Search results for "juvenile"
showing 10 items of 366 documents
Diel feeding periodicity, daily ration and prey selectivity in juvenile brown trout in a subarctic river
1999
Feeding of age-1 brown trout Salmo trutta in a third-order river in northern Finland was usually highest in the twilight hours and lowest around midday. Diel periodicity in food intake was less distinct and rarely significant for age-0 trout. Daily rations declined seasonally, being lowest in October, and highest in June (age-1 trout) or early August (age-0 trout). Prey selection did not differ between day and night, but differences between age classes and sampling dates were distinct. Age-0 trout preferred Ephemerella nymphs in summer and Micrasema larvae later in the season. Age-1 trout fed selectively on caddis larvae on all sample dates. Aerial insects and Baetis nymphs were avoided by …
Low frequencies noise effects on behaviour of Sparus aurata juveniles
2019
Human activities in the oceans, such as marine traffic and Deep Sea Mining (DSM), are increasing in the last years (Ross 2005; Calvo et al 2016). Underwater noise in the oceans, especially at lower frequencies, is mainly produced by marine traffic and DSM could increase this noise in the next future. Marine Strategy Framework Directive promotes the achievement of a good quality environmental status and aims to monitor “continuous low frequency sound” trend in the ambient noise level within the 1/3 octave bands centred at 63 and 125 Hz. The aim of this study is to evaluate the behavioural changes of Sparus aurata juveniles exposed to a four different acoustic signals in a tank. The emitted s…
Longer wavelengths of light improve the growth, intake and feed efficiency of individually reared juvenile pikeperchSander lucioperca(L.)
2009
We tested the effects of monochromatic light on the specific growth rate (SGR), feed intake and feed efficiency (FE) of juvenile pikeperch, Sander lucioperca (L.). Pikeperch were reared individually for 42 days in aquaria covered with blue, green, yellow or red gelatin filters or white paper (control; n=5). Linear regression analysis indicated a significant positive effect of longer wavelengths of light on the condition factor (CF), FE and SGR. The final weight, SGR and CF were significantly higher in fish reared under red than under white light, and FE was better under green, yellow and red light than under white light (Dunnett's post hoc test, P<0.05) while blue was comparable to white li…
Cohort-Dependent Sex Ratio Biases in the American Crocodiles (Crocodylus acutus)of the Tempisque Basin
2015
A male-biased sex ratio of 3:1 has been reported for a population of American crocodiles (Crocodylus acutus) in the Tempisque River Basin, Guanacaste, Costa Rica. If confirmed, this would constitute one of the largest male-biased sex ratios reported for any population of a member of the genus Crocodylus. Here, we examine the aforementioned population of C. acutus and report on sex ratios of hatchling, juvenile, and adult age classes within a sample of 474 crocodiles captured in the Tempisque Basin between May 2012 and June 2014. Hatchling sex ratio is exceptionally male biased (3.5:1), an imbalance that is maintained in juveniles but is reduced in adults (1.5:1). Mark–recapture data documen…
The Body Size of Headstarted and Wild Juvenile European Pond Turtles (<i>Emys orbicularis</i>)
2017
Headstarting is a popular conservation technique in which animals are raised under artificial conditions, and then released into natural habitat. The objective of this procedure is to grow animals to a size at which they are less vulnerable to predators. However, there is still little empirical evidence for the long-term effectiveness of the technique. Therefore, we compared body size of juvenile «wild» (= not taken to artificial rearing) and headstarted European pond turtles ( Emys orbicularis ), from two populations (in central and western Poland). Immediately after hatching there were no differences in size of the turtles, but after seven-ten years headstarted turtles were smaller. This …
Probabilistic maturation reaction norms assessed from mark-recaptures of wild fish in their natural habitat
2014
Published version of an article in the journal: Ecology and Evolution. Also available from the publisher at: http://dx.doi.org/10.1002/ece3.1044 Open Access Reaction norms are a valuable tool in evolutionary biology. Lately, the probabilistic maturation reaction norm approach, describing probabilities of maturing at combinations of age and body size, has been much applied for testing whether phenotypic changes in exploited populations of fish are mainly plastic or involving an evolutionary component. However, due to typical field data limitations, with imperfect knowledge about individual life histories, this demographic method still needs to be assessed. Using 13 years of direct mark-recap…
The impact of wildlife and environmental factors on hantavirus infection in the host and its translation into human risk
2023
Identifying factors that drive infection dynamics in reservoir host populations is essential in understanding human risk from wildlife-originated zoonoses. We studied zoonotic Puumala orthohantavirus (PUUV) in the host, the bank vole ( Myodes glareolus ), populations in relation to the host population, rodent and predator community and environment-related factors and whether these processes are translated into human infection incidence. We used 5-year rodent trapping and bank vole PUUV serology data collected from 30 sites located in 24 municipalities in Finland. We found that PUUV seroprevalence in the host was negatively associated with the abundance of red foxes, but this process did no…
Los tiempos de la delincuencia juvenil: tiempo de ocio y actividades cotidianas en los delitos cometidos por menores
2022
Se analiza la distribución temporal de los hechos que dan lugar a infracciones atribuidas a menores de edad en los expedientes de la Fiscalía Provincial de Valencia durante el año 2011. Analysis of temporal distribution of facts qualified as infractions attributed to juveniles by Valencian Provincial Office of the Prosecutor during the year 2011. [full text
Evaluation of the disease course of Italian children with juvenile idiopathic arthritis treated with etanercept: preliminary results in 772 patients
2014
The advent of biologic medications has considerably increased the potential for treatment benefit in juvenile idiopathic arthritis (JIA), with clinical remission being now achievable in a substantial proportion of patients.
Effects of physical activity on postural balance in children with juvenile idiopathic arthritis: results from a pilot study
2017
Background: The juvenile idiopathic arthritis (JIA) is the main rheumatic disease in pediatric age. The rheumatic diseases are main causes of physical disability and have high economic costs for society. The aim of this study was to evaluate if the physical activity can prevent the decline in balance related diseases in children with previous diagnosis of JIA. Materials and Methods: Fifty-six subjects were enrolled in this study. Thirty-nine healthy subjects were included in the control group (CG) and seventeen in juvenile idiopathic arthritis group (JIAG). Subsequently, the JIAG was stratified in two ones, respectively: JIAG active (JIAG-ACT) and JIAG sedentary (JIAG-SED). The analysis was…