Changes in Lengths of Fixed and Preserved Young Freshwater Fish

Abstract

The lengths of body parts of several species of young freshwater fish were measured to determine short- and medium-term effects of fixation and preservation. Shrinkage (up to 4.9%) was the rule, but lengths also increased, or remained static; rigor mortis was probably the main cause of immediate change. However, measurement error probably affected precision in the smallest lengths. Body parts changed differentially; these changes were not species specific, nor was type of fixative or preservative significant. Trunk and snout to vent length indicated most susceptibility to change (especially shrinkage); head length was least affected. Changes were considered of little or no practical consequence for taxonomy and growth studies.