Abstract The endangered razorback sucker Xyrauchen texanus is endemic to the Colorado River system in western North America and threatened with extinction because of limited recruitment. To assist management recovery efforts, we developed methods for cryopreservation sperm, evaluated influence various factors on motility thawed examined effect fertilization cooling rate addition caffeine. Sperm samples cryopreserved 10% methanol (MeOH) had significantly higher postthaw than did preserved 5%...

Our objectives were to determine if larval spotted salamanders, Ambystoma maculatum, derived from four populations, differed in growth, survival, activity, and metamorphosis, these populations responded differently predation pressure. Using a 4 x 2 randomized block design, equal numbers of larvae reared artificial pools the presence absence natural predator, bluegill sunfish, (Lepomis macrochirus.). Population source was prominent factor observed differences activity. Fish significantly...

More than 300 of the ~6180 known reptile species are critically endangered or endangered, with more 200 amphibian extinct, and ~1230 ~6800 endangered. To assure survival these conservation breeding programs (CBPs) being established. The perpetuation genetic variation is required in both CBPs natural populations, to maintain health reproduction, enable adaptation environmental change. However, over time often lost small fragmented populations. Reproduction technologies including gene banking...

Our purpose was to determine how nonlethal prey injury and habitat complexity mediate the dynamics of a predator–prey system. We assessed rates predation by crayfish Procambarus acutus on Hyla chrysoscelis tadpoles with four levels tail loss (0, 25, 50, 75% total length removed), in habitats three (zero, low, high density screen) 4 × 3 factorial design. also examined effects tadpole sprint velocity distance traveled. Tadpoles were preyed upon significantly more often than other tail-loss...

Cambarus (Depressicambarus) harti (Piedmont Blue Burrower) is a state-endangered primary burrowing crayfish found in highly organic soils associated with seepage areas only Meriwether County, GA. As the case many native crayfishes, virtually nothing known about biology and ecology of this species. To help fill gap, current study provides information on population demographics, environmental correlates activity, behavior, habitat fidelity C. harti. Field surveys from type locality revealed...

We investigated chela autotomy in young of the year crayfish, Procambarus clarkii (Girard, 1852), from two perspectives. wished to determine (1) influence crayfish density and refuge availability on frequency autotomy, (2) impact growth survival reared at low high densities refugia levels. A 13.1 % surviving were observed with least one missing. There was a greater percentage missing tanks stocked (18.1%) compared (8.2%). no differences (16.3%) (10.0%) refugia. The loss males (15.8%) higher...

was greatest in moist and emergent water levels. Both species produced greater biomass the high nutrient treatment than low treatment. Root: shoot ratio increased for both with decreasing level; however, root: of Echinochloa significantly lower that Phalaris at Interspecific competition did not adversely affect survival or allocation strategy either species; rather, their mixture monoculture suggests intraspecific is relatively more important both. In wetlands, may be successful fluctuating...

Abstract We developed methods for the cryopreservation of sperm endangered Colorado pikeminnow Ptychocheilus lucius. Sperm were collected from a captive broodstock population reared and maintained at Dexter National Fish Hatchery Technology Center. Our objectives to (1) evaluate effects on motility 24-h storage in Hanks' balanced salt solution (HBSS); (2) characterize duration; (3) examine relationship between osmotic pressure; (4) effect four cryoprotectants (dimethyl sulfoxide [DMSO],...

Fallicambarus gordoni, a crayfish found only in pitcher-plant bogs, is restricted to the DeSoto National Forest, Perry County, Mississippi, U.S.A. The species active from late fall through spring, and apparently estivates during summer when bogs are dry. Ovigerous females were winter, small juveniles collected February. Form I males throughout much of year, except months no collected. Burrows F. gordoni complex similar structure those fodiens. Catch per unit effort ranged 0.02-0.17,...

Flow cytometry (FCM) and computer-assisted sperm motion analysis (CASA) methods were developed validated for use with endangered razorback suckers Xyrauchen texanus collected (n=64) during the 2006 spawning season. Sperm motility could be activated within osmolality ranges noted milt collections (here 167-343 mOsm/kg). We hypothesized that quality of into isoosmotic (302 mOsm/kg) or hyperosmotic (500 Hanks' balanced salt solution would not differ. Pre-freeze viabilities similar between...

Body reflections in the ultraviolet (UV) are a common occurrence nature. Despite abundance of such signals and presence UV cones retinas many vertebrates, function majority taxa remains unclear. Here, we report on an unusual communication system razorback sucker, Xyrauchen texanus , that involves flash produced by quick eye rolls. Behavioural experiments field observations indicate this form is used to signal territorial between males. The shows highest contrast region visual spectrum ( λ...

Abstract We examined methods for detecting environmental DNA of the invasive white river crayfish Procambarus zonangulus. In a laboratory experiment, we investigated detection capability in benthic sediment samples and water six flow-through tanks. Additionally determined whether density (low = 0.67 or high 2.69 crayfish·m-2) time tanks influenced detectability (collection on Days 2, 5, 8 15). Species-specific primers probes were designed P. zonangulus their specificity was tested against...

The thermal environment is a major factor influencing amphibians. For example, amphibian reproduction occurs in specific temperatures, and minor changes this aspect could have negative impacts on biological process. Understanding the potential effects of temperature reproductive output important from both an ecological captive breeding colony point view. I examined axolotl reared egg to adult at 4 temperatures (15 °C, 19 23 27 °C) These axolotls (n = 174) were measured weighed, dissected,...

We developed methods for the collection, handling, and refrigerated storage of sperm from endangered razorback sucker Xyrauchen texanus. Sperm samples were obtained 56 78 male suckers collected Lake Mohave (Colorado River) during 1994 1995 spawning seasons. There significant differences among osmolalities blood plasma, ovarian fluid, seminal plasma. Maximum motility was observed 3 s after dilution with river water maintained 16 ± 8 (mean SD). Motility ceased 70 32 addition water. Given short...

Es wurde untersucht, ob dichteabhangiges Wachstum und Kannibalismus Faktoren sind, die sich populationsregulierend auf einen Jahrgang des Fluskrebses Procambarus clarkii (Girard, 1852) auswirken konnen. Fluskrebse gleichen Geschlechts etwa gleicher Korpergrose wurden in zwei Populationsdichten kunstlichen Teichen ausgesetzt, ein niedriges bzw. hohes Angebot an Ruckzugsmoglichkeiten (Verstecken) aufwiesen. Nahrungsangebot Wasserqualitat waren so bemessen, das sie keine limitierenden...

Abstract Native fishes reared in hatcheries typically suffer high predation mortality when stocked into natural environments. We evaluated the behavior of juvenile bonytail Gila elegans, roundtail chub robusta, razorback sucker Xyrauchen texanus, and Sonora Catostomus insignis response to introduced channel catfish Ictalurus punctatus flathead Pylodictis olivaris. Our laboratory tests indicate these species did not inherently recognize as a threat, but they can quickly (within 12 h) change...

Hatchery-reared juvenile, <25-cm TL (total length), razorback suckers appeared curious and showed no sign of predator avoidance when initially placed with large (>45-cm TL) flathead catfish. Predator-naïve juveniles (20- to 25-cm exhibited discernable preference provided areas without (52 percent 48 percent, n = 16 observations; 46 54 20 observations) However, once predation occurred, use predator-free nearly doubled in two trials (36 64 50 33 67 12 observations). A more stringent test...

Abstract The southeast United States is the epicenter of global crayfish biodiversity, but these species are among some most threatened in world. Life history and biological trait data deficiencies, particularly burrowing species, hampers efforts for accurately assessing imperilment rates informing conservation efforts. Rising temperatures a threat to aquatic ectotherms it important evaluate tolerances determine if they at or near their upper thermal limits. We conducted dynamic temperature...

Abstract I surveyed the peer-reviewed literature for studies on crayfish population genetics over last 20 years (1996 to 2015). My objectives were determine if there is research disparities based conservation status, ecological group, geographic location, and genetic methods used. Additionally, wished overall trends in related variability, systematics, technique development. An extensive search yielded 201 articles with information published 335 of 590 species found worldwide. The majority...

Fallicambarus gordoni, a crayfish found only in pitcher-plant bogs, is restricted to the DeSoto National Forest, Perry County, Mississippi, U.S.A. The species active from late fall through spring, and apparently estivates during summer when bogs are dry. Ovigerous females were winter, small juveniles collected February. Form I males throughout much of year, except months no collected. Burrows F. gordoni complex similar structure those fodiens. Catch per unit effort ranged 0.02-0.17,...