II. —22.

Food-supply for Trout. Investigations concerning the food-supply were continued throughout the year, and it is found that there is no shortage either in lakes or rivers. Smelts (commonly called inanga ) have multiplied to such an extent in Lakes Rotorua and Rotoiti that tliev are to be seen m countless numbers. Efforts to transplant this fish to Lake Rotokakahi eventually proved successful, and they are now well established there. Smelts have not been discovered in either Lake Tarawera or Lake Okareka, where it is intended to try and establish them. It has been discovered that a small fresh-water shrimp belonging to the species Paracorophium excavatum abounds in Lake Rotorua, and that this crustacean forms a considerable portion of the trout's diet at certain times of the year. Another interesting discovery made in Lake Rotokakahi and Lake Tarawera during the latter part of December and throughout January was that Daphnia Thomsoni were in large numbers in both the lakes mentioned. While it was not proved that they formed part of the trout's food, it was definitely established that the toitoi were feeding on them. Scientific Operations, lhe mortality amongst the toitoi in Lake Rotorua was more noticeable than during the previous year. These fish were found washed upon the shores and were infested by the Nematode worm found in trout and also with the external parasite Ichthyphthiuius multifiliis. With the exception of Lake Rotoiti, where the mortality was small, observations show that the toitoi was seriously affected in Lake Rotorua only. Statistical Records— Records were again compiled by officers of this Department, and much valuable information,was obtained concerning conditions pertaining to pisciculture throughout the whole district. Culling of Trout. The only work undertaken of this nature was done at the barriers in the Hatchery Creek, where 304 fish were destroyed. Destruction of Shags and Hawks— Bonus was paid on 449 shags' heads and 1,702 pairs of hawks' feet. In addition, ammunition was supplied to officers of the Department at Waikaremoana and Tokaanu, and they accounted for a number of these birds. Facilities for Anglers— The Information Bureau at Taupo has been kept open continuously, including holidays, and has been well patronized. The huts and camping-sites on the Tongariro River were again very popular with anglers. The tracks and roads giving access to various waters were kept in repair, and a new cattle-stop was built near Down's Pool at the Tongariro. Prosecutions for Breaches of Acts and Regulations.—Twenty-six informations were laid against persons for breaches of the Fisheries and Animals Protection and Game Acts and Regulations. In all cases convictions were recorded. The convictions under the Animals Protection and Game Act included cases of being in possession of absolutely protected birds without lawful authority and of resisting and obstructing a ranger while investigating reports as to native-pigeon shooting. Tagging of Trout.—The tagging of trout was again carried out at the Hatchery Creek and 193 fish were tagged. The attached table gives particulars of the tagged fish retaken.

Explosives and Dangerous Goods. Explosives Licenses.—lmportation licenses for the following explosives were issued during the year : Gelignite, 795,000 lb. ; blasting-gelatine, 5,000 lb. ; gelatine dynamite, 2,500 lb. ; A2 monobel, 238,100 lb. ; quarry-monobel, 11,250 lb. ; samsonite, 205,550 lb. ; blasting-powder, 61,250 lb. ; blastincpellets, 107,5001b. ; smokeless powder, 4,705 lb. ; detonators, 1,600,000 ; E.D fuses 802 000- fireworks, 1,172. Other licenses were issued during the license year ending the 30th June, 1931, as follows (corresponding figures for the previous year in parentheses) : Conveyance, 249 (240) ; sale 622 (624) ■ storage, 388 (385). ' ' . Examination of Explosives.—ln the course of the usual examination of shipments of explosives arriving in the country, one consignment from England, shipped on the | Port Huon," was found to be in an unsatisfactory condition. The circumstances were similar to those of the " Port Hardy " consignment mentioned in last year's annual report and the affected explosives were dealt with in the same manner—viz., thorough overhaul, followed by reconditioning where necessary. Samples of reconditioned explosives are being kept under observation. Arrangements have since been made for most of the gelatinous explosives to be imported from Australia in future.

7

No S and 68 I DatBtamied ' Date Locality , ... . . L ™S th Length ! Weight j Weight ! tagged. I retaken> tagged Locality retaken. when when when 1 when I I I tagged. retaken, j tagged. j retaken. 395 R. 1?. 24/10/30 27/9/31 Hatchery Hatoherv Stream.. 23J 24 4 8 e' °o' Stream 524 R. P. 10/6/29 28/6/31 Ditto .. Hut Pool .. 24 (?) 4 12 6 0 529 R. F. 12/6/29 16/8/31 „ .. Hatchery Stream.. 24 25 5 8 6 8 552 R. M. 22/7/31 16/2/32 „ .. Tauranga-Taupo 24J (?) 5 0 7 8 Outlet 589 R. P. 22/7/31 26/12/31 „ .. Hatepe River .. 26-J- (?) 5 12 4 0 948 R. M. 30/9/31 7/11/31 „ .. Jerusalem Bay .. 22 (?) 3 8 4 8 967 R. P. 23/7/30 20/5/31 ,, .. Gull Beach .. 25 25A 4 12 I 6 8 999 R. P. 24/10/30 | 20/11/31 ,, .. Whangamata Bay j 24 (?) 5 o ' 4 8 1103 R. M. 24/10/30 ' 20/7/31 ,, .. Hatchery Stream.. 18+ 201 2 8 ! 3 4 24 / 10 /30i 14/7/31 „ .. ,, .. 20 2 24 3 0 1 5 0 1326 R. P. 15/7/29 j 9/7/31 ,. .. „ .. 25 5 12. j 5 0