Feeding habits of the cardinalfish Apogon lineatus in Tokyo Bay, Japan

The feeding habits of Apogon lineatus in Tokyo Bay were examined based on 6 77 specimens. The vacuity index was relatively high (26.1%). The diet of th e fish was composed primarily of shrimps (frequency of occurrence (%F), 76. 2; weight percentage (% W), 73.9; ranking index (RI), 5631), especially Cra ngon affinis (%F, 59.2; %W, 56.2; RI, 3327). Fishes (%F, 5.9; %W, 4.2; RI, 25), including Chaeturichthys sciistius, were also found in the diet. Shrim ps were found to be important throughout the year. However, conspecific egg masses with the surfaces digested were observed in the stomachs of many ma les during the breeding season. This finding suggests that this species eng ages in filial cannibalism.