Correlates of reproductive success in stream-dwelling male rock bass,Ambloplites rupestris (Centrarchidae)

Synopsis Reproductive success was determined for individual male rock bass, Ambloplites rupestris, inhabiting the Middle Thames River near London, Ontario. Successful males produced numbers of young similar to rock bass breeding elsewhere, but the probability of males producing any young at all was comparatively small. Flooding, predation, and fouling of nests by algae were the major causes of brood mortality. Brood vulnerability was greatest within the egg, when nests were probably most conspicuous to predators. Male reproductive success was positively correlated with large size, early nesting, warm water conditions, and minimal flow rates. Larger males were chosen preferentially by females, and renested more often.