THE SHARKS OF PIZION REEF - TRUK LAGOON
© Ian Robertson, 2002

Location
Pizion Reef is part of the fringing reef on the SSE of Chuuk (Truk) Atoll, East Caroline Islands, due south of Weno island.  A shallow limestone reef, just breaks the surface but, according to the Admiralty hydrographic chart, it plunges to 101 fathoms (185 m) in almost no distance at all.  Ideal for shark action! The Odyssey picked up her mooring in about 5 m of water amongst coral bommies.  There was a slight ocean swell and the sea was a delightful turquoise blue at 28°C. 

A Look-see Dive
In we went for a look-see and a wall-dive.  From the boat, the coral gardens extended south and then abruptly ended in an intense blue. As I approached the edge of the garden I briefly saw the flash of a distant grey tail between two lumps of coral – a tail I knew well.  Ah-ha!  Reaching the edge, the coral garden sloped very steeply from 5 m to 20 m and then fell vertically into an intense indigo blue abyss with 30 m visibility.  And there they were, cruising the wall at all depths.  Sleek, grey, lithe, torpedo-like shapes, a bit less than 2 m long, with pointy noses and slender tails marked with dark grey along their trailing edges.  Some had a small edging of white along the trailing edge of their dorsal fins; others did not.  Definitely Carcharhinus amblyrhynchos, the grey reef shark.  I hung there assessing the situation, alert for any territorial behaviour – there was none.  They were clearly aware of us but disinterested.  The cruising continued but at a distance.  I eased out of the coral garden and we descended the slope.  The sharks remained both distant and disinterested.  I reached the edge and sank a short way down the coral wall to 34 m, looking down on still more greys cruising the indigo blue depths.  Photographing these distant beasts would be difficult as I was using the wide-angle 15 mm lens – a mistake.

The peaceful waters of Pizion Reef on the outside of Truk Atoll

We explore the coral gardens and slope bordered to the south
by a steep wall to over 180 m

I ascended slowly, trying hard to capture the ambiance of the reef and these sleek grey beasts on film.  I really needed to change lenses.  As I returned to the coral garden I realised I had missed something.  Flitting low amongst the coral were other, small, torpedo shapes 1-1.5 m long; these were brown on top with cream underneath and had distinct black tips to their dorsal, pectoral and lower caudal fins.  Beneath the black tip on the dorsal fin was a creamy band.  This was the first time I had seen the blacktip reef shark, Carcharhinus melanopterus – what a thrill.  They, too, were shy and I battled to get sufficiently close for a good picture.  At last, by lying very still and not breathing, one did come close enough for a truly lovely shot (the last frame of the film) with the sunlight from the waves dappling its upper body.  I left the water with a happy grin, knowing I had a good one!

Coy, disinterested grey reef shaks cruise the depths of Pizion Wall
but do not come close

The Black-tip Reef Shark - Charcarhinus melanoptris -
with 15 mm lens. Patience and stillness is rewarded
 
Shy Black-tip Reef Sharks cruise the coral gardens - normally very shy when there is no food around

Shark Feeding
While we dried off, the crew threw some bait in the water.  In moments, the stern of the boat was surrounded with wriggling and thrashing small brown and larger grey bodies snapping and gulping anything that hit the water.  Quite a show! 

The crew prepare shark bait and throw it off the fan-tail

Bronze-coloured blacktip reef sharks come for the bait
followed by grey reef sharks

After a good surface interval and the usual thorough dive briefing, we entered the water as a group.  I took the 28 mm lens this time! There were more sharks, closer and somehow expectant.  We worked our way to the drop-off where there is a natural amphitheatre.  The sharks, all grey reefies, preceded us – a bit like my old tom-cat, when he knows he is about to be fed.  They milled around, clearly knowing what was about to happen.  Nothing threatening, just expectant.  In the centre of the amphitheatre was a small pulley pinned to the coral.  We settled into good viewing spots and emptied our BCs.  A small aluminium dinghy hovered above.  A weighted steel cable was lowered and Capt. Lenny threaded it through the pulley and attached a lift bag.  The sharks cruised closer and more quickly, passing within metres of us but clearly not interested, just ready.  Up went the lift bag.  Tension and excitement among the sharks increased. The boat crew retrieved the lift bag and attached the bait (a tuna head) and pulled on the cable.  Down came the bait, up went the sharks and it was on for one and all.  Several grabbed the bait, tearing at it and the water was filled with fast moving, whirling, flashing bodies.  What a site!  One tore a bit off and swam away gulping, pursued by two others.  Others just milled around in excitement, wondering where the food was.  The water around where the bait was became clouded with bits of fish.  What was truly amazing was that some of the larger reef fish involved themselves in the feeding frenzy, apparently with impunity.

The sharks gather excitedly and flash past us
waiting for the show to begin
More cruising grey reef sharks
The skipper sends up the lift bag with the pulley line attached.
Down came the bait and it's on for one and all. A feeding frenzy

The Silvertip
And suddenly, there, in the melee, was what I had come to see.  A big, smart, muscular 2 m shark with a more rounded dorsal and all fin trailing edges trimmed with white - the silvertip reef shark c. albimarginatus.  She was the star of the show and came quite close at times.  She joined in the fun but seemingly not quite with the enthusiasm of the others – presumably recently fed. I was on the outer edge of the group next to the drop-off. She cruised past me in the blue water, probably about 8 m away. What a beautiful creature! She lowered her pectoral fins, swung head on and charged. I brought up the camera defensively with the large strobe attached and snapped her just as she turned sideways at the end of her charge. A memorable picture. I was later to learn that this behaviour is not unusual for the silvertip. It certainly produced an adrenaline rush.

The silvertip reef shark - Carcharhinus albimarginatus.
The pectoral fins move down as it prepares to charge
Typical threat posture with downthrhust pectorals as the shark
turns at the end of its charge

As the bait was consumed, things quietened down and the sharks returned to their expectant cruising, flashing between us on occasion.  The water cleared.  Up went the lift bag, down came the bait and again it was on with several sharks that had got lucky, absconding with their prize, gulping furiously.  One swam straight at Hannes, who was videoing the proceedings, clearly trying to escape its compatriots, and Hannes fended it off with the camera.  The water cleared, the sharks settled down, up went the bag, down came the bait and it was on for a third time.  After that was consumed, the sharks quickly returned to their distant, disinterested cruising, clearly recognising that the show was over - for us and for them.

A grey reefie gulps the last of the bait and the others
wonder where it all went.
A grey reefie female comes close - flash-fill.

So what did I learn?  Yet again, I was impressed with the accuracy with which the shark targets its food.  They did not attack one another and were left alone when they had the food entirely in their mouths.  If the food was sticking out of the mouth, that was something different!  A careful look at the photos indicates that all I could see from underneath were females!  At no time did I feel seriously threatened, despite being so close to excited beasts.  The shark is a truly magnificent creature and definitely should not be made into soup for the jaded palates of the rich Chinese.  I had to tear myself away from that indigo drop-off at Pizion Reef.  Warm sand, warm sun, warm clear sea, warm rain, coconut palms - sob - withdrawal symptoms again!

Pictures taken with a Nikonos V on Kodak Ektachrome
Article previously published in Dive Log Australia, Novenber 2003, No 172 pp 36-37.

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