Size and Shape Variability of Bones in Perch Perca fluviatilis Linnaeus, 1758 in the Storage Reservoirs of Liquid Radioactive Wastes

Abstract

The size and shape variability of three bones of river perch from two adjacent reservoirs in the upper reaches of the Techa River (the Southern Urals, Russia), the Techa storage reservoir cascade of liquid radioactive technogenic wastes (contaminated for over 50 years), and Lake Irtyash (control) has been studied using geometric morphometrics methods. Perch bones in adjacent populations differ in shape; however, they are similar in growth rates. The range of sex variability of the bone shape is on average 5.4 times less than the intergroup differences of the perch population. With age, the frontal bone growth rates slow down, the praeoperculum growth rates do not change, and the cleithrum increases. Sexual dimorphism in bone sizes of older fish and a low level of sex differences in the shape of the frontal bone and praeoperculum in the Techa cascade population has been revealed. These data characterize a high degree of phenotypic plasticity of the perch and adaptive restructuring of its morphogenesis associated with the local environment of technogenic reservoirs.