540 U. S. BUREAU OF FISHERIES 
The initial steps in an extensive program of selective breeding of 
brook trout have been taken at the Holden station. By a rigid 
selection of the parent stock it is planned to develop strains in which 
desirable characters will become fixed and thus create a brood stock 
that will exhibit superior qualifications with regard to disease re- 
sistance, rapid growth, early maturity, prolific egg production, and 
greater vigor. During the past season, eggs were taken from fish 
selected for early maturity and rapid growth and also from fish 
characterized by desirable form and color. Fingerlings that show 
great resistance to disease and rapid growth have been segregated 
for future breeding purposes. 
It is evident that practical results from these experiments can not 
be expected for some time, but it is believed that in a few generations 
it will be possible to develop a strain of brook trout much better 
adapted to hatchery requirements than the stock now available. 
A necessary preliminary of the work in selective breeding is the 
expansion of the capacity of the Holden station. The construction 
of trout ponds has been continued during the past year, so that there 
are now in use eight rearing ponds, one small pond for brood stock, 
and several hundred feet of raceways. There is opportunity for the 
further extension of the pond system, and it is essential that a num- 
ber of ponds and raceways be constructed in the near future if the 
progress of the investigations is not to be hampered seriously. 
The abundance of good trout streams in the vicinity of the Holden 
hatchery has afforded an opportunity for the inauguration of much 
needed field work on certain ecological aspects of fish planting. It is 
planned to extend the scope of this work considerably during 1927. 
Cooperation has been maintained with the Vermont Department of 
Fish and Game in investigations of hatchery mortalities and a survey 
of waters for the purpose of formulating a stocking program. 
POND CULTURE 
The investigation of various problems relating to the propagation 
and rearing of pondfishes was inaugurated at the Fairport (Iowa) 
biological station during the summer of 1926 by Dr. H. S. Davis, 
assisted by Russell F. Lord and the station force. This is a field 
that has received very little attention in this country, although pond 
culture has reached a comparatively high stage of development in 
Europe. Details of the work are given on p. 678. 
During the past summer 21 ponds were utilized in these investi- 
gations, which, although only preliminary in nature, already have 
yielded valuable results. The experiments were confined almost 
entirely to problems connected with the propagation of the large- 
mouth bass and bluegill sunfish, but it is planned to broaden the 
ee of the work in the future so as to include other species of pond- 
shes. 
One of the problems of fundamental importance in pond culture — 
is the proper treatment of the ponds to produce the maximum amount 
of food. Questions arise as to the quantity and type of rooted vege- 
tation, the advisability of wintering the ponds wet or dry, the effect 
on the rooted vegetation and plankton of cultivating the bottom and 
treating with lime. These and many other problems of a similar 
nature are receiving consideration in the experiments at Fairport. 

