An examination of the available data on filter feeding in bivalve molluscs has recently shown that most methods agree well when the necessary prerequisites are fulfilled (Riisgård 2001a). It remains still a matter of discussion whether the filtration rate is physiologically regulated (Bayne et al. 1993; Bayne 1993, 1998, 1999, 2000; Hawkins et al. 1999; Cranford & Hill 1999) or it should be conceived as a basically autonomous process (Jørgensen et al. 1986a, 1988, 1990; Jørgensen 1990, In his introduction to the Plymouth “TROPHEE” workshop, dealing with physiology of bivalve suspension feeding, Bayne (1998) was a spokesman for physiological regulation of the filtration rate, rejecting the concept of bivalve Filter feeding as a basically autonomous process as advanced by Jørgensen (1990, 1996). The present comment attempts to find some concrete starting points for solving the current controversy and to make the substance of the controversy more transparent.