Water Currents through Permeable Gravels and their Significance to Spawning Salmonids, etc.

Abstract

FIELD observations using soluble dyestuffs introduced in crystalline form have demonstrated the existence of a well-defined flow of water beneath the river-bed at such sites as are chosen for the redd by spawning salmon and trout. Situations where the gravel is consolidated beneath the surface are avoided. These observations have considerable interest both as regards ‘selection’ of spawning sites calculated to afford adequate aeration for ova and alevins and, in a wider context, in the ecology of various invertebrates or their larvæ¹.