Drift of Invertebrates in Two Streams of Kunashir Island (Kuril Islands)

Abstract

The drift parameters and indicators of the quantitative development of zoobenthos in the watercourses of this island in the Kuril Islands archipelago have been estimated for the first time. Hydrobionts drifting during the day are smaller than those drifting in the dark, which may be a consequence of the food selectivity of visually oriented drift-feeding fish. Since the upstream movement of zoobenthos contributes to the overestimation of the coefficients of a specific drift rate, it is proposed to use the drift intensity during one exposure of the net for calculations.