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Geographic area. The models generally are applicable to riverine or lacustrine habitat of striped bass throughout the 48 conterminous States. However, the models may require modification for use in some localized habitats. Season. The riverine model is applicable during the spawning season; the lacustrine model is applicable during the period when habitat quality is expected to be critical for the life stage under consideration. Summer requirements of striped bass may not be adequately addressed for shallow, eutrophic, warmwater reservoirs or for Coldwater lakes where winter ice or freeze-over occurs for several weeks. If a model is applied for a specific life stage, the HSI obtained will apply only to the season or period when the life stage of interest occurs. Cover types. The lacustrine model is applicable to permanent freshwater reservoirs. The riverine model is most applicable to sections of streams that are utilized or likely to be utilized as striped bass reproductive habitat. This model could be applicable to a few mainstem reservoirs where water velocity and other requirements for spawning and hatching are within suitable ranges or to riverine habitat that striped bass occupy for reasons other than spawning, such as some estuarine streams. Minimum habitat size. The minimum area of lacustrine habitat required to sustain a population of striped bass has not been established. The species is a pelagic feeder and probably prefers relatively large, deep, open water areas that are capable of supporting a clupeid forage base. The Striped Bass Committee, American Fisheries Society, considers the minimum habitat size to be 1,215 ha (3,000 acres) (Crance 1985). Successful striped bass fisheries have been established in reservoirs ranging in size from 40.5 to 73,305 ha (100 to 181,000 acres) (Bailey 1975). The area and volume of lacustrine habitat utilized by adults during the warmest period of the year may be reduced greatly due to high temperatures in the epilimnion and low dissolved oxygen levels in deeper and cooler areas, coupled with a cool temperature preference by adults. Depth might be a limiting factor in lacustrine habitat if adult fish cannot retreat to a suitable depth to escape excessive light. The minimum length of stream required for riverine reproductive habitat can be roughly estimated by calculating the product of current velocity and hatching time. The minimum length of stream required is about 52.6 km or 32.7 miles (48 h x 30.5 cm/s or 1 ft/s) if eggs must float for 48 hours (approximate time for hatching at optimum water temperature) before hatching, a minimum current velocity of 30.5 cm/s (1 ft/s) is required for egg flotation, and eggs move downstream at current velocity. However, this estimate may not represent the actual minimum stream length required because: (1) eggs do not move at current velocity; (2) water temperature may vary enough between stream sections to alter hatching time; (3) suspension of the newly hatched embryo may be required for about 15 hours post-hatch, increasing the distance required; and (4) the role of currents within reservoirs, especially headwater areas, is unknown. 19