Factors and Phases of Acclimatization 



The possibility of entry of a foreign organism into the composition 

 of biota formerly foreign to it results from two factors--enclogenous and 

 exogenous. The endogenous factor is the genuine capability of the 

 incoming organism to exist in the new body of water, determined by the 

 agreement of the abiotic characteristics of the body of water with those 

 required by the exota. Of decisive significance is the presence of 

 conditions necessary for the most labile period of the life cycle: 

 spawning and the initial stages of development. The exogenous factor is 

 the possibility of a species occupying an ecologic niche in a new body 

 of water by expelling a local species with an analogous ecologic 

 profile, or by moving into an unoccupied ecologic niche which 

 corresponds to the ecologic valence of the intruder. Obviously, 

 addition to endogenous (essentially autoecologic) and exogenous 

 (synecologic) factors, the geographic factor is also important: 

 total correspondences of the conditions in the recipient water to the 

 conditions in the donor body of water, or the primary area of 

 distribution. 



in 



the 



■■hases of acclimatization during introduction of 

 i hydrobiont into a new body of water (according 

 to Zinkevitch, 1940, altered): I-VIII, Phases 

 of acclimatization; 1-5, Periods of 

 acclimatization. 



Anthropogenic transplantation and introduction of exota into new 

 bodies of water is performed by man either intentionally 

 (transplantation) or when these organisms use human transportation 

 equipment without human intention (autotransplantation) . During 

 acclimatization in the recipient body of water, in most cases the exota 

 encounter significant resistance from the local biota, or insufficient 

 agreement of abiotic conditions to the specific conditions necessary for 

 life of the transplanted species. 



In case of successful introduction of 

 phases of acclimatization occur (Zenkevitch 

 phase of barely noticed appearance (due to 

 intruder, there is usually a phase of rapid 

 the fact that the intruding species has no 

 competitors in the new body of water, provi 

 sufficient. In certain cases, the rate of 

 be compared to an ecologic explosion (Elton 

 massive increase in the population of the i 



an intruding organism, eight 

 , 1940). After the first 

 the small population) of the 

 multiplication, a result of 

 natural enemies or serious 

 ding the quantity of food is 

 this initial development may 

 1960). As a result of the 

 ntruding species, saturation 



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