recognized pollution problems, while continuing to address old problems that 

 remain a concern (Figure 1). The approach draws upon a number of different 

 sources to assist in the identification of present and potential contami- 

 nant effects. It is actually little more than application of the logic of 

 the scientific method. Information and data that relate to topics of con- 

 cern are reviewed by scientists and resource managers to develop an over- 

 view of a problem and to determine data needs. A research design is then 

 formulated to provide information on the real or potential effects a con- 

 taminant may have on aquatic organisms or ecosystems. From the results of 

 such research, we may often be able to make remedial recommendations. Cor- 

 rective or preventive alternatives that include one or more of the following 

 may then be recommended: 



a) legislative action to regulate or prohibit the manufacture, 

 use, or disposal of a chemical, 



b) modification of management techniques or practices to protect 

 fish or other aquatic resources from the contaminant, 



c) changes in the development, use or application of certain 

 chemicals, 



d) suggested substitute chemicals which prove less harmful, 



e) selection of a less harmful activity or process over one that 

 is proven deleterious. 



Our strategy insures that resource managers are involved in the process 

 of problem identification and formulation of research design, so that the 

 objectives and results are applicable to the actual environmental problems 

 that confront the aquatic resources. It also assures consideration of the 

 most vulnerable resources that may be impacted by a contaminant. 



The key to applying this strategy successfully at the national level is 

 to simultaneously identify the most critical resources of concern and the 

 activities and contaminants most likely to adversely affect those resources. 

 Limited funds and manpower dictate the necessity of identifying the most 

 critical or vulnerable biota and habitat that may be affected by any con- 

 taminant or polluting activity of man. This identification requires that 

 we develop a comprehensive inventory of resources and habitat under our 

 protection. We must distinguish between localized problems and those that 

 are widespread. Problems of short duration (e.g., one-time occurrences) or 

 those which are in the process of remediation must be recognized, but re- 

 search emphasis must be oriented toward long-term contaminant problems that 

 have potentially devesting impacts in the foreseeable future. 



It has been estimated that the number of potential chemical contaminants 

 that may pollute U.S. lakes and streams could exceed 87,000. There are 129 

 priority toxic substances listed by the U.S. Environmental Protection Agency 

 (EPA) for immediate assessment of production, distribution, disposal, toxi- 

 city, fate within the environment, and ecological impacts. Hundreds more of 

 these chemicals are awaiting ecological hazard evaluation. Though some of 



