up to 250 egcs on fixed objects. In April, according to Herter, the development lasted 

 about /i5 to 55 days, in July 2S to 30 da;^ until liatching. Four v/eeks after hatching 

 the progeny are sex-ripe. 



The eggs deposited in the pond, as well as the parasites also, may be easily destroy- 

 ed by a draining of less than 2^ hours (Loojen). The parasites can also not endure freez- 

 ing for a fev; hours. A rise 01 the pH value by liming to over 9.8 likevfise causes certain 

 destruction. The parasitee may be most simply and completely removed from the fish by 

 the lysol bath, for v/hich Schaeperclaus gives the following directions. 



Bathing directions for Lysol baths . 



1. Fishes to be freed of carp lice are caught in a basket net. The basket 

 net must not be smaller meshed than necessarj' and must not be filled too full in 

 order not to hamper the free movements of the fishes v;hen dipping, 



2. The basket net with the fishes is dipped for 5 to 15 seconds (according 

 to the size of the fishes) into a previously prepared 0,2 percent lysol solution. 

 The dipping tjjne is to be verified as exactly as possible by counting (21, 22, 

 23, etc) or by means of a second timer. The lysol solution is best placed in 



a large, not too shallow, v/ooden tub, in vjhich 2 cc of lysol are dissolved in 

 each liter of v;ater (2.^3 fluid ounces of lysol in 10 gallons of v;ater). The 

 occurrence of a slight cloudiness is without significance, 



3» After taking it uut and draining off the lysol solution, the net is 

 placed in the largest possible tub containing clean pond v.-ater. If larger 

 quantities of fishes are to be bathed it is an advantage to have numerous tubs 

 T/ith clean water ^n hand, because the loosened carp lice swimming about in the 

 water must be killed from time to time by the addition of caustic liiiie or lysol. 

 Besides this it is to be recommended that the net should be briefly and vigor- 

 ously rinsed in several tubs, 



4.. The bathed fishes are dumped on a sorting table and any remaining carp 

 lice are removed with soft rags or soft brushes which have been saturated with 

 some of the sane 0.2 percent l:/sol solution. (In some cases partial dipping of 

 the fishes is done in evaporating dishes containing lysol solution). Blunt 

 tweezers may also be used to remove occasional especially contrary parasites, 



5, After this the fishes are placed in another pond, ih the hibernation 

 pond or — if they are to be sold — in the reservoir. Temporary storage in 

 strongly flowing water has a special advanl,age. As vath all baths, temperature 

 variations are to be avoided in transfer procedures. 



Cases occur, where fishes are so strongly infested that it is advisable to under- 

 take an emergency fishing out and to use the lysol bath, even in the middle of summer. 

 Cramps, which may occur with the bathed fishes, disappear in the shortest time without 

 leaving any injuries . 



No fishes which are infested with carp lice or fish leeches must get into the 

 hibernation pcnds: The parasites would not let the fishes come to rest. Beside the 

 carp louse, Chilodon especially is destroyed and removed by the above mentioned lysol 

 bath. Costia, Cyclochaete and Gyrodactylus are more resistant, 



Ergasilus disease . The "gill crustacean" Ergasilus sieboldi belonging to the 

 family of the Copepoda, and parasitic on the gills of various fishes (especially of 

 tenches, pikes, and bleaks is predoninantly a parasite of lake fishes. In the most 

 recent years it has almost completely destroyed t:ie tench stocks of many lakes. Hitherto 

 it could justly be said of tenches from ponds, that they are q-dte safely free from 

 Ergasilus. But recently I have also found more and more Ergasilus on the gills of 

 tenches even in several very large pond industries, Lehmann found quite a strong attack 

 of Ergasilus sieboldi amoni^ rainbow trout. The pond operator must furthermore carefully 



211 



