European anchovy Engraulis encrasicolus , with total lengths ranging from 40·0 to 132·5 mm, were sampled during October 2002 and May 2003 in the northern Adriatic Sea in order to estimate their energy densities ( E D ). A highly significant ( P E D (y)(J g −1 wet mass) and per cent dry mass ( x ) was found: y = 321 x − 3316·9 ( n = 161, r 2 = 0·82).