BULLETIN OF THE UNITED STATES FISH COMMISSION. 299 



159.-IVOTES OIV A DISEASE AFFECTINO CRAVFFISH IIV GERMANV.* 



By C. RAVERETWATTEL. 



The disease affecting crawfish, which is now doing so much damage 

 in France, rages with perhaps even more severity in some parts of Ger. 

 many and Austria, where this epidemic is the object of the research of 

 many investigators whose hibors have often been mentioned in the 

 Bulletin of oar society. One of the last numbers of the periodical of 

 the German Association of Fish -culture t contains some information on 

 this subject which has seemed to me worthy of recapitulation, because 

 it states some new facts which it may be useful to record. 



Max von dem Borne, founder of the important fish- cultural establish- 

 ment at Berneuchen, has observed the progress of this disease in the 

 Mietzel River,| a stream GO kilometers [about 33 miles] in length, which 

 flows from the Lake of Soldin and empties into the Oder River near 

 Clewitz. The Mietzel, which is unfortunately obstructed by eight dams 

 which hinder the passage of fish, is a stream abounding in fish, and 

 moreover greatly esteemed until recently for the abundance and size of 

 its crawfish. 



"At Berneuchen," says Max von dem Borne, '' where the river belongs 

 to me for about 10 kilometers [about 6 miles] we have also this year 

 (1883) taken many crawfish, which have been made use of at the time 

 of reproduction." During the first fortnight of September they began 

 to see these crustaceans leave the water and scatter along the banks 

 for several yards. On the 10th of that month they could still make a 

 good catch. But soon a sort of migration took place ; the crawfish 

 seemed to flee, to abandon the Mietzel. Numbers of them, large and 

 small, dead or dying, could be found daily on a horizontal metallic lattice 

 placed at the mouth of the brook for trout. Most of them were muti- 

 lated, having lost one or more members. On September 14, sixty of 

 these crustaceans, kept in a well-boat in the middle of the river, died in 

 a mass, and on proceeding to fish the river on the 16th and 17th, it was 

 learned that there was not a single living crawfish left. 



It was in 1880, and from the Oder, that the disease began to invade 

 the lower course of the Mietzel. The following year it ascended as far 

 as the dam of the metallurgical works at Kutzdorf. In 1882 it appeared 

 further up. Finally, in 1883, one could see it gain ground and hasten 

 its advance from month to month, for, during the month of October 

 alone, it i^assed over two dams. The waters of the Mietzel are not pol- 



* La maladie des £crevisses en AUema(jne. From the Bulletin Mensuel de la Societ4 Na- 

 tionale d'Acclhnatation de France. February, 1884, p. 200. Translated from the French 

 by H. P. Jerrell. 



\Circulare des Deutsclien Fischerei-Verein, 1883, No. 5. 



t Max von dem Borne, Die Krehapest in der Mietzel. 



