The use of species criteria in studies to quantify a streamflows that should be left in a river for the needs of the fishery began some time before 1965.  This paper presents results, up to point of writing, of an investigation to understand how and why species criteria were developed.  In all cases the reason for species criteria was to link something about the biology of fish to he physical characteristics of a stream.  The development of species criteria was not independent of water management considerations.  The needed to link fish biology, stream morphology and hydraulic, and water management started in the northwest states of Washington and Oregon, and the province of British Columbia.  Some of the needs to development an instream flow requirement were a results of proposals to construct reservoirs and some were as a need to develop a condition on a water right the fishery.  This paper is a work in progress.  One of the objectives of the paper is to ask for help in locating information now know to the authors.