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Mary C. Freeman

Publications and source records attributed to Mary C. Freeman.

44 records · Page 3Linked to original sources
USGS1997

Transferability of habitat suitability criteria for fishes in warmwater streams

We developed habitat suitability criteria and tested their transferability for nine fishes inhabiting unregulated Piedmont and Coastal Plain streams in Alabama. Criteria for optimal habitat were defined as those ranges of depth, velocity, substrate type, and cover type for which a species' suitability index (proportional abundance divided by proportional habitat availability, scaled from 0 to I) equalled or exceeded 0.4. We evaluated the transferability of criteria between study sites by testing the null hypothesis that species occurrence in a sample was independent of whether or not the sample was taken in optimal habitat. We also tested criteria transference to a large, flow‐regulated river sampled during low‐flow periods. Depth, velocity, and most substrate criteria developed for the bronze darter Percina palmaris successfully transferred between unregulated streams and to the flow‐regulated river samples. All criteria developed for a pair of closely related, allopatric darter species. the newly described lipstick darter Etheostoma chuckwachatte and the greenbreast darter E. jordani , transferred successfully when applied between species (in the unregulated sites) and to the regulated river samples. In contrast, criteria for the Alabama shiner Cyprinella callistia failed nearly all tests of transferability. Criteria for the speckled darter E. stigmaeum , the blackbanded darter P. nigrofasciata , an undescribed Percina species, and a pair of related, allopatric Cyprinella species transferred inconsistently. The species with good criteria transference had high suitability indices for the shallow depths. fast current velocities. and coarse substrates characteristic of riffle species. We suggest that microhabitat criteria for riffle fishes are more likely to provide a transferable measure of habitat quality than criteria for fishes that, although restricted to fluvial habitats, commonly occupy a variety of pool and riffle habitats.

North American Journal of Fisheries Management↗
USGS1995

Movements by two small fishes in a large stream

Movements by adult Percina nigrojasciata and juvenile Lepomis auritus were examined in a large Coastal Plain stream in the southeastern United States. I marked fishes with subcutaneous injections of acrylic paints to indicate capture location within a 550-m long study site. Recaptures over an 18-month period primarily occurred within 33m of the original capture location, suggesting long-term residence in relatively small areas. However, 11 Percina and three Lepomis moved at least 100 m (maximum distance moved = 200 m for Lepomis, 420 m for Percina), and individuals of both species shifted between distinctly different mesohabitats (boulder riffle, sand pool, and gravel riffle). Distance moved did not strongly relate to time between captures. Long-distance movements (> 33 m) by Percina mostly occurred from Nov. through June. The winter and springtime movements by darters occurred in upstream and downstream directions and into all three mesohabitats, and at least 40% of these movements were unassociated with periods of extreme high flow. Periodic long-range movements may allow small fishes to respond to variation in resources over a large area and across a variety of stream habitats.

Copeia↗
USGS1993

Effects of habitat availability on dispersion of a stream cyprinid

We analyzed temporal changes in the dispersion of the rosyside dace, Clinostomus funduloides , (family Cyprinidae) in a headwater stream, to assess the role of habitat availability in promoting fish aggregation. The dace foraged alone and in groups of up to about 25 individuals, and dispersion varied significantly among monthly censuses conducted from May through December. In two of three study pools, dace aggregated during July, October and/or December, but spread out during other months, especially during September when dispersion did not differ significantly from random. Dispersion was not significantly correlated with the total amount of suitable habitat available to foraging dace, but during summer, corresponded to the availability of depositional areas adjacent to rapid currents. Foragers aggregated in eddies or depositional areas during high stream discharge in July, and shifted out of depositional areas when current velocities declined from July to September. During late autumn, however, aggregations formed independently of changes in habitat conditions, and dace dispersion did not vary significantly among months in a third pool. The study suggests that dace dispersion cannot be predicted from the overall availability of suitable habitat as estimated from point measurements of depth and velocity; both the occurrence of a specific habitat feature (i.e., eddies adjacent to high velocity currents) and seasonal differences in behavior more strongly influenced the spatial distribution of foragers.

Environmental Biology of Fishes↗
USGS1992

Group foraging by a stream minnow: shoals or aggregations?

The importance of social attraction in the formation of foraging groups was examined for a stream-dwelling cyprinid, the rosyside dace, Clinostomus funduloides. Dace arrivals and departures at natural foraging sites were monitored and tested for (1) tendency of dace to travel in groups, and (2) dependency of arrival and departure rates on group size. Dace usually entered and departed foraging sites independently of each other. Group size usually affected neither arrival rate nor departure probability. Thus, attraction among dace appeared weak; foraging groups most often resulted from dace aggregating in preferred foraging sites. The strongest evidence of social attraction was during autumn, when dace departure probability often decreased with increasing group size, possibly in response to increased threat of predation by a seasonally occurring predator. Dace also rarely avoided conspecifics, except when an aggressive individual defended a foraging site. Otherwise, there was little evidence of exploitative competition among dace for drifting prey or of foraging benefits in groups, because group size usually did not affect individual feeding rates. These results suggest that the benefits of group foraging demonstrated under laboratory conditions in other studies may not always apply to field conditions.

Animal Behaviour↗