The central mudminnow, Umbra limi (Kirtland), a habitat specialist and resource generalist

The central mudminnow, Umbra limi (Kirtland), successfully inhabits a variable and unpredictable environment in southern Manitoba streams. Umbra accomplishes this by specializing in habitat and generalizing in resources utilized and life history strategies displayed. Mudminnows are restricted to still waters and show a preference for a variety of cover types. They are morphologically, physiologically, and behaviourally specialized for this habitat. Umbra limi inhabits areas subjected to hypoxia and all sizes are able to use both atmospheric and aquatic respiration. Mudminnows are euryphagic carnivores that eat aquatic and terrestrial invertebrates and fish. They feed from a variety of locations (benthic, midwater, and surface) and organisms attached to vegetation are included in the diet. Activity patterns (including feeding) vary daily and seasonally. Differences in rate of growth, age at first maturity, gonadal development, and survival occur between sexes. Individual and population variability is apparent. Spawning time varies and there is evidence for delayed spawning under unfavourable conditions.