CHANGED HABITS

Hokitika Guardian, 1 October 1927, Page 1

CHANGED HABITS

TWO FISH PUOTILEMS. WHITEHALL AND ATLANTIC SALMON. WELLINGTON September 29. Conservation of New Zealand whitebait supplies is discussed by Dr. Hoffoi'd Chief Inspector of Fisheries, in the annual report presented to the House to-day. As no detailed information had lieon collected regarding catches, lie (stints out there is therefore no statistical evidence whether abundance of whitebait is being maintained or not but from what can la' gathered in a general way it is evident that except in rivers which are remote from populated areas there has been a considerable diminution in the abundance of those fish of recent years, fn some rivers which are now in close proximity to urban populations ii would appear tint tthe whitebait fisheries have been reduced to a. mere vestige of what they were in former times.

Air Ilefford considers that it is time to pay special attention to this most important, of all native fresh-water fishes. The view has been put forward that tile rapid growth and line condition of trout in .Vow Zealand rivers have been very largely due to this item in their food supplies, and that the superiority in si/e and abundance of the brown trout of a generation ago was in consequence of the abundance of whitebait and inanga food which was then to be found in all rivers. Ibis reasoning doubtless, hold good to a, considerable degree, especially is certian of our rivers hut if does not cover the whole of the problem. I he subject of the relation of acclimatised lisli to their indigenous lood supplies is one of great importance, but in Xew Zealand it has scarcely been touched upon up to the present time, although two biologists have made brie! essays in this field. Research problems of this sort, however, cannot he solved by investigations of brief duration, but require a more comprehensive and continuous scheme ol work than has hither to been possible. Measures lor conservation ol whitebait must be based on understanding of tile life history of the species, about which very little is known at the preson t time. .More especially we requite

to know its spawning places and the extent of its migration. It is of importance to ascertain, for instance, whether whitbait which run up a particular river are derived from parent fish which inhabited the same river or whether they may he derived from the stock of some other river. It has been stated that shoals of whitebait are to he found in the open sea, but tliis needs scientific confirmation. Preliminary arrangements have been made for investigation of these problems of whitebait biology, and it is expected that in ibis course of the current year some useful light may be thrown upon this question. The problem of better regulation of fishing operations has also received attention. especially with regard to Hokitika lishiug, where the, present position is far from satisfactory and involves tln> local inspector in an undue amount of trouble and responsibility It would apear concludes this report, that fresh legislation will be necessary before any fundamental improvement can ho alfectcd. ATLANTIC SALAIOX.

Another interesting aspect of Now Zealand fisheries is discussed in relation to \tlantie salmon fishing. The season for this species at Te Anna was probably the most successful ever experienced. A question arises as to whether any appreciable proportion of New Zealand Atlantic minion migrate to the sea. Tt is understood that a certain number have been caught in tidal waters near the mouth of the Waiau in the Tuatapere neighbourhood as well as in the River AVaiaurahiri which flows into the sea twenty miles or >o from the .AVaTau mouth. These fish must have been to sea, in which ease it is very probable their scales would show markings of a different character from those of fish which remain in fresh water, hut hitherto no scales from these sea-run fish have been obtained . All that can be said at present it that there is a high degree of probability that the majority of the fish caught in Lake Te Anna have never left fresh water. Their habits in fact resemble those of lake trout which is sufficient to account for the close resemblance of their scale tnsirkngs to those of trout., It has indeed been suggested (hicl’ly on the basis ol evidence from scale structure, that the At lautie salmon of Te Anau may not Ire a, pure species, hut may have been hybridised with brown trout. To clear

up ibis question of specific identity a few Te Anau salmon have been examined with regard to -Certain structural characters, so that the points distinguishing them from trout may he elucidated. 'Quite definite results have been obtained, which in Air Hotfold's opinion prove the purity of the strain. He concludes by suggesting that the little growth of the Te Anau salmon after maturity shows that it the establishment of Atlantic salmon is to he permanently satisfastory they must he induced to emigrate to sea and feed in salt water whch is in tact, their ancestral habits.