28 AMEEICAN CATFISHES. 



determined to place sunken boards in the ponds where these fish are kept, in such num- 

 bers that each individual fish should have a home of his own as well as a nesting place. 

 The water in the ponds was drawn to near the bottom and inch boards 12 inches wide 

 and 5 or 6 feet long were used, one end being driven into the embankment a few inches, 

 the other end being fastened to the bottom by driving a 1 by 3 inch stake down at the 

 end and nailing through this into the board. In most cases this left an opening under 

 the center of the board, but where it did not the catfish very soon dug out the earth 

 and made the place to suit themselves. In fact, the writer would recommend that 

 this feature be left to the fish, for it was observed that they dug out the earth and occu- 

 pied these boards, which were flat on the bottom, before they did the ones along the 

 embankments where an opening was all ready for them. We shall also in future 

 use a board about 3 feet long, as that proves ample for the needs of the fish, requires 

 less lumber, and is less in the way during seining operations. The board should also be 

 well tramped down into the mud so that the stakes will not hang the seine, the stake 

 and board being a little below the general level of the bottom of the pond. If put in 

 thus, it might be well to make the beginning of a depression under the board with a 

 shovel or mattock, as otherwise the board might be overlooked by the fish. This, 

 however, is not likely. 



I would here make a special note, special because I believe that it is important in 

 the production of bullheads in numbers. Although the fish ordinarily use the boards in 

 spawning, it was noted that early in the season while the water was yet cool they did 

 not use these, but resorted to the shallows of the ponds where the water is about a foot 

 deep and there established their beds, making a depression in the mud and weeds 

 shaped like a track made by a moccasin-covered foot, the depression being about 18 

 inches long and 6 wide at the broader end. The parent fish, with their heads to the 

 broader end of the depression, here deposit the eggs. We had no boards in water less 

 than 2 feet in depth, but by accident one board was left on the embankment with one 

 end in the pond in about 6 inches of water. This was early occupied by a pair of 

 catfish and a large brood produced. 



All this demonstrates that to be most effective a portion of the boards should be in 

 the shallow water for the use of early spawners. It also strongly suggests that the 

 flow of water into the pond should be so regulated as to produce the highest tempera- 

 tures attainable in the early part of the season. In the morning the supply should 

 be reduced or cut off entirely, while at night, when the water may be warmer than the 

 air, it should be turned on in full supply. 



In this connection I would recommend that where practicable water for the supply 

 of catfish ponds would best be taken from some other pond, so that a higher tempera- 

 ture may be maintained, especially early in the season and during periods of low 

 atmospheric temperature. We have about 32 or 33 catfish in each of our ponds K and 

 M, the former being of about twice the area of the latter. K is supplied direct from the 

 springs, M from a 2-inch iron pipe from pond L, one of our largest and warmest ponds. 

 The catfish hatch has been more than double in M what it has been in K and, for all 

 we know, one pond is as favorable for the fish as the other, both having muddy bot- 

 toms and an abundance of vegetable growth. W^e believe that the temperature of 

 the two ponds is responsible for the difference. As soon as the weather grew hot all 

 of the beds were placed under boards in 2 or 3 feet of water and not one in the shallows. 



This matter of temperature may account for the unfavorable results some seasons 

 when practically no catfish are hatched in even the wild ponds, and other conditions 

 than temperature may also have a controlling influence. It is probable that muddy 

 water would be unfavorable and even low atmospheric pressure also, fishes being more 

 susceptible to changes of pressure than air-breathing animals. 



From the start we have watched the developments in our catfish ponds K and M. 

 The first point of special note is that the fish were seen spawning about a month earlier 

 than usual, although it must be admitted that a much closer watch was kept (daily. 



