| Abstract: | Biostatistical measures of variability as the mean-squared deviation are not only used for characterizing a measurement series, but they are an immediate expression of the biological variability. Physiological and ecological data are often variance-inhomogeneous: the standard deviation is a (frequently linear) function of the mean value which is described as the sigma function. On this basis, the salt tolerance of fish fry and of marble carp hybrids (Aristichthys nobilis × Hypophthalmichthys molitrix) with or without a preceding adaptation is investigated in the range of 0 … 14% salinity. The change in mortality leads also to differences in weight due to both, reduced growth and higher mortality of the weaker, smaller individuals. The empirical sigma functions of these experiments prove a true adaptation of fish up to a salt concentration of 8% salinity at least for a retention of 14 days. |
