Balance 127 



and crappies of 0.26 pound are listed as being liarvestable. Converted to 

 inches, these weights would represent lengths of 5.0 inches and 7.5 inches, 

 respectively, for bluegills and crappies; for most parts of this country 

 these minimum lengths for harvestable fish should be increased to at 

 least 6.0 inches (0.18 to 0.20 pound) for bluegills and other sunfish and 

 8.0 inches for crappies (0.30 to 0.35 pound). Neither gizzard shad nor 

 gars are usually considered harvestable in a practical sense, and buffalo 

 cannot be harvested by hook-and-line except by accidental snagging. 

 Disagreement on minimum harvestable (useful) sizes for bluegills and 

 other sunfish by only one inch ( 5 inches to 6 inches ) might make a great 

 deal of difference in designating a population of fishes as desirable or 

 undesirable (e.g., balanced or unbalanced). 



The use of the term "balance" in referring to fish populations that 

 produce satisfactory yields is untenable because: 



(1) Balance has already been defined in biological terminology, so 

 that the term should not be applied with specific reference to pond fish 

 populations. 



(2) The simple predator-prey relationship which is the basis for 

 "balance" in fish populations is an oversimplification of what actually is 

 taking place.^^^ ^^ Fishery biologists should be no more willing to accept 

 such a relationship tlian are game biologists to accept a fox-rabbit 

 "balance" or a prairie dog-coyote ratio. 



(3) Selected species, numbers, and sizes of fishes released in an arti- 

 ficial lake habitat represent the ultimate in artificial ecosystems and can 

 hardly be expected to show any great stability or "effective compensatory 

 reaction to the disturbing forces which operate upon it."^^ Therefore, 

 "balance" is quite without meaning when applied to such a population. 



LITERATURE 



1. Allen, K. R., Am. Fish. Soc. Trans., 71, 275-283 (1942). 



2. Ball, R. C, Jour. Wildl. Mgt., 16(3), 266-269 (1952). 



3. Ball, R. C, and Ford, J. R., Mich. St. Coll. Ag. Exp. Sta. Bull, 35(3), 

 384-391 (1953). 



4. Ball, R. C, and Tait, H. D., Mich. St. Coll. Ag. Exp. Sta. Tech. Bull, 231, 

 1-25 (1952). 



5. Ball, R. C, and Tanner, H. A., Mich. St. Coll Ag. Exp. Sta. Tech. Bull, 

 223, 1-32 (1951). 



6. Barney, R. L., and Canfield, H. L., Fins, Feathers and Fur, 30, 3-7 (1922) . 



7. Bennett, G. W., ///. Nat. Hist. Surv. Bull, 23(3), 373-406 (1945). 



8. Bennett, G. W., Ill Nat. Hist. Surv. Bull, 24(3), 377-412 (1948). 



9. Bennett, G. W., Am. Fish. Soc. Trans., 80, 231-239 (1951). 



10. Bennett, G. W., Jour. Wildl Mgt., 16(3), 249-253 (1952). 



11. Bennett, G. W., Ill Nat. Hist. Surv. Bull, 26(2), 217-276 (1954). 



