Bucksport; in the State of Maine, near the mouth of the Penobscot River.
The location was primarily determined by the necessity of being near a
supply of living adult salmon, to be used for breeders.

After an exploration of the headwaters of the Penobscot, which lie
mostly in an uninhabited wilderness, the conclusion was reached that the
chances of securing a sufficient stock of breeders were much greater at
the mouth of the river, where the principal salmon fisheries are
located; but to avail ourselves of the supply here afforded we must take
the salmon at the ordinary fishing season, May, June, and July, and keep
them in confinement until the spawning season, which is here the last of
October and first of November. As the salmon naturally pass this period
of their lives in the upper parts of the rivers, it was thought
essential to confine our captives in fresh water.

Later experiments in Canada indicate that they will do as well in salt
water, but the construction and maintenance of inclosures is much easier
when they are located above the reach of the tide, to say nothing of the
proximity of suitable fresh water for the treatment of the eggs. In the
precise location of the inclosures several changes have been made, but
they have always been in fresh water, and within convenient distance (5
to 10 miles) of the place where the salmon were captured.

In our experiments and routine work we have made use of four inclosures,
which I will now describe.

No. 1. In Craig's Pond Brook, a very pure and transparent stream, an
artificial pond 40 square rods in area and 7 feet in extreme depth, was
formed by the erection of a dam. The bottom of this pond was mainly a
grassy sod newly flooded. About half the water came from springs in the