Investigation of population structure of Neogbius caspius using geometric morphometric of otolith in southern Caspian Sea

The otoliths or hearing stone are calcified structures that are part of the auditory system of teleost fishes. The high morphological variability of otoliths has been used widely in identification of fish species and population. Analysis of population structure is the first step in proper management of species and biodiversity conservation. Gobiidae have the second place after Cyprinidae in species richness and abundance in the southern part of the Caspian Sea. The members of this family play major role in food chains of economically valuable animals including Sturgeon fishes and Caspian seal. A few studies have been conducted in analyzing of population structures of Gobiidae so far. The aim of present study is investigation of geographical variability in otoliths shape of caspian goby, Neogobius caspius, in southern Caspian Sea in order to understanding population structure of this species. In total, ۱۱۰ otoliths of N. caspius were collected by special hand trawl net from four localities: Anzali, Nowshahr, Babolsar and Amirabad. After extraction of otoliths and taking digital image using stereomicroscope equipped with camera, shapes were compared between localities based on Elliptical Fourier shape descriptors of otolith outline. The results of PCA analysis identified separate groups within our studied samples. The differences found in the otolith shapes among specimens of Anzali, Nowshahr, and Babolsar-Amirabad strengthens the existence of separated phenotypic populations of N. caspius in the southern Caspian Sea. So, otolith shape morphometry, probably represent a valuable tool for population identification of N. caspius.

کلیدواژه ها:

Gobiidae ، population structure ، Elliptical Fourier analysis