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WILLIS, MURPHY, AND GUY REVIEWS IN FISHERIES SCIENCE TABLE 5 Generally Accepted Stock Density Index Ranges for Balanced Fish Populations Species PSD RSD-P RSD-M Ref. Largemouth 40-70 100 0-10 Gabelhouse (1984a) bass Bluegill 20-60 5-20 0-10 Anderson (1985) Crappies in 30-60 >10 Gabelhouse (1984b) midwestern ponds White crappies in 40-70 100 0-10 Willis (1984) Kansas reservoirs White bass 40-70 10-40 0-10 Willis (1984) Walleye 30-60 Anderson and Weithman (1978). Northern pike 30-60 Anderson and Weithman (1978) Yellow perch 30-60 Anderson and Weithman (1978) Note: PSD =proportional stock density, RSD-P =relative stock density of preferred-length fuh; RSD-M = relative stock density of memorable-length fish. TABLE 6 Stock Density Index Objective Ranges for Largemouth Bass and Bluegills under Three Different Management Strategies Largemouth bass Bluegill Option PSD RSD-P RSD-M PSD RSD-P Panfish 20-40 0-10 50-80 10-30 Balance 40-70 10-40 0-10 200 5-20 Big bass 50-80 30-60 10-25 10-50 0-10 Note: The largemouth bass objective ranges were provided by Gabelhouse (1984a). The Bluegill objective ranges for balanced populations were provided by Anderson (1985), while Bluegill objective ranges for the panfuh and big bass options are proposed here after consultation wtih D. W Gabelhouse (personal communication, Kansas Department of Wildlife and Parks, Emporia). no such bimodal pattern was observed for PSD (Figure 2). Further investigation indicated that nearly all stock-length (>_13 cm) black crappies were from the 1988 year class. Thus, PSD in the spring was 3 and mean length was 181 mm. By fall, PSD had increased to 100 and mean length has increased to 244 mm. The large increase in PSD was due to growth of the single cohort in the adult population. Vll. SUMMARY AND RESEARCH NEEDS At the least, stock density indices can be used to quantify size structure for fish populations. Acceptance of the five-cell length categorization model proposed by Gabelhouse (1984a) would ease communication within the fisheries profession. At the most, stock density indices reflect the population rate functions of recruitment, growth, and mortality. However, these interpretations have been most successful in populations with relatively consistent recruitment and those without angler over- exploitation. Where recruitment is inconsistent or populations overharvested, PSD 216