摘要：We introduced a new four-parameter growth equation and tested it with observed growth data sets for a variety of aquatic species. The equation is: W = W f ,—(W f —W 0 )/ c· (1—W 0 /W f ) · [1—exp(kt)] exp(kt) where W f , and W 0 , are the upper asymptotic and initial values respectively, and c and k are constants. The new equation is a modification of the logistic and the Spillman equations with a special value of parameter c. Unlike the logistic and the Spillman functions, the new model has an unfixed value of the inflection point as dictated by the additional parameter c. We compared the model to the logistic, Spillman, Gompertz, and Bertalanffy equations using 10 sets of reference growth data of freshwater species ranging from protozoans to crustaceans to fishes. The new equation yielded excellent fits to each data set, which suggests that it is worthy of being considered by freshwater growth data analysts.
