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M. R. Dewey

Publications and source records attributed to M. R. Dewey.

13 recordsLinked to original sources
USGS2006

Patterns of foraging and distribution of bluegill sunfish in a Mississippi River backwater: Influence of macrophytes and predation

We studied the trophic interactions and spatial distributions of bluegills Lepomis macrochirus and largemouth bass Micropterus salmoides in a macrophyte bed in Lake Onalaska, a backwater lake in the upper Mississippi River. The diets of adult and age-0 bluegills were similar and changed seasonally probably in response to changes in life stages of macroinvertebrates (i. e. emergence of winged adults). Diets and diel patterns of abundance of bluegill suggest that age-O and adults were feeding in the vegetated, littoral zone. Predation by age-O largemouth bass appears to influence use of vegetated habitat by age-0 bluegills. In summer, when most age-O bluegills were vulnerable to predation by age-O largemouth bass, bluegill abundance was strongly correlated with vegetation biomass. In October and November, piscivory by age-O largemouth bass was limited by gape. Consequently, the relationship between the abundance of age-O bluegills and vegetation biomass was weakened because predation risk by age-O largemouth bass was reduced.

Wisconsin↗
USGS2006

Bioenergetic relations in submerged aquatic vegetation: An experimental test of prey use by juvenile bluegills

We experimentally tested the hypotheses that bluegills in vegetated habitats grow more rapidly than in nonvegetated habitats because (1) vegetated habitats contain a greater caloric density and (2) are less susceptible to energetic depletion. The 10-week experiment was conducted in enclosures containing factorial combinations of the presence or absence of Vallisneria americana and juvenile bluegills Lepomis macrochirus. After 6 weeks, Vallisneria-only treatments contained a mean of 1048 cal/m2 in the benthos, whereas treatments with both Vallisneria and bluegills contained 610 cal/m2. Hyalella azteca, a preferred prey of bluegill, were nearly depleted in nonvegetated enclosures, whereas Hyalella densities in enclosures with Vallisneria were much less effected by fish. Bluegill growth was significantly greater with Vallisneria than without but declining water temperatures after week 6 resulted in slower growth despite abundant prey. Ultimately, growth of bluegill resulted from an interaction between availability and ingestion of prey, and water temperature. ?? Munksgaard, 1998.

Ecology of Freshwater Fish↗
USGS2004

Hydrologic and hydraulic factors affecting passage of paddlefish through dams in the Upper Mississippi River

Populations of paddlefish Polyodon spathula have been adversely affected by dams that can block their movements. Unlike high-head dams that preclude fish passage (unless they are equipped with fishways), the dams on the upper Mississippi River are typically low-head dams with bottom release gates that may allow fish passage under certain conditions. We evaluated the relation of dam head and river discharge to the passage of radio-tagged paddlefish through dams in the upper Mississippi River. Radio transmitters were surgically implanted into 71 paddlefish from Navigation Pools 5A and 8 of the upper Mississippi River and from two tributary rivers during fall 1994 through fall 1996. We tracked paddlefish through September 1997 and documented 53 passages through dams, 20 upstream and 33 downstream. Passages occurred mostly during spring (71%) but also occurred sporadically during summer and fall (29%). Spring passages varied among years in response to hydrologic conditions. We evaluated patterns in upstream and downstream passages with Cox proportional hazard regression models. Model results indicated that dam head height strongly affected the upstream passage of paddlefish but not the downstream passage. Several paddlefish, however, passed upstream through a dam during periods when the minimum head at the dam was substantial ( ≥1 m ). In these cases, we hypothesize that paddlefish moved upstream through the lock chamber.

Illinois, Iowa, Minnesota, Wisconsin↗
USGS2003

Movement and habitat use by radio-tagged paddlefish in the upper Mississippi River and tributaries

We used radio telemetry to evaluate the movement and habitat use of paddlefish Polyodon spathula in the upper Mississippi River and two tributary rivers. Radio transmitters were surgically implanted into 71 paddlefish in Navigation Pools 5A and 8 of the upper Mississippi River, the Chippewa River, and the Wisconsin River during fall 1994 through fall 1996. Radiotagged paddlefish were located through summer 1997. The range of paddlefish movement was typically low during all seasons except spring, but some paddlefish moved throughout the 420-km extent of the study area. Paddlefish tagged in the Chippewa River were closely linked with the upper Mississippi River, as substantial portions of the population inhabited the adjacent Navigation Pool 4 each spring; paddlefish in the Wisconsin River, however, rarely ventured out of that tributary. The use of aquatic area types by paddlefish varied among the study reaches. A cartographic model of paddlefish habitat suitability was developed for Navigation Pool 8 based on geographic information systems (GIS) coverages of bathymetry and current velocity. The value of paddlefish habitat in the cartographic model increased with depth and decreased with current velocity. For example, areas modeled as excellent corresponded to regions classified as having both deep water (greater than or equal to6.0 m) and negligible (<5 cm/s) current velocities. Our study suggests that aquatic area types are an inadequate basis for making sound management decisions regarding the critical habitats of paddlefish in complex riverine systems because such strata rely on gross geomorpological features rather than on the physicochemical variables that fish use to choose habitats. The development of systemic GIS coverages of such variables could improve the understanding of fish habitat selection and management in the upper Mississippi River.

North American Journal of Fisheries Management↗
USGS1997

The influence of seine capture efficiency on fish abundance estimates in the upper Mississippi River

The effects of season, presence of vegetation, and time of day on seine capture efficiency for fish were evaluated using test enclosures in the upper Mississippi River. Overall capture efficiency of the seine haul was 49% (53% during the day and 43% at night). During daytime tests, the efficiency ranged from 39% to 74% but did not differ statistically between sites or among dates. At night, the efficiency was higher at the vegetated than at the nonvegetated site (55% vs 32%) and declined through time from 56% in May to 28% in October. Although susceptibility to capture differed among taxa, we could not predict either total catch efficiency or efficiency within a given taxon for a given sample. Adjustment of catch data with various estimates of efficiency reduced the mean absolute error for all sampling dates from 51% to 24%, but the error of the adjusted data still ranged from -58% to +54% on any given sampling date. These results indicate that it is difficult to make accurate adjustment of catch data to compensate for gear bias in studies of seasonal habitat use.

Journal of Freshwater Ecology↗
USGS1992

Classification of a wetland area along the upper Mississippi River with aerial videography

We evaluated the use of aerial videography for classifying wetland habitats along the upper Mississippi River and found the prompt availability of habitat feature maps to be the major advantage of the video imagery technique. We successfully produced feature maps from digitized video images that generally agreed with the known distribution and areal coverages of the major habitat types independently identified and quantified with photointerpretation techniques. However, video images were not sufficiently detailed to allow us to consistently discriminate among the classes of aquatic macrophytes present or to quantify their areal coverage. Our inability to consistently distinguish among emergent, floating, and submergent macrophytes from the feature maps may have been related to the structural complexity of the site, to our limited vegetation sampling, and to limitations in video imagery. We expect that careful site selection (i.e., the desired level of resolution is available from video imagery) and additional vegetation samples (e.g., along a transect) will allow improved assignment of spectral values to specific plant types and enhance plant classification from feature maps produced from video imagery.

Mississippi River↗
USGS1992

Habitat use by larval fishes in backwater lake of the upper Mississippi River

Light traps were used to sample larval fishes in Lawrence Lake (Pool 8, upper Mississippi River) from late May through mid-August 1990. Catches differed considerably between vegetated sites and an adjacent open-water area and were highly variable among vegetated stations. Sunfishes ( Lepomis spp.) dominated the vegetated sites. Brook silversides ( Labidesthes sicculus ), Cyprinidae and gizzard shad ( Dorosoma cepedianum ) dominated catches at the open-water site. There was no difference in fish use of vegetated habitats near and far from the main channel of the Mississippi River. Taxonomic diversity was greatest at stations with emergent vegetation.

Journal of Freshwater Ecology↗
USGS1989

Comparison of fish catches with buoyant pop nets and seines in vegetated and nonvegetated habitats

Two models of pop nets were developed to sample fish in shallow riverine waters, one for use in vegetated areas and the other for nonvegetated areas. Both nets have a mechanical release mechanism that can be tripped from the water surface. Replicated field tests were conducted to compare pop-net catches with bag-seine collections every 2 weeks from May through mid-October. Overall, total catch per effort did not vary significantly ( P < 0.05) between the two gears at either the vegetated or nonvegetated site. However, collections with the pop net were not as diverse as with the seine at either sampling site, perhaps because the area sampled by pop nets (5.6 m 2 ) was smaller than the area swept by the average seine haul (70-140 m 2 ). The pop net effectively sampled fish in shallow nonvegetated habitats and was useful in heavily vegetated areas where seining or electroshocking was difficult.

North American Journal of Fisheries Management↗
USGS1989

Effects of water temperature on the mortality of field-collected fish marked with fluorescent pigment

The cumulative effects of collection, handling, and marking with fluorescent pigment on the mortality of adult minnows, young-of-the-year centrarchids, and large centrarchids and percids was determined at five water temperatures (10-20.6 degree C) in field trials. There have been few field trials of this type. The mortality of centrarchids and percids was directly related to temperature and decreased noticeably when the temperature was below 19.5 degree C. The mortality of minnows decreased somewhat as river temperatures cooled but was always at least 50%. Variation was high in the temperature-related patterns of mortality in different taxa and sizes of fish. This variation complicates the accuracy and usefulness of pigment in marking field-collected fish for mark-recapture studies in warmwater systems.

North American Journal of Fisheries Management↗
USGS1989

Movements of striped mullet, Mugil cephalus, tagged in Everglades National Park, Florida

The movements of striped mullet, Mugil cephalus, were studied from fish tagged in Everglades National Park. Florida. A total of 16,604 fish were tagged from March 1984 to September 1985. During the period December 1984 through February 1985 recaptured tagged fish moved significantly further and more northerly out of the Park's waters than they did the rest of the year. Tags were returned from 2.8% of the fish tagged along the west coast and from 0.3% of the fish tagged in Florida Bay and west coast mullet form a series of spatially overlapping stocks.

Bulletin of Marine Science↗