Fluctuating asymmetry in Perch, Perca fluviatilis (Percidae) from three lakes of the Region Umbria (Italy) as a tool to demonstrate the impact of man-made lakes on developmental stability

Fluctuating asymmetry (FA), the random deviation from perfect bilateral sym metry, is the basis of an acknowledged method to analyse developmental stab ility in animals and plants. This study investigates the fluctuating asymme try in perch (Perca fluviatilis L.) from one natural lake (Trasimeno) and t wo regulated lakes (Corbara, Piediluco) of central Italy. Seven morphometri c (pec toral and ventral fins length, pre-pectoral fin distance, pre-ventra l fin distance, pectoral-ventral fins distance, postorbital distance, head length) and six meristic (lateral line scales, pectoral and ventral fins ra ys, mandibular pores, upper and lower gill rakers) bilateral characters wer e selected to detect fluctuating asymmetry. Total and standard length, weig ht, sex and age were employed to investigate growth of perch. On the basis of FA levels a comparison of the three lakes was then made. Statistical ana lysis shows a relationship between fluctuating asymmetry levels and growth, and the possibility to order the lakes according to FA levels. Therefore, FA can be considered a tool to detect stress occurring during development.