Age, Growth, and Food of Northern Pike in Eastern Lake Ontario

摘要

Northern pike (Esox lucius) from eastern Lake Ontario were sampled with gill nets and trap nets in 1972-1973. Fish of age-groups IV, V, and VI were predominant in the catch. Although males were slightly longer after the 1st yr of life, females gained a 25-mm advantage in the 2nd yr and a 30-mm advantage in the 3rd yr. In later years, the increments of growth of males and females were similar. All males were mature after 2 yr and females after 3 yr. The stomachs of northern pike contained only fish; the alewife (Alosa pseudoharengus) was the principal forage species consumed. Electivity indexes for alewives, white perch (Morone americana), and yellow perch (Perca flavescens), the three most common species in the diet, indicated a positive selection for alewives that increased from June to October during a period when the relative abundance of alewives steadily decreased.