THE ENEMIES OF FISli. 515 



flowing tbrougli the pond are accidentally carried beyond the limits of 

 the pond develop very successfully. 



Arrangements may be made accordingly. To take out the old fish 

 after spawning is easier said than done. Although the salmonoids as 

 a general rule, that is, as long as they find a sufficient quantity of insects, 

 crustaceans, worms and snails, are not very dangerous depredators, they 

 love to eat the spawn of fish. Nearly all fish will be guilty of the same 

 offense when tempted by such delicate morsels. Trout which have ac- 

 quired a taste for such food may prove very dangerous to their younger 

 comrades. The fish-of-prey, properly so called, the j)ike, the barbel, 

 " Wels," burbot, and eel are well known as such, and they are caught 

 wherever this is possible. 



Among the amphibia, the water-salamander, the water-toad, "Unke," 

 and the frog should be kept away from the fish-ponds as much as pos- 

 sible, because they may inflict great damage to eggs and young fish. 



In order not to pass the reptiles, we wiU also mention among the 

 enemies of fish the crocodile and the water-snake. 1 do not know 

 whether our common Coluber natrix likes fish as well as it does frogs 

 and tritons. 



All aqnatie birds are born enemies of fish. The water-fowl seems to 

 be the most harmless of all, although it cannot be trusted entirely. The 

 stork is decidedly worse than his reputation. But the most dangerous 

 enemies are the herons, which, especially during moonlight nights, do 

 great damage. Among the birds-of-prey the Circus rufus, the Pandion 

 halicetus, and the Halicetus albicilla are the most dangerous and powerful 

 enemies of fish. A most dangerous enemy is the kingfisher, Alcedo 

 ispida. The crow, Corvus corona, also likes fish, and is remarkably 

 skillfid in catching them. The wagtail, Motacilla fiava, and alba, and 

 the water-ousel, Ginclus aquaticus, are likewise fond of fish-eggs and 

 young fish. 



Among the mammals, the enemies of fish are not so numerous, but 

 the few are all the more dangerous. Of the Cetacea, we must men- 

 tion the fin-fish, the narwhal, and the dolphin, and of the Phocidw, 

 the seal. The water-rat, Rypodwus amphibius, and the browii rat, Mus 

 decnmamis, shotild be kept away from fish-ponds as much as pos- 

 sible. Although the first-mentioned lives on reeds, it does damage 

 by undermining the dikes, whilst the last-mentioned most assuredly 

 hurts the fish. Brehm has given detailed reports of the great damage 

 done to fish by the Crossopus fodiens, which eats the eyes and brains of 

 living fish, even those of considerable size. The domestic cat does not 

 disdain fish-food, and I have often watched cats lying in wait for fish on 

 the banks of ponds. The best known and most dangerous enemies of 

 fish are the otters, the Yison Intreola and americanus, the Enhydris 

 lutris, and the Lutra vulgaris. The reputation of the last-mentioned 

 kind is so bad, that I need not say any more about it, but only recom- 

 mend the excellent methods of catching them introduced by Yon der 



