140 American Fisheries Society. 



This table shows production in thousands of fingerling small-mouth 

 bass by length of arrows. Those to right indicate maximum possible pro- 

 duction aided by the factors named. Arrows to left indicate direct limita- 

 tion by factor named. Hence longest arrow from the right aad shortest 

 from the left are limiting factors. 



Only five factors are dealt with in order to simplify the chart. The 

 arrow from breeding areas represents eggs hatched converted to potential 

 fingerlings after factors not shown in this chart have exerted their effect. 

 Specific accuracy is not attempted, but the general reactions shown are 

 believed by the author to be substantially correct. 



In State D still further improvement is noted. The vegeta- 

 tion is now capable of sheltering and supporting more fingerlings 

 than the potential provided by the full use of the increased avail- 

 able breeding grounds. The same is true of the snails, molluscs 

 and insect life and the forage fish. As, however, increase in con- 

 ditions favoring the bass have reacted favorably on the hostile 

 fishes also, we find them increasing and holding bass production 

 down to 45,000 — 15,000 below possible maximum under the 

 present adjustment. 



State E, the most interesting of all, is intended to show the 

 gradual readjustment of the various factors to the new balance 

 of higher production. Owing to the constant increase in vegeta- 

 tion, the forage fish, through the shelter afforded and food fur- 

 nished, are at their maximum. The snails, molluscs and insect 

 life, however, are decreasing on that account and the available 

 breeding areas are becoming less, due to plant invasion. The 

 increase in forage fish and efforts to eliminate fishes antagonistic 

 to the bass has resulted in a decrease in enemy activity more 

 than compensating the loss of breeding area and leaving the 

 total number of fingerlings surviving the summer at 50,000. 



These charts indicate that, unless the only limiting factor in 

 a lake, pond, or stream is insufficient breeding areas, or other factor 

 wholly effective before the stage at which plantings are made, it is 

 a total loss to introduce young fish of species already established 

 without making suitable adustments providing for them, since they 

 will be consumed together zvith the percentage already being 

 eliminated by other factors. Thus if there is a shortage of spawn- 

 ing beds and it remains unremedied, any possible gain, to the angler 

 even through lavish stocking is purely transitory, since the availa- 

 ble breeding ground is the neck of the bottle through which any 

 incraa:ie in niaiure fish must pass to become peitnanent. 



