Dugong dugon - 22 December 2007
Franco Banfi, recently assigned to the tourism promotion authority of PNG to compile and underwater image library, dived with us at the end of his trip this December. On our last days diving, we planned to show Franco and his partner Sabrina, Pakawala, the Fresh Water sinkhole. Unfortunately it was overcast and raining so Franco requested instead to do another shoot on the "Deep Pete", which those that have dived this plane wreck will know is a photographers gift. After the dive in the sit interval, Apo and George spotted a Dugong close by. Dorian suggested to Franco to try and approach it on snorkel. Well what an experience.. Franco has done this before with Whales and other marine mammals so has a good idea how to approach without scaring it away.
“ I approached it slowly and it looked as if it was going to swim away” of course his camera with wide angle dome port and strobes would have been quite imposing. “I then turned away and started swimming towards the boat, turning around slowly I saw that it was following me. At this point I knew that it was curious so I took the opportunity to get close. The strobes where a little distracting for him, but he was happy to stay with me.”
Franco managed to snorkel with the Dugong for almost 40min !! in the 7 years we have been operating in Kavieng we have only managed to see 2 whilst diving and one other in a sit interval at Nago which Lynn Sutherland managed to capture on her video, but only fleetingly.
We often spot them from the boat in this area when we are heading out for dives but they duck down pretty quickly as we pass.
“It is not so much the photos but the experience that was so amazing” Franco told us later that evening.
As you know we can't guarantee this experience to everyone, but the more you are in the water the greater chance of having one of these lifetime close encounter experiences.
We are glad to have been able to offer Franco this experience. A big thanks to Apo and George for their great spotting during the sit interval.
On the Dugong
The Dugong or Sea Cow is a marine mammal occasionally spotted around the waters of PNG. Like Whales, Dugongs evolved from terrestrial mammals which returned to the sea, possibly from the group that gave rise to elephants. All dugongs world wide are endangered species. The waters around Kavieng particularly Nango and Nusa Islands include some submarine meadows of sea grasses where dugongs may graze contentedly like giant sluggish underwater lawn mowers. Dugongs are the only herbivorous animals alive now that are completely marine. Once dugongs lived in herds of up to a hundred, but after being hunted for centuries for their meat, dugongs are now quite rare.
Dugongs feed mainly on the more delicate and nutritious sea grasses, which they search out with sensory bristles on the upper lip. The lip itself is a versatile tool that digs out clumps of grass, roots and all, and carriers them to the mouth. Their teeth are surprisingly large for docile vegetarians. Fully grow, a dugong may be 3 metres long, and weigh over 300kg. Dugongs may live up to 75 years and mate for life.
Reference : leaflet prepared as resource for the World Heritage/Ecotourism programme, a joint SI/NZ Government project funded by NZODA
Franco Banfi resides in Lugano in southern Switzerland, and has been a professional photographer for over 15 years. His most notable major publications are two books on diving - Papua New Guinea and Dive Guide to Papua New Guinea - which he produced in 1996.
In addition to these books, Banfi's articles with accompanying photographs on PNG have been published in numerous dive magazines around the world, in most cases featuring a PNG photo on the front cover. The exceptional quality of his work and his reputation as a professional have been instrumental in helping to place PNG in the forefront as a premier dive destination. He remains one of the most influential underwater photojournalists today. www.banfi.ch
“Flashing Clam” Ctenoides ales (Bivalvia: Limidae)
Late January 2007, Cara spotted two “Flashing Clams” under a ledge at Namnamin. “ Out of the corner of my eye I spotted a few blue streaks, thinking it was cleaner shrimps at work I went closer to investigate and to my surprise found these spectacular Clams. Lucky there was just enough light available to create the blue streaking, without any light I wouldn’t have noticed them. I couldn’t tell you how many times I have swam under this ledge and have never noticed them before, there is just so much to see underwater, you never know what you may have missed”
A Friend Simon Foale introduced us to these fascinating little Clams in the Solomon Islands. I knew from Simon that these clams have to be illuminated to be able to create this effect. The Brighter the light the more spectacular this lightning like effect. A torch shone directly on the clam creates the most brilliant white sheet lightning effect.
Download Video (right click and choose Save As... to save the file to your computer)
On the Mechanism of Streak like Flash on the Mantle of
Ctenoides ales (Bivalvia: Limidae)
Shuzo OKUBO*, Tadahide KUROKAWA", Tohru SUZUM", Shoji FUNAKOSHI",
and Tadashi Tsuni*
(*Shima Marineland Foundation, Ago cho, Mie 517 05 Japan and **National Research Institute
of Aquaculture, Nansei cho, Mie 516 01 Japan)
Abstract: Generation of the streak like flash in the inner fold of the mantle in Ctenoides ales was investigated by video camera recording, and stereo, light, fluorescence and electron microscopy. The stereo microscopy revealed the presence of a pale white band along the entire width of the marginal edge of the shell side surface of the inner fold. ~Since the flashing could not be seen in the dark, it was not due to the luminescence but the reflection of light. The light microscopy showed that the band region consisted of about ten rows of epithelial cells, cylindrical and 40 gm tall and 10 gm wide. The cytoplasm was densely filled with fine granules, eosinophilic in H E staining. Under the electron microscope, those granules appeared as electron dense vesicles, 03 0.6 gm in diameter, each containing a highly electron dense spherical core, 0.2 0.3 gm in diameter. The cell had a nucleus, few mitochondria and lysosomes, however, other cellular organelles such as Golgi apparatus, rough and smooth endoplasmic reticulum were not evident, in the present observation. We assume that the electron dense vesicles packed in the cytoplasm function to reflect light strongly. This highly reflecting structure found in C. ales is quite different from those have been reported in eyes of scallop and squid, and in iridophores of giant clam, cuttlefish, long spined sea urchin and of fishes.
The video observation showed that the mantle made a movement to roll the white band towards the shell side and then, within a second, the rolling movement was released. The phase of the movement was different by the portions of the mantle, and the mantle edge made a wave like motion. When the pale white band was hidden by the roll, the reflection of light disappeared. When the rolling was released, the reflection of light reappeared. Since the "roll and release movement" repeat quickly, it looks as though a streak like flash run along the mantle margin.
VENUS (Jap. Jour. Malac.)
Vol. 56. No. 3 (1997): 259 269