Survival Assessment of Freshwater Fish Driven by Salinity Based on S-Shaped Algorithm

Salinity is an important ecological factor affecting the survival of fish, and, to a certain extent, the increase of the salinity value will directly cause the death of a large number of freshwater fish. Therefore, it is very necessary to establish the freshwater fish salinity-mortality curve, and to assess the survival of freshwater fish caused by salinity. In the present study, the function of salinity-death rate, based on hyperbolic tangent function, was constructed by means of comparative analysis from the general phenomenon of the mortality of freshwater fish caused by salinity, and the function was validated based on the data of the experimental biology method. The study results demonstrated that both the correlation coefficient and Nash coefficient of the efficiency of the calculated value and experimental value were high. In addition, in the estimation of the mortality rate of the freshwater fish caused by salinity there were applicability and accuracy of the application of the salinity-mortality function.