PEOGRESS IN BIOLOGICAL INQUIBIES, 19 2 9 



1105 



While it will, of course, require several years before results of 

 permanent value can be expected from this breeding work the 

 outlook is very encouraging and there is every reason to believe 

 that in this way it will be possible to produce a marked improvement 

 in the quality of hatchery tish. The marked differences in the vigor 

 and growth of the offspring of different pairs are especially note- 

 worthy. In many instances the parents of these fish showed little 

 difference in either size or vigor and in ordinary hatchery practice 

 would have unquestionably been considered of equal value for 

 breeding purposes. 



Value of vanous sized fish for stocking purposes. — In order to 

 obtain more accurate data regarding the survival of hatchery fish 

 when used for stocking purposes, arrangements have been made to 

 stock several streams in the vicinity of the Pittsford station with 

 fingerling trout of various sizes. It is planned to stock a stream 



E'iGURB 7. — Spawning selected pairs of trout used in breeding experiments at the 

 Pittsiford (Vt.) experimental hatchery. By careful selection of the parents, a 

 superior strain of brood fish is developed 



with trout of a certain age for two or three years and through coop- 

 eration of the local fish and game associations obtain data on the 

 catch of a number of anglers on the stream. Later the same stream 

 will be stocked with fish of a different size and the catch of the same 

 anglers compared with their catch in previous years. In this way it 

 is hoped to obtain data which will have a direct bearing on the much- 

 discussed problem of the relative value of trout of different ages for 

 stocking purposes. 



Propagation of graylings. — During the summer of 1929 a shipment 

 of several thousand grayling eggs was received at the Pittsford sta- 

 tion from the Meadow Creek (Mont.) substation of the bureau. 

 These eggs were received in exceptionally good condition and hatched 

 with very little loss. Although it is generally believed that grayling 

 are very difficult to rear no trouble was experienced in getting the 

 fry to feed on very finely ground beef liver. They made a very rapid 



