Morphometric characteristics of spiny-cheek crayfish Faxonius limosus (Rafinesque, 1817) from the Danube River on the territory of Serbia

Abstract

Abstract: Twenty-three morphometric characteristics of spiny-cheek crayfish Faxonus limosus from Danube, Serbia, were analyzed to describe the general body shape. Forty-eight specimens were caught in May 2022 and January 2023 and measured for morphometric variation. Also, the values of two crayfish condition indices, Fulton’s condition factor (FCF) and crayfish constant (CC), were determined. Most of the analyzed characteristics were moderately variable (CV 10-30%). Principal component analysis (PCA) was applied to the morphological measurements. All the variables make similar contributions to the variance of the first principal component. The highest contributions are from variables CEF and ARL.ARW, CPH, ABH, CPW, and ROW significantly contributed to the second principal component variance. The population of spiny-cheek crayfish at the investigated site has a relatively stable age structure.