Reighard. — Knowledge of Breeding Habits 103 



the introduction of suitable fishes a barren pond thus 

 treated might be made again productive. 



I have attempted to show that through a knowledge of 

 the breeding habits of fishes we may hope to preserve or 

 increase our supply of fishes by one or more of the follow- 

 ing means: 



1. By wiser selection of the waters in which fish are to be planted. 



2. By the preservation of existing breeding grounds. 



3. By the prohibition of fishing on breeding grounds while permitting 

 it in adjacent waters. 



4. By the construction of breeding grounds in ponds from which 

 they have disappeared through the operation of natural forces. 



For the fisheries interests a knowledge of breeding 

 habits appears to be more important than a knowledge of 

 food habits. Yet our knowledge of breeding habits is 

 still very meager. One of the purposes of the present 

 paper is to stimulate an interest in them with the hope 

 that thereby our knowledge may be increased. 



LITERATURE CITED. 



Pond, R. H.: 



1905 — The Biological Relation of Aquatic Plants to the Substratum. 

 U. S. Commission of Fish and Fisheries, Report of the Commis- 

 sioner for the year ending June 30, 1903, pp. 482-586, 6 figures. 

 Washington, 1905. 



Shelford^ V. E.: 

 1911 — Ecological Succession. III. A Reconnaisance of its Causes 

 with Particular Reference to Fish. Biological Bulletin, Vol. XXII, 

 pp. 1-38. 



DISCUSSION 



Prof. Ward, of Illinois: The substance of this paper must be very 

 prominently in mind as it was continually emphasized in the paper by 

 President Townsend and those of you who recall Prof. Dyche's paper 

 of last year will remember that one of the very first things he con- 

 sidered in the construction of ponds was the maintenance of proper 

 breeding areas for the fish. To have successful fish ponds we must 

 take into account the habits of the animals to be kept in those ponds. 

 I was asked some months ago to examine a pond installed by a south- 

 ern Georgia fishing club, to tell them why they failed to get fish. The 

 pond was just a receptacle containing a certain number of gallons of 

 water, and without any shore area or plant growth whatever. The 

 reason that fishes did not thrive was perfectly evident, but it had not 

 occurred to the members of the club that the fish required any speciaf 

 place to breed. I am confident that many of the failures experienced 

 in private culture are caused by lack of proper breeding places for 

 the fish. 



Mr. Nesley, of New York: While working on Lake Erie I found 

 just the condition mentioned by Professor Ward. The southern side 

 of Lake Erie has become so contaminated by the large cities that the 

 majority of the whitefish spawn on the Canadian side. The State De- 

 partment of Fisheries was compelled to go over on the Canadian side 

 to collect eggs for the reason that the bottom there was not polluted. 



