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WILIIS, MURPHY, AND GUY REVIEWS IN FISHERIES SCIENCE alone will provide little interpretive information on density, growth, and mortality. Therefore, fishery managers should use stock density indices as only one of the assessment tools in their "arsenal." By combining size structures indices with other tools such as CPUE, fish condition, and growth assessment, population and commu- nity analyses will be more reliable. We see two primary research needs involving stock density indices. First, there is a need to apply stock density index assessment to Coldwater populations and assess the interpretive value. Work with brook trout in small Wyoming beaver ponds has been quite encouraging (Johnson et al., 1992). The application to Coldwater populations may be a complex task, as tremendous differences among Coldwater populations can occur as habitat changes from small streams, to larger rivers and lakes, and to the ocean for anadromous species. Gabelhouse (1984a) did provide the ranges from which stock, quality, preferred, memorable, and trophy lengths might be chosen for salmonids based on percentages of world-record lengths. However, he did not recommend standardized lengths within these ranges. We believe that Anderson (1980) suggested an appropriate technique to allow further development of stock density indices for Coldwater populations when he recom- mended different stock and quality lengths for book trout depending on whether fish were sampled from lakes or streams. Second, there is a continuing need to assess the utility of stock density indices by collecting regional databases and determining the relationships between stock density indices and population density, recruitment, growth, and mortality. To date, such assessments have indicated that stock density indices are most likely to reflect population density and the rate functions in small waters, simple rather than complex fish communities, and waters that have not been overexploited. ACKNOWLEDGMENTS We thank Mike Brown, Don Gabelhouse, and Rob Neumann for their assistance during the development and review of this manuscript. The manuscript was approved for publication by the South Dakota Agricultural Experiment Station as Journal Series No. 2723. It represents Contribution TA31053 of the Texas Agricultural Experiment Station, Project Number 6843-H. REFERENCES Anderson, R. O. Factors influencing the quality of largemouth bass fishing. In: Black Bass Biology andManagement. pp. 183-194 (Stroud, R. H. and H. Clepper, Eds.). Washington, D.C.: Sport Fishing Institute (1975). Anderson, R. O. Management of small warm water impoundments. Fisheries (Bethesda), i(6):5-7, 26-28 (1976). Anderson, R. O. New approaches to recreational fishery management. In: New Approaches to the Management of Smalllmpoundments. pp. 73-78 (Novinger, G. D. and J. G. Dillard, Eds.). Bethesda: North Central Division, American Fisheries Society. Special Publication Number 5 (1978). Anderson, R. O. Proportional stock density (PSD) and relative weight (W~): interpretative indices for fish populations and communities. In: Practical Fisheries Management: More 218