The restricted movement paradigm (RMP), which states adult fish do not move out of a pool or restricted stream reach, does not fully define the movements of stream fishes. Although stream fishes may spend the majority of their time in a home pool, they also make regular exploratory trips away from the home pool. Recapture of Ouachita Highlands stream fish marked with passive integrated transponder (PIT) tags showed that the majority of the uniquely marked fish in this study were in the pools of initial collection. The following percentages of marked fish were recaptured outside the pool of initial collection: 12% of creek chub Semotilus atromaculatus; 33% of blackspotted topminnow Fundulus olivaceus; 12% of green sunfish Lepomis cyanellus; and 14% of longear sunfish Lepomis megalotis. Standard lengths and weights did not differ significantly between nonmobile and mobile recaptured fish, and patterns of multiple recaptures indicated exploratory, round-trip movements. Such regular exploratory trips suggest that the area of use by and critical habitat for stream fishes may be greater than commonly estimated.

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SynopsisFishes that act as nest associates spawn simultaneously with nest-building hosts and then abandon their eggs. The proposed benefit for this behavior is increased brood survivorship, arising from the physical environment provided by the nest or the parental care provided by the host. Field and enclosure experiments indicated that associates benefit from the parental care provided by the host, and not from the physical environment provided by the nests of hosts. This information, along with the effect of nest association on host reproductive success, is necessary before the nature of this nesting symbiosis can be characterized.

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