Competition 123 



Lake was supporting a rapidly expanding fish population, while the fish 

 in Park Pond were more crowded and more heavily parasitized (Figure 



5.6). 



Competition for Specific Habitats 



This type of competition may be more common than is the general 

 crowding of fishes, particularly in the case of competition for spawning 

 areas by sunfishes, or competition for limited shallow bottom areas for 

 bottom-loving bullheads. Control of a specific habitat within an aquatic 

 environment may allow a single species of fish to hold dominance over 

 other components of a fish population. 



Starvation 



Most fishes are well equipped to withstand prolonged periods of starva- 

 tion. In some laboratory experiments by Dr. Marian F. James,^^ bass were 

 held in aquaria at room temperature without food for several months. 

 During this period they lost nearly half of their body weight, and some 

 died of starvation. Some were brought back to their original weights 

 through repeated force feeding of small amounts of food. After having 

 been starved for 2 or more months, these bass were no longer interested 

 in food and would pay little or no attention to live minnows released in 

 the aquaria with them. 



Other laboratory experiments indicated that in order to maintain a con- 

 stant weight bass required about 1 per cent of their body weight per day 

 in tlie form of fish. These fish were able to live for an indefinite period on 

 a maintenance diet with no indication of ill health. It is not unlikely that 

 food ingestion at this level may occur frequently in populations of 

 stunted fish. 



Inter- and Intraspecific Competition 



In considering competition among the fishes in an aquatic habitat, one 

 usually considers competition between the several species first, but intra- 

 specific competition— competition between individuals belonging to a 

 single species— may be more continuous or severe than that between 

 species. In describing the fish inhabiting Lake Gogebic, Eschmeyer -^ 

 stated that walleye and the northern pike dominated the game fish 

 population. Other species of game and pan fish were present in small 

 numbers: largemouth and smallmouth bass, black crappies, rock bass and 

 seasonally, brook trout. Young of the yellow perch were abundant, but 

 adults were relatively scarce. On the basis of Eschmeyer's study of various 

 phases of the life history of the walleye in this lake, it is probable that 

 intraspecific competition among walleyes was more severe than inter- 

 specific competition between walleyes and other kinds of fish. 



