TEMPERATURE OF OCEAN.

Oamaru Mail, Volume XXXIX, Issue 10760, 6 May 1911, Page 3 (Supplement)

TEMPERATURE OF OCEAN.

Sir John Murray called attention !to the fact that the temperature of the ocean is changing. Tlie Atlantic, deeps are colder now than at tlie time of the Challenger expedition, : 35 years ago, and there is apparently a cycle of this change in the. North Atlantic. In the North Sea the spawning grounds are distinctly the places of currents from the Atlantic, and for the different fish correspond'with the degree of salinity of the water. What tlie reason for this is has not yet been determined, but'it is important from the food of man standpoint to know where the fish are to be found and why the places to which they resort change;:: The different,': fish select spawning, grounds, and they distribute themselves, from-a given centre, this having been determined by means of marked individuals.

Another interesting story was the. means of telling the age of fish. . The otoliths, or as they are popularly called. earbones, can be used for this purpose on much the saijne;grihciple as the trunk of a tree giv^s/evidence of its- growth . In both there are rings, one for- each year. The' scales of certain of .-iHe fishes give similar indications. The herring may grow to eleven or twelve years. By the width in the earlier rings * the fish may be located, as to springer, fall hatch. Further than this, the"re is evidence of certain years being better for the propagation of fishes than others. The catches of a number of seasons point to 1904 as a prolific year, and the fish born in that year'formed, an important portion of the catch till within a year or two. The sea is crbwded with life.jSo; minute are the forms that nets of .hard-? ly greater coarseness than a silk pocket handkerchief are'used, it having been found that what' were formerly, considered to be fine nets caught less than. 2 per cent, of the actual life in . the water through which they were takeii. The surface growth —plankton, it? js called —consists of "plants and animals, and these require'food just as any other,, plants or animals db. "The the sea is a great floating meadow," said the speaker, "and there is more vegetable matter in it, including to. the depth of a hundred fathoms, than-Oil any meadow or forest tract on land.". He suggested that it might be possible to cultivate the ocean by furnishing to the water, perhaps by means- ; 'of sewage, some lacking elements, so that certain places might be made attractive to food fish and be economically valuable. He noted'further how at the meeting of'cold and warm currents tftfe life is particularly abundant. One such, place is the elbow of Cape Cod, aild there'the plants and' animals congregate. These small plaiits are the fundamental food ; supply riot only of the surface larger'organisms'but of those depths belowV / . Jk