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Douglas B. Noltie

Publications and source records attributed to Douglas B. Noltie.

7 recordsLinked to original sources
USGS2006

Influence of water flow on Neosho madtom (Noturus placidus) reproductive behavior

The Neosho madtom is a small, short-lived catfish species endemic to gravel bars of the Neosho River in Kansas, Oklahoma and Missouri, U.S.A. It spawns during summer in nesting cavities excavated in gravel. Although the species has survived dam construction within the Neosho River basin, its declining numbers resulted in it being added to the federal threatened species list in 1991. To test how water flow affects the reproductive behavior of Neosho madtoms, we compared activities of male-female pairs in static versus flowing-water aquaria. Using a behavioral catalog, we recorded their behavior sequences during randomly selected 5-min nighttime periods. For males and females, Jostle and Embrace were the most performed reproductive behaviors and the Jostle-Embrace-Carousel was the most performed reproductive behavior sequence. Water flow decreased the mean frequency of occurrence, percentage of time spent and mean event duration of male Nest Building. Because Neosho madtom courtship, reproduction and parental care is a complex and extended process, disturbances such as heightened river flows during the species' spawning season may negatively affect nest quality and reproductive success.

American Midland Naturalist↗
USGS2005

Laboratory agonistic interactions demonstrate failure of an introduced crayfish to dominate two imperiled endemic crayfishes

Following its introduction into the St. Francis River drainage, Missouri, U.S.A., the woodland crayfish, Orconectes hylas has expanded its range there; simultaneously populations of two imperiled endemic species, the Big Creek crayfish, O. peruncus, and the St. Francis River crayfish, O. quadruncus have declined therein. In seeking a basis for this decline, our study objective was to test whether the outcome of aggressive inter-specific interactions would favor O. hylas. We studied agonistic encounters between size-matched pairs of same-sex individuals of the introduced and the endemic species in a laboratory setting, first with juveniles and then with adults. Within each life stage, we conducted four sets of laboratory experiments, with approximately 20 trials in each set: (1) O. hylas males versus O. peruncus males, (2) O. hylas males versus O. quadruncus males, (3) O. hylas females versus O. peruncus females, and (4) O. hylas females versus O. quadruncus females. In addition, these same four experiment sets were repeated using larger adult O. hylas crayfish matched with smaller-sized adult endemics, mimicking the mismatch in adult sizes that occurs in the wild. Within each experiment, every trial was analysed to quantify the frequency of occurrence of three initiation behaviors and to determine the overall outcome of the trial. Results did not show O. hylas (juveniles or adults) to be behaviorally dominant over either endemic species. Orconectes hylas displayed the majority of one of the initiation behaviors significantly more often than did the endemic species in only two of the twelve experiments. Because direct aggressive interaction was not demonstrated to be the mechanism whereby O. peruncus and O. quadruncus are being replaced by O. hylas, other life history and ecological factors will require investigation. ?? Koninklijke Brill NV, 2005.

Crustaceana↗
USGS2004

Intra-strain dioxin sensitivity and morphometric effects in swim-up rainbow trout ( Oncorhynchus mykiss )

Inter and intra-specific differences in sensitivity of early life stage salmonids to 2,3,7,8-TCDD exposure have been reported, but intra-strain differences have not been found in the literature. Our results indicate that intra-strain variability in terms of embryo mortality (LD50) is small in Eagle Lake strain of rainbow trout, LD50 values ranging from 285 to 457 pg TCDD egg g −1 . These results confirm Eagle Lake as a less sensitive strain within rainbow trout, and do not indicate overlap with reported LD50 values for brook or lake trout. Our results also demonstrate that although generalized edema in regions including the yolk-sac are frequently associated with mortality following dioxin exposure, not all edematous fish die. We detected dose-dependent decreases in cranial length, eye diameter, mass, and total length ( P <0.05) in viable swim-up rainbow trout. These effects are presumed to indicate more subtle dose-dependent disruptions of the viteline vein vasculature and, therefore, in access to energy sources. A tendency for dose-dependent decrease in liver glycogen reserves concurred with previous results on salmonids and with the well described TCDD-induced alterations in intermediate metabolism of rats and chicken embryos (wasting syndrome). This syndrome could be contributing to the reduced growth that we observed.

Comparative Biochemistry and Physiology, Part C: T↗
USGS2003

Comparison of prehatch C-start responses in rainbow trout and lake trout embryos by means of a tactile stimulus test

The C-start in teleost fishes, a type of startle response, mediates the ability to respond to abrupt, unexpected stimuli and is characterized by a short-latency, C-type fast start acceleration. In prehatch fish embryos, the C-start appears necessary for mechanical breakdown of the egg chorion and successful hatching by way of increased embryo movement and distribution of the hatching enzymes. In later stages, the C-start plays an important role in predator avoidance. Using tactile stimulation, we evaluated the C-start response in rainbow trout Oncorhynchus mykiss at 170 degree-days, when 6.6% of embryos exhibited C-starts, and lake trout Salvelinus namaycush embryos at 320 degree-days, when 23% of embryos exhibited C-starts. Triplicate groups of embryos were later tested at three developmental stages: early (220 and 360 degree-days for rainbow trout and lake trout, respectively), middle (260 and 480 degree-days, respectively), and late (320 and 560 degree-days, respectively). The proportion of trout embryos exhibiting C-start increased through time, such that 100% had responded by the late stage, just prior to hatching. C-starts could be obtained by repeated stimulation, and the relative activity of the embryos (based on the number of flexures per stimulus) also increased over time. Rainbow trout and lake trout showed very similar C-start responses at parallel developmental stages, and these patterns of response were similar to those reported in other fish species.

Transactions of the American Fisheries Society↗
USGS2003

In ovo exposure to o,p -DDE affects sexual development but not sexual differentiation in Japanese medaka (Oryzias latipes).

Despite being banned in many countries, dichlorodiphenyltrichloroethane (DDT) and its metabolites dichlorodiphenyldichloroethylene (DDE) and dichlorodiphenyldichloroethane (DDD) continue to be found in fish tissues at concentrations of concern. Like o,p -DDT, o,p -DDE is estrogenic and is believed to exert its effects through binding to the estrogen receptor. The limited toxicologic data for o,p -DDE suggest that it decreases fecundity and fertility of fishes. We conducted an egg injection study using the d-rR strain of medaka and environmentally relevant concentrations of o,p -DDE to examine its effects on sexual differentiation and development. The gonads of exposed fish showed no evidence of sex reversal or intersex. However, other gonad abnormalities occurred in exposed individuals. Females exhibited few vitellogenic oocytes and increased atresia. Male testes appeared morphologically normal but were very small. Gonadosomatic index values for both sexes were lower for exposed fish. Our observations of abnormal female and very small male gonads after in ovo o,p -DDE exposure may be indicative of effects on early endocrine processes important for normal ovarian and testicular development.

Environmental Health Perspectives↗
USGS2002

Ontogenetic improvement of visual function in the medaka Oryzias latipes based on an optomotor testing system for larval and adult fish

We developed a system for evaluation of visual function in larval and adult fish. Both optomotor (swimming) and optokinetic (eye movement) responses were monitored and recorded using a system of rotating stripes. The system allowed manipulation of factors such as width of the stripes used, rotation speed of the striped drum, and light illuminance levels within both the scotopic and photopic ranges. Precise control of these factors allowed quantitative measurements of visual acuity and motion detection. Using this apparatus, we tested the hypothesis that significant posthatch ontogenetic improvements in visual function occur in the medaka Oryzias latipes , and also that this species shows significant in ovo neuronal development. Significant improvements in the acuity angle alpha (ability to discriminate detail) were observed from approximately 5 degrees at hatch to 1 degree in the oldest adult stages. In addition, we measured a significant improvement in flicker fusion thresholds (motion detection skills) between larval and adult life stages within both the scotopic and photopic ranges of light illuminance. Ranges of flicker fusion thresholds ( X ±SD) at log I=1.96 (photopic) varied from 37.2±1.6 cycles/s in young adults to 18.6±1.6 cycles/s in young larvae 10 days posthatch. At log I=−2.54 (scotopic), flicker fusion thresholds varied from 5.8±0.7 cycles/s in young adults to 1.7±0.4 cycles/s in young larvae 10 days posthatch. Light sensitivity increased approximately 2.9 log units from early hatched larval stages to adults. The demonstrated ontogenetic improvements in visual function probably enable the fish to explore new resources, thereby enlarging their fundamental niche.

Animal Behaviour↗