Fluctuating Asymmetry in Asteriscii Otoliths of Common Carp (Cyprinus carpio) Collected from Three Localities in Iraqi Rivers Linked to Environmental Factors

Fishes

Kélig Mahé¹  Laith Jawad² 

[1] IFREMER, Fisheries Laboratory, 150 Quai Gambetta, BP 699, 62321 Boulogne-sur-Mer, France;School of Environmental and Animal Health Sciences, Unitec Institute of Technology, 139 Carrington Road, Mt Albert, Auckland 1025, New Zealand;

关键词: asteriscus;    side effect;    growth;    otolith shape;    geographical effect;    temperature effect;   

DOI  :  10.3390/fishes7020091

来源: DOAJ

【 摘 要 】

Otoliths, calcified structures in the inner ears, are used to estimate fish age, and their shape is an efficient fish stock identification tool. Otoliths are thus very important for the management and assessment of commercial stocks. However, most studies have used left or right otoliths, chosen arbitrarily without evaluation of the difference between these otoliths. In this study, the asteriscii otoliths from 263 common carp (Cyprinus carpio; Linnaeus, 1758) were sampled in three Iraqi rivers to test the potential asymmetry and the geographical effect on otolith growth from three measurements (length, width and weight), and on shape from two shape indices (ellipticity and form-factor). Among all asteriscii otolith features, there was significant fluctuating asymmetry between fish length and every otolith descriptor. At one fish length, the size and/or the shape of otoliths could be different between two individuals and/or between left and right asteriscii otoliths for the same individual. Moreover, the relationship between fish length and otolith shape/growth was significantly dependent on the studied geographical area and, more especially, the environmental effects as the water temperature and pH. Finally, the relationships between fish length and otolith shape indices showed that the otolith evolves into the elliptical shape during the life of the fish. To use the otolith shape, it is essential to take into account the developmental stage of individuals to integrate the ontogenetic effect. Our results highlight the importance of verifying potential otolith asymmetry, especially for the asteriscii otoliths (lagenar otoliths) before their use in fisheries research.

【 授权许可】

Unknown