GREAT BARRIER REEF

Evening Post, Volume CIX, Issue 42, 19 February 1930, Page 7

GREAT BARRIER REEF

SCIENTISTS' RESEARCHES

WORK OF EXPEDITION

Until complete publication of tlic researches of the British, scientists who recently spent about a year. on'the Great Barrier Keef has been made, the economic value of the expedition's work cannot be properly assessed. To the lay mind there seems something idyllic in cruising about opalescent seas and coral islets for months at a stretch, studying the dimensions of the trochus, the profuse vegetation on sand caps, and the teeming life about "coral gardens," resplendent with colbur. ' The last of the expedition, says the Melbourne "'Age," left Low Island in July, last year, and tho money raised .for the expedition (less than £9000, .apart. from assistance by tho Queensland Government,' shipping companies, and scientific bodies) ' proved sufficient. As, however, only a small sum remains available for publication, additional funds will bo required .for this purpose. PEARLING INDUSTRY. In a filial report on the expedition; published in "Nature," Dr. CM. Yonge mentions an investigation of the pearling industry at Thursday Island, and of the work of Papuan Industries, Ltd., at Badu Island. The party, ho states, was especcially impressed with the policy of the Queensland Government, .which, aims at making the islanders self-supporting. They already run some thirty boats, cutters, and luggers, which-collected a considerable proportion of the £00,000 worth of trochus shell exported from Thursdays Island during 1928. Dense shoals of "sardines" (a small clupeoid) congregate around- the shores of Murray Island during the-day. time, dispersing at night, presumably for food, for their stomachs are always found empty during the day. : They probably come inshore for protection, as they are pursued relentlessly by 'sharks and other predatory fish. So • dense are the shoals, and so easy of access, that the: natives are able to catch them with multipronged spears, as many as six fishy being sometimes caught with:one throw of the spear. The more usual method- of capture, however, is by means of a cast net. The economic possibilities of this fishery are apparent; the fish are always present, always accessible, and in practically unlimited numbers. Apart from existing fisheries, pearl shell, trochus, beche-de-mer, and turtle, Dr. Yonge states, there should be great possibilities ■in the development of a. trade iv cured fish with the East, while the value of dugong oil is such that a development of this fishery would probably be a sound commercial ■undertaking. Tho labour question is greatly simplified by the presence of . a .highly-intelligent and physically almost perfect population on the islands. BIOLOGICAL EXAMINATION. Included in tho expedition's work was much biological examination, investigation of the breeding seaspns of selected corals, chemical analysis of sea constituents, the breeding of beche-de-mer, the cutting up and planting of sponges. Economic reeearch workers, on behalf of the Government of Queensland, discovered that the trochus, contrary to general reports, discharges its eggs freely into tho sea between March and July. Dr. Yonge adds that this work represents the first accurate information about the breeding and growth of this economically most -valuable animal. Corals kept. for. I'qul- mouths in a light tight box on the reef flat showed no ill effects other than those', caused by the heavy deposition, of sediment which smothered some, the survivors were pale, almost all the algae being dead,.but otherwise . healthy, further evidence has but ccwlfirmcd the view previously expressed ths.t the algae are useless as food for the co W, but may be of vital importance as ttw source of an accessory supply of oxygen. Dr. Yonge expresses gratification that the work of the expedition, especially on the economic side, will be continued by the "Queensland Government, to whom the huts on Low Island and- the bulk of. the equipment have been given. . : A description of' the geography of' the reefs is given in a recent issue of "Discovery" by Mr. J. A. Steers, M.A., lecturer at the University of Cambridge. Taken as a -whole, he says, the lagoon enclosed by the reefs' is really a considerable sea, and even if the Pacific swell does not penetrate it, • there are often large waves in the lagoon. This' is helped by the general trend of the coast, reefs, and lagoon to the west of north, and so roughly parallel'to'the direction of .the southeast trades, which are the prevalent winds. The depth of the lagoon is fairly uniform, varying from 10 to 25 fathoW Only occasionally'are greater depths found, usually in association with islands and straits. In the Whitsunday Passage some soundings reach 50 fathoms. PICTURESQUE ISLANDS. The mainland is a typically "drowned" coast; there are many drowned vslleys, now often partly or wholly silted up. Mr. Steers saw. many coastal features to support the view that the reef originated in subsidence due to faulting. High islands within the lagoon also furnish evidence in -favour o£ submergence. These islands are very picturesque,. with, narrow intricate channels among, them." Some reach elevations of a thousand feet; usually they are well forested, and the trees extend from practically high tide level1 right up to the summits. .These islands" are, in-fact/sub-merged mountain chains, and in many cases aro partly or wholly surrounded by small fringing reefs, wbicb. are quite distinct from the Barrier Keefa proper. These fringing reefs, too, help to protect the islands from any serious marine erosion. Further north, beyond Cape Melville, the islands and mainland are formed of sandstones, and the whole aspect is much more barren. The most magnificent of the high islands is Hinchiubrook, about half-way between Townsville and Cairns. The scenery of this island is truly mountainous, great crags and precipices facing the seaward side. Jfot far are the Family Islands, small and rounded domes of granite, densely forested. They do not rise more than 100 ft or so from the sea, but seen from Dunk Island \ they afford one of the finest views in tho Barrier waters. According to Mr. Steers, although . the Barrier region shows much evidence for submergence, there has been, comparatively recently, in a geological sense, a slight upward movement, in two stages, of the land relative to the sea. On many parts of the mainland and on the islands are found* platforms of marine erosion which are now above abrasion level.