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Movement Patterns (movement + pattern)
Kinds of Movement Patterns Selected AbstractsInvestigation of hatching and early post-embryonic life of freshwater crayfish by in vitro culture, behavioral analysis, and light and electron microscopyJOURNAL OF MORPHOLOGY, Issue 7 2008Günter Vogt Abstract The late embryonic and early post-embryonic life period of freshwater crayfish, which is the main time period of organogenesis, is poorly investigated because of the protective brooding behavior of crayfish mothers. A combination of in vitro culture, behavioral observations, and microscopic investigations of organs involved in hatching, attachment, exploration of the environment, and searching and processing of food yielded deeper insights in this important period of life. Experiments were performed with the robust parthenogenetic marbled crayfish. The following results were obtained: (1) Marbled crayfish can be raised in simple in vitro systems from 80% embryonic development to juvenile Stage 4 with up to 100% survival; (2) Hatching is prepared by chemical weakening of the egg shell and completed by levering actions of the hatchling's appendages; (3) The telson thread, a safety line that keeps the hatchling secured to the mother, is formed by secretions from the telson and the detaching inner layer of the egg case; (4) Molting Stage-1 juveniles are secured by an anal thread that results from delayed molting of the hindgut; (5) Active attachment of the hatchlings to the maternal pleopods with their 1st pereiopods is achieved by an innate fixed action pattern; (6) In vitro, juveniles are motile from Stage 2 despite incomplete development of their balance controlling statocysts. Movement pattern and social behavior vary greatly among individuals; and (7) Feeding starts in Stage 3, when the mouthparts and the gastric mill are fully developed. Onset of feeding is innate and does not require maternal contributions. In vitro culture of the isogenic marbled crayfish is recommended for broader use in research because it enables not only time and stage-specific sampling but also precisely timed experimental manipulations. J. Morphol., 2008. © 2008 Wiley-Liss, Inc. [source] Movement of two grassland butterflies in the same habitat network: the role of adult resources and size of the study areaECOLOGICAL ENTOMOLOGY, Issue 2 2003Christine Schneider Abstract. 1., Movement patterns of two butterfly species (meadow brown Maniola jurtina L. and scarce copper Lycaenae virgaureae L.) were studied in a 172 ha area within a landscape with a high percentage of suitable habitats for mark,release,recapture experiments. 2., Adult resource density, but not patch size or larval food plant abundance, influenced the numbers and the fractions of residents, emigrants, and immigrants. 3., Differences between species were observed in movement frequency and maximum distances moved but not in mean distances moved. 4., The scarce copper showed much greater movement ability than expected from the results of published studies. This is believed to be a result of the comparatively large size of the study area and the high cover of suitable habitat (>50%). 5., The mean and maximum distances travelled by butterflies reflected differences in the size of the study area. [source] Lateral movement of common carp (Cyprinus carpio L.) in a large lowland river and floodplainECOLOGY OF FRESHWATER FISH, Issue 1 2009M. J. Jones Abstract,,, Common carp (Cyprinus carpio L.) are a major freshwater invader and knowledge of their movements is important for planning control efforts. To investigate the movement patterns of common carp, radio-tags were implanted into 46 adult fish; 37 near a large floodplain wetland, the Barmah-Millewa forest, and 9 in the Murray River approximately 175 km upstream. Tagged fish were located every second week between August 1999 and March 2001. Common carp occupied total linear ranges (TLR) between 0.4 and 238 km (mean 30 ± 61 km), with 25 fish (62.5%) occupying a TLR < 10 km. Two fish made large distance movements approximately 650 km downstream. Fish sex, the number of locations, time at large, or tagging location explained little variability (P > 0.05) in TLR. Monthly distance from release varied from 0.04 to 238 km (mean 15 ± 44 km), and was not significantly related to river discharge and water temperature, but 29 of 31 (93.5%) fish tagged at Barmah moved from the Murray River into adjacent floodplain habitats upon flooding. Five fish (12.5%) moved large distances (>127 km) upstream of the Barmah-Millewa forest. Fourteen fish (35%) showed site fidelity to within 20 m and usually occupied one or two home sites. Twenty-six fish (65%) showed site fidelity to within 100 m occupying up to five sites during the study period. Movement patterns of common carp were complex, and individuals exhibited different strategies, which is typical of invasive species. Efforts to control and potentially reduce common carp populations in regulated river-floodplain environments should target key floodplain access points and over-wintering habitats to reduce adult biomass, spawning and recruitment levels. [source] Movement patterns of endangered Roanoke logperch (Percina rex)ECOLOGY OF FRESHWATER FISH, Issue 3 2008J. H. Roberts Abstract,,, Using mark,recapture methods, we studied movements of endangered Roanoke logperch (Percina rex Jordan & Evermann), a benthic darter, at 12 riffle,run sites over a 9-year-long period in the Roanoke River, Virginia, USA. Our primary objective was to characterise movements among transects within sites, but we opportunistically recorded two between-site movements as well. Our recapture rate was low (22 of 485 marked fish), but most recaptured fish exhibited movements between tagging and recapture, relocating either to another transect within a site (12 fish) or to another site altogether (two fish). Within sites, Roanoke logperch exhibited fidelity over time to the areas in which they were initially marked. These restricted areas were lengthier than transects (>15 m) but shorter than entire riffle,runs (<150 m). The two between-site movements were extensive (3.2 and 2.5 km), observed over a long mark,recapture interval (2 and 5 years, respectively), and may have represented migratory or dispersal movements. Their detection required an unusually extensive study design. Both small- and large-scale movements fulfil important ecological functions for Roanoke logperch, and greater study of such movements in this and other darter species is needed to inform conservation choices. [source] Bigeye tuna (Thunnus obesus) vertical movements in the Azores Islands determined with pop-up satellite archival tagsFISHERIES OCEANOGRAPHY, Issue 2 2008H. ARRIZABALAGA Abstract Movement patterns of 17 bigeye tuna (Thunnus obesus) near the Azores Islands were analyzed between April and May 2001 and 2002 using pop-up satellite archival tags. Despite short attachment durations (1 to 21 days, 8.2 days on average), their vertical movements revealed much shallower distribution of bigeye tuna in comparison with previous studies in the tropical Pacific and tropical Atlantic. Depth and temperature histograms were unimodal, although overall depth distribution during the day was deeper than during the night due to daily incursions in deeper waters. Although generalized additive models showed significant non-linear relationships with weight of the fish and sea level anomaly (as a proxy for variability of thermocline depth), the effect of these variables on bigeye depth appeared minor, suggesting that vertical movements of bigeye in the Azores during the spring migration may be influenced by food availability in upper water layers. [source] Movement patterns of the round stingray Urobatis halleri(Cooper) near a thermal outfallJOURNAL OF FISH BIOLOGY, Issue 6 2006J. J. Vaudo Fine-scale movements and site fidelity of round stingrays Urobatis halleri at Seal Beach California, U.S.A., were examined using acoustic telemetry. Actively tracked fish generally exhibited limited nearshore movement, with greater distances travelled at night when the tide was ebbing than during the day with ebbing tides. Increases in round stingray activity were associated with increases in ambient temperature. Passively tracked fish showed seasonal patterns in their presence at Seal Beach. Males left Seal Beach during the autumn, returned the following spring, and remained in the area until the following autumn. Females spent far less time at Seal Beach, remaining in the area for a few weeks during June and July. Passively tracked round stingrays were recorded more often in the warm waters of the San Gabriel River mouth (the location of a thermal outfall from an electric-generating station) than adjacent beaches, with fish often returning to Seal Beach after periods of absence. Anthropogenic effects resulting from coastal development may have created environmental conditions (i.e. warmer water and finer sediments) that influence the movements and site fidelity of round stingrays. [source] Movement patterns and study area boundaries: influences on survival estimation in capture,mark,recapture studiesOIKOS, Issue 8 2008Gregg E. Horton The inability to account for the availability of individuals in the study area during capture,mark,recapture (CMR) studies and the resultant confounding of parameter estimates can make correct interpretation of CMR model parameter estimates difficult. Although important advances based on the Cormack,Jolly,Seber (CJS) model have resulted in estimators of true survival that work by unconfounding either death or recapture probability from availability for capture in the study area, these methods rely on the researcher's ability to select a method that is correctly matched to emigration patterns in the population. If incorrect assumptions regarding site fidelity (non-movement) are made, it may be difficult or impossible as well as costly to change the study design once the incorrect assumption is discovered. Subtleties in characteristics of movement (e.g. life history-dependent emigration, nomads vs territory holders) can lead to mixtures in the probability of being available for capture among members of the same population. The result of these mixtures may be only a partial unconfounding of emigration from other CMR model parameters. Biologically-based differences in individual movement can combine with constraints on study design to further complicate the problem. Because of the intricacies of movement and its interaction with other parameters in CMR models, quantification of and solutions to these problems are needed. Based on our work with stream-dwelling populations of Atlantic salmon Salmo salar, we used a simulation approach to evaluate existing CMR models under various mixtures of movement probabilities. The Barker joint data model provided unbiased estimates of true survival under all conditions tested. The CJS and robust design models provided similarly unbiased estimates of true survival but only when emigration information could be incorporated directly into individual encounter histories. For the robust design model, Markovian emigration (future availability for capture depends on an individual's current location) was a difficult emigration pattern to detect unless survival and especially recapture probability were high. Additionally, when local movement was high relative to study area boundaries and movement became more diffuse (e.g. a random walk), local movement and permanent emigration were difficult to distinguish and had consequences for correctly interpreting the survival parameter being estimated (apparent survival vs true survival). [source] Mammal mycophagy and fungal spore dispersal across a steep environmental gradient in eastern AustraliaAUSTRAL ECOLOGY, Issue 1 2009KARL VERNES Abstract We examined changes in the types of fungi consumed by six species of small mammals across a habitat gradient in north-eastern New South Wales that graded from swamp, to woodland, to open forest and then to rainforest. All mammals ate some fungus, but only bush rats (Rattus fuscipes) regularly did so, and their diet included most of the fungal taxa that we identified across all mammals in the study. The composition of bush rat diet changed significantly with each change in habitat from woodland, to forest, to rainforest. In particular, there was a significant difference in the diets of rats caught either side of the open forest-rainforest ecotone, which marks the change in fungal community from one dominated by ectomycorrhizal fungi, to a community dominated by arbuscular mycorrhizal fungi. Movement patterns of bush rats living around the open forest-rainforest ecotone suggest that they transport fungal spores between these contrasting fungal communities. Therefore, bush rats have the potential, by way of spore dispersal, to influence the structure of vegetation communities. [source] Perceptual organization of motions in pigeons (Columba livia)1JAPANESE PSYCHOLOGICAL RESEARCH, Issue 3 2004TOMOKAZU USHITANI Abstract:, We investigated whether pigeons perceived relative motion of more than one object. We trained pigeons to match a white target dot moving vertically at a constant speed to one color and the same dot moving diagonally to another. In Experiment 1, we presented an additional yellow dot (accompanying dot) moving horizontally near the target. We hypothesized that the pigeons would match the diagonal motion to the color for "vertical motion" and vice versa if they perceived relative motion of the target and the accompanying dot. We reduced the size and the speed of the stimuli by half in Experiment 2 and changed the movement pattern of the target to a sine-function in Experiment 3. In Experiment 4, we presented two accompanying dots. However, the results of Experiments 1 to 4 showed no evidence that pigeons perceived relative motion. In Experiment 5, we substituted a moving frame for accompanying dots. The pigeons tended to respond to the color corresponding to the relative motion. These results suggest that pigeons may organize a set of moving objects as one object moving relative to the other in some stimulus displays in which the second object constitutes an explicit reference frame. [source] Changes in swimming depths of Atlantic salmon Salmo salar post-smolts relative to light intensityJOURNAL OF FISH BIOLOGY, Issue 4 2008J. G. Davidsen Eight hatchery-reared Atlantic salmon Salmo salar post-smolts, implanted with acoustic depth sensing transmitters and manually tracked for 5,12 h in the Hardangerfjord (Norway), spent most of their time (49,99%) at 1,3 m depth during the day, whereas four of seven fish tracked were found close (<0·5 m) to the surface at night, with a strong negative cross-correlation between general swimming depth and surface light intensity. Hence, the actual swimming depth of post-smolts during their early marine migration may depend on the light conditions, although the individual variation in vertical movement pattern was large. No cross-correlations were found between light intensity and swimming depth during daytime periods with rapid changes in light intensity, indicating that other factors than light intensity were important in initiating the irregular dives that were recorded down to 6·5 m depth. [source] Adaptations to humeral torsion in medieval BritainAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 2 2006Jill A. Rhodes Abstract Adaptations to the humeral torsion angle have been identified in the professional throwing athlete. This movement pattern increases the humeral torsion angle, and also increases the extent of external rotation movements in the dominant, throwing limb when compared with the nondominant limb. The purpose of this paper is to test the hypothesis that the humeral torsion angle is an adaptation to upper limb use. This project examines the humeral torsion angle in a number of medieval British populations, as well as a modern cadaver-based sample. The results identify significant differences in the humeral torsion angle both between and within male (P < 0.001, ANOVA) and female (P < 0.014, ANOVA) populations, although the results are not consistent with expected behavior patterns. Statistically significant differences between males and females within the same site were identified in 2 of the 5 samples examined. The mean level of bilateral asymmetry does not approach that reported for the professional throwing athlete. However, a number of individuals have high levels of asymmetry in excess of that identified in the professional throwing athlete. This analysis demonstrates the need for individual rather than population-based analyses, as the heterogeneity within population samples obscures individual variation in activity patterns. The diversity within British medieval society and a lack of specific known behaviors prevent further identification of the functional significance of the humeral torsion angle within the archaeological record examined here. Am J Phys Anthropol, 2006. © 2005 Wiley-Liss, Inc. [source] Eye movements in German-speaking children with and without dyslexia when reading aloudACTA OPHTHALMOLOGICA, Issue 6 2010Susanne Trauzettel-Klosinski Acta Ophthalmol. 2010: 88: 681,691 Abstract. Purpose:, The phonological difficulty and orthographic regularity of a language influence reading strategies. Only a few studies have been conducted in readers of German, which has a high grapheme,phoneme correspondence. The aim of this study was to investigate, firstly, the influence of different levels of phonological difficulty of reading material in German on reading in children and, secondly, to compare the reading strategies of German children with findings in English-speaking readers. Methods:, Eye movements in 16 German children with dyslexia and 16 age-matched control children (mean age 9.5 ± 0.35 years) in the third and fourth grades of school were recorded by scanning laser ophthalmoscope while they read aloud two texts of differing levels of difficulty. Results:, In the dyslexia group, reading speed was slowed, and the number of saccades and regressions was raised markedly, although the percentage of regressions only slightly. The number of eye movements increased in both groups with increasing text difficulty, although much more in the dyslexia group than in the control group, whereas fixation duration was not influenced. Conclusions:, Phonological difficulty influences reading speed and eye movement pattern: children with dyslexia markedly increase their number of eye movements and analyse the text in smaller units per fixation, but keep fixation duration constant. This strategy reflects their favouring of the indirect, sublexical route of grapheme,phoneme conversion, whereas readers of English-language texts are more likely to prefer the whole-word approach, i.e. the direct, lexical route that is associated with orthographic memory. [source] Validity of ,post-traumatic stress disorder with secondary psychotic features': a review of the evidenceACTA PSYCHIATRICA SCANDINAVICA, Issue 1 2009M. H. Braakman Objective:, To review the evidence from empirical studies regarding the validity of ,post-traumatic stress disorder with secondary psychotic features' (PTSD-SP) as a separate diagnostic entity. Method:, The authors performed a review tracing publications between 1980 and January 2008. Results:, Twenty-four comparative studies were included. These studies indicate that PTSD-SP is a syndrome that comprises PTSD-symptoms followed in time by the additional appearance of psychotic features. The psychotic features are not confined to episodes of re-experiencing, but remain present continuously. PTSD-SP seems to have some biological features differentiating it from schizophrenia and PTSD, e.g. there are differences in smooth pursuit eye movement patterns, concentrations of corticotropin-releasing factor and dopamine ,-hydroxylase activity. Conclusion:, There is currently not yet full support for PTSD-SP as a nosological entity. However, the delineation of PTSD-SP from other psychiatric syndromes is notable and biological studies seem to support the validity as a separate diagnostic entity. [source] Short-term plasticity in children's speech motor systemsDEVELOPMENTAL PSYCHOBIOLOGY, Issue 8 2006Bridget Walsh Abstract Speech production is a highly skilled behavior that requires rapid and coordinated movements of the orofacial articulators. Previous studies of speech development have shown that children have more variable articulatory movements compared to adults, and cross-sectional studies have revealed that a gradual transition to more stable movement patterns occurs with age. The focus of the present investigation is on the potential role of short-term changes in speech motor performance related to practice. Thus we developed a paradigm to examine the influences of phonological complexity and practice on children (9 and 10-year-olds) and adults' production of novel nonwords. Using two indices that reflect the degree of trial-to-trial consistency of articulatory movements, we analyzed the first and last five productions of the novel nonwords. Both children and adults accurately produced the novel nonwords; however, children showed a practice effect; their last five trials were more consistently produced than their first five trials. Adults did not show this practice effect. This study provides new evidence that children show short-term changes in their speech coordinative patterns with practice. In addition, the present findings support the contribution of neuromotor noise or background, inherent variability to speech motor development. © 2006 Wiley Periodicals, Inc. Dev Psychobiol 48: 660,674, 2006. [source] Human fetal and neonatal movement patterns: Gender differences and fetal-to-neonatal continuityDEVELOPMENTAL PSYCHOBIOLOGY, Issue 4 2001C. Robert Almli Abstract Longitudinal quantification of leg movements per minute for human subjects during both fetal and neonatal periods was accomplished from videotapings conducted antenatally (ultrasonography 30, 34, and 37 weeks gestational age) and postnatally (birth and 6 weeks of age). Fetal/neonatal subjects displayed decreasing numbers of leg movements per minute during antenatal development (30 to 37 weeks), followed by increasing numbers of leg movements per minute during postnatal development (birth to 6 weeks of age). Male subjects displayed greater numbers of leg movements per minute than female subjects during both antenatal and postnatal development. Fetal-to-neonatal continuity for numbers of leg movements per minute was found for comparisons between fetal (37 weeks gestational age) and neonatal (during sleep states at birth) measures, and females displayed a stronger and different movement continuity pattern than males. These results indicate a differential time course for neurobehavioral development of male and female fetuses/neonates, and the findings have implications for the clinical assessment of fetal neurobehavioral development and well-being. © 2001 John Wiley & Sons, Inc. Dev Psychobiol 38: 252,273, 2001 [source] Survival, movement, and resource use of the butterfly Parnassius clodiusECOLOGICAL ENTOMOLOGY, Issue 2 2004Julia N. Auckland Abstract., 1. A mark,recapture study was conducted on the American Apollo butterfly Parnassius clodius Menetries during three field seasons (1998,2000) to examine its movement patterns over the course of a season within a sagebrush meadow in Grand Teton National Park, Wyoming, U.S.A. The study examined how resources affected butterfly distribution patterns and used mark,recapture data to gain insight into movement differences between sexes and over time. 2. The average straight-line movement of P. clodius was 202 m day,1, adjusted for sampling effort at different distances. Movement estimates in all 3 years were highly correlated with the average distance between plots sampled. 3. Butterfly abundance was correlated positively with per cent cover of its host plant Dicentra uniflora, but this relationship decreased in importance during the peak of the flight period when individuals may be more interested in finding mates. There was a weak, positive correlation between butterfly abundance and the abundance of its primary nectar source, Eriogonum umbellatum in 1999, but no relationship in 2000. 4. Survival, recapture, and transition probabilities were estimated using open population, capture,recapture models. Survival and recapture probability decreased over the course of each season, while the probability of moving between plots increased. Recapture probability was significantly lower for females than for males among all 3 years, but there was no difference between the sexes in survival rate. [source] Associations between host migration and the prevalence of a protozoan parasite in natural populations of adult monarch butterfliesECOLOGICAL ENTOMOLOGY, Issue 2 2000Sonia M. Altizer Summary 1. Monarch butterflies Danaus plexippus (L.) (Lepidoptera: Nymphalidae) are susceptible to infection by the obligate protozoan parasite Ophryocystis elektroscirrha (McLaughlin and Myers) (Apicomplexa: Neogregarinida). Because monarchs form resident and migratory populations in different parts of the world, this host,parasite system provides the opportunity to examine how variation in parasite prevalence relates to host movement patterns. 2. Parasite prevalence was evaluated using 14 790 adult monarchs captured between 1968 and 1997. Comparison of three populations in North America indicated that parasite prevalence is associated negatively with host dispersal distances. A continuously breeding, nonmigratory population in southern Florida showed high prevalence (over 70% heavily infected). The western population migrates moderate distances to overwintering sites on the Pacific Coast and has intermediate prevalence (30% heavily infected). The eastern migratory population, which travels the longest distance to Mexican overwintering sites, has exhibited less than 8% infection throughout the past 30 years. 3. Variation in parasite loads within North American migratory populations was investigated to determine whether the prevalence of heavy infection and average parasite loads declined during migration or overwintering. Average parasite loads of summer-breeding adults in western North America decreased with increasing distance from overwintering sites. This suggests that heavily infected monarchs are less likely to remigrate long distances in spring. No differences in the frequency of heavily infected adults were found among eastern or western North American monarchs throughout the overwintering period, however, suggesting that this parasite does not affect overwintering mortality. 4. Changes in the prevalence of monarchs with low parasite loads demonstrate that spore transfer occurs during migration and overwintering, possibly when adult butterflies contact each other as a result of their clustering behaviour. 5. This study of geographical and temporal variation in O. elektroscirrha among populations of D. plexippus demonstrates the potential role of seasonal migration in mediating interactions between hosts and parasites, and suggests several mechanisms through which migratory behaviour may influence parasite prevalence. [source] Informed dispersal, heterogeneity in animal dispersal syndromes and the dynamics of spatially structured populationsECOLOGY LETTERS, Issue 3 2009Jean Clobert Abstract There is accumulating evidence that individuals leave their natal area and select a breeding habitat non-randomly by relying upon information about their natal and future breeding environments. This variation in dispersal is not only based on external information (condition dependence) but also depends upon the internal state of individuals (phenotype dependence). As a consequence, not all dispersers are of the same quality or search for the same habitats. In addition, the individual's state is characterized by morphological, physiological or behavioural attributes that might themselves serve as a cue altering the habitat choice of conspecifics. These combined effects of internal and external information have the potential to generate complex movement patterns and could influence population dynamics and colonization processes. Here, we highlight three particular processes that link condition-dependent dispersal, phenotype-dependent dispersal and habitat choice strategies: (1) the relationship between the cause of departure and the dispersers' phenotype; (2) the relationship between the cause of departure and the settlement behaviour and (3) the concept of informed dispersal, where individuals gather and transfer information before and during their movements through the landscape. We review the empirical evidence for these processes with a special emphasis on vertebrate and arthropod model systems, and present case studies that have quantified the impacts of these processes on spatially structured population dynamics. We also discuss recent literature providing strong evidence that individual variation in dispersal has an important impact on both reinforcement and colonization success and therefore must be taken into account when predicting ecological responses to global warming and habitat fragmentation. [source] Lateral movement of common carp (Cyprinus carpio L.) in a large lowland river and floodplainECOLOGY OF FRESHWATER FISH, Issue 1 2009M. J. Jones Abstract,,, Common carp (Cyprinus carpio L.) are a major freshwater invader and knowledge of their movements is important for planning control efforts. To investigate the movement patterns of common carp, radio-tags were implanted into 46 adult fish; 37 near a large floodplain wetland, the Barmah-Millewa forest, and 9 in the Murray River approximately 175 km upstream. Tagged fish were located every second week between August 1999 and March 2001. Common carp occupied total linear ranges (TLR) between 0.4 and 238 km (mean 30 ± 61 km), with 25 fish (62.5%) occupying a TLR < 10 km. Two fish made large distance movements approximately 650 km downstream. Fish sex, the number of locations, time at large, or tagging location explained little variability (P > 0.05) in TLR. Monthly distance from release varied from 0.04 to 238 km (mean 15 ± 44 km), and was not significantly related to river discharge and water temperature, but 29 of 31 (93.5%) fish tagged at Barmah moved from the Murray River into adjacent floodplain habitats upon flooding. Five fish (12.5%) moved large distances (>127 km) upstream of the Barmah-Millewa forest. Fourteen fish (35%) showed site fidelity to within 20 m and usually occupied one or two home sites. Twenty-six fish (65%) showed site fidelity to within 100 m occupying up to five sites during the study period. Movement patterns of common carp were complex, and individuals exhibited different strategies, which is typical of invasive species. Efforts to control and potentially reduce common carp populations in regulated river-floodplain environments should target key floodplain access points and over-wintering habitats to reduce adult biomass, spawning and recruitment levels. [source] Movements and habitat use of common carp (Cyprinus carpio) and Murray cod (Maccullochella peelii peelii) juveniles in a large lowland Australian riverECOLOGY OF FRESHWATER FISH, Issue 2 2007M. J. Jones Abstract,,, Native Murray cod (Maccullochella peelii peelii) are listed as a nationally vulnerable species, whereas non-native common carp (Cyprinus carpio) are widespread and abundant. Understanding key aspects of life history, such as movement patterns and habitat selection by juvenile Murray cod and common carp, might be useful for conserving Murray cod populations and controlling common carp numbers. We used radio-telemetry to track eight juvenile Murray cod and seven juvenile common carp in the Murray River, Australia, between March and July 2001. Common carp occupied a significantly greater total linear range (mean ± SD: 1721 ± 1118 m) than Murray cod (mean ± SD: 318 ± 345 m) and the average daily movement was significantly greater for common carp (mean ± SD: 147 ± 238 m) than for Murray cod (mean ± SD: 15 ± 55 m). All Murray cod and five of the seven common carp displayed site fidelity or residency to one, two or three locations. Murray cod were found only in the mainstream Murray River among submerged woody habitats, whereas common carp occurred equally in mainstream and offstream areas, and among submerged wood and aquatic vegetation. Murray cod were found in deeper (mean ± SD: 2.3 ± 0.78 m) and faster waters (mean ± SD: 0.56 ± 0.25 m·s,1) compared with common carp (mean ± SD: 1 ± 0.54 m; 0.08 ± 0.09 m·s,1) respectively. The presence of juvenile Murray cod only amongst submerged wood is an indication that these habitats are important and should be preserved. Conversely, juvenile common carp were equally present among all habitats sampled, suggesting that habitat selection is less specific, possibly contributing to their widespread success. [source] Testing the ability of habitat selection theory to predict interannual movement patterns of a drift-feeding salmonidECOLOGY OF FRESHWATER FISH, Issue 1-2 2000N. F. Hughes Abstract , This article extends the logic of a habitat selection model (Hughes, Ecology, 1998) to make predictions about the way body size will influence the probability that fish will make a long distance interannual movement, from the feeding position it occupies in one summer to the position it occupies the next. The model predicts that the probability of this kind of movement will fall as fish grow and reach zero for the largest fish in the population. I tested these predictions using data on Arctic grayling Thymallus arcticus in the lower 140 km of a 260-km-long interior Alaskan river. Both predictions of the model were well supported by the data. As expected, the probability a fish will make a long-distance interannual movement decreased with fish size, and the largest fish in the population had a movement probability of zero., [source] Evaluation of the effects of catch-and-release angling on the Atlantic salmon (Salmo salar) of the Ponoi River, Kola Peninsula, Russian FederationECOLOGY OF FRESHWATER FISH, Issue 1-2 2000F. G. Whoriskey Abstract , We studied the effects of catch-and-release fishing upon the Ponoi River's Atlantic salmon populations. The Ponoi River is located on the Kola Peninsula of the Russian Federation, and has recently been developed for sports fishing. Angler exploitation rates are estimated to range from 10.4% to 19% of the river's salmon, thus the possibility of significant levels of post-release mortality is of concern. We radio-tracked fish caught and released by anglers in 1995 and 1996. Despite our simple equipment and the large size of the river, we were able to relocate most fish. These fish had high rates of survival, and anglers recaptured about 11% of them per year a second time. This is very similar to the recapture rates observed for Floy-tagged fish released in an angler-based mark-recapture assessment. We also held 62 angled fish for 24 hours in a live cage to evaluate rates of delayed mortality. Only one of the 62 fish died, and it was heavily scarred with gillnet marks. Most fish that are fatally stressed by angling die within 24 h (e.g., Booth et al. 1995). In 1996, up to 10% of our Floy-tagged fish were angled and released twice, and about 0.5% were angled and released three times. No significant biases were detected in the post-angling movement patterns of these fish. The multiple captures and lack of movement bias suggest that fish behavior was little altered by the angling experience. Nine fish Floy tagged prior to spawning have been recovered as typical emaciated kelts. Three were killed, and a post mortem exam showed all had spawned. Parr numbers at all monitored sites have been steadily increasing since the advent of catch-and-release fishing. By contrast, parr growth rates are generally unchanged or significantly better., [source] Evidence for functional compartmentalization of trigeminal muscle spindle afferents during fictive mastication in the rabbitEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 4 2000K. -G. Abstract Primary afferent neurons innervating muscle spindles in jaw-closing muscles have cell bodies in the trigeminal mesencephalic nucleus (NVmes) that are electrically coupled and receive synapses. Each stem axon gives rise to a peripheral branch and a descending central branch. It was previously shown that some spikes generated by constant muscle stretch fail to enter the soma during fictive mastication. The present study examines whether the central axon is similarly controlled. These axons were functionally identified in anaesthetized and paralysed rabbits, and tonic afferent firing was elicited by muscle stretch. For the purpose of comparison, responses were recorded extracellularly both from the somatic region and from the central axon in the lateral brainstem. Two types of fictive masticatory movement patterns were induced by repetitive stimulation of the masticatory cortex and monitored from the trigeminal motor nucleus. Field potentials generated by spike-triggered averaging of action potentials from the spindle afferents were employed to determine their postsynaptic effects on jaw-closing motoneurons. Tonic firing of 32% NVmes units was inhibited during the jaw-opening phase, but spike frequency during closing was almost equal to the control rate during both types of fictive mastication. A similar inhibition occurred during opening in 83% of the units recorded along the central branch. However, firing frequency in these was significantly increased during closing in 94%, probably because of the addition of antidromic action potentials generated by presynaptic depolarization of terminals of the central branch. These additional spikes do not reach the soma, but do appear to excite motoneurons. The data also show that the duration and/or frequency of firing during the bursts varied from one pattern of fictive mastication to another. We conclude that the central axons of trigeminal muscle spindle afferents are functionally decoupled from their stem axons during the jaw-closing phase of mastication. During this phase, it appears that antidromic impulses in the central axons provide one of the inputs from the masticatory central pattern generator (CPG) to trigeminal motoneurons. [source] Do male and female black-backed woodpeckers respond differently to gaps in habitat?EVOLUTIONARY APPLICATIONS (ELECTRONIC), Issue 3 2010Jennifer C. Pierson Abstract We used population- and individual-based genetic approaches to assess barriers to movement in black-backed woodpeckers (Picoides arcticus), a fire-specialist that mainly occupies the boreal forest in North America. We tested if male and female woodpeckers exhibited the same movement patterns using both spatially implicit and explicit genetic analyses to define population structure and movement patterns of both sexes among populations. Three genetic groups were identified, a large, genetically continuous population that spans from the Rocky Mountains to Quebec, a small isolated population in South Dakota and a separate population in the western portion of their distribution (Oregon). Patterns of genetic diversity suggest extensive gene flow mediated by both males and females within the continuous boreal forest. However, male-mediated gene flow is the main form of connectivity between the continuously distributed group and the smaller populations of South Dakota and Oregon that are separated by large areas of unforested habitat, which apparently serves as a barrier to movement of female woodpeckers. [source] Angler awareness of aquatic nuisance species and potential transport mechanismsFISHERIES MANAGEMENT & ECOLOGY, Issue 6 2009K. K. GATES Abstract, The role anglers play in transporting aquatic nuisance species (ANS) is important in managing infestations and preventing introductions. The objectives of this study were to: (1) quantify angler movement patterns in southwestern Montana, ANS awareness and equipment cleaning practices; and (2) quantify the amount of soil transported on boots and waders. Mean distance travelled by residents from their home to the survey site was 115 km (±17, 95% CI). Mean distance travelled by non-residents was 1738 km (±74). Fifty-one percent of residents and 49% of non-residents reported occasionally, rarely or never cleaning their boots and waders between uses. Mean weight of soil carried on one boot leg was 8.39 g (±1.50). Movement and equipment cleaning practices of anglers in southwestern Montana suggest that future control of ANS dispersal may require restricting the use of felt-soled wading boots, requiring river-specific wading equipment or providing cleaning stations and requiring their use. [source] Age-related movement patterns and population structuring in southern garfish, Hyporhamphus melanochir, inferred from otolith chemistryFISHERIES MANAGEMENT & ECOLOGY, Issue 4 2009M. A. STEER Abstract, The southern garfish, Hyporhamphus melanochir (Val.), is an important inshore fishery species in South Australia. Over the past few years there have been concerns with this fishery, which is now considered to be over-exploited. Currently, the fishery is assumed to consist of two separate stocks, but there is no understanding of movement patterns both within and between these two stocks to justify this assumption. Otolith chemistry was used to infer age-related patterns of movement, delineate potential sub-populations and determine the extent of mixing within South Australian coastal waters. Results indicated that the population structuring of garfish is more complex than previously assumed and it seems that stocks can be discriminated at a much finer spatial scale. Garfish collected from sites separated by <60 km displayed significantly different chemical signatures (relative concentrations of 7Li, 24Mg, 55Mn, 88Sr and 138Ba) in their otoliths, especially during their second year of growth, indicating that they had inhabited different water bodies. From a broader perspective, South Australian garfish can be partitioned into six regional components with various levels of inter-mixing. From these results, it was suggested that assessment and management of the fishery may have to be restructured to align with the smaller spatial units. [source] Growth and movement patterns of early juvenile European anchovy (Engraulis encrasicolus L.) in the Bay of Biscay based on otolith microstructure and chemistryFISHERIES OCEANOGRAPHY, Issue 3 2010NAROA ALDANONDO Abstract Various hypotheses have been put forward to explain the mechanisms in the Bay of Biscay that result in a good recruitment of European anchovy. Anchovy larvae from the spawning area in the Gironde River plume are advected towards off-shelf waters, where juveniles are commonly observed. Otolith microstructural and chemical analysis were combined to assess the importance of this off-shelf transport and to determine the relative contribution of these areas for anchovy survival. Chemical analysis of otoliths showed that anchovy juveniles in the Bay of Biscay can be divided into two groups: a group that drifts towards off-shelf waters early in their life and returns later, and a group that remains in the low salinity waters of the coastal area. The first group presents significantly faster growth rates (0.88 mm day,1) than those remaining in the coastal waters (0.32 mm day,1). This may be due to off-shelf waters being warmer in spring/summer, and to the fact that the lower food concentration is compensated for by higher prey visibility. Furthermore, the group of juveniles that drifted off the spawning area and had faster growth rates represents 99% of the juvenile population. These findings support the hypothesis that anchovy in the Bay of Biscay may use off-shelf waters as a spatio-temporal loophole, suggesting that transport off the shelf may be favourable for recruitment. [source] Horizontal and vertical movements of juvenile bluefin tuna (Thunnus orientalis) in relation to seasons and oceanographic conditions in the eastern Pacific OceanFISHERIES OCEANOGRAPHY, Issue 5 2007TAKASHI KITAGAWA Abstract Electronically tagged juvenile Pacific bluefin, Thunnus orientalis, were released off Baja California in the summer of 2002. Time-series data were analyzed for 18 fish that provided a record of 380 ± 120 days (mean ± SD) of ambient water and peritoneal cavity temperatures at 120 s intervals. Geolocations of tagged fish were estimated based on light-based longitude and sea surface temperature-based latitude algorithms. The horizontal and vertical movement patterns of Pacific bluefin were examined in relation to oceanographic conditions and the occurrence of feeding events inferred from thermal fluctuations in the peritoneal cavity. In summer, fish were located primarily in the Southern California Bight and over the continental shelf of Baja California, where juvenile Pacific bluefin use the top of the water column, undertaking occasional, brief forays to depths below the thermocline. In autumn, bluefin migrated north to the waters off the Central California coast when thermal fronts form as the result of weakened equatorward wind stress. An examination of ambient and peritoneal temperatures revealed that bluefin tuna fed during this period along the frontal boundaries. In mid-winter, the bluefin returned to the Southern California Bight possibly because of strong downwelling and depletion of prey species off the Central California waters. The elevation of the mean peritoneal cavity temperature above the mean ambient water temperature increased as ambient water temperature decreased. The ability of juvenile bluefin tuna to maintain a thermal excess of 10°C occurred at ambient temperatures of 11,14°C when the fish were off the Central California coast. This suggests that the bluefin maintain peritoneal temperature by increasing heat conservation and possibly by increasing internal heat production when in cooler waters. For all of the Pacific bluefin tuna, there was a significant correlation between their mean nighttime depth and the visible disk area of the moon. [source] Vertical movements of bigeye tuna (Thunnus obesus) associated with islands, buoys, and seamounts near the main Hawaiian Islands from archival tagging dataFISHERIES OCEANOGRAPHY, Issue 3 2003Michael K. Musyl Abstract To learn more about the movement patterns of bigeye tuna (Thunnus obesus), we deployed archival tags on 87 fish ranging in fork length from 50 to 154 cm. Thirteen fish were recaptured, from which 11 archival tags were returned, representing in aggregate 943 days-at-liberty. We successfully retrieved data from 10 tags, representing 474 days in aggregate. The largest fish recaptured was 44.5 kg [131 cm fork length (FL)] and the smallest 2.8 kg (52 cm). The deepest descent recorded was 817 m, the coldest temperature visited 4.7°C, and minimum oxygen level reached ,1 mL L,1. Fish spent little time at depths where water temperatures were below 7°C and oxygen levels less than ,2 mL L,1. Five fish were recaptured near the offshore weather buoy where they were tagged. Based on vertical movement patterns, it appeared that all stayed immediately associated with the buoy for up to 34 days. During this time they remained primarily in the uniform temperature surface layer (i.e. above 100 m). In contrast, fish not associated with a floating object showed the W-shaped vertical movement patterns during the day characteristic of bigeye tuna (i.e. descending to ,300,500 m and then returning regularly to the surface layer). Four fish were tagged and subsequently recaptured near Cross Seamount up to 76 days later. These fish exhibited vertical movement patterns similar to, but less regular than, those of fish not associated with any structure. Bigeye tuna appear to follow the diel vertical movements of the deep sound scattering layer (SSL) organisms and thus to exploit them effectively as a prey resource. Average night-time depth was correlated with lunar illumination, a behaviour which mimics movements of the SSL. [source] Disturbance history influences the distribution of stream invertebrates by altering microhabitat parameters: a field experimentFRESHWATER BIOLOGY, Issue 5 2008MICHAEL EFFENBERGER Summary 1. We investigated the effects of local disturbance history and several biotic and abiotic habitat parameters on the microdistribution of benthic invertebrates after an experimental disturbance in a flood-prone German stream. 2. Bed movement patterns during a moderate flood were simulated by scouring and filling stream bed patches (area 0.49 m2) to a depth of 15,20 cm. Invertebrates were investigated using ceramic tiles as standardized substrata. After 1, 8, 22, 29, 36 and 50 days, we sampled one tile from each of 16 replicates of three bed stability treatments (scour, fill and stable controls). For each tile, we also determined water depth, near-bed current velocity, the grain size of the substratum beneath the tile, epilithic algal biomass and standing stock of particulate organic matter (POM). 3. Shortly after disturbance, total invertebrate density, taxon richness and density of the common taxa Baetis spp. and Chironomidae were highest in stable patches. Several weeks after disturbance, by contrast, Baetis spp. and Hydropsychidae were most common in fill and Leuctra spp. in scour patches. The black fly Simulium spp. was most abundant in fill patches from the first day onwards. Community evenness was highest in scour patches during the entire study. 4. Local disturbance history also influenced algal biomass and POM standing stock at the beginning of the experiment, and water depth, current velocity and substratum grain size throughout the experiment. Scouring mainly exposed finer substrata and caused local depressions in the stream bed characterized by slower near-bed current velocity. Algal biomass was higher in stable and scour patches and POM was highest in scour patches. In turn, all five common invertebrate taxa were frequently correlated with one or two of these habitat parameters. 5. Our results suggest that several ,direct' initial effects of local disturbance history on the invertebrates were subsequently replaced by ,indirect' effects of disturbance history (via disturbance-induced changes in habitat parameters such as current velocity or food). [source] | ||||||||||||||||||||||||||||||||||||||||