Variable triplefin

Transcription

The fishes that prefer the deep are only occasionally seen by snorkeldivers. The deep reef has no seaweeds because it is too dark. Only animals live here from sparse phytoplankton and zooplankton. It is a tranquil place where fish prefer to be where the current sweeps past rocky outcrops, bringing the food towards them. The butterfly perch forms sparse groups, never far away from the safety of the rock. The scarlet wrasse is a busy-body, forever nervously speeding here and there. Many fish like these young giant boarfish practise hang-gliding on the currents with their large breast and hip fins. They can grow as big as snapper. The stranger here is a tarakihi which is more common in the south. Occasionally boarfish stray into the shallows where they can be seen by snorkellers. The most amazing fish here is the john dory, stalking rather large fish. Here it is seen flat on its side, looking like a stone while stalking the koheru in the background, who don't see much of a fish as the attacker comes closer. But at the very last moment its mouth flips forward to engulf its prey. From there on its tiny but sharp teeth hold the prey firmly, as it is swallowed whole. The largest habitat is the sea bottom which consists of sand. The sandy sea bottom does not give protection unless one can burrow like this sand flounder. and this fanworm. But the sand is home to little creatures like clams, crabs, slaters and worms which are then food for others. Thus sandy patches surrounded by rocky reefs, provide both food and shelter, attracting many species. One of our most colourful and amazing fishes is the goatfish which has two chin barbels with which it can finger and taste what is in the sand. It finds food so easily that enough time remains for resting and socialising. It often forms loose family groups like this one with two males, five females and three young. Goatfish can change their colours swiftly and particularly the males excel at spawning time. Here we see two large goatfish in dark red suits, drawing the attention of a cleaner fish nearby. At night the females look like this. Look at the variations in colour on this picture. But please note that all these colours can be seen only in artificial light like that from a dive torch, because the water dims the red colours. When the light is turned off, the fish look indeed quite dull. The Porae is a large visitor of sandy patches where it balances itself with two long fin rays as it stands upside down, grubbing the sand. It sleeps in the protection of the reef in dark brown pyjamas. On the sand one occasionally encounters one of three stingray species. The smallest is the eagle ray, with a head, shoulders and a thin tail with a fin on it. Before lift-off it must push itself up with its wing tips, after which it flies smoothly through the water, like an eagle. Eagle rays mainly eat shellfish like scallops and the strong Cooks turban shell which it cracks with a loud crunch, leaving its shattered remains behind, looking like pearls amongst the grey pebbles. All stingrays give live birth and here we see a just-born eagle ray baby accompanying a much larger short-tailed stingray. The short-tail stingray is the largest of the three and can become colossal but usually it measures no more than 2 metres across. It has no head, a pointed snout and a thick tail with one to three barbs. A stingray breathes in through its mouth or through a special opening near its eye, which allows it to breathe while hidden under the sand. The long-tailed stingray has an unmistakably long tail. It is inquisitive and can be approached. Under caves and overhangs one finds fish that are either very shy, or that come out at night. Caves can be large enough to swim through or just enough for fish to sleep in. Even the insides of wrecks form caves for large numbers of bigeye who emerge at night. Small fish only need small cracks in the rock like these bigeyes do. These slender roughies share the den of a breeding female octopus, coming out at night and returning faithfully at dawn. The dwarf scorpionfish spends much time in caves and cracks, ambushing the bigeyes and slender roughies. It has many colour patterns to perfect its camouflage. Can you see it? What about this one? The red cod sleeps in caves during the day but prowls at night. With its barbels it can find prey in the dark. The common conger eel lives in narrow caves by day, but comes out at night to hunt and crush goatfish in its formidable jaws. It always finds its way back home where the meal is shared with shy cleaner shrimps. It can grow very large... The yellow moray eel is usually found in crevices, but occcasionally comes out during the day in depths too deep for snorkelling. Red crayfish or rocklobster hide in crevices by day to forage in the open at night. With their feet they taste as they walk. The little fishes of the reef are found at all depths, some adapted to fierce wave action, others to life amongst seaweeds. Many are able to change their costumes. What if your world looked like this, or this, or like this with flower animals? It is the magical world of the little fishes, each of which is unique to New Zealand. The smartest is the crested blenny, a little slime fish with a single back fin but without scales. It is cautious and moves very fast when it has to. Here it peeps out of a hole in the rock, ready to clean other fishes. Its face is quite cute, with crests over its eyes. Most little fishes belong to the family of triplefins with three fins on their backs, like this variable triplefin in its nest-guarding costume. Most triplefin are also variable in colour and therefore difficult to tell apart, but they all lack swim bladders so that they fall back to the bottom when they stop swimming. Amazingly, the schooling triplefin swims most of the day, close to the rock face where it returns to rest, also darkening its skin while sleeping. The common triplefin is usually whitish with a black stripe, but it can assume six different patterns. Here it is jet-black. The variable triplefin has the most costumes, probably more than ten different ones, depending on its mood. Amazingly, it can also change the colour of its tailfin. The chocolate or banded tiplefin resembles a bar of chocolate, and although it can change colour, never loses the bar pattern. The spectacled triplefin always has dark eyes and many costumes to match, like this black dress. The blue-eyed triplefin cannot be misidentified because it has always blue eyes and red bars on its white body. It looks so cute with its red lipstick. During spawning, it has an orange head. Many triplefins do not advertise themselves but camouflage instead. This cryptic triplefin is found in very shallow water where waves make life almost impossible. Many more triplefins exist, but they are not common in the marine reserve. Another very strange little fish is the smooth pipefish with black dots on its yellow-green back. It is almost invisible amongst the kelp. Seahorses have tough outer skins and they swim with their back fin and two almost invisible breast fins behind their cheeks. The female lays the eggs into the male's broodpouch for some 200 babies. From invisibly small eggs, these grow until the father pops them out of his pouch. This father is in his final days, and when the tiny babies emerge, they are already as long as a finger nail. The little fishes have problems because they do not produce many eggs, even though they guard their nests. Worse still, their worlds are degrading because they all live on the coast where pollution gradually destroys their magical worlds. Discovering New Zealand's underwater world never ceases to amaze, as there are many more fish species to discover, and also molluscs, crustaceans, echinoderms and other lower animals. Study the Seafriends web site to prepare your discoveries.