GBR

VulcanSpirit
Richard & Alison Brunstrom
Mon 4 Aug 2014 12:34
The crew of the Vulcan Spirit has been temporarily augmented by the addition of Alison’s sister Louise taking advantage of the ridiculously long summer break enjoyed by the UK teaching profession to visit us here in Australia. Here she is arriving at Proserpine airport – possibly the only airport in the world with no cafe on the Arrivals side – with her big sister:
 
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The ship then set sail for Bait Reef, part of the inside edge of the Great Barrier Reef which around here is about 40nm offshore. Diving here was disappointing (as it often is on the inside edge of a coral reef) but there were compensations. One was the ‘tame’ big fish, particularly this very friendly Napoleon Wrasse Cheilinus undulatus:
 
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This one is a juvenile (the two black lines behind the eye are a giveaway) at well over a metre long. Adults are really big fish, growing to well over 2m in length and weighing up to 200kg. As you can see they have huge jaws – luckily this one was friendly, and proved very partial to bread:
 
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They have extremely mobile large eyes which closely follow your movements and give them an appearance of intelligence. Lovely animals.
 
And the second compensation was that snorkelling over the top of the reef at high tide was excellent.  A couple of pretty fish photos; this one is a coral rabbitfish Siganus corallinus
 
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And this is a shoal of yellowback fusiliers Caesio teres:
 
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But the real prize of the trip was the biggest giant clam Tridacna gigas that we have seen in the Pacific so far:
 
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As you can see this is huge by clam standards, and probably hundreds of years old. And I learned something interesting about them the other day. I knew they have primitive eyes which detect movement and cause the valves to close in defence, but as it turns out I didn’t know the half of it. Here are some eye-spots in close-up:
 
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Not only do they have eyes, but they use some of these as lenses to bring light deep down inside their tissues. Their living flesh is full of symbiotic algae which photosynthesise thus providing the clam with about half its total nutrients (the rest comes from filter feeding). Wonderful.
(N.b. Underwater shots courtesy of Louise Baker with her new camera!)