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USGS2000

Copepod (Crustacea) emergence from soils from everglades marshes with different hydroperiods

During a severe drought period in the winter and spring of 1989, we made three collections of dried marsh soils from freshwater sloughs in Everglades National Park, Florida, at sites characterized by either long or intermediate annual periods of flooding (hydroperiod). After rehydrating the soils in aquaria, we documented the temporal patterns of copepod emergence over two-week periods. The species richness of copepods in the rehydrated soils was lower than in pre-drought samples from the same slough sites. Only six of the 16 species recorded from the Everglades emerged in the aquarium tests. The long hydroperiod site had a slightly different assemblage and higher numbers of most species than the intermediate-hydroperiod sites. More individuals and species emerged from the early dry-season samples compared with samples taken later in the dry season. The harpacticoid, Cletocamptus deitersi, and the cyclopoid, Microcyclops rubellus, were abundant at most sites. The cyclopoids - Ectocyclops phaleratus, Homocyclops ater, and Paracyclops chiltoni - are new records for the Everglades. We infer that 1) only a subset of Everglades copepod species can survive drought by resting in soils; and that 2) survival ability over time differs by species.

Journal of Freshwater Ecology↗

USGS2000

Proposed standard-weight (Ws) equations for kokanee, golden trout and bull trout

We developed standard-weight (W s ) equations for kokanee (lacustrine Oncorhynchus nerka ), golden trout ( O. aguabonita ), and bull trout ( Salvelinus confluentus ) using the regression-line-percentile technique. The W s equation for kokanee of 120–550 mm TL is log 10 W s = −5.062 + 3.033 log 10 TL, when W s is in grams and TL is total length in millimeters; the English-unit equivalent is log 10 W s = −3.458 + 3.033 log 10 TL, when W s is in pounds and TL is total length in inches. The W s equation for golden trout of 120–530 mm TL is log 10 W s = −5.088 + 3.041 log 10 TL, with the English-unit equivalent being log 10 W s = −3.473 + 3.041 log 10 TL. The W s equation for bull trout of 120–850 mm TL is log 10 W s = −5.327 + 3.115 log 10 TL, with the English-unit equivalent being log 10 W s = −3.608 + 3.115 log 10 TL.

Journal of Freshwater Ecology↗

USGS2011

Fish species composition two second-order headwater streams the North Central Appalachians ecoregion

Fish species composition was determined for two second-order headwater streams within the North Central Appalachians ecoregion in northern Pennsylvania. The two streams were widely spaced geographically (over 193 km apart) and occurred in different drainage systems. Streams were sampled in the spring and fall over two years (1996–98) yielding similar fish assemblages. A total of five species was collected. Mottled sculpin ( Cottus bairdli ), slimy sculpin ( Cottus cognatus ), brook trout ( Salvetinus fontinalis ), and brown trout ( Salmo trutta ) were the dominant adult fishes. Two creek chubs ( Semotilus atromaculatus ) were also collected. No significant differences were found in sculpin weight, sculpin length, salmonid length, or brook trout length between streams. Paired t-tests detected eight significant seasonal differences within sites. Brook trout and mottled sculpin lengths were significantly greater in fall versus spring, while the reverse was found with slimy sculpins. Catches per unit effort were similar between the two streams, yielding 8.46 and 8.07 fish per minute of electrofishing. Both streams were very similar in faunal assemblages attributed to small, coldwater, high quality headwater streams in other regions.

Pennsylvanaia↗

USGS2011

Proposed standard-weight (Ws) equation and length-categorization standards for brown trout (Salmo trutta) in lentic habitats

We developed a standard-weight (W s ) equation for brown trout ( Salmo trutta ) in lentic habitats by applying the regression-line-percentile technique to samples from 49 populations in North America. The proposed Ws equation is log 10 W s = −5.422 + 3.194 log 10 TL, when W s is in grams and TL is total length in millimeters. The English-unit equivalent is log 10 W s = −3.592 + 3.194 log 10 TL, when W s is in pounds and TL is total length in inches. The equation is applicable for fish of 140–750 mm TL. Proposed length-category standards to evaluate fish within populations are: stock, 200 mm (8 in); quality, 300 mm (12 in); preferred, 400 mm (16 in); memorable, 500 mm (20 in); and trophy, 600 mm (24 in).

Journal of Freshwater Ecology↗

USGS2011

Water quality in three creeks in the backcountry of Grand Teton National Park, USA

This study was conducted in Grand Teton National Park during the summers of 1996 and 1997 to investigate the water quality in two high human use areas: Garnet Canyon and lower Cascade Canyon. To evaluate the water quality in these creeks, fecal coliform, Giardia lamblia , coccidia, and microparticulates were measured in water samples. No evidence of fecal coliform, Giardia lamblia , or coccidia, was found in Garnet Creek. The water quality and general water chemistry of Garnet Creek was similar to the reference site. No Giardia lamblia or coccidia were found in Cascade Creek, but fecal coliforms were present. The isolated colonies of Escherichia coli from Cascade Creek matched the ribosome patterns of avian, deer, canine, elk, rodent, and human coliforms.

Wyoming↗

USGS2001

The fish community of a small impoundment in upstate New York

Moe Pond is a dimictic impoundment with surface area of 15.6 ha, a mean depth of 1.8 m, and an unexploited fish community of only two species: brown bullhead ( Ameiurus nebulosus ) and golden shiner ( Notemigonus crysoleucas ). The age-1 and older brown bullhead population was estimated to be 4,057 individuals, based on the Schnabel capture-recapture method of population estimation. Density and biomass were respectively estimated at 260 individuals/ha and 13 kg/ha. Annual survival rate of age-2 through age-5 brown bullheads was estimated at 48%. The golden shiner length-frequency distribution was unimodal with modal length of 80 mm and maximum total length of 115 mm. The golden shiner population estimate was 7,154 individuals, based on seven beach seine haul replicate samples; the density and biomass were 686 shiners/ha and 5 kg/ha, respectively. This study provides an information baseline that may be useful in understanding food web interactions and whole-pond nutrient flux.

New York↗

USGS2002

Effects of Photoperiod on Behavior and Courtship of the Neosho madtom (Noturus placidus)

To test effects of long and short day-length on behavior of the Neosho madtom ( Noturus placidus ), we held six pairs of fish in separate tanks under 16 hr (L): 8 hr (D) (long-day) and six pairs under 12 hr (L): 12 hr (D) (short-day) photoperiods. An ethogram was created and behavior was electronically and continuously recorded. Two-minute intervals for each hour over four 4-day periods were examined, and proportion of time active and performing specific behaviors in each tank was analyzed to compare differences between treatments. Individuals held under 16 L, 8 D were more active during the light cycle than those in 12 L, 12 D. Specific behaviors examined included resting, swimming, feeding, aggression, cavity enhancement, and courtship. A higher proportion of time was spent performing cavity enhancement, cavities were deeper, and gravel size in cavities was smaller for those fish in the long-day treatment. Throughout the experiment various courtship behaviors were observed in male-female pairs held in 16 L, 8 D, but no such behaviors were observed in 12L, 12D. The relationships between a long photoperiod and activity, cavity enhancement, and courtship behaviors illustrate the influence of photoperiod on the Neosho madtom reproductive cycle.

Journal of Freshwater Ecology↗

USGS2002

A comparison of diets of blueback herring (Alosa aestivalis) and threadfin shad (Dorosoma petenense) in a large southeastern U.S. Reservoir

The objective of this study was to determine dietary overlap between blueback herring and threadfin shad in J. Strom Thrumond Reservoir, South Carolina/Georgia. We also evaluated prey selectivity for each speices and diet differences between two size categories of blueback herring. Diet and zooplankton samples were collected every other month from April 1992 to February 1994. We examined stomachs containing prey from 170 large blueback herring (>140mm), 96 small blueback herring (<140mm), and 109 threadfin shad, and we also examined 45 zooplankton samples. Large blueback herring diets differed significantly from threadfin shad diets on 11 of 12 sampling dates, and small blueback herring diets differed from threadfin shad diets on all sampling dates. In general, blueback herring consumed proportionally more copepods and fewer Bosmina sp. and rotifers than threadfin shad. Large and small blueback herring diets were significantly different on five of eight sampling dates, primarily due to the tendency of small blueback herring to eat proportionally more Bosmina sp. than large blueback herring. Both blueback herring and threadfin shad fed selectively during some periods of the year. Diet differences between the species may contribute to their coexistence; however, both blueback herring and threadfin shad showed a strong preference for Bosmina sp., increasing the chance that they may negatively influence one another.

Georgia, South Carolina↗

USGS2003

Biological characteristics of the blue sucker in the James River and the Big Sioux River, South Dakota

Little is known about the relative abundance and biology of the blue sucker ( Cycleptus elongatus ), a species that may be declining in some parts of its range. We described the age, growth, condition, length distribution, and habitat preference of the blue sucker in two South Dakota rivers. Specimens were collected from the James River (n=74) and Big Sioux River (n=28) during the summer of 2000. Although five macrohabitats were sampled with electrofishing and hoopnets, most individuals were collected from riffle habitats and downstream of rock dams. Total length-weight relationships were log 10 W= −6.14+3.37 (log 10 L) (r 2 = 0.92) for blue suckers from the James River and log 10 W= −6.52+3.50(log 10 L) (r 2 = 0.97) for fish from the Big Sioux River. Mean condition factors (K = W(10 5 )/L 3 ) of blue suckers were 0.79 (SE = 0.07) for the James River and 0.73 (SE = 0.07) for the Big Sioux River. Blue suckers between 500 and 700 mm dominated length distributions (range = 374–717 mm) of both samples. Ages ranged from two to nine years, but six-year-old fish were captured most frequently. Blue suckers grew rapidly during juvenile stages (< age 5); however, growth slowed afterward.

South Dakota↗

USGS2003

Distribution and movement of juvenile paddlefish in a mainstem Missouri River reservoir

Hatchery-raised paddlefish ( Polyodon spathula ) were implanted with ultrasonic transmitters and tracked from August to November 1998 and March to November of 1999 and 2000 to determine diel movements and seasonal distribution in Lake Francis Case. South Dakota. Juvenile (340 to 432 mm eye to fork length) paddlefish (N=32) exhibited variable movement patterns but remained in the upper reservoir reaches throughout the three-year study. Movement rates ranged hm 35 to 3,464 m/h with 90% of all locations in the upper third (51 kml of the reservoir. Increased movement rates were weakly correlated with increased water temperature (r=0.16, P=0.04). Daytime paddlefish movement peaked in July and August. However, diel movements were variable among seasons. In spring, movement rates did not differ among diel periods, whereas summer movements were lower during crepuscular periods and fall movements were lowest during the day. Although paddlefish were stocked at two locations in Lake Francis Case, they appeared to disperse and use reservoir areas similarly.

Missouri↗

USGS2003

Cladoceran zooplankton abundance under clear and snow-covered ice

We described the distribution of cladoceran zooplankton under the ice in a natural, glacial lake. Local light availability apparently altered the spatial distribution of cladocerans. Light levels measured under snow-covered areas (0.178 lux) were an order of magnitude less than those measured at the same depth under clear ice (1.750 lux). Cladoceran density under snow-covered areas was significantly higher ( Bosmina spp.=3.34/L; Daphnia spp.=0.61/L) than cladoceran abundance under clear ice ( Bosmina spp.=O.91/L; Daphnia spp.= O.19/L).

Journal of Freshwater Ecology↗

USGS2003

Fish community responses to the establishment of a piscivore, northern pike (Esox lucius), in a Nebraska Sandhill lake

Northern pike ( Esox lucius ) was first documented in West Long Lake, Nebraska, in 1998 when two pike <380 mm were collected. In 2002, a Peterson mark-recapture population estimate on northern pike revealed density and standing stock (i.e., biomass) estimates of 35.8 fish/ha (95% CI= ± 8.8) and 22.0 kg/ha (95% CI= ± 5.4), respectively. Consequently, West Long Lake was sampled in 2002 to compare relative abundance, size structure, and growth of bluegill ( Lepomis macrochirus ), largemouth bass ( Micropterus salmoides ), and yellow perch ( Perca flavescens ) prior to and after the establishment of a high-density northern pike population. Bluegill, largemouth bass, and yellow perch relative abundances were significantly lower in 2002 than 1998. Similarly, size structures of all three species were significantly different between years. Size structure declined for both bluegill and yellow perch, and increased for largemouth bass. Growth was significantly higher for bluegill, largemouth bass, and yellow perch in 2002 than 1998. While the fish community changes were expected with the establishment of northern pike, they occurred in a relatively short time period (i.e., four years).

Nebraska↗

USGS2003

Relationship among side channels, fish assemblages, and environmental gradients in the unimpounded Upper Mississippi River

We analyzed fish abundance and environmental data collected over nine years from six side channels of the unimpounded upper Mississippi River between river km 46.7 and 128.7. A partial canonical correspondence analysis revealed differences in fish assemblages and environmental factors correlated with the six side channels. Fishes correlated with open side channels represented large river species tolerant of current and/or turbidity. Fishes correlated with closed side channels represented assemblages preferring either moderate to low turbidity/current or pools.

Upper Mississippi River Valley↗

USGS2003

Egg-to-fry survival of two strains of Atlantic salmon (Salmo salar) in stream incubators under laboratory conditions

Egg-to-fry survival of two strains of Atlantic salmon (Salmo salar) was evaluated under laboratory conditions in two commercial stream egg incubators. The survival was also examined based on egg developmental stage (i.e., green eggs, eyed egggs, advanced eggs). There was no significant difference in survival of eggs in the Jordan-Scotty and Whitlock-Vibert incubators. However, the survival of Sebago strain Atlantic slamon eggs was significantly higher than that of Penobscot stream eggs, and survival increased with advanced egg developmental stage.

Journal of Freshwater Ecology↗

USGS2003

Aquatic invertebrate assemblages in shallow prairie lakes: Fish and environmental influences

We sampled zooplankton and benthic macroinvertebrate assemblages in 30 shallow natural lakes to determine the effects of the environment (i.e., habitat and fish abundance) on invertebrates. Zooplankters were identified to genus, and up to 120 individuals per genus were measured. Macroinvertebrates were identified to order, class, or family. Fish communities were also sampled. Relative abundances of zooplankton and macroinvertebrates were low at increased chlorophyll a concentrations, although mean zooplankton length increased with total phosphorus, possibly because of an increased proportion of microzooplankton (rotifers and copepod nauplii) at higher phosphorus levels. Canonical correspondence analysis revealed that zooplankton and macroinvertebrate abundance was influenced by submersed vegetation coverage, whereas zooplankton abundance and size structure were also related to productivity (i.e., chlorophyll a and total phosphorus). However, relative abundance of fish species or fish feeding guilds was not strongly correlated with zooplankton or macroinvertebrate abundance or zooplankton size structure. Physical habitat (e.g., vegetation coverage) may exert substantial influences on invertebrate assemblages in these lakes , possibly providing a refuge from fish predation.

Journal of Freshwater Ecology↗

USGS2003

Demographics and chronology of a spawning aggregation of blue sucker ( Cycleptus elongatus ) in the Grand River, Missouri, USA

The blue sucker ( Cycleptus elongatus ) was sampled as individuals arrived, spawned, and departed from a spawning rime in the Grand River of northcentral Missouri, USA. The Grand River basin was not known to support blue sucker reproduction with few individuals ever recorded. The spawning site is unique in character for the lower river. Individuals began arriving in early April when water temperatures reached 10–12°C. Females with freely-flowing roe were sampled in late April after a large rise in river stage and concurrent lowering of the water temperature 4–5 degrees to 16.5°C. The spawning aggregation had a mean age of 15 y and ranged from 9 to 22 y based on scales that probably underestimated true ages. Males outnumbered females 5.5:1. Mean length was 659 mm for males and 721 mm for females. Females were longer at age than males and no significant age-length relationship was evident.

Missouri↗

USGS2003

Snorkeling as an alternative to depletion electrofishing for assessing cutthroat trout and brown trout in stream pools

We compared abundance and length structure estimates of cutthroat trout (Oncorhynchus clarki) and brown trout (Salmo trutta) of 15 cm total length or greater obtained by snorkeling in stream pools with estimates obtained by depletion electrofishing . We sampled 12 pools in each of two streams formed by large springs in the Salt River Valley of western Wyoming. Snorkeling counts provided a relatively accurate index of depletion electrofishing estimates of abundance of cutthroat trout , but not brown trout . Linear regression analysis showed that snorkeling counts were significantly related to depletion electrofishing estimates for both cutthroat trout (P < 0.001) and brown trout (P = 0.002), but the coefficient of determination for brown trout (r 2 = 0.33) was low compared to cutthroat trout (r 2 = 0.95). Frequencies of fish in three length classes observed by snorkeling and depletion electrofishing were close to being significantly different for cutthroat trout (P = 0.066) and substantially different for brown trout (P= 0.005). Snorkeling frequently failed to observe fish in the shortest length class (15–29 cm total length) of both cutthroat trout and brown trout .

Journal of Freshwater Ecology↗

USGS2003

Habitat selection of the channel darter, Percina (Cottogaster) copelandi, a surrogate for the imperiled pearl darter, Percina aurora

Percina (Cottogaster) aurora is an imperiled species under consideration for listing by the U.S. Fish and Wildlife Service. To better understand habitat use of P. aurora , we studied a related and more abundant Cottogaster species, Percina copelandi , from the Ouachita River, Arkansas. We used a laboratory stream system to examine mesohabitat selection (pools versus riffles) and microhabitat selection (substratum particle size) of P. copelandi over three temperature regimes (summer, spring, and winter). Percina copelandi selected pool habitats over riffles and selected pools with coarse substrata ( e.g. , cobble) over fine substrata ( e.g. , gravel). In riffles, P. copelandi selected large substrata during winter and spring but did not show particle size selection during summer. These data, and various published and unpublished field data for P. aurora , suggest that habitat use of P. aurora is also centered around deep runs and pools, with large substrata likely being more important at low water temperatures.

Journal of Freshwater Ecology↗