Comparative Morphometrical Study of Gills of Carp Fish (Cyprinus Carpio L.) and Catfish (Silurus Triostegus (Heckel)) In Tigris River Water

Abstract

The aim of this study is to know the morphological and anatomical differences of gills of fish between the two speciescarp fish (Cyprinus carpio carpio) and catfish (Silurus triostegus (Heckel)) that live in the Tigris River in mousl city.Twenty-four samples of carp and twenty-four samples of cat fish were taken from three different areas of the Tigris River in the city of Mosul, where the gills were removed, prepared, and the necessary measurements were made.,where calculation of arch length,, number. and length. of gill rakers, the length of filament and head morphometric, the carp fish its consider herbivores, have longer gill arches than cat fish. the raker gills of catfish exhibit considerable variances in the ultrastructure of their surfaces,,which are identified adaptive, changes in relation. to fish food and feeding ecology because its consider carnivores . the length of raker in the carp fish higher than catfish because the nature of food Because it needs more filtration of food,the gills filament have no different in the length because they live in the same river and contain the same concentration of oxygen . the head morphometric show difference between two species and this differed depended to type.