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.

No abstract

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.

No abstract

The Redeye Bass, Micropterus coosae, was described from the Mobile River basin, Chattahoochee, and Savannah rivers in Alabama and Georgia, USA, by Hubbs and Bailey (1940). At that time the authors recognized significant variation in the Black Warrior River population, and noted that with further study this form may be recognized as a separate taxon. An examination of variation in morphology and mitochondrial DNA supported this observation, and highlighted additional species-level variation, resulting in descriptions of a total of four new species: Micropterus cahabae, new sp., restricted to the Cahaba River system; Micropterus tallapoosae, new sp., restricted to the Tallapoosa River system; Micropterus warriorensis, new sp., from the Black Warrior River system; and Micropterus chattahoochae, new sp., from the Chattahoochee River system. Micropterus coosae is restricted to the Coosa River system. The new species differ from each other and from M. coosae by a combination of pigmentation and scale count characteristics, development of the tooth patch, and divergence within the ND2 gene. While two of these species are relatively common in upland streams within their ranges, M. warriorensis, M. cahabae and M. chattahoochae are uncommon and may warrant protection.

Detection of aquatic species is imperfect, especially if the species is rare and exhibits spatial and temporal variability. Many fish species require a number of sampling trips before detection is positive. And yet, information on species persistence is critical for effective conservation efforts. New forensic genetic techniques, such as environmental DNA (eDNA), have been developed and successfully used to validate the presence of exotic aquatic species in new areas. We compared detection of a federally listed, threatened, migratory fish species the Slackwater darter (Etheostoma boschungi); using eDNA to concomitantly collected field collections. Detection probabilities for this species are variable, but consistently low in recent collections. Our results indicated that detection using eDNA was vastly more effective than traditional sampling at confirming the presence of the Slackwater darter. Positive detection at non-breeding sites was half of the detection rate at breeding sites, most likely to the greater area available in non-breeding streams. These data suggest that eDNA is an effective tool for quickly evaluating a relatively large number of sites for the presence of rare aquatic species.

No abstract

Nest association, or the habit of spawning in the nest of another species, is a widespread reproductive strategy among North American fishes, especially minnows. The hosts of nest associates include sunfishes and nest-building minnows. Previous experiments demonstrated that nest associates benefited from the parental care of hosts. The purpose of this study was to determine the effect of nest associates on hosts, and thereby characterize the relationship as parasitic, mutualistic or commensal. Since hosts with associates had higher reproductive success than those without associates in this experiment, I characterize nest association as a mutualistic relationship, at least in some systems. The dilution effect is the proposed mechanism responsible for the higher reproductive success of hosts with associates.