marine mammals.
So stay tuned for exciting news on the whale blog
Gillespie, D. and O. P. Chappell. 1998. Automated cetacean detection and monitoring. In: Proceedings of the Seismic and Marine Mammals Workshop, London. M. L. Tasker & C. Weir (eds.). 6pp. 23-25 June 1998.