Crescent-tail Bigeye (Priacanthus hamrur): Bigeyes, also called Goggleyes or Bullseyes are nocturnal. Hence the especially large eyes to make the most of the dim light. During the day they hang suspended off the reef face often with their mouths open filtering-out the zooplankton and fish larva swept in by the ocean currents. As daylight fades they start feeding on bottom-dwelling invertebrates like crustaceans. Growing to 35 cm, Bigeyes are mostly seen in their red livery but they can rapidly change colour to plain silver, or when the mood takes them silver and red bars.

 

 

Moon Wrasse: (Thalassoma lunare) Very inquisitive towards snorkellers, the 22cm Moon Wrasse features a body vertically-lined with incomplete red. It varies in colour from dark green for the females to bright blue for the males and has pink bands radiating from the eyes. The pectoral fins of the male often feature bright colours.



Scribbled Leatherjacket: (Aluteres scriptus) What a wonderfully evocative name this member of the Filefish family has. It is not at all common in the Maldives but you will know it if you are lucky enough to see it. It averages 60 cm but can grow to a metre in length – a third of which is its extremely long tail. It is beautifully coloured in pale blue and yellow with plenty of black spots. It has an extremely varied diet including hydrozoa, sea anemones, gorgonias, tunicates and algae.

Squaretail Coral Grouper: (Plectropomus areolatus) Common in the Maldives the Squaretail Coral Grouper can be recognised by the straight vertical edge of the caudal or tail fin. Colour can vary from cream to black, but always with dark-edged round blue spots, and length ranges from 60 to 75 cm.

Sergeant Major: (Abudefduf vaigiensis) Named after the stripes it carries, the Sergeant Major, which can grow up to 15 cm, is very common in the Maldives. It will form large schools off the deep drop-off. Easily recognised by its four vertical thick blue stripes on a silver body with yellow blotches in between on the upper back. At spawning time the male prepares a nest on a bare patch of hard bottom that the female fills with as many as 25,000 eggs. These hatch a week later.

Porcupine Ray (Urogymnus asperrimus): The strange-looking Porcupine Ray is not a resident of the Maldives but is a frequent visitor. Covered with plate-like tenticles and sharp thorns, it is also known as the Roughskin Stingaree, Rough-skinned Ray, Solander’s Ray and Thorny Ray. The Porcupine Ray has an oval-shaped disc that can be up to a metre in disc width. Its dark-tipped tail with its dark tip lacks stinging spines and skin folds. The Ray's colour is whitish-grey to brown above and white below. This one was photographed in the lagoon of Biyadhoo Atoll.

Two-lined Monacle Bream (Scolopsis bilineata): A frequently-seen inhabitant of the Lagoon’s rubble area, the 20 cm Two-lined Monacle Bream looks as though it can’t make up its mind. It darts from one place to another stopping dead each time in a questioning way. In fact it has excellent eyesight and looks for signs of worms and small creatures in the rubble and sand. The slightest movement .. and lunch is served. Look for a grey body, the distinctive white head-stripe outlined in black that runs from under the eye to the middle of the back, the outsized eye and the darkened skin under the dorsal fin.

Nudibranch: This is the famous mollusc without a shell i.e. 'nudi' in Latin. Most of them have very bright colours, this type – Phyllidia in particular, to warn off predators. They move like a slug so they are always vunerable. Some species feed on the fire coral, Hydrozoa, and are able to transfer a part of the stinging cells into their own tissues. Others cover themselves in a pseudo-shell made up of the calcerous spicules of the sponges on which they feed. Still others have special glands that secrete repellent substances. Whatever their form they make great photographs for the snorkeller.

Not So Great Barrier Reef. Half of the Great Barrier Reef's coral has disappeared in the past 27 years and less than a quarter could be left within a decade unless action is taken, a landmark study has found. A long-term reef investigation by scientists at Townsville's Australian Institute of Marine Science found that of the 50% destroyed coral 24% had been wiped out by intense tropical cyclones, 21% by Crown of Thorns Starfish outbreaks and 5% by coral bleaching.

Even if nothing changes for the worse in the next 20 years the reef will be in a perilous state. Global warming models project increases in water temperatures will lead to more intense cyclones. The frequency of Crown of Thorns outbreaks has increased from one in every 50-80 years before European agricultural runoff, to the currently observed frequency of one in every 15 years. Runoff waters carrying fertilisers and other agricultural nutrients into the ocean were thought to increase the survival of Crown of Thorns larvae by encouraging the growth of algae eaten by the offspring. Warmer waters were also responsible for coral-bleaching events, where the tiny organisms living inside the coral skeleton "bleached" and died with the rising temperatures. The growing frequency and intensity of mass coral bleaching is directly attributable to rising atmospheric greenhouse gases.

"Coral cover is the simplest index of reef health, and the health of the Great Barrier Reef has gone down dramatically," said institute senior scientist Hugh Sweatman. "The coral provides shelter and food for thousands of organisms so you don't just lose the corals themselves you lose the species that depend on them."

At 214 reef sites surveyed, the coral cover halved from 28% to 13.8% between 1985 and 2012. Two-thirds of the loss occurred since 1998. Only three of the 214 reef sites exhibited no impact. The coral damage was most pronounced in the central and southern regions of the 2000-kilometre reef, with the remote northern section remaining largely unaffected.

Cuttlefishes (Sepia officinalis) are classified as Cephalopoda which also includes squid, octopuses and nautiluses but despite their name, they are not fish but molluscs. They have an internal shell – the cuttlebone, large W-shaped pupils, eight arms, and two tentacles furnished with denticulated suckers, with which they secure their prey. They generally range in size from 15 cm to 25 cm and can be seen in the Lagoon between beach and Reef Crest. Cuttlefishes eat small molluscs, crabs, shrimp, fish, octopuses, worms, and other cuttlefishes. Their predators include dolphins, sharks, fish, seals, seabirds and other cuttlefishes. Their life expectancy is about one to two years. Cuttlefishes are sometimes referred to as the "chameleon of the sea" because of their remarkable ability to rapidly alter their skin color at will. Cuttlefishes change color and light polarisation to communicate to other cuttlefishes and to camouflage themselves from predators.

What will I see at the Reef Drop-off? The Reef Drop-off, for its first 50m, is the habitat for many reef fish who find shelter on the Reef Face and eat the plankton in the nearby sea. The Reef Face is usually the richest habitat. Its complex growths of coral provide cracks and crevices for protection, and the abundant invertebrates and algae offer an ample source of food. Fish that cruise the boundaries of the Reef Drop-off include predators, such as pompanos, groupers, certain types of shark, and barracudas. If you are lucky enough to have seagrass meadows nearby you will see mackerel, snapper, porgies and grunts. Herbivorous and plankton-eating fish include fusilier, ray, chromis, and the nocturnal squirrelfish and cardinalfish.

Thin Time for Shelled Creatures: Ocean acidification caused by climate change is making it harder for creatures from clams to sea urchins to grow their shells scientists said today. A thinning of the protective cases of mussels, oysters, lobsters and crabs is likely to disrupt marine food chains by making the creatures more vulnerable to predators, which could reduce human sources of seafood. Human emissions of greenhouse gases include carbon dioxide from burning fossil fuels, and some of that carbon dioxide ends up in the oceans, where it dissolves to form acid. The ocean acidification makes it harder for creatures to extract calcium carbonate - vital to grow skeletons and shells according to the study in the journal Global Change Biology.

What will I see in the Reef Lagoon? The Reef Lagoon or reef flat can be entirely enclosed creating a stretch of quiet water or it can be a protective area bordering a beach, or a flat, rocky area between the reef and the shore. Whatever its character the lagoon offers protection to juvenile and small fishes. Consequently, the number of species living there is often the highest of any reef zone. Stretching from the beach to reef crest, the lagoon's sandy bottom is littered with chunks of coral. As one swims towards the crest the flat area becomes more rocky and the number of browsing fishes higher. You will spot juvenile sharks and rays, Black-spotted Pompanos, juvenile Triggerfishes, a large variety of Goatfishes, Sandperches, Monacle Breams and the occasional school of Mullets.

Giant Clams: Snorkelling over the Reef Drop-off one is immediately struck by the beauty of the 'underwater garden' comprising table corals – often hundreds of years old - waving soft corals with brightly coloured fish darting in and out and above all the varied colours of the giant clams. Clams are bivalves which have turned themselves over so that the hinge that joins the two shells is pointed downwards. The mantle between the two shells is upwards and spills out of the shell. This mantle can vary in colour from bright blue, through green and yellow to brown depending on the influence of microscopic algae called zooxantellae cultivated by the clam which then feeds on part of them. Its upward position enables the clam to expose its body to maximum sunlight in order to grow the zooxantellae as abundantly as possible.

Starry Pufferfish (Arothron stellatus): Up to a metre long the Starry Pufferfish is an impressive sight. The fish seems almost unseaworthy as it swims very slowly rocking from side to side with the currents on the outer edge of the Drop-offs where it is often found. It particularly likes coral rich areas. The predominant colour of the Starry Pufferfish is grey, light for the body and darker for the hundreds of dot and dash markings that cover it from snout to tail. Also distinctive is the black dot dash markings at the base of the pectoral fins. It's diet comprises a wide range of bottom-dwelling animals and some algae.

Snorkelling while the time is right. If you want to snorkell on some decent coral reefs do it now because in 20 years there won't be any left according to Roger Bradbury, a resource management ecologist at the Australian National University. Within a human generation they will collapse, he says. There will be remnants here and there but the global coral reef ecosystem will cease to be.

Over fishing, ocean acidification and pollution are pushing coral reefs into oblivion. Each of these forces alone is capable of causing the global collapse of coral reefs; together they assure it. Each is growing broadly in line with world economic growth.

Global fishing pressure is still accelerating; it is set to double in a decade even as the global fish catch is declining each year.

Ocean acidification is yearly more extreme because of increased carbon dioxide absorption from the atmosphere. Coral can make their calcareous skeletons only within a special range of temperature and acidity. That range will be exceeded in the next 20 to 30 years.

As for pollution, coral reefs can't survive in nutrient-rich waters. The only things that are encouraged are microbes soaking up the sun's energy by photosynthesis and lots of jellyfish feeding on them. What will be left is a slimy algal-dominated hard ocean bottom.

So remember: the underwater photographs that you take today could be of historic interest tomorrow.

Did You Know? Over 4,000 species of fish inhabit coral reefs. Healthy reefs can produce up to 35 tons of fish per square kilometer each year, but damaged reefs produce much less.

Humpback Red Snapper (Lutjanus Gibbus): The Humpback Red Snapper prefers waters that are not too deep and are rich in currents so they can be seen often both on the Reef Crest and on the slope of the Drop-off. A very distinctive fish growing to 25 cm its silver grey body is outlined by black dorsal and anal fins and a black forked tail with rounded ends and a broad upper lobe giving it the alternative name of Paddletail. In bright contrast are the orange pectoral fins and the yellow rimmed eyes. The Humpback is often seen in red livery also with yellowish pectoral fins. The head in both versions features a slightly concave profile. Diet comprises invertebrates and small fishes and an occasional feed on zooplankton.

Black Pyramid Butterflyfish (Hemitaurichthys zoster): A typical plankton feeder, the Black Pyramid Butterflyfish, which is very common in the Maldives, can be found in schools feeding near the surface of the Reef Drop-off. The 18 cm Butterflyfish is identified by the broad black, white, black body stripes with a yellow flash on the dorsal fin.

Orange-spine Unicornfish (Naso Lituratus): So called because of the bright orange defensive spine scalpels on its tail, the Orange-spine Unicornfish is seen often in the shallow inner Lagoon and the Reef Crests. Just to confuse matters some fish books call it the Yellowkeel Unicornfish. No matter. The thing to remember is it's the one that looks like Elvis Presley with yellow hair. It has a yellow-edged black mask extending from eyes to snout, a mouth that looks like it has applied lipstick and a black and yellow dorsal fin. A 45 cm grey body and a white tail edged in black complete the ensemble.