PAPUA NEW GUINEA 2008

 

Daru & Bobo (Bristow) Islands
Western Province
11-28 April 2008


Map showing the fieldwork localities on Daru and Bobo Islands,
Western Province, PNG.

click to enlarge map

Located in the southwest of Papua New Guinea (PNG), up against the border with West Papua (Indonesia), Western Province is the largest PNG province with a surface area of 99,300sq.km.* (38,340sq.miles), but a population of only 153,000**.

This is a remote region of mangrove and freshwater swamps, monsoon forests, seasonally flooded grasslands and huge crocodile-infested rivers ie. the Fly, Strickland, Bensbach, Mai Kussa, Oriomo, Binaturi, Pahoturi. There are few roads and most travel is by boat along the rugged coast or inland up the rivers. The administrative centre, with a population of 15,000, is tiny Daru Island a few kms off the southeastern coast, the only place not in danger of complete inundation during the wet season. Western Province easily earns the nickname of Papua New Guinea’s “Wild West”. The neighbouring island is known as Bobo or Bristow Island, an unihabited mangrove swamp once thought inhabitated by a large Saltwater crocodile (Crocodylus porosus) population.

* 9x the size of Yorkshire, 5x the size of Wales, or almost equal to the US states of Indiana and Delaware combined.
** Twice the population of Kidderminster, half the population of Cardiff, or equal to Rockford, Illinois (the 135th largest US city).
(All figures from Wikipedia)

Approaching Daru by sea.
Daru sea front.
Daru jetty.
The view from the New Century Hotel at low tide.

 

Market outside New Century Hotel. Firewood for sale.
Fish, meat and prawns for sale. Fruit and vegetables for sale.

There were plans to build a deep-water port in the mangroves of the eastern corner of Daru but there are concerns that the destruction of the mangroves in the development area may affect the survival of a rare snake, the Banded mangrove snake*** aka the Trans-Fly mangrove snake, (Cantoria annulata), a small marine snake belonging to the Homalopsidae****. The Banded watersnake is known from only 7-8 specimens collected over the last 100 years, the last 3 decades ago from Sudarso Is. (formerly Prins Frederik Hendrik Is.) in the Indonesian province of West Papua, and from three locations in Western Province, PNG: Daru and Bobo (Bristow) Islands, and the Oriomo River at Abam.

*** Not to be confused the black and yellow mangrove snake (Boiga dendrophila), a large treesnake from SE Asia.
**** Homalopsidae was formerly the Colubridae subfamily Homalopsinae, a group of rear-fanged mud and mangrove snakes contined to South East Asia and Australia.

Mangroves at eastern end of Daru Island.

 

The only known photograph of the rare
Banded mangrove snake
, Cantoria annulata,
from Fred Parker’s 1983
Snakes of Western Province.


An EIS (Environmental Impact Statement) was required by PNG Sustainable Development and my AVRU colleague David Williams and I were commissioned to conduct the herpetological study that centred on the rare snake.

I went out to Daru a few days ahead of David to conduct a recce of the mangroves and check out the boat and boatman availability. We were to be based in the New Century Hotel, managed by a Malay called Julius Caesar, close to the Daru jetty.

We collaborated with the PNG Sustainable Development Program (PNGSDA) and Western Province Sustainable Aquaculture (WPSA) fisheries advisor Reuben Oaveta. In the field we were ably assisted by PNGDSA/WPSA staffers Jimmy Peter, Dan Kawi, Tabeg Gibia, Prabe Molang, Putua Segeam, Joel Bewan Jaea, Lena Apuri, Robbie Gumoi and Nixon Dareda, and dinghy operators Kewon John and Gideon Oma.

First swamp recce with boys from PNGSDP,
(back) Jimmy Peter, (front L-R) Putua Segeam, Tabeg Gibia, Lena Apuri, and Dan Kawi.

The Iho Creek area had a sizeable population of Mud lobsters (Thalassina anomala) their high muddy mounds dominating the area. Along with the Red mangrove, (Rhizophora mangle) the mud lobster is the architect of the mangrove swamp (see also the mangrove swamps on Pulau Tiga, Sabah).

Active burrow of a Mud lobster, Thalassina anomala

When David arrived we began a series of extensively herpetofaunal surveys of Daru Island and neighbouring Bobo Island.

Daru mangrove swamp at low tide, Red mangrove, Rhizophora mangle
As the tides rises the roots are submerged. At high tide the swamp is an extensive wetland area.

 

At high tide Iho Creek is navigable by boat.
Iho Creek meets Iho track, Jimmy hauling boat. The track back to Daru town.

 

From outside Bobo (Bristow) Island appears pristine.
But enter by one of the channels and huge areas of clear-felling are soon visible.
One of the many small wood-cutter's outrigger canoes in the Bobo Island channels.

We did not find any specimens of the rare banded watersnake, hardly surprising considering its rarity, but we did record several other mangrove specialists. The Crab-eating mangrove snake, aka White-bellied mangrove snake (Fordonia leucobalia), was the most commonly encountered snake in the mangrove swamps or on the mudflats and during our stay. We recorded twelve live and six dead specimens from Iho Creek and Perfume Point.

The inappropriately named Perfume Point.
Perfume Point is "home".

Perfume Point is one of the most inappropriately named places I have ever visited. Far from sweet smelling, it is largely a giant rubbish dump with even creeks and beaches strewn with discarded trash ranging in size from rusting ships to syringes and needles. Apart from the Crab-eating mangrove snakes, Perfume Point is also home to many refugees from West Papua, Indonesian New Guinea.

This species exhibits considerable variation in colouration with all grey specimens dominating but speckled black and creams specimens also common and even yellow specimens as I encountered in 1986 on the mainland.

Crab-eating mangrove snakes, Fordonia leucobalia, from Perfume Point and Iho Creek
Mark and Dan Kawi releasing Crab-eating mangrove snakes.

This is one of the few snakes that dismembers its prey prior to ingestion, seizing freshly moulted crabs or mud lobsters and shaking them vigorously to break the legs off.

The commonest small lizard in the mangrove swamps is the Shore skink (Emoia atrocostata) a medium-sized skink with its dark colouration and elongate head, and a member of the second largest skink genus in New Guinea. The most frequently encountered large lizard is the Mangrove monitor lizard (Varanus indicus). We sighted large numbers of mangrove monitors on trees along the Oriomo River and up mangrove-shrouded creeks on Bobo Island. We also encountered groups of wood-cutters off Bobo Island who were skinning and cooking monitors onboard their rafts and canoes.

LIZARDS from DARU ISLAND
click on an image to enlarge
Shore skink, Emoia atrocostata
Mangrove monitor lizard, Varanus indicus
Wood cutters with four dead Mangrove monitors.

The cutting of mangrove swamp wood is a dangerous act against conservation. Southern Papuan mangrove swamps are a unique habitat but the collection of dead mangrove wood for sale as firewood is not an issue. However, the wood cutters venture up the channels of Bobo Island and clear fell huge areas inside the swamp. Concern about this practise was voiced by a Papuan mangrove biologist at UPNG and proof of is practice was witnessed by us. The wood cutters also kill, skin and eat Mangrove monitor lizards which, although currently numerous, are a CITES protected species. Of the two crimes against conservation the cutting of mangrove wood is the greater.

Pretty girls selling firewood in Daru,
but sadly the truth is not so attractive.

Bristow Island was once well known for its large population of Saltwater crocodiles (Crocodylus porosus) but they were believed extirpated. However, the habitat is still prefect with numerous mud-flats and side-creeks that cannot be penetrated by boat, as well as abundant prey. It was no surprise to us that we sighted a medium-sized specimen, a female or a small male, lurking near a mudbank with a safe retreat into a shallow side-creek. And where you find one 'saltie' you can be certain there are others close by. There is also still a crocodile farm on Daru Island. In the past crocodile skins were one of the main exports from the island with several skinning and tanning companies based in the town.

The location on Bobo Island were we sighted a Saltwater crocodile, Crocodylus porosus
Saltwater crocodile, Crocodylus porosus
in a Daru crocodile farm

The Amethystine python (Morelia amethistina) is one of the most widely distributed and frequently encountered New Guinea pythons and we found two specimens during the survey on Daru. The first was a 2.56m female found coiled on a mangrove stump protruding from the water in the Iho Creek. Iho Creek extends in from the sea and at high tide is navigable by boat all the way up to a muddy track, from where it is possible to walk back to Daru town. The female python looked underfed and may have been post-parturate. She offered little resistance to being captured. I removed the second specimen, a male of 2.75m, from the hollow wall of an outside bathroom in the yard of a Daru house. He was less accommodating of capture and bit me several times as I struggled out from under the structure with him in one hand. Both specimens were documented, photographed and released in a protected part of the mangroves near a large flying fox rookery.

2.56m female Amethystine python,
Morelia amethistina
2.75m male Amethystine python,
Morelia amethistina
Mark releasing the male Amethystine python on Daru Island.

A frequently encountered snake in PNG is the Brown treesnake (Boiga irregularis) and we obtained a specimen near Iho Creek but it was not photographed (this species is amply represented elsewhere on the PNG expedition pages).

The only frog identified during the trip to Western Province was White's tree frog (Litoria caerulea), specimens being found on the roads around Daru town after rain. A number of other small treefrogs were sighted after rain but none were collected or identified.

White's treefrog, Litoria caerulea

However, our primary reason for being in Western Province was to search for the rare Banded mangrove snake (Cantoria annulata). Our research suggested that the habitat around Daru has changed considerably since it was recorded there. Gone are most of the coral reefs and seagrass plains. Talking to villagers and also on the phone to the retired kiap or colonial patrol officer, and herpetologist Fred Parker, we came to the conclusion that the snake showed a preference for these lost habitats, as well as riverine Nipa palm stands. It therefore seems unlikely that it still occurs on Daru and would be affected by the deep water port project. There are other areas in the Southern Trans-Fly where suitable habitat may still exist so the mangrove snake may not actually be extinct.

Being based on Daru, the central point for Western Province, proved interesting because we met with important provincial officials at our hotel and renewed acquaintances with friends from the past, such as Lala, the Kiwai woman who gave me my blacksnake tattoo in 1986, Hon. Tupolam Gire, the counciller of Giringarande with whom I filmed in 2000 and Elijah, my guide at Oriomo during fieldwork in 1986.

To bearded blokes 22 years older. Meeting Elijah, my guide from Oriomo in 1986.

 

And a final thought!
One of many churches on Daru, used 1 day a week, empty 6 days a week.
Daru's only hospital or haus sik, used 7 day a week, never empty, over-crowded.