M. Mearelli

Effects of short‐ and long‐term thermal stress in perch (Perca fluviatilis) determined through fluctuating asymmetry and HSP70 expression

Abstract The effect of short‐ and long‐term exposure to temperature ranges near the optimal developmental values of perch (Perca fluviatilis) during pre‐ and post‐natal development was studied. A fertilized egg raft was divided and placed in four tanks kept at 10°, 17°, 20° C and variable temperature (10° to 20° C), respectively. Short‐time effects of temperature were investigated analyzing fluctuating asymmetry by measuring three meristic and seven morphometric bilateral characters. Perches reared below 17° C or at variable temperature were less asymmetric than those reared at 20° C. Perches reared at 10° C showed a non‐homogeneous trend of the characters analysed. Long‐term effects were investigated by studying the liver and skeletal muscle 70 kDa heat shock proteins (HSP/HSC70) three and six months after hatching. Two HSP isoforms, HSC73 (73 kDa) and HSP72 (72 kDa), were detected in perch liver by immunoblotting. HSC73 was present at the two developmental stages and at all temperature conditions, while HSP72 was detected only at the variable temperature and 20° C. The muscle tissue always showed the HSC73 form. Our data suggest that below 20° C only some morphological characters were affected, whereas the 20° C temperature and, presumably, higher ones, seemed to have both short‐ and long‐term effects.

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

Abstract Fluctuating asymmetry (FA), the random deviation from perfect bilateral symmetry, is the basis of an acknowledged method to analyse developmental stability in animals and plants. This study investigates the fluctuating asymmetry in perch (Perca fluviatilis L.) from one natural lake (Trasimeno) and two regulated lakes (Corbara, Piediluco) of central Italy. Seven morphometric (pectoral and ventral fins length, pre‐pectoral fin distance, pre‐ventral fin distance, pectoral‐ventral fins distance, postorbital distance, head length) and six meristic (lateral line scales, pectoral and ventral fins rays, mandibular pores, upper and lower gill rakers) bilateral characters were selected to detect fluctuating asymmetry. Total and standard length, weight, 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 analysis shows a relationship between fluctuating asymmetry levels and growth, and the possibility to order the lak...