November 12, 1886.] 



SCIENCE. 



429 



by eating insects and seeds of weeds during eleven 

 months of the year, is balanced by the evil they 

 do during early harvest, is a question which has 

 never been properly investigated. The starling is 

 the bird whose record is most unsullied, as no one 

 has aught but good to say about it. Immense flocks 

 of them are now to be met with in all populated 

 parts ; and it is difficult to realize what insect 

 devastation the country would be subject to, but 

 for their presence. Australian magpies, minahs, 

 and laughing jackasses have been introduced, but 

 don't increase. 



The attempts to acclimatize fish in this country 

 have been in great part successful, though some 

 notable failures have also been made. Several 

 shipments of salmon ova have been made from 

 Britain and America : in several instances all 

 were dead on arrival in the colony. As long ago 

 as 1874 some of these fish were successfully hatched 

 out in the ponds on the Makarewa, a small tributary 

 of the Oreti, and they grew well. A number of 

 them were placed in the Aparima, a beautiful 

 stream which flows into Foveaux Straits ; but 

 from that day to this they have never been heard 

 of. Others were washed out of the ponds by a 

 heavy flood, and these also have failed to put in 

 an appearance again. 



In 1878 California salmon were also turned out 

 in large mmibers in several South Island rivers, as 

 many as 31,000 fry being liberated in two of the 

 Otago streams ; but these likewise have not been 

 met with again. Whether they have all been 

 destroyed or not is difficult, if not impossible, to 

 find out. The previously introduced brown trout, 

 the enormous indigenous eels, and the ubiquitous 

 shags (cormorants) probably made great havoc in 

 their ranks ; but, presuming that some got away 

 to sea, it is certainly remarkable that they do not 

 seem to have found their way back to the rivers 

 again. Had they done so, they would almost 

 certainly have been met with by the numerous 

 anglers who fish the southern streams for six 

 months of the year. Only this year a most suc- 

 cessful importation of Scotch salmon ova was 

 made by the government, and young fish are now 

 in the ponds of half a dozen of the local societies. 

 The Otago society have about 4,000 of these. 

 When at an age fit to turn out, it is intended to 

 hberate all but a few hundred, which will be 

 retained in the ponds. It is thought, that, though 

 in opposition to their visual and instinctive habits, 

 it may be possible to retain these fish, and breed 

 from them in confinement. Should this prove to 

 be the case, it will only be a question of time be- 

 fore the colony is well stocked with salmon. 



The most remarkable results in fish acclimatiza- 

 tion have certainly been achieved in regard to 



brown trout. These fish were introduced in 1868, 

 partly from Britain, but chiefly from Tasmania, 

 where they had been introduced a short time 

 previously. The rate at which they have in- 

 creased in the New Zealand rivers and lakes has 

 simply been marvellous. Fish only five years old 

 have frequently been found to weigh from ten 

 to fourteen pounds, while in the lakes they have 

 reached still larger dimensions. This remarkable 

 rate of growth appears to have been due to the 

 fact that there was a great abundance of suitable 

 food in the streams, and few native fish to com- 

 pete with them. Of late years the size of the fish 

 taken has not been so large, showing partly that 

 the food-supply has fallen off, and partly that the 

 larger fish are being caught. These ten- and 

 twenty-pound trout are themselves the greatest 

 destroyers of ova and yotmg fish, and are there- 

 fore not encouraged. 



To show how remarkably changes of condition 

 may aflfect the fish-supply in these waters, one 

 case may be cited. The Lea stream, a tributary 

 of the Taieri River, and a typically perfect trout- 

 stream, was stocked in 1869 with 98 small trout. 

 These increased in numbers very rapidly, so that 

 in ten years the stream was full of splendid large 

 fish, and it became the favorite stream of Dunedin 

 anglers. Since 1880 some 19,000 young flsh have 

 been liberated, but the flshing has gradually fallen 

 off, and now it is difficult to get a good basket. 

 Some attribute this to the eels, which are large 

 and numerous ; others to the shags. Both sur- 

 mises are probably incorrect, as eels and shags 

 are destroyed whenever opportunity offers, and 

 are not apparently more abundant than they were 

 ten years ago. The real reason seems to be, that 

 with the enormous increase of starlings, which 

 has already been referred to, there has been, in 

 all parts where these birds abound, an almost 

 total disappearance of grasshoppers and other 

 large insects. The food-supply in the smaller 

 streams has thus been greatly diminished, and 

 they cannot support the number of fish they did 

 at first. 



Of late years other varieties of trout have been 

 introduced, such as Scotch burn and Loch Leven 

 trout. It will be an interesting study for the 

 naturalist of the future to observe whether the 

 varietal differences which characterize these forms 

 will remain persistent, or whether all will revert 

 to one common and indistinguishable type. Other 

 fish, such as American white-fish, perch, tench, 

 etc., have also been introduced, but up to the 

 present they have not made any remarkable pro- 

 gress. 



From the foregoing record of facts, it will be 

 seen that a remarkable field of observation for 



