FISHES OF THE YELLOWSTONE NATIONAL PARK. 7 



Twin Lakes. Whitefish were planted in 1899, but have never been 

 heard of since. 



Beaver Lake (connects with Obsidian Creek}. Eastern brook trout 

 are plentiful in the lake, but the rainbow trout also planted there have 

 never been heard of. 



De Lacy Lake. The rainbow trout planted in 1895 have not been 

 observed. 



Ice Lak.e (near Gardiner River}. Eastern brook trout planted here 

 have never been reported. 



Ice Lake (between Fountain and Excelsior Geysers}. Blackspotted 

 trout planted in 1905 have not been heard of. 



Upper Basin Lakes (in FireJwle Basin}. Black bass planted in 1895 

 never have been observed. 



FISHING RULES AND REGULATIONS. 



The following rules and regulations applicable to fishing in the park 

 have been prescribed by the superintendent: 



Fishing with nets, seines, traps, or by the use of drugs or explosives, or in any other 

 way than with hook and line, is prohibited. Fishing for purposes of merchandise or 

 profit is forbidden. Fishing may be prohibited by order of the superintendent of the 

 park in any of the waters of the park, or limited therein to any specified season of the 

 year, until otherwise ordered by the Secretary of the Interior. 



All fish less than 8 inches in length should at once be returned to the water with 

 the least damage possible to the fish. Fish that are to be retained must be at once 

 killed by a blow on the back of the head or by thrusting a knife or other sharp instru- 

 ment into the head. No person shall catch more than 20 fish in one day. 



PARASITES OF THE TROUT. 



It has long been known that in certain waters of the Yellowstone 

 Park trout are infested with parasitic worms, while in other park 

 waters they were free from this parasite. Yellowstone Lake fish 

 appear to be the most seriously affected, and the fact of this para- 

 sitism has been of no little concern to anglers, consumers of fish, 

 and fish culturists in that region. 



This parasite is a tapeworm, to which the late Prof. Joseph Leidy, 

 who first described the species, gave the name of Dibothrium cordiceps. 

 In the larval stage this worm occurs in cysts among or on the viscera 

 of the trout, free among the viscera, beneath the peritoneal lining 

 of the abdominal cavity, or in the muscular tissue. a 



It is only the larval or intermediate stage that occurs in the trout, 

 the host of the adult appearing to be an entirely different animal, 

 as is the case with all tapeworms. Briefly, its life cycle seems to be as 

 follows : Starting with, the egg in the water, it develops into a ciliated 



a A full discussion of this subject will be found in the following paper: A contribution to the life history 

 of Dibothrium cordiceps Leidy, a parasite infesting the trout of Yellowstone Lake. By Edwin Linton. 

 Bulletin U. S. Fish Commission, vol. ix, for 1899, p. 337-358, with plates. 



95872 15 2 



