Growth 81 



although every species of fish probably is characterized by a maximum 

 size (length and weight), this size is so much greater than the average 

 maximum attained by any given individual of any selected species in 

 most waters that fishing contests with prizes for the largest examples of 

 each kind of fish have flourished and will continue to flourish as long 

 as man is interested in angling. 



Growth stoppage in fishes is not associated with sexual maturity as it 

 is in most warm-blooded animals, and fishes continue to grow throughout 

 life, although growth is relatively slower in larger and older fishes than 

 in smaller and younger ones. 



Effects of Starvation 



Under conditions of near-starvation, fishes may remain the same size 

 for an indefinite period, and after months or years of life on a maintenance 

 diet, they still retain the capacity to grow rapidly to large average sizes 

 should an abundance of food suddenly become available.^' ^^ This was 

 demonstrated with bluegills when fish 3 to 5 years old and averaging 

 0.08 pound each were moved into a renovated pond where food com- 

 petition was probably absent ( Figure 4.4 ) . The fish grew to average about 

 0.40 pound each in one growing season, although they had been badly 

 stunted in past years. 



Growth of Fish in New Waters 



Fish often grow rapidly and reach exceptionally large sizes when first 

 introduced into new waters. This superior growth is largely due to an 

 abundance of food and space and possibly an absence of parasites and 

 other biological forces which may slow down the rate of growth in waters 

 where these fish have been present for some years. 



One of the most interesting of introductions was that of the importation 

 of certain game and food fishes from Europe and North America into the 

 waters of South Africa.^' -' ^ The importation of trouts into South Africa 

 came early with the brown trout in 1892 and the rainbow in 1897. Intro- 

 ductions of exotic fishes were carp from England in 1896, European 

 perch in 1915, and largemouth bass from an English hatchery in 1927. 

 Fish importations to South Africa from the United States were small- 

 mouth bass from Maryland in 1937, bluegills from Maryland in 1938, and 

 spotted bass from Ohio in 1939. The live-bearing top minnow gambusia 

 appeared in South Africa in 1936 from an unknown source. Following are 

 some records of catches of warm-water fishes of known ages, that had 

 been stocked in South African waters: 



A largemouth bass caught on January 19, 1949, by Mr. D. S. Stewart 

 and reported by Mr. H. Manson, Hon. Secretary of the White River 

 Angling Society, was 23 inches long, girth 17 inches and weight 7 pounds 



