Eutrophication as a driver of r-selection traits in a freshwater fish.

This study tested whether eutrophication could influence life-history traits of a cyprinid, Chanodichthys erythropterus, in 10 Chinese lakes. Using the von Bertalanffy growth model, the asymptotic length (L∞ ) and the growth performance index (IGRO ) were significantly affected by eutrophication. The gonado-somatic index (IG ) and relative fecundity (FR ) were significantly lower in mesotrophic lakes than in eutrophic and hypertrophic lakes. These results indicate that increasing eutrophication affects the life-history tactics of a freshwater fish.

Strengthening the link between climate, hydrological and species distribution modeling to assess the impacts of climate change on freshwater biodiversity.

To understand the resilience of aquatic ecosystems to environmental change, it is important to determine how multiple, related environmental factors, such as near-surface air temperature and river flow, will change during the next century. This study develops a novel methodology that combines statistical downscaling and fish species distribution modeling, to enhance the understanding of how global climate changes (modeled by global climate models at coarse-resolution) may affect local riverine fish diversity. The novelty of this work is the downscaling framework developed to provide suitable future projections of fish habitat descriptors, focusing particularly on the hydrology which has been rarely considered in previous studies. The proposed modeling framework was developed and tested in a major European system, the Adour-Garonne river basin (SW France, 116,000 km(2)), which covers distinct hydrological and thermal regions from the Pyrenees to the Atlantic coast. The simulations suggest that, by 2100, the mean annual stream flow is projected to decrease by approximately 15% and temperature to increase by approximately 1.2 °C, on average. As consequence, the majority of cool- and warm-water fish species is projected to expand their geographical range within the basin while the few cold-water species will experience a reduction in their distribution. The limitations and potential benefits of the proposed modeling approach are discussed.

Temporal variation of heavy metal contamination in fish of the river lot in southern France.

The present study aims at assessing the current situation of the heavy metal contaminated River Lot (SW France). Several fish species were captured in October 1987 and 2007 at three sampling sites. The concentration of copper, zinc, cadmium and lead were quantified in fish muscle and liver as well as in environmental samples (water, sediment, moss). The decrease in heavy metal concentrations in fish tissue between 1987 and 2007 reflects the decrease of heavy metal concentrations in the environment. Concentrations found in 2007 are comparable to those published by a study conducted in the 1990s. The situation of the River Lot has improved over the last 2 decades, although there is still margin for amelioration according to US EPA criterion to protect freshwater aquatic life. The average concentrations of cadmium in fish muscle in 2007 were above the maximum safe for human consumption defined by the European Commission.

Long-term changes in water physicochemistry in the Adour-Garonne hydrographic network during the last three decades.

This study details a trend analysis covering a 30-year period (1975-2004), for 19 physicochemical parameters at 45 surface water sites in the Adour-Garonne basin, south-west France. To perform statistical analysis, we used the annual average of each variable. The analysis revealed sites affected by strong patterns of temporal variation and sites with weak or imperceptible changes of water quality. More than half the studied sites were affected by chemical changes. Trends were generally clearest in the River Garonne continuum, but similar tendencies could also be identified in tributaries. The overall trends indicated the onset of an increase of water temperature starting about 20 years ago and partial recovery from eutrophication during the last decade. As expected, the strongest trend affected the temperature regime of the hydrosystems, there being a more significant warming during the second decade of the study (1984-1994). Additionally, at many sites nutrient loads were lower between 1995 and 2004. This confirms a downward trend in eutrophication status resulting from more stringent control of sewage treatment despite the constant increase of anthropic pressure. Sites that did not present any trends are extreme sites located at each end of the river gradient: headwater and downstream sites under tidal influence. Other sites not affected by changes are those strongly perturbed by human activities showing a high level of degradation.

Legal issues in the treatment of a violent manic patient in a non-gazetted setting: a case report.

INTRODUCTION: Psychiatrists in non-gazetted treatment settings, like psychiatric wards in restructured general hospitals and private hospitals, face a major problem when psychiatric patients who require admission are either not competent or refuse to consent to admission and treatment, although they are clearly in need of such inpatient management. Admission to the state mental hospital is often refused by their relatives for a number of reasons, like the stigma attached to admission to such a hospital, and the fear that future employment prospects might be affected. CLINICAL PICTURE: Mr X, a manic, violent patient, had no insight into his disorder and refused admission and treatment for his manic episode. He was the head of a large corporation, and his relatives were apprehensive he would make decisions that could jeopardize the company. TREATMENT: He refused oral medication, could not tolerate parenteral haloperidol and had lithium nephrotoxicity. Inpatient electroconvulsive therapy had to be administered, after which he responded satisfactorily. CONCLUSION: The legal implications in this case, like consent for treatment and admission, and ethical issues, are discussed.

Phenotypic modification of roach (Rutilus rutilus L.) infected with Ligula intestinalis L. (Cestoda: Pseudophyllidea).

In European freshwater, cyprinid fish may be heavily infected by plerocercoids of the pseudophyllidea cestode Ligula intestinalis (L.). During their development, these parasites grow rapidly to a large size in the fish's body cavity, characteristically distending the abdomen. In this study, the influence of this tapeworm on roach (Rutilus rutilus L.) morphology was analyzed. Forty-five infected and 45 uninfected roach were collected from the Lavernose-Lacasse gravel pit in Toulouse, south western France and examined for 40 morphological measurements to study phenotypic modification of the body and 14 bilateral characters for an analysis of asymmetry. Results indicate that the degree of bilateral asymmetry does not change between infected and uninfected roach, despite the strong host-morphological modifications such as deformation of the abdomen, fin displacements at the level of the tail, and sagging of the vertebral column. The intensity of abdominal distension and fish morphology changes depends on the total parasite biomass present. Differences were observed in morphology at different levels of infection, which relate to established effects of L. intestinalis on the physiology and behavior of intermediate hosts. These morphological changes induced by the parasite could increase trophic transmission to the definitive avian hosts.

Long-term recovery of macrobenthos and fish assemblages after water pollution abatement measures in the River Petite Baïse (France).

Riverine ecosystems are subject to a large variety of man-made influences, and in recent years a new public awareness of the need to protect rivers has emerged within the industrialized world. The present study focuses on the effect of abatement of pollution from one factory on the recovery of fish and macroinvertebrate species richness in the River Petite Baïse over a 20-year period (1973-1993). Until 1973, the Petite Baïse (75 km in length) received not only factory waste (nitrogenous rich effluents) but also the untreated sewage of many villages and agricultural runoff from the river's catchment. In 1970, macroinvertebrates and fishes were absent in the river despite having initially been classified as of the barbel Barbus barbus zone, and extensive efforts were made by the factory to reduce pollution to allow the riverine community to recover. Regular surveys between 1973 and 1993 revealed a progressive improvement in water quality and the recolonization of the river by macrobenthic and fish populations. Macrobenthic fauna species richness gradually increased from zero in 1970 to level 8 or 9 in 1993 (Verneaux and Tuffery method), reflecting improvements in river water quality. Fish were not observed until 40 km downstream of the factory in 1978, 16 km in 1980, and approximately 5 km by 1990. Fish species richness increased from five in 1978 (barbel, chub Leuciscus cephalus, stone loach Barbatula barbatula, minnow Phoxinus phoxinus, gudgeon Gobio gobio) to eight in 1990 (the carnivorous brown trout Salmo fario, the omnivorous chub, and six benthophagous fishes: gudgeon, barbel, minnow, stone loach, sofie Chondrostoma toxostoma, carp Cyprinus carpio). Fish biomass 45 km downstream the factory increased from 1 g/m2 in 1978 to more than 5 g/m2 by 1990. Recolonization of the river, in particular those areas furthest downstream from the factory, occurred as a result of reductions in the nitrogen inputs emanating from the factory.

Artificial neural networks as a classification method in the behavioural sciences.

The classification and recognition of individual characteristics and behaviours constitute a preliminary step and is an important objective in the behavioural sciences. Current statistical methods do not always give satisfactory results. To improve performance in this area, we present a methodology based on one of the principles of artificial neural networks: the backpropagation gradient. After summarizing the theoretical construction of the model, we describe how to parameterize a neural network using the example of the individual recognition of vocalizations of four fallow deer (Dama dama). With 100% recognition and 90% prediction success, the results are very promising.

Classifying individuals among infra-specific taxa using microsatellite data and neural networks.

The method of neural networks was tested for its ability to assign individuals on the basis of their multilocus genotypes, using a data collection of 430 honeybees and 8 microsatellite loci. This data set includes various taxonomical levels (populations within the same subspecies, various subspecies belonging to the same evolutionary lineage, and the 3 lineages of the species). Qualitative genotypic data have been submitted to 2 types of transformation (simple coding and coding plus factorial correspondence analysis), and they have been partitioned in 2 sets, a training set of 300 individuals and a testing set of 103 individuals. Two procedures ("leave one out" and "hold out") were applied to evaluate the quality of prediction. Compared to discriminant analysis, neural networks performed better in terms of correctly classified individuals at any taxonomical level. For instance, with the simple coding and the hold out procedure, the proportions of correctly assigned individuals from the testing set were 66.2%, 82.3% and 100% at the populations, subspecies and lineage level, respectively. The potential use of neural networks in populations genetics is discussed.