630 REPORT OF THE COMMISSIONER OF FISHERIES. 
the water in the interior to a height of 2 or 3 feet above that in the 
surrounding marsh. This was here accomplished in the same way as 
at Port Clinton, except that steam power was used for the purpose 
instead of gasoline engines. 
The pond then consists of a ditch 7 to 10 feet deep around the entire 
circumference, the water over the central area having a rather uniform 
depth of 1 to 2 or 3 feet. The fresh water that was pumped in was 
originally turned immediately into the circumferential ditch, or could 
be carried by a wooden flume over into the central area. The first 
year the pond was used there was found to be great mortality among 
the fish, a condition probably due to the large amount of freshly 
exposed soil with which the water came in contact, so that it became 
charged with humic acid and other products of organic decay until it 
was unfit for the fish. This condition continued in spite of the fact 
that fresh water was continually pumped in, especially during the 
warmer weather, and it was found later that the water at the bottom of 
the ditch was very foul and with a bad odor. In the succeeding year 
flumes were arranged so that the fresh water was carried at once to 
the bottom of the ditch, and the conditions were found to be much 
improved. There would probably have been less danger in any case 
during the second year, as the soil had undoubtedly by that time 
become very well leached out. 
Here, as in the pond previously described, it was found that the fish 
gathered around the stream of incoming water, and here also advan- 
tage was taken of this fact in capturing them. The pond could be 
drained, if necessary, by changing the elevator over to the inner side 
of the embankment and discharging the water from the pond back into 
the surrounding marsh. 
There is one other style of pond in use in this region that should be 
mentioned, in order to make the present account complete. These 
have been constructed especially by the farmers along the southern 
shore of Sandusky Bay. They are situated on higher ground than 
those ponds which have just been described, ground that is usually at 
least a few feet above the mean level of the bay, and are formed simply 
by scraping the soil out of an area covering usually not over one-fourth 
to one-half acre, the soil that is removed being used to build the 
embankments. The water is supplied by windmills or, ina number of 
cases, by artesian wells. This water would seem not to be well adapted 
to carp ponds, being cold and strongly mineral, with a very decided 
sulphurous taste; and yet the carp are said to do very well in it. As 
the ponds contain practically no natural food supply, the fish have to 
be fed regularly to keep them from falling away greatly in weight. 
For this purpose a variety of things are used, but shelled corn is prob- 
ably employed more than anything else. In one such pond, which 
contained about 10 tons of fish, the carp were said to have been fed 
