FISHERY CONTROL

New Zealand Herald, Volume LXXIV, Issue 22627, 15 January 1937, Page 11

FISHERY CONTROL

DANGER OF DEPLETION AUCKLAND SCHNAPPER TRADE RECENT EXPLOITATION The depletion of fish od the New Zealand roasts through human agencies, the lack of detailed knowledge* and the need for extensive study of the problems involved to allow adequate control of the situation was stressed by the chief inspector of fisheries, Mr. A. h. Hcfford, iu a paper to the zoology section.

The history of the world s fisheries showed that exploitation had greatly outpaced conservation, said Mr. Hefford, who recalled, however, that the Maoris had enforced conservation through the tapu. Ho outlined the history of fishery regulations in New Zealand with special relorence to the schnapper fishing about Auckland. The regulations of 1928 were the first based on a biological basis, but they were a quack remedy to the extent that a full understanding of the conditions that applied was not available. The increase in elliciency of Danish seiners and the fact that Auckland's export trade in schnapper had increased 500 per cent since 1930 had made even seino net fishermen wonder whether this degree of exploitation could continue without causing a shortage. Schnapper had so Jar well maintained their preponderance in the fish fauna of north New Zealand, but this balance had not taken the human predator into account.

It was possible that through ignorance of vital statistics the moment for saving flounder stocks from depletion, iu the Hauraki Gulf and other waters of the Dominion, had already been missed. Mr. Hefford also gave details of the blue cod and hapuku fisheries and the evidence that was available of depletion of these species. "Conservation is a paramount consideration, but a question that is immediately present to the mind of the administrator is the inexpedience and indeed the injustice of interfering with fishing enterprise unless lie is sure of his ground," said Mr. Hefford. The information that must urgently be obtained for this purpose with regard to all commercially important species was first, a statistical record of abstractions; second, a biometrieal survey of vital statistics of existing stocks; and third, biological data regarding reproduction, growth and migrations.

FIGHTING MARINE BORER INGENIOUS SCHEME PRESERVATION OF TIMBER PILES How, by utilising the simple facta that oil floats on water and that the tides rise and fall, a process lias been perfected to control boring organisms that destroy marine structures, was the interesting story revealed in a, paper by Messrs. R. A. Johnson, supervising research engineer of the Maritime Services Board of New South Wales, and F. A. McNeill, of the Australian Museum, to a joint meeting of the zoology and engineering and architecture sections.

With the warning of tho serious collapse of an important harbour structure at San Francisco, the authors, with Mr. T. Jredale, of Sydney, were commissioned to investigate the problem for the Maritime Services Board. The investigation has covered a period of 10 years. The new treatment, which has a potential saving for the future of tens of thousands of pounds in the maintenance and renewal of timber piles, involves the placing of a floating galvanised iron collar containing creosote round the piles. This moves up and down by tidal action and is transferred from pile to pile daily. The success of the process is based on biological knowledge that has arisen from research into the manner of living of marine boring organisms in eastern Australian waters and was pointed to as an example of advantageous co-operation between engineer and zoologist in economic scientific research. The authors urged a systematic, comprehensive investigation into New Zealand's marine borer problems with the object of making the maintenance of the Dominion's sea ports less costly.

THE COSMIC BAYS AUSTIN ALI AN RESEA RCHES "Cosmic ravs were discovered in 1909 by l)r. H ess, an Austrian professor and a recent recipient of a Nobel prize,'' said Mr. A. R. Hogg, the director of the Commonwealth Solar Observatory at Canberra, in an address to the physics section. One of th<» principal activities of the Canberra Observatory is the studv of these rays.

"This strange radiation, which is believed to come to us from outer space, is very penetrative, and the rays have been detected after passing through more than 2500 feet of rock," said Mr. Hogg. "The recording instruments therefore are encased in load, which, while cutting out all extraneous interference, yet offers no harrier to the free passage of the rays it is desired to study."

It was of the profoundest interest to scientists to ascertain all that could be observed of cosmic rays, and to this end instruments have been set up on the liner Aorangi and at Christchurch, as well as Canberra. Although the Canberra results rover only six months of observing, Mr. Hogg was able to demonstrate clearly to his audience that the cosmic rays come not only from the stars in cosmic space, but also in appreciable quantities from the sun. Recent experiments at Canberra and elsewhere have indicated that the cosmic rays are composed principally of electrically-charged particles moving at speeds close to that of light.