An experimental investigation of refuging behaviour in a minnow

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Abstract
An artificial stream was used to experimentally investigate refuging behaviour in the creek chub (Semotilus atromaculatus). When shelters were limited, adults dispersed from and returned to the area of the stream containing shelter on a diel cycle. Thus, they exhibited refuging behaviour as defined by Hamilton and Watt (W. J. Hamilton and K. E. F. Watt. 1970. Refuging. Annu. Rev. Ecol. Syst. 1: 263–284). However, when shelters were unlimited, adults did not aggregate in one location, indicating that adult refuging is conditioned by the dispersal of suitable shelters and that it is not a communal process as in roosting birds. In contrast with adults, when shelters were limited, young creek chub did not refuge. The differences in behaviour of the two size–age groups are consistent with observations from the natural stream, in that young chub can utilize small cover objects such as submerged leaves or employ crypsis to escape detection, rendering them less dependent than adults on cover. Further, high densities of juveniles in refuge locations would reduce their foraging efficiency and increase the risk of predation by piscivorous adults.