BULLF.TIN OF THE UNITED STATES FISH COMMISSION. 337 



Vol. TI, No. 39. TVashing^ton, D. C. Dec. SO, 1886. 



104 THE EIVKITIIES OF PONU CIII.TITRE IN CEIVTRAfi EUROPE.* 



By Dr. BERTIIOI^D BEWECKE. 



Ill Central Europe the only mammals wLich commit depredations in 

 fisli ponds are tlie water-shrew and the otter. 



The water-shrew (Sorex fodiens Pall.) is a pretty little animal, measur- 

 ing; 10 to 12 centimeters [about 4 inches] in length, including the tail, 

 which is 5 to 7 centimeters [about 2.^ inches] long. Its thick and soft 

 fur is black on the back and sides, and whitish or grayish on the 

 throat, breast, and belly. The snout is somewhat elongated, and can 

 easily be moved in different directions. The helix of the ear is small ; 

 and when diving under the water, the animal can turn it over, so as to 

 close the opening of the ear. Tlie feet are bordered all round with 

 bristles, which spread out iu the water and form a good oar. Below 

 the tail there is a keel-shaped row of long hairs. The water-shrew is 

 very common in nearly all the waters of Europe, and lives in mouse- 

 holes, or in burrows which it makes, and which have several openings, 

 one of wliich is invariably below the water. It is an expert swimmer 

 and diver, and eats insects, worms, and any other small animals which 

 it can overpower. As it is exceedingly voracious, it becomes very 

 dangerous to the spawn and young fry of fish; but it even attacks large 

 fish, to which it clings like a leech and eats their eyes and brain. In 

 hatching establishments especially it can do a great deal of harm by de- 

 stroying the eggs and young fish, and also cause great injury in ponds 

 and ditches, if found in large numbers. Hatching establishments must 

 be protected against them by carefully stopping up all holes in the walla 

 and the floor. The water-shrew can easily be caught in the neighbor- 

 hood of the ponds in mouse traps baited with pieces of fish or roe. 



The otter {Lut.ra vulgaris Erxl.) is a strong kind of marten with a flat 

 head, a blunt snout, short round ears, and strong low legs, with webbed 

 toes; the fur is exceedingly thick and smooth, dark brown on the top, 

 and grayish-brown below. The body measures 80 to 100 centimeters 

 [about 3 feet] in length, including a tail 40 centimeters [about 15 inches] 

 long. The otter lives along riv^ers and lakes whose shores are covered 

 with trees or bushes. It lives in barrows which it makes, or in old 

 fox-holes, which have several entrances, one of which always opens 

 under the water. It is a skilful swimmer and diver, lives on fish and 

 crustaceans, and becomes very injurious by the circumstance that in 



* ''Die Feinde der Teichwirtschaft." From Die Teichwirtschaft, Berlin, 1885. Trans- 

 lated from the German by Herman Jacob.son. 

 Bull. U. S. F. C. 80 22 



