The influences of eight water temperature and three discharge variables on the time and duration of spawning by smallmouth bass Micropterus dolomieui were evaluated in three mainstem sections and two tributaries of the New River in Virginia and West Virginia. Stepwise discriminant analysis was used to assess the relative importance of each variable in distinguishing between days when spawning did and did not occur. Spawning occurred from late April through mid-July at mean daily water temperatures ranging from 12.5 to 23.5øC. Frequency distributions of spawning dates were nearly identical among study sites, as was the timing ofhydrologic events. Spawning activities were interrupted by flooding in June and resumed when water levels were receding. Mean daily water temperature explained most of the variation among groups of daily stream conditions related to spawning activities. Discriminant functions developed from three temperature variables and one discharge variable correctly classified 72% of the days on which spawning did and did not occur. The functions should be useful in predicting smallmouth bass spawning times in other streams.

Four artificial structures in Lake Anna, Virginia, were chosen to develop and refine a sampling technique designed to assess the effectiveness of structures in attracting fish. Several underwater observation techniques were tried before one suited to the prevailing restrictive and low‐visibility conditions was devised and applied to the four structures in summer and autumn 1988. Three consecutive fish counts were made at nine sampling locations per structure. Bluegills Lepomis macrochirus less than 15 cm in total length dominated counts at all structures and were used to evaluate the sampling technique, Counts of bluegills made immediately after divers descended were significantly (P < 0.05) lower than counts made 3 and 5 min after descent. Differences among initial and subsequent counts appeared related to bluegill adaptation to divers and diver adaptation to low light levels underwater. The cumulative mean number of bluegills counted over nine sampling locations per structure and the associated variability tended to stabilize by the time fish at the sixth or seventh location had been counted. Sampling seven locations per structure was sufficient to obtain an index of bluegill density. Differences in bluegill density from summer to autumn were apparent at two structures that were more than 4 years old but not at two 6‐month‐old structures.

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