60 Carrying Capacity, Productivity, and Growth 



CARRYING CAPACITY AND STANDING CROP 



In contrast to carrying capacity, which emphasizes maximum poundage 

 and a stated interval of time, the term standing crop, is applied to some- 

 thing very definite, namely, the poundage of a given species or complex 

 of species of fishes present in a body of water at a given time. When one 



3 4 5 6 7 89 

 Number of Species 



13 



24 



Figure 4.1. Relationship between standing crops of fishes and num- 

 bers of species in midwestern reservoirs. [From Carlander, K.D., /. Fish 

 Res. Bd. Canada, 12 (4) (1955)] 



drains a pond and makes a census of the fish, the census total is the 

 standing crop of that pond at the time it was drained. The same fish in 

 the same pond may be censused at a later date to give a different standing 

 crop figure, influenced, perhaps, by a change in the relative abundance of 

 various kinds of fishes present. Still, both census figures represent standing 

 crops of this pond. In theory, the standing crop might be lower than, equal 

 to or in excess of the carrying capacity of the pond. 



The relationship of numbers of fishes to carrying capacity and standing 

 crop is not well understood (although, in general, large numbers of fishes 



