74 Tkirty-iSccuiid Annual Meeting 



cure daphnids enough to feed them. In this case one catches 

 some of these minute crustaceans and with them stocks some 

 casks such as are used in kitchen-gardens. ******:= 

 Unfortunately, the plentiful multiplication of daphnids is lim- 

 ited to water warmed by the heat of spring time and can only be 

 applied to the feeding of trout fry in localities where this fish 

 spawns late. Elsewhere one must resort to the foods called arti- 

 ficial, such as curd; yolk of eggs hardened by boiling; sheep's 

 brains; blood, coagnilated or cooked; chopped liver of beef or 

 mutton; spleen, etc." Plainly in France the use of daphnids has 

 not yet become an important practice in fish culture; and the 

 same may be said of other countries. At Craig Brook the breed- 

 ing of daphnids in fish ponds was tried about ten years ago and 

 there appeared at first a prospect of important success; but 

 though the little crustaceans were made astonishingly abundant, 

 the salmon fry introduced into the ponds soon exhausted the sup- 

 ply and it was found impossible to secure its renewal, even 

 though the fish were removed and the pond left to itself. It is 

 a matter of common observation that the season when daphnids 

 especially abound is always the spring and early summer, and it 

 is reasonable to attril)ute our failure in part to the progress of 

 the season. But Lugrin was able to show his visitors extremely 

 al)un(la.nt stocks of daphnids and accompanying forms in liis 

 ponds in October and again in winter when ice had to be l)rokeii 

 to make the examination. I have myself known daphnids to 

 come into a hatchery at Bucksport in winter with the supply- 

 wattT in such quantities as to clog the flannel screens to the ex- 

 tent of overflowing. In this case the hatchery had just been built 

 and the water supplying it came from a pond that covered a tract 

 of low land now for the first time overflowed. So, although it may 

 be true that the rule is witli daphnids, to multiply and rei)lenish 

 the waters in the spring and early summer, and to pass the rest 

 of the year in a dormant state, it seems to be quite within tlv^ 

 limits of possibility that, if desirable, they could be produced for 

 fish food at all seasons. I say "if desirable" because it would 

 seem that the necessity of using such minute food as daphnids 

 would pass away each siimmer with the growth of the fish, n 

 trout or salmon having by midsunnuer become large enough to 

 swallow comfortably an animal many times larger than an ordi- 

 nary daphnid. 



