1921.] Tillyard.—Neuropteroid Insects as Trout-food. 279 
I would therefore recommend that this lake, together with all streams 
flowing into it, and the Pouto River flowing out of it, to within a mile of 
its entry into the Tongariro River (or to such point as will be suitable for 
the erection of nets to prevent access of trout), should he proclaimed as a 
sanctuary for the native aquatic fauna , and that immediate steps should 
be taken to eliminate from this area any of the trout that were surrepti¬ 
tiously introduced. 
3. Following upon 2, steps should be taken to have an exhaustive 
scientific survey made of the natural trout-food existing within the bounds 
of the sanctuary, and experiments made with a view to improving it. 
I think this could be done by erecting a small biological station in a con¬ 
venient locality near the sanctuary lake, and either placing it under, the 
charge of a competent biologist, or else affording facilities for leading 
scientists to visit the station and study the fauna. In this connection 
I should like to point to the Cass Biological Station, which is under the 
charge of Professor C. Chilton, and is owned by Canterbury College, as 
an excellent example of what can be accomplished in this direction at a 
very moderate cost. 
With respect to methods for reducing the number of trout, I would 
point out, in particular, that oversized fish are a serious menace to the 
success of a trout-fishery, because they not only consume far more food than 
do their equivalent weights of smaller fish, but they also take possession 
of the best feeding-grounds, prevent the younger fish from obtaining an 
adequate food-supply, and frequently themselves make inroads upon the 
smaller trout. With the maximum possible native food-supply, a New 
Zealand fishery ought not to be expected to produce anything beyond a steady 
and assured supply of reasonable-sized fish; and it should be one of the 
chief aims of a scientific directorate to produce this very desirable result. 
Consequently means must be devised not only for reducing the general 
very obvious conditions of overstocking in the lakes which I visited, but 
also for removing “ pirates ” and over-sized fish wherever possible. 
4. A more vigorous policy of netting the trout, either by the use of 
trawlers or small launches, on Lakes Taupo, Rotorua, and Tarawera The 
money realized by the sale of such trout, either fresh or smoked, should be 
devoted to objects which might further the scientific study and direction 
of the fisheries—as, for instance, the provision of a biological station 
advocated under recommendation 3. 
5. The adoption of the regulations generally in use in the South Island 
concerning permissible baits : i.e., besides the artificial fly, it should be 
allowable to take trout on the natural fly, grasshopper, &c. I am well 
aware that all true sportsmen abhor anything but the artificial bait; but 
it is time that they realized that every inducement must now be offered 
to get a marked reduction from the present seriously overstocked condition 
of the lakes. 
6. Limitation of spawning to certain selected streams, which should be 
changed from year to year when practicable. This has already been dealt 
with in connection with recommendation 1. 
The above recommendations, if adopted, may be expected to show 
good results, in the case of the Taupo fisheries, within a few years’ time. 
The fisheries of Lakes Rotorua and Tarawera are a more formidable 
problem, and it would be advisable to attempt the solution, in these cases, 
only in the light of the experience gained from the treatment of the Taupo 
fisheries. 
