678 U. S. BUREAU OF FISHERIES 
This limited experience has demonstrated already that the demands of this 
sort of work, as regards time, effort, and space, are heavy and that the wisdom 
of having a hatchery devoted exclusively to this type of investigation is un- 
questionable. It is evident that the selective breeding experiments will require 
several years in the immediate future that will be barren of results; but the 
ultimate outcome will be of fundamental value. If it is not already evident. 
I should state in closing that all of the work at the Holden station is extremely 
practical and has as its aim the immediate application of all es to the 
improvement of fish cultural practice. 
POND CULTURE 
By Russet F. Lorp 
Doctor Davis already has given an idea of the program we have initiated in 
the past summer at the Fairport biological station. Although fishponds may 
be small, pond culture is a large subject, notwithstanding. Many elementary 
and practical questions concerning the propagation of our pondfishes have not 
yet been answered satisfactorily. Here are some examples: 
What is the best number of fish to rear in a pond of certain size? 
Should adults and young be raised together, or should young fish be removed 
to rearing ponds? 
If the latter, at what stage in their development and by what method? 
Should species be isolated in separate ponds? 
If this is not necessary, what species can be raised together best? 
Is the use of fertilizer practical? 
If so, what kind of fertilizer should be used, in what amounts, when should 
it be applied, and for what reasons? 
Questions thus pile up; questions as to the best varieties of aquatic vegetation, 
questions concerning the relation of aquatic vegetation to plankton and other 
natural food, questions as to the use of forage minnows—in short, a great 
problem of ecological relationship. 
Various experimental data, from 22 pends, are being collected at Fairport in 
an attempt to answer these questions. Mot a single conclusion has been reached 
so far as to any of these. They could not possibly be settled in a short time. 
Indications, however, are numerous. 
One phase of these experiments consists of systematic observations on each 
pond, in which records of the amounts of net plankton and nanoplankton per 
unit volume of water, water temperature records (surface and bottom twice 
daily), pH determinations, turbidity readings, and chemical determinations of 
dissolved oxygen are being secured and filed. A check has been made on the 
rates of growth of different species in the different ponds, also. Commercial 
fertilizer has been applied for varying periods and in varying amounts for cer- 
tain series of ponds. 
This is the briefest possible review of this phase of the work and does not 
attempt to go into any of the details. On the forage minnows, however, I shall 
spend a little more time. Perhaps if I tell you some of the things contained in 
a more or less complete report on one of the species experimented with, it will 
give you an idea of how the work has been carried on. 
It was planned to experiment with various minnows in the hope of finding 
several species that would be suitable as forage fish in the bass ponds. The 
golden shiner (Abramis crysoleuwcus) and the black-head minnow (Pimephales 
promelas) were the only two suitable species that could be secured in numbers 
sufficient for practical experiments. Work was done also with the common 
goldfish. 
Pond No. B 138, of 1,482 square feet (0.034 acre), was used as the rearing 
pond for the black-head minnows. This small pond had been wintered dry. 
On April 23, 4% pounds of fertilizer were placed in it and the water turned in. 
On June 5, 4% pounds of fertilizer also were placed in it, and then from June 
19 to August 30, inclusive, 2 pounds of fertilizer were applied at approximately 
five-day intervals. 
On May 1 the pond was stocked with 72 adult black-head minnows. On May 
15, 19 more were introduced, bringing the total up to 91 adults for the pond. 
These fish were secured in the sloughs of the Mississippi and Cedar Rivers. 
The pond was watched carefully for the first signs of spawning. 
