Shape and structure diversity of three bones in Abramis brama (L.) under technogenic pollution of water reservoirs in the Middle Urals

We analyzed shape and structure diversity of the os dentale, os operculum and cleithrum in Abramis brama (L., 1758) from control and impact populations under chronic technogenic pollution in the upper reaches of the Iset River (the Middle Urals) by means of geometric morphometrics and phenetics. Permanent anthropogenic impact on natural fish populations may lead to morphogenesis disturbance. It is important to identify how powerful the technogenic impact is on morphogenesis in a population and how long-term technogenic impact appears in consequent phenotypic changes. The solution to these problems will help a more exact understanding of evolutionary mechanisms and ecological processes. We investigated three reservoirs. The control Lake Shitovskoye (57°07'41"N, 60°28'23''E) is not contaminated. Thermal and chemical pollution from the district (regional) thermal gas power station has spread to the part of the water cooling reservoir Lake Isetskoye (57°00'34''N, 60°25'02''E). The Pond Nizhneisetskiy (56°45'30''N, 60°41'00"E) in Yekaterinburg is subjected to technogenic pollution by petroleum products and heavy metals. We used landmarks to describe bone shapes. The bone structure was studied considering its non-metric features. We calculated the indicators of intra-population morphological shape and structure diversity and analyzed the index of relative structural complexity. Preliminarily, we registered insignificant differences between the variances of diversities in non-standardized and size-standardized configuration of landmarks. It means a weak allometry influence on the diversity of bone shapes in the studied A. brama. The increased diversity of shape and structure was identified in impact populations. It shows that a wide range of morphogenetic trajectories formed in impact populations. In A. brama population of the Pond Nizhneisetskiy which had lived in isolation for 30 generations under chronic ground and water pollution by petroleum products and heavy metals, we revealed a significant enhancement in the structural diversity of fish skeleton, as well as in A. brama population of the water cooling reservoir Isetskoye under chemical and thermal pollution (see Figures). Simplification of the structural organization and an increase in the diversity of bone shapes was only found in impact population of the Pond Nizhneisetskiy. We found low values of parameters of relative structural complexity in os dentale and os operculum, while the development of non-metric features in cleithrum was more resistant to technogenic pollution stressful effects. We observed low values of diversity of bone shapes in the fish of the impact Lake Isetskoye. In fish from Lake Isetskoye the possible reasons of different morphogenetic shape and structure effects are discussed in the paper. The control samples of fish dwelling under natural conditions from Lake Shitovskoye in 2001 and 2005 were characterized by a narrow range of morphogenetic trajectories and small values of shape and structure diversity. The article contains 5 Figures, 1 Table, 26 References.

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