Osburn. — Conditions Detrimental to Bass. 47 



Lake Erie. The first season they did not reproduce; the second season, 

 when it was evident that they were not going to reproduce, a number of 

 them were opened and we found the ovaries degenerated and in a very 

 bad condition. This was attributed to the larval stage of the tapeworm 

 parasite ; the larvae were actually present in the ovaries and also in the 

 intestines. It was very evident that those fish would not reproduce 

 that season, and it is questionable whether they ever would have re- 

 produced. I was wondering whether that was due to a parasitic condi- 

 tion peculiar to those lake waters only, or whether the same thing had 

 been found in other sections of the country. 



Dr. Osburn: The larvae of some parasites penetrate quite young 

 and remain there until the fish are eaten by something else; it is their 

 only means of getting out. Whether they would be the same parasites 

 found in Lake Erie I could not tell without examining them. 



Mr. Foster: They were pronounced the same. 



Dr. Osburn: You may have the same parasite there, for all I 

 know. Some of them have a wide distribution, but some, I know, are 

 limited to the Lake Erie drainage. 



Mr. Foster: It has been brought out today that many waters 

 which are re-stocked do not need re-stocking, and it has even been 

 deemed necessai-y to defend the hatcheries in their work. I suggest 

 that an ounce of protection is worth a pound of propagation. I am 

 sure that that principle v/ill hold good in many cases. 



Dr. Osburn : Quite right. In many cases we would not need to re- 

 stock if we would only give a little better protection. 



Mr. Burnham: Mr. Titcomb says that in Connecticut the impres- 

 sion prevails that the large-mouth is more destructive to the young of 

 other species than the small-mouth. In our ponds at Louisville we pro- 

 duce young sunfish in the ponds with the small-mouth black bass, and 

 the bass do not seem to consume the young sunfish to any appreciable 

 extent. In regard to the large-mouth, they do not seem to have re- 

 duced the number of young catfish along the Mississippi river to any 

 considerable extent. 



Mr. Culler : Can Dr. Osburn say what percentage of the stomachs 

 of large and small-mouth bass that he opened contained catfish? 



Dr. Osburn: I have found catfish in their stomachs, but I could 

 not eive you the percentage. 



Mr. Culler: From the fish culturist's standpoint, do you think it 

 advisable to take the adult fish out of Lake Erie and put them in streams 

 in the southern part of Ohio in v/hich the conditions are not adaptable 

 to them? 



Dr. Osburn : The same species occur, of course, in both waters ; we 

 have evidence that they do establish themselves in southei'n streams. 

 In connection with our studies we have seined out fish in the southern 

 streams of Ohio where they had been planted at least a year before, 

 and we know they were Lake Erie fish because they carried special 

 Lake Erie parasites. 



