IN TOUCH WITH NATURE

Otago Witness, Issue 3889, 25 September 1928, Page 5

IN TOUCH WITH NATURE

By

THE SUCKER FISH.

J. Drummond, F.L.S., F.Z.S.

A correspondent at Takapau, Hawke’s Bay, has- asked for information as to “ the bird commonly known as the redbill, black and white.” which, he states, usually arrives in Canterbury in September and October. The red-bill ■is greenish-black. Its cousin, the oyster catcher, is greenish-black above and white below, with a white band on each wing. This evidently is the bird the corresponl.dent means Both species have" some i right to the title “ red-bill,” as the bills iof both are crimson. Both have crimson | legs, and this has given them their com- | mon ornithological title, Hrematopus, ■ blood-red legs or feet. The correspon- ' dent asks particularly if the black and i white bird migrates. When the breeding season is over it assembles in large , flocks on the coast, but for the breeding season many pairs retire up river beds, | going in some cases far into the mouu- ' tains. Others nest on sandy spits. The red-bill (using the title as usually applied -to the bird with the one-colour costume) is rarer than the oyster-catcher. It sometimes breeds in river beds, but usually it ; selects places near the sea. Sounds and , inlets on the West Coast of the South Island are amongst the red-bill’s most favourite haunts, lhe oyster-catcher has a wide ran ? e. extending from the Chatham Islands and both the main islands of New Zealand to Australia and the Moluccas, lhe red-bill is found in only New Zealand and Australia. Both species bear the same Alaori name. Torea. In the breeding season the oyster-catehcr, usually very noisy, develops “an intensity ot slyness almost supernatural ” but | it hardly is less adept than the red-bill in luring strangers from its voung and eggs.

Some years ago a northern correspondent sent a fish about five inches long a peculiar development on the top of its head. Members of the group to which this fish belong attracted curiosity ages pgo. but only recently has accurate information as to their peculiar development been disclosed. It is one of the suckerfishes. The development usually is called a disc, although its shape is oval. The corrugated disc is a modification of the spines of a fin on the back. It is comprised of plates. B.v erecting the plates, a vacuum is caused. The flat surface of the disc is applied to the skin of a large fish and the sucker-fish is carried about on a system of free transport to seas that iL by its own efforts, might never reach. When a shoal of small fishes is reached, the sucker-fish relaxes its hold, and swims in the rich feeding-ground, making a hearty meal. Having satisfied its hunger, it seeks another big fish on which to fasten. There it digests its meal, while it is carried in comfort to further feedinggrounds

The grip provided by the force of the vacuum is so strong that it is difficult to remove a sucker-fish except by sliding it along the surface to which it is attached. On the other hand, it has no difficulty in voluntarily letting go at a moment’s notice. Sharks, for some reason, are its favourite hosts. In shark-fishing in other places than New Zealand, a large shark is seldom caught without several suckerfishes on it, but no sooner is the shark hauled out of the water than they drop off and go back into the water. They may even shift their position while the shark is being hauled. The wet surface of the disc of a captured sucker-fish was applied to a table and was allowed to adhere. So great was the adhesion that it was impossible to pull the fish off the table by a fair vertical strain. Off Panama, Mr W. Beebe, of New York, who seems to be fascinated bj’ sharks and their ways, caught a requiem shark. While it was still in the water several suckerfishes clung tenaciously to its skin, slid over its body 7, or swam alongside. Only when the long lobe of the shark’s tail-fin was drawn clear of the water did'"‘the last of its little companions leave it. They reminded him of feather-flies sliding and scurrying over and among a bird’s feathers.

Turning this accomplish, nent to account natives in Madagascar and East Africa keep sucker-fishes in captivity. A metal ring is fastened round the tail in front of the hind fin. A long cord is attached to the ring. The fishes, placed in buckets, are taken out in canoes. When a turtle appears, a sucker-fish is thrown overboard, the line is paid out until the turtle is reached, and fish and turtle are pulled in. The same use of the suckerfish is made in Torres Straits. There a line is fastened through a hole bored into the fish’s tail. The fish is thrown towards a turtle, swims up to it, and holds fast. A man with a rope around his arm dives overboard, follows th 4 line to the turtle, and takes it captive. Occasionally suckerfishes are found attached to a vessel. It is believed that in these cases they have lost, their sharks, and have mistaken vessels for large sharks or whales.

Warm seas are favoured by this lazy little creature, so strangely adapted. Few individuals are found in New Zealand waters. The first one, reported about 30 years ago, was delicate in its coat of slate-blue. It had fixed itself to the back of a swordfish. The one sent by a correspondent was brownish red. In the tropics sucker-fishes show extraordinary powers of changing their colours. When they are excited they produce bands of brilliant white all the length of their bodies. In a few seconds these are buried beneath pigment, and the fishes become a uniform monotonous neutral grey, equal in tone on all parts of the-body. Fishes and land animals usually arp- darker abeve, paler below.— It is stated that a sucker-fish, when attached to another fish, often reverses this scheme, being pale on on the back and dark underneath.

It does no harm to the object of its attentions. This association between the sucker-fish and the shark, the turtle, and other creatures has several parallels. The sucker-fish' is not a parasite. It is merely a “ free-tripper,” a passenger which does not go further than demanding transport.

ibis association between creatures in which neither is harmed but only one is benefited is so clearly recognised that it is called syucecy, living together. Another instance of this is the pilot fish’s habit of swimming with sharks. Still another is the habit of small birds, grakles, of building in the interstices of ospreys’ nests, and benefiting by the ospreys’ guardianship of their own young.

In Indian seas there is a close connection of the sucker-fish, but with a disc represented by a few short spines, separated. This, apparentlj’, is a'survivor of an ancestral type from which the more specialised sucker-fish has evolved. The lineage is an ancient and honourable one. It goes back to at least the Dawn of Recent Life. Entombed in rocks of that momentous period, there has been discovered a fossil sucker-fish that differs from its relatives of these times in having the disc much narrower. The disc then was worn behind the head instead of on the broad flat upper surface. In structure and position it was more like an ordinary fin of the back. The old-time sucker-fish’s forked tail seems to show that it was a strong swimmer. A suggestion has been made that it swam more and held on less. The evidence it supplies is that sucker-fishes have sprung from fishes which, like the modern pilotfishes, made a practice of associating with sharks, found it easier to be carried long distances than to swim all the way, and, perhaps unconsciously, developed their suckers rather than their fins.

While bearing the popular name given here, sucker-fishes are known also by their Roman name. Rhmora, to hinder. In ichthyological literature they bear their old Greek title, Echeneis, to stop a ship. The significance of these titles lies in legends that sucker-fishes, in spite of favourable winds, tides, and oars, could hold a ship back. On Caligula’s return from Astura to Antium the emperor’s five-banked galley made no way. It was the only ship of the whole fleet affected. Sailors, plunging into the sea, searched the galley’s sides and brought up a suckerfish that adhered to the rudder. The emperor, when this was shown to him, expressed strong indignation that such a little thing should impede"'" his progress and make powerless the efforts of some 400 mon. He was surprised that a fish should exert so much power in the water and be so helpless on board. At the battle, of Actium a sucker-fish was credited with having actually stopped the shin of Antonius when he was hastening to exhort his men. He was compelled to leave it and to go aboard another.

Air W. B. Eyre, Devonport, Auckland, has written to draw the attention of readers of this column to “as beautiful a sight as the imagination "can conceive.” This is the wooing of a pair of blackbacked gulls, which may be seen on the waterfront at Devonport /day in, day out, rain, sunshine, wind, or calm. “It is pretty to watch them day after day,” he writes, “ seldom more than a few yards apart, sometimes one sleeping or resting, while the other watch. They may be seen between the beach by the bathing sheds on the Windsor Reand a few low rocks just awash at high water. They have frequented that place for 18 months. Passing there almost every morning in March last, 1 noticed that the two handsome birds seemed to be attracted to each other From that day to this they have been wonderful pals, and a treat to watch. Sometimes, but seldom, one is absent, but for a few seconds. Soon there is a whirr of wings, and after a few spirals the foraging bird drops into the water or on to the rocks beside its mate. Their hunting-ground, 1 think, is not more than 500 yards; it is east of the beach by the dressing sheds. I have not seen them west of that beach, although their foraging may take them further up <"r down the harbour. For more than 30 years I have lived on or near the waterfront, but I never before saw gulls become pals in that way.”

There is a little greyish-brown bird, with black cheeks, throat, and forehead, and a black ring, round its neck, whictn once was plentiful in sandy bays from the Great Barrier Island south off Otago, but it has not been reported for many years, and. apparently, has become very rare on the mainland of New Zealand. It lives on the Chatham Islands as well as on the mainland, and on the Chathams it may still be present in fairly large numbers. It is called the sand-plover, because it usually was se°n in sandy places near the coast, never go’ng inland. Chatham Islanders who go out in their boats and launches to The Sisters, a group of rocky, wave-beaten islets, may find the sand-plover there, in the company of albatrosses and Nellies, which rest on those islets after wandering over the ocean. Trees do not grow on The Sisters. The only shelter from the gales is a wiry grass. In building a home, the sand-plover collects a few leaves of the grass, twists and bends them into a circle, and in that flimsy nest lays about three eggs, not much more than an inch long, usually creamy or buff in colour, embellished by small dark spots and lines.