Factors simultaneously affecting the growth of the rainbow trout (Oncorhynchus mykiss).

Growth of rainbow trout (Oncorhynchus mykiss) is examined in relation to simultaneous variation of initial weight, initial density, temperature and time (days). Twenty-six lots of medium weight were set up, ranging from 92 to 372 g; initial density ranged from 7.2 to 38.8 kg/m3; and temperatures from 14 degrees C in winter to 20 degrees well into spring. Experimental periods carried out were of 7, 20, 38 and 26 days duration. By multiple correlation and regression analysis, predictive equations for increments in weight, final density were obtained in relation to the afore mentioned variables and ranges. The values of multiple correlation obtained were highly significant. We confirmed that the effect of each factor on growth is modified by the simultaneous action of the other variables.