Investigation of the Definitive Age of Freshwater Decapod Crustaceans, \u3ci\u3eOrconectes propinquus\u3c/i\u3e and \u3ci\u3eProcambarus clarkii\u3c/i\u3e, via Growth Bands in the Calcified Regions Of the Eyestalk and Gastric Mill

Abstract

A preliminary study that utilized the calcified regions of the eyestalks and gastric mills of decapod crustaceans for chronological age determination. The procedure is based on the traditional method for growth analysis of concentric growth bands in otoliths, shells, and genital plates. Transverse cross sections of the eyestalks and prepyloric, pyloric, and zygocardiac ossicles of the gastric mills of Orconectes propinquus and Procambarus clarkii crayfish showed the presence of alternating dark and light growth bands. These growth bands were recorded as a finer secondary series of growth bands found within the broader primary growth bands. Size modal comparisons showed that the secondary growth bands accumulated and became broader with increasingly mature crayfish specimens. Secondary growth bands potentially identified the molt history of the crayfish and post-molting growth of the calcified structures