RED MOKI Threatened Fish of the Rockey Reel

Forest and Bird, Volume 21, Issue 2, 1 May 1990, Page 21

RED MOKI Threatened Fish of the Rockey Reel

by

and

Ann

Basil Graeme,

Forest and Bird Central North Island conservation officers

E FIRST SAW A BIG RED MOKI while diving at our only mainland marine reserve, near Leigh. Head down, he was pon- | derously "bumping" though the kelp forest, sorting the sediment for crabs, amphipods and brittle stars. Typically he took little notice of us. At more than 60cm this was a large male and therefore of great age, at least half a cen-

"tury or more. His size would have won him a large territory on this deep reef. At night he would sleep in a cave in his territory. At rest his eight bold red-brown stripes fade. Red moki spend more than half the time asleep, sometimes sleeping standing head down after feeding.

Red moki are fish of the rocky reef. They are found all around New Zealand but are most numerous in the north. In autumn the females, who live on the shallow reefs, swim down during the day to spawn with the males after dusk. Females prefer males holding territories with caves, so the older and bigger red moki attract many mates. Desirable territory also attracts rivals so the owner must drive off these challengers. If plain obstruction is not enough, the resident male will engage his rival in a joust, using his own superior weight to roll his opponent into the ground. If that fails he will bite the intruder. By the end of the breeding season an old male will have lost many scales and his tail fin will be tattered. During the fighting the female may swim away so the male has to round her up, driving her back to his territory and biting her tail if she tries to escape. It is thought that spawning happens inside the cave. Nothing is known of the earliest stages of the red moki’s life. Their larvae presumably spend several months floating in the plankton. Between September and November juveniles 3 to 4 cm long appear in very shallow water or in rock pools. They can be recognised by their distinct bands, and are solitary and intensely territorial. Unlike the adults they feed diligently in the Corallina seaweed and grow rapidly to reach about 15cm after six months. They are approaching maturity at two years when the female is about 25cm long and the male about 30cm. Then they enter loose social groups on deeper reefs in 5 to 15 metres of water. From now on the red moki grow slowly and take several decades to double in size. Then territorial behaviour reappears and the oldest and largest males secure breeding territories on the reefs below 15 metres. They will defend their territories all year around. Threats to the Red Moki In many ways red moki are like our great flightless parrot, the kakapo. Like them, red moki are ponderous and non-aggressive. Their mating rites are akin to the "lek" behaviour of the kakapo, where the male defends a courting and mating arena. Again like the kakapo, before the coming of humans red moki had few enemies, and were unafraid and defenceless. Like the:kakapo, this is their downfall. Asleep a lot and seemingly half asleep even when awake, red moki are easy targets for _ spear fishers. A trigger-happy spear fisher can easily annihilate the large red moki around a reef, wiping out the breeding population. There is a pressing need to educate spear fishers. Some dive clubs already promote voluntary restraints. However, for red moki living on popular diving reefs, marine

reserves will be the only sanctuary. Spear fishing is bad enough, but the wholesale slaughter of the set net is even worse. All the big red moki in an area can be caught in a single set net operation, killing the breeding fish and setting back the population for decades. Being sedentary and territorial, adults do not migrate quickly to the depleted. reef, and the population must slowly re- ~ establish from the growing juveniles. And even the red moki's fondness for seeking shelter in caves may lead to disaster. Commercial fishers report that red moki are frequently trapped in crayfish pots, up to 30 in a single pot being recorded from the Hauraki Gulf Protection Measures Outside New Zealand's two small marine reserves, red moki are fair game, with virtually no restrictions on their exploitation. Red moki caught in set nets by commercial fishers are called "by catch’. This means that the red moki were not the fishers’ target but just an accidental catch. Although fishers are required to record their bycatch MAF has no Statistics about the red moki catch, how many, how large, or where they are caught. This lack of basic data does not prevent the red moki being sold in fish shops. The Wider Problem — Set Nets on Reefs Red moki can be regarded as an indicator of the health of the reef system. Their decline is paralleled by that of other reef species — the coloured wrasse, the large grouper, porae and even the common and fearless leather jacket. Few accessible reefs now have natural

numbers of red moki, grouper and porae, and many reefs are now deserts, denuded even of smaller fish like demoiselles, maomao and leather jackets. The set net is appropriately called the "grab all’ in Tasmania. Helped by the spear fishers, the set net is efficiently destroying the reef community. Prize winning underwater photographer Andy Belcher says: "Set netting has ruined Mayor Island reefs. They used to be alive with fish of all sizes. Now you can swim and swim

and never seéa di fish. It's a desert out Doc Officer Allan jones has just surveyed Mayor Island t to produce a marine reserve proposal. His observations bear out Andy's comments. "Mayor Island was subject to heavy set netting, but there’s not much netting now that the fish have gone. The only big red moki left are in places where the shape of the reef discouraged spear fishers and prevented nets being set."

A ban on set nets is essential to save the vanishing red moki and.all the beautiful and varied fish of the.reefs. Why do we accept and even admire biting , these restricted populations of native species, when we would deplore such killing of seagulls or even sparrows? It is time we took a more enlightened attitude towards our reef fish, which are just as much a part of New Zealand's natural heritage as our native birdlife. y& ag