Rhinopias - Diving The Wallace Line, Western Indonesia

There are parts of Indonesia that are special places, especially those that fall along what has been named by biologists as the Wallace Line.  This imaginary line (actually it is defined geologically) separates the ecozones between Asia and broadly-speaking Australia.  Along the line the biodiversity is exceptionally high and there are many rare, uncommon and distinctly unusual species. 

In April 2011, I spent a tad over 3 weeks diving several areas along the Wallace Line n search of some of these species.

LEFT: A purple phase Weedy Scorpionfish (Rhinopias frondosa) although brighly coloured is highly camouflaged amongst the surrounding coral rubble.

The water will be cold - I had been told....

I’d been warned that the water would be cold.  Despite the warning, I still gasped as I fell from the boat into the 21 degree water.  Considering I was diving in Indonesia, which straddles the equator, it was surprising to be almost suffering heat exhaustion on the surface and then to be exhibiting the mild symptoms of hyperthermia 10 minutes later.

LEFT: A purple phase Weedy Scorpionfish (Rhinopias frondosa).  It's interesting that many fish cannot see colour, but can define tones.  So, why is Rhinopias coloured so brightly.

I was diving in the region of Alor and Flores in search of unusual fish and nudibranches.  In particular I was hunting (photographically speaking) a relatively uncommon and rare fish with the spectacular name of Rhinopias.  I’d only seen fish belonging to this genus a couple of times when diving in Papua New Guinea, and on these dives I was unfortunate to not have my underwater camera with me.

Rhinopias sp. - An Unusual Fish Species

Rhinopias means “long nasal septum”  and comes from the Greek and Latin translation.  All species belonging to this genus have this same characteristic -  a long slender snout leading to a huge cavernous mouth.  What separates the different species is subtle characteristics such as the type and number of appendages, and size of pectoral fins, and the locations in which the fish is found.  Colour and size, which can be controlled by food supply and environment. have no direct relationship to each species.

 Cold Water & Muck Diving

The water was mind-numbing cold and despite wearing a full wetsuit, I found it increasingly difficult to maintain my vigilance searching along the muddy bottom for the prized fish.  This area was not a beautiful reef in  brilliantly clear sunlit water, but rather rocky substrate adjacent to a village populated by a few thousand Indonesians living an almost “hand to mouth“ traditional lifestyle.  The visibility was limiting due to silt and debris entrained within the water column, and the bottom strewn with silt-covered boulders.  This was one of the favoured habitats Rhinopias; this style of diving is what has been named by the diving community as “muck diving”.

LEFT (2 images):  A Paddle-flap Scorpionfish (Rhinopias eschmeyeri).  Note the different colour hue and the lack of white "highlighted" eyebrows to that of the same species in upper photograph; variation is common amougst Rhinopias sp.

Muck diving came of age after intrepid divers decided to begin to explore the not so often dived areas adjacent to bridges, rivers, marshes, wetlands and villages.  You won’t the usual reef dwellers here, but you are liable to find the unusual, the ugly, and the strange.  You may also come across the juvenile forms of many of the more common reef species, as these backwaters are a safer habitat for small fry.

To add to discomfort a chilly thermocline had developed at a depth of 25 meters and I was reluctant to sink into the shimmering layer as the water here was colder than the warmer water above.  The shimmering water meandered its way across the rocky slope enveloping me for a minute or so before moving deeper; it was like going from a warm bath to a bath with floating ice cubes – then back again.

Why Are Rhinopias Special

Rhinopias is a genus of scorpionfish (Scorpanidadae) containing six species, and like other scorpionfish, utilise camouflage to blend in with their surroundings;  I’ve always found it odd that a bright red, pink, yellow or purple fish can be almost invisible as you swim over it.  Even when photographing the Rhinopias, I often find myself searching for the animal after swimming off a distance before making another run to take photographs - so good is nature to have provided such as tantalizingly beautiful veil of deception.

LEFT: A yellow phase Weedy Scorpionfish (Rhinopias frondosa) showing detail of the lure appendage over the cavernous mouth.

Rhinopias are rare fish, and sometimes appear in the aquarium trade, where they fetch high prices.  They are lie and wait predators and generally are not fast swimmers.  Their camouflage is unusual as the fish are brightly coloured over an often dappled base colour.  This bright colouring however, doesn’t appear to offer any resistance to their reputation of being exceptionally dangerous bottom dwellers.  To add to their concealment, are variously sized appendages which assist to breakup the visual outline of the fish and help disguise the large lips and mouth.

The appendage above the head of Rhinopias is used a lure and is often waved about like a small worm on a hook.  Any interested passer by, stopping to investigate the waving appendage is quickly consumed as the fish opens its mouth and lunges quickly forward.  The movement and opening of the mouth is enough to create a vacuum which sucks into the mouth any unsuspecting small fry.

Photographing Rhinopias

The most difficult part of photographing Rhinopias is actually finding the fish.  Because this species often resides in silty and muddy environments, ensuring that the water remains as clean as possible is a photographer’s first task.  Inappropriate fin movement and hand placement can completely envelope you and the fish with silt removing any opportunity you may have had to produce a good photograph.  Therefore, good diving practices are required and neutral buoyancy must be maintained at all times; a somewhat trying task when swimming in a current.

Visibility was quite poor during this particular dive and despite being slack tide, the tidal current carried  copious volumes of silt and debris from a the mouth of a nearby stream.  Backscatter was a major concern and to minimise this backscatter (seen as bright spots in a photograph) accurate strobe placement is essential.  I wanted the light from the twin strobes to just touch the fish and not illuminate the background water and entrained silt. 

The photographs were taken with a Canon 5D MK2 in a Subal housing.  The camera and strobes were set to manual to allow complete control over shutter speed, aperture and exposure.

Jostling With the Current

The current, heavy camera housing and twin strobes conspired against me as I jostled for a suitable shooting position.  Several times I had to float past the fish, turn and swim back up-current for another run, because I was not in the correct shooting position.  Everything from strobe placement, shooting angle, aperture and exposure had to be pre-visualised so as to acquire a successful photograph. 

The prize photograph is a Rhinopias lunging with its mouth open, but despite repeated attempts none of the fish I observed appeared interested in doing this for the camera, despite being offered a few tender morsels as a reward!

In my next post dealing with this visit to Indonesia, we’ll look at some of the other bizarre creatures encountered whilst diving: crocodile eels, rare nudibranchs, colourful morays and frogfish. 

If you have liked this post, why not let me know in the comment field below.

Hammerhead Sharks, Indonesia

I had be told that this area was prone at certain times of the year to schools of hammerhead sharks, however, didn’t expect to see them.  I’ve dived with lone hammerheads on several occasions, but I have never encountered a large school.  Sharks aren’t common to see, and when you do see them often they are fleeting glimpses that last less than a few seconds.

LEFT:  A Scalloped Hammerhead Shark surrounded by Banner Fish cruises past.

The water I was diving was along the edge of a tectonic plate and as such was very deep; a coral encrusted shelf sloped away into the abyss and the sea bottom was over a kilometre below.  Unfortunately, on this day the weather was overcast and the water was not as clear as I would have liked.  The current has picked up along the reef edge and entrained quite a bit of silt and sand in the water column.  Levelling out at a tad over 30 meters (100 feet) I hovered above a sandy plateau that extended a short distance before dropping off to unimaginable depth.

The Edge of the School

I then saw my first hammerhead in the distance.  It was a large individual reaching roughly 4 meters (15 feet) in length.  It kept its distance and disappeared as quickly as it had appeared. Making my way over the sandy plateau I began to descend further until reaching 47 meters (150 feet) in depth.

LEFT:   Swimming into the school, several Scalloped hammerhead sharks patrol beside me.

It was then that I saw a mass of movement directly in front of me; I had reached the edge of a school of Scalloped Hammerhead sharks.  Quickly counting, I calculated that 9 sharks were immediately within my vision, these sharks swam past me to be replaced by more sharks following.  I swam into the school and all I could see was shark!  Every few meters there was a shark, followed by another which was beside another – there were sharks everywhere – WOW.  I noted that all the individuals were females and I wondered where the males were!

I knew I had to photograph quickly as the time allowed at 47 meters is minimal and I was already at the verge of entering decompression.  Moving my strobes out from the housing, I attempted to position them in such as way as to minimise the back scatter, that I knew would occur from the suspending silt and sand.  I fired a few frames and as the duel strobes (flashes) whined to recharge, I observed that the sharks became a little agitated; one individual dropped its pectoral fins and arched toward me like a fighter plane peeling away from the squadron.  The shark came within arm’s reach before veering off to join its brethren.   The reason for the behaviour is quite simple, and occurs with most active sharks when divers use electronic strobes.  The recycling from the battery pack to the flash cell causes a high frequency whine which is picked up by the Ampullae of Lorenzini, the name for a shark’s super-sensory electrical device; this momentarily excites the shark.

Fearful

I wasn’t prepared for the fast approach and immediately felt apprehensive; suffering the effect of slight narcosis did not add to the situation.  As my heart rate increased due to my sudden apprehension, two hammerheads swam in my direction to investigate; sharks are similar to dogs in that they can smell fear!  In situations like this fear can feed on fear itself and spiral until one looses control of the situation. 

Realizing this, I regained my composure, aimed and fired off another frame followed by another.  I swam towards the school again and was annoyed that there was so much sediment in the water; I hoped the light from the flashes was not reflecting on the sediment, but there was little time to look at the camera LCD screen to check – things were happening very fast as hammerheads glided in from the main school to investigate me and my whining strobes!

I was over 45 meters in depth and well into a 15 minutes decompression obligation (the time I would have to spend at a shallower depth to allow nitrogen off gassing; failure to complete this time may lead to decompression sickness).  I was trying to swim somewhat beneath the sharks so I could shoot with a slight upwards angle; a photographic composition like this would show the power, size and presence that such an animal deserved. 

I Wanted the Perfect Shot

I wanted to get the perfect shot.  I wanted the right composition and exposure.  I wanted three sharks in the correct position.  But, there wasn’t the time.  To continue would be foolhardy.  I then realized that my time was up.  I had to depart immediately for a shallower depth or suffer the consequences of either low air or too greater decompression obligation.  It’s at times like this that you must understand that the photograph is second to your own safety. 

I had reached the threshold and I was pleased that I had listened to reason and not continued.  With slight regret at not been able to take the perfect photograph, I slowly ascended to my decompression depth.  However, I was elated at being able to swim with of a school of hammerheads at close quarters; the experience transcends the photographs! 

BELOW:  A Scalloped Hammerhead shark swims above me before changing direction abruptly to make another pass. Encounters with large predatory animals are uncommon and this experience will remain with me for sometime.  Most of the images on this dive were shot at 35mm at ISO400, 1/125th @f8.

Natural History

Scalloped Hammerhead Sharks (Sphyrna lewini) are probably the most commonly found species of hammerheads located in coastal regions, appearing in very shallow waters such as estuaries and inlets. Their distribution in the water reaches from the surface down to a depth of approx. 275 m. The young, however, remain mostly in shallow waters along the shore to avoid the danger of falling into the mouths of predators. At certain times of the year and places, and during certain phases of their lives, scalloped hammerheads form very large schools, sometimes counting hundreds of individuals, but they also swim the oceans alone. Some populations remain stationary, others clearly wander, migrating in the direction of the poles in summer. Some sexually-related migrations have also been observed, e.g. females who undertake migrations during particular periods of their sexual development. 

As already mentioned, this shark species tends to form huge schools whose function is presumed to be manifold and may, among other things, concern feeding habits and reproduction. Although many studies also consider this behaviour to be a group protective function, this is somewhat questionable since the animals have practically no natural enemies after reaching full maturity. Groups of scalloped hammerheads prefer staying in regions which have pinnacles or sea mounts which reach from great depths practically to the water's surface. Latest research also shows that these sharks can make use of the earth's magnetic field during their migrations.

Why No Location Mentioned

You may wonder why I have not mentioned the location.  The reason is that all sharks are in danger from being over harvested by fisherman.  Schools of sharks such as the school I had encountered are in demand by the fishing fleet, not for meat, but for their fins.  The sharks are caught on long lines and pulled to the side of the boat, and a very sharp knife used to slice off their fins.  The doomed creature is then pushed away from the boat and left to die an agonising death.  The fins are used in shark fin soup which is a Chinese delicacy.