MICRONUCLEI AND FLUCTUATING ASYMMETRY IN BROWN TROUT (SALMO-TRUTTA) -COMPLEMENTARY METHODS TO BIOMONITOR FRESH-WATER ECOSYSTEMS

In this work we measured both micronuclei number in kidney erythrocyte s and fluctuating asymmetry in wild brown trout (Salmo trutta), caught in different fluvial ecosystems of Asturias (northern Spain) characte rized by different levels of anthropic influence. Brown trout samples from rivers with high anthropic influence possessed significantly high er averages of both micronuclei and fluctuating asymmetry than brown t rout samples from less anthropic-influenced rivers. These findings dem onstrated the sensitivity of the micronucleus test in kidney erythrocy tes to biomonitor freshwater ecosystems. The positive association foun d between micronuclei average and fluctuating asymmetry at the populat ional level suggests that fluctuating asymmetry tests could be potenti al indicators of environmental threat, Variation of fish asymmetry wit h ageing indicates that fluctuating asymmetry surveys of wild populati ons should be carried out in trouts of the same age class. (C) 1998 El sevier Science B.V.