MLS of bend in river, TILT DOWN and PAN of shallow clear water flowing over rock bottom to CS of man taking water samples (0:31). MLS of two men on riverbank, ZOOM OUT to MWS of bend in river with tall cliff on left bank (0:35). HAMS of man knee deep in river taking water samples, ZOOM OUT to MWS (0:30). MS of two men examining sample (insects) collected in net (0:41).