H.—2

30

September 10, Maramata Stream ... ... ... ... 50,000 10, Waione Stream ... ... ... ... 50,000 10, Mangakahu Stream ... ... ... 50,000 20, Rangitaiki River ... ... ... ... 50,000 23, Mangaorewa Stream ... ... ... 50,000 23, Mangapouri ... ... ... ... 50,000 „ 27, Wanganui River at Taumarunui ... ... 50,000 October 1, Rangitaiki River near Galatea ... ... ... 50,000 13, Lake Rotongata ... ... ... ... 50,000 13, Lake Rotoehu ... ... ... ... 50,000 24, Raurimu ... ... ... ... 15,000 November 18, Bay of Plenty (Mr. Withy) ... ... ... 45,000 December 17, Waitomo Stream ... ... ... ... 40,000 Okere Ponds ... ... ... ... 5,000 Waikuta Hatchery... ... ... ... 15,000 Total ... ... ... ... 1,320,000 In addition, 60,000 eyed ova were supplied to the Wellington Acclimatisation Society, making a total of 1,380,000 ova and fry distributed—a record result for any New Zealand trout-hatchery. The above points of distribution are shown on the attached map. Each of the consignments was taken out and liberated by Mr. Rutherford personally, involving an enormous amount of work and skilful attention, often under the most trying circumstances. The total cost of this work amounted in all to only £102. In order to distribute the fry at a reasonable cost they were taken out as soon as the yolk-sac was absorbed—that is, twentytwo to thirty days after hatching. They are then as strong as is necessary to fend for themselves, and take directly to natural feeding. The method adopted by some of keeping the fry in the hatchery under artificial feeding until six to ten weeks old may give a slightly better result in some cases, but where the available supply of ova is practically unlimited the extra cost of keeping and the very largely increased cost of transport renders the earlier liberation much more economical. At twenty-one days old 50,000 fry can be transported in the standard ten-gallon can without loss, whereas at six weeks old not more than 10,000 can be accommodated in the same can and at the same cost of transport. The loss in transport was practically nothing, and in no single case did it exceed 1 per cent, even on long and difficult journeys. This active policy of distribution will result in some three or four years' time in a large increase in the fishing facilities of the district, as well as in maintaining and improving the strain in the waters already stocked. Constant allegations are made that the quality of the fish in Lake Rotorua is deteriorating, and that diseases are rife. Special attention has therefore been devoted to the collection of data on this matter. On the 3rd June a weir and trap of wire netting was erected in the Ngongotaha Stream, the most important breeding-stream in the district, just above the Tauranga Road, and for twenty-one days the fish going up the stream to spawn were passed over this weir by hand, morning and evening, and inspected individually. Some 1,800 fish were thus examined. Of these, only twenty-six (1£ per cent.) were found to be actually diseased—a very small proportion indeed. In addition, 270 (15 per cent.) were found in poor condition—too poor to produce good stock—and were destroyed. The remaining 83J per cent, were healthy trout in good condition, the proportion being about 94 per cent, of rainbow (Salmo irideus) and 6 per cent, of brown trout (Salmo fan's). This effectually disposes of the pessimistic accounts that have been given by some fishermen as to the condition of the lake fish —at least, as far as concerns those that go up the streams to breed. Similar investigations will be carried on this year, and will be extended to determining the average conditions of the fish remaining in the lake, where it is quite possible that the proportion of poor-condition fish may be found to be larger owing to their not going up to spawn. It is generally observed among fishermen that the condition of the fish has been markedly improving for the past three years. This may possibly be due to the large quantity that are being taken out on the fly, as the poor-conditioned fish rise to the fly much more readily than the healthy ones. In this connection the Curator has co-operated actively with the Chief Veterinarian, Mr. Gilruth, in a pathological examination of a large series of individual specimens of trout, and valuable results will probably ensue in the matter of tracing the origin and development of the diseases to which the fish are subject. In the meantime the observations show that only the very poor-conditioned fish are subject to these diseases, and that the ordinary process of cleaning and cooking entirely removes the diseased portions, and renders the flesh quite wholesome for human consumption While the allegation that Lake Rotorua is overstocked with trout still remains unproved, there is no doubt that the trout have caused a serious diminution in the quantity of native crayfish or koura, and the small varieties of fish which serve as their food. Special attention has therefore been directed towards the question of trout-foods. A shipment of the ova of the cisco lakeherring was brought over from America, but, owing to the extreme difficulty of transport from such a distance, was not successful. The main causes of the want of success on this occasion are now avoidable with the hatchery in regular work, and I have little hesitation in saying that the next experiment in this direction will show very different results. Fresh-water shrimps and whitebait have also been brought up from the Waikato River at Mercer, and are doing well at the hatchery. The shrimps particularly will probably form a valuable fish-food in time, and will take the place of the koura.