Change in the relative gut content (GI) over time in the round goby (Neogobius melanostomus) in two different seasons (season A represented by T = 20 °C and season B represented by T = 14 °C) fed with three different prey species: 1. Pisidium sp. (red); 2. Chironomus sp. larvae (green); 3. Dikerogammarus villosus (blue), and in two different feeding modes: 1. Non-con = non-continual feeding mode (shown by dashed lines) and 2. Con = continual feeding mode (shown by solid lines). Relative gut content expressed as a ratio of the dry weight (DW) of the tested food (food A) for each treatment at the time of sampling vs. fish dry body weight [g.g-1]. Whiskers represent 95% confidence intervals around mean estimates.