Aquatic-life depletion-sampling device and technique

In a preferred embodiment, a cylindrically-shaped forwardly-screened vessel having an open lower end and an open or netted upper end, and at a rearward wall of the vessel there being a curved collector plate having centrally thereof an outlet port to which is anchored a narrowing sock tapering to a narrow opening including a sample bag-fastening device together with a detachable filter-sample bag of typically cloth, and the cylindrical walls at the open bottom having a sharpened edge facilitating twisting rotatably to and fro into a sea, lake, river, or stream bottom to be sampled, or having, in the case of impermeable substrate, an attachable foam ring, prior to agitation. Upon agitation, the tidal, stream or artificially-induced current flows through the screen forwardly portion carrying plant and animal life rearwardly through the outlet port through the tapering sock into the filter-sample bag which retains specimens for subsequent identification or counting, or both. Replacing sampling bags, and sampling is repeated several times for the same location before moving the vessel.