Biology of pike, Esox lucius (Esocidae), in the lower plain of Friuli‐Venezia Giulia (north‐eastern Italy)

Abstract This study investigates the biology of Esox lucius in an irrigation ditch, Storta Roggia (Torviscosa, Udine), in the lower plain of Friuli‐Venezia Giulia (north‐eastern Italy). About twenty fish were captured monthly from May 1996 to May 1997. Variables such as age (as determined from reading scales) and stomach contents were recorded from these fishes. Additionally, the gonads were excised and fixed to assess the reproductive stage. These fishes were from eight age‐classes (0–7 years). Age classes 6 and 7 were chiefly females. Their diet was chiefly fish and benthic macroin‐vertebrates. Their reproductive period was from the second half of March to May. Several female specimens collected within the second half of April and May were in a spent‐spawning condition or with degenerative oocytes. Some male pike from age‐class 1 attained maturity, while females did not attain sexual maturity until age‐class 2 or later.