119 research outputs found
Is a cannibal different from its conspecifics? A behavioural, morphological, muscular and retinal structure study with pikeperch juveniles under farming conditions
Cannibalism is defined as the act of killing and consuming the whole, or major part, of an individual belonging to the same species, irrespective of its stage of development. Intra-cohort cannibalism in fish larval or juvenile stages, which is a major economic problem, has been widely studied in captive fish populations. In our study, we investigated the influence of animal personality (with cross-maze and conspecific choice tests) on intra-cohort cannibalism using pikeperch Sander lucioperca as a model species. Furthermore, we investigated the morphological (geometric morphological analysis) and anatomical (histological analysis of retinal and muscle tissue sections) differences between cannibal (C) fish (TL = 34.6 ± 9.4 mm, n = 25) and conspecific fish randomly sampled from rearing tanks, herein called âpotential non-cannibal fishâ (PNC) (TL = 31.4 ± 10.5 mm, n = 42). We did not find any behavioural differences (swimming activity, exploration, conspecific choice) between cannibal and potential non-cannibal fish that could explain asynchrony in the onset of cannibalism. Moreover, we did not observe any morphological differences between the two groups (C and PNC fish). However, we did detect anatomical differences in two retinal layers (ganglion cell layer and inner nuclear layer) that were thicker for cannibals. These two layers are involved in the collection of information by photoreceptors and allow the shapes, colours and movements of objects to be detected in the water column. The onset of cannibalism therefore appears to be linked to environmental condition-dependent individual development, with some individuals exhibiting precocious anatomical, and probably physiological, development, rather than to individual personality.info:eu-repo/semantics/acceptedVersio
The onset of piscivory in a freshwater fish species: analysis of behavioural and physiological traits
The onset of piscivory in fish, resulting in a shift from zooplankton or invertebrate to fish prey, was studied on pikeperch (Sander lucioperca) larvae displaying and not displaying piscivorous behaviour at different ages (23, 30, 37, 44 and 52âdays postâhatching) using behavioural (attack, capture and swimming activity), morphological (allometry) and digestive enzymatic (trypsin, αâamylase and pepsin) analyses. The shift from zooplanktonic food items (Artemia nauplii) to a piscivorous diet did not occur at the same time for all individuals within the same cohort. Predation tests, conducted under controlled conditions (20°C; ad libitum feeding), showed that some larvae attacked fish prey as early as the age of 3âweeks [11.0â±â1.3âmm total length (TL)], whereas others did not start until the age of 6âweeks (16.6â±â1.9âmm TL). Piscivorous individuals were bigger, with larger heads, longer tails, higher acid protease and lower alkaline protease activities, than nonâpiscivorous conspecifics. In conclusion, high interindividual variability in morphological and digestive system developments linked to the development of predatory abilities could induce cannibalism in fish.info:eu-repo/semantics/acceptedVersio
Improving pikeperch larviculture by combining environmental, feeding and populational factors
Pikeperch (Sander lucioperca) has a high potential for inland aquaculture diversification in Europe. Bottlenecks (i.e. low survival, cannibalism and deformity rates) hamper further expansion of pikeperch culture, because of the weak production performances at the nursery level. To improve the production of pikeperch juveniles under recirculation system we used a pilot scale larval rearing system (700 L tanks) and multifactorial designs. Three successive larval rearing trials (duration: 35-49 days) were conducted to identify the best combination of environmental, feeding and population factors. Considering the main significant effects observed on survival, growth, swim bladder inflation rates and biomass gain, a favourable combination of twelve factor (F) modalities was proposed (F1- initial density: 100 larvae.L-1, F2- no sorting of fish jumper, F3- no sibling population, F4- eggs from large females, F5- discontinuous feeding, F6- no co-feeding, F7- light intensity: 50 lx, F8- beginning of the weaning at 16 dph (days post-hatching), F9- weaning duration: 9 days, F10- water renewal rate of 100 % per hour, F11- tank cleaning during morning and F12- tank bottom-up water current). A final validation step was realized over a last trial (seven replicates, duration: 49 days), and validated with the best productive results obtained over the global experimental period (2015-2018). These results were: a final body weight of 815.64 ± 95.34 mg, a survival rate of 16.9 ± 1.7 %, a specific growth rate of 15.1 ± 5.9 %.d-1, a final fish biomass of 9.55 ± 0.23 kg, a swim bladder inflation rate of 92.6 ± 3.2 % and a food conversion rate of 0.65 ± 0.02 (dry food). The final stocking density was 13.6 kg.m-3 of rearing volume. Authors were able to validate and provide a reliable basic protocol for pikeperch larval rearing using recirculating units.info:eu-repo/semantics/publishedVersio
Geology of the Dhaulagiri-Annapurna-Manaslu Himalaya, Western Region, Nepal. 1:200,000
Geological mapping of mountains belts is fundamental to understanding their structure and evolution. Here, a 1:200,000 scale geological map of the central Himalaya of Western Region, Nepal is presented. This map represents a compilation of previously published maps, integrated with new geological field data. The wide spatial coverage of the map and the accompanying cross sections reveal the detailed structure of the Dhaulagiri-Annapurna-Manaslu Himalaya. The addition of modern topographic and infrastructure data makes this map suitable for navigation through the region
Thermokinematic evolution of the Annapurna-Dhaulagiri Himalaya, central Nepal: The composite orogenic system
The Himalayan orogen represents a ââComposite Orogenic Systemââ in which channel flow, wedge extrusion, and thrust stacking operate in separate ââOrogenic Domainsââ with distinct rheologies and crustal positions. We analyze 104 samples from the metamorphic core (Greater Himalayan Sequence, GHS) and bounding units of the Annapurna-Dhaulagiri Himalaya, central Nepal. Optical microscopy and electron backscatter diffraction (EBSD) analyses provide a record of deformation microstructures and an indication of active crystal slip systems, strain geometries, and deformation temperatures. These data, combined with existing thermobarometry and geochronology data are used to construct detailed deformation temperature profiles for the GHS. The profiles define a three-stage thermokinematic evolution from midcrustal channel flow (Stage 1, >7008C to 550â6508C), to rigid wedge extrusion (Stage 2, 400â6008C) and duplexing (Stage 3, <280â4008C). These tectonic processes are not mutually exclusive, but are confined to separate rheologically distinct Orogenic Domains that form the modular components of a Composite Orogenic System. These Orogenic Domains may be active at the same time at different depths/positions within the orogen. The thermokinematic evolution of the Annapurna-Dhaulagiri Himalaya describes the migration of the GHS through these Orogenic Domains and reflects the spatial and temporal variability in rheological boundary conditions that govern orogenic systems
The management of bronchus intermedius complications after lung transplantation: A retrospective study
<p>Abstract</p> <p>Background</p> <p>Airway complications following lung transplantation remain a significant cause of morbidity and mortality. The management of bronchial complications in Bronchus Intermedius (BI) is challenging due to the location of right upper bronchus. The aim of this study was to analyze the results of BI Montgomery T-tube stent in a consecutive patients with lung transplantations.</p> <p>Methods</p> <p>Between January 2007 and December 2010, 132 lung transplantations were performed at Foch Hospital, Suresnes, France. All the patients who had BI Montgomery T-tube after lung transplantation were included in this retrospective study. The demographic and interventional data and also complications were recorded.</p> <p>Results</p> <p>Out of 132 lung transplant recipients, 12 patients (9 male and 3 female) were entered into this study. The indications for lung transplantation were: cystic fibrosis 8 (67%), emphysema 3 (25%), and idiopathic pulmonary fibrosis 1 (8%). Most of the patients (83%) had bilateral lung transplantation. The mean interval between lung transplantation and interventional bronchoscopy was 11.5 ± 9.8 (SD) months. There was bronchial stenosis at the level of BI in 7 patients (58.3%). The Montgomery T-tube number 10 was used in 9 patients (75%). There was statistically significant difference in Forced Expiratory Volume in one second (FEV1) before and after stent placement (p = 0.01). The most common complication after stent placement was migration (33%).</p> <p>Conclusion</p> <p>BI complications after lung transplantation are still a significant problem. Stenosis or malacia following lung transplantation could be well managed with modified Montgomery T-tube.</p
Submarine reworking of exhumed subcontinental mantle rocks: field evidence from the Lherz peridotites, French Pyrenees
Multi-traits study of intra-cohorte cannibalism in early life stages of pikeperch (Sander lucioperca)
Le cannibalisme intra-cohorte est lâacte de tuer et consommer tout ou partie dâun individu conspĂ©cifique du mĂȘme Ăąge. Longtemps considĂ©rĂ© comme un artefact dâĂ©levage, le cannibalisme est maintenant admis comme un phĂ©nomĂšne naturel pouvant ĂȘtre soumis Ă des mĂ©canismes de sĂ©lection. Chez les TĂ©lĂ©ostĂ©ens, il est majoritairement rĂ©fĂ©rencĂ© au niveau des premiers stades de vie. En condition dâĂ©levage, plusieurs facteurs biotiques et abiotiques ont Ă©tĂ© testĂ©s sans rĂ©ussir Ă totalement lâĂ©liminer chez de nombreuses espĂšces. Dans ce contexte, cette thĂšse a pour objectifs de mieux comprendre la mise en place et le maintien du cannibalisme, chez le sandre, en se focalisant sur le lien entre cannibalisme, personnalitĂ© et mise en place de lâichtyophagie. Cette thĂšse a Ă©tĂ© divisĂ©e en trois parties : (i) description du cannibalisme chez les premiers stades de vie du sandre et Ă©tude de lâinfluence de certains facteurs dâĂ©levage, (ii) dĂ©termination des traits de personnalitĂ© chez les juvĂ©niles, et mise en Ă©vidence de lâapparition du comportement piscivore chez les larves, (iii) recherche des liens entre cannibalisme, personnalitĂ© et mise en place de lâichtyophagie. Cette thĂšse a montrĂ© que les facteurs dâĂ©levage testĂ©s nâont pas dâinfluence sur le cannibalisme. Elle a permis de dĂ©montrer lâexistence de syndromes comportementaux dĂšs les premiers stades de vie, que lâichtyophagie ne se mettait pas en place au mĂȘme Ăąge chez tous les individus et que celle-ci Ă©tait liĂ©e Ă la personnalitĂ©. Nos rĂ©sultats montrent, Ă©galement, que le cannibalisme chez les premiers stades de vie du sandre serait liĂ© Ă la mise en place dâune ichtyophagie prĂ©coce et non Ă une personnalitĂ© particuliĂšre. On peut en dĂ©duire que le cannibalisme ne repose pas, au cours du dĂ©veloppement, sur les mĂȘmes caractĂ©ristiques individuelles que lâichtyophagieIntra-cohort cannibalism is the act of killing and consuming the whole, or major part, of a conspecific individual of the same age. Most often considered as an artefact of captive conditions, it is now assumed that cannibalism is a natural phenomenon, which could be submitted to selection. In Teleosts, it is mostly found in early life stages. In rearing conditions, several biotic and abiotic factors have been already tested, yet without successfully stop it in several species. In this context, the aim of this thesis is to better understand the onset and the stability of cannibalism, in pikeperch, by focusing on the link between cannibalism, personality and the onset of ichtyophagy. This study comprised three main parts aiming at: (i) describing the cannibalism in early life stages and studying the impact of rearing factors, (ii) determining personality traits in juveniles and describing the onset of ichtyophagy in larvae, (iii) searching the link between cannibalism, personality and onset of ichtyophagy. This thesis showed that rearing factors have no impact on cannibalism. Furthermore, we found behavioural syndromes in early life stages and that the onset of ichtyophagy did not occur at the same time for all individuals. Our results highlight that cannibalism seems to be linked to the onset of ichtyophagy rather than individual personality. In conclusion, cannibalism is not due, throughout the development, to the same individual characteristics than ichtyophag
Ătude multi-traits du cannibalisme intra-cohorte chez les premiers stades de vie du sandre (Sander lucioperca)
Intra-cohort cannibalism is the act of killing and consuming the whole, or major part, of a conspecific individual of the same age. Most often considered as an artefact of captive conditions, it is now assumed that cannibalism is a natural phenomenon, which could be submitted to selection. In Teleosts, it is mostly found in early life stages. In rearing conditions, several biotic and abiotic factors have been already tested, yet without successfully stop it in several species. In this context, the aim of this thesis is to better understand the onset and the stability of cannibalism, in pikeperch, by focusing on the link between cannibalism, personality and the onset of ichtyophagy. This study comprised three main parts aiming at: (i) describing the cannibalism in early life stages and studying the impact of rearing factors, (ii) determining personality traits in juveniles and describing the onset of ichtyophagy in larvae, (iii) searching the link between cannibalism, personality and onset of ichtyophagy. This thesis showed that rearing factors have no impact on cannibalism. Furthermore, we found behavioural syndromes in early life stages and that the onset of ichtyophagy did not occur at the same time for all individuals. Our results highlight that cannibalism seems to be linked to the onset of ichtyophagy rather than individual personality. In conclusion, cannibalism is not due, throughout the development, to the same individual characteristics than ichtyophagyLe cannibalisme intra-cohorte est lâacte de tuer et consommer tout ou partie dâun individu conspĂ©cifique du mĂȘme Ăąge. Longtemps considĂ©rĂ© comme un artefact dâĂ©levage, le cannibalisme est maintenant admis comme un phĂ©nomĂšne naturel pouvant ĂȘtre soumis Ă des mĂ©canismes de sĂ©lection. Chez les TĂ©lĂ©ostĂ©ens, il est majoritairement rĂ©fĂ©rencĂ© au niveau des premiers stades de vie. En condition dâĂ©levage, plusieurs facteurs biotiques et abiotiques ont Ă©tĂ© testĂ©s sans rĂ©ussir Ă totalement lâĂ©liminer chez de nombreuses espĂšces. Dans ce contexte, cette thĂšse a pour objectifs de mieux comprendre la mise en place et le maintien du cannibalisme, chez le sandre, en se focalisant sur le lien entre cannibalisme, personnalitĂ© et mise en place de lâichtyophagie. Cette thĂšse a Ă©tĂ© divisĂ©e en trois parties : (i) description du cannibalisme chez les premiers stades de vie du sandre et Ă©tude de lâinfluence de certains facteurs dâĂ©levage, (ii) dĂ©termination des traits de personnalitĂ© chez les juvĂ©niles, et mise en Ă©vidence de lâapparition du comportement piscivore chez les larves, (iii) recherche des liens entre cannibalisme, personnalitĂ© et mise en place de lâichtyophagie. Cette thĂšse a montrĂ© que les facteurs dâĂ©levage testĂ©s nâont pas dâinfluence sur le cannibalisme. Elle a permis de dĂ©montrer lâexistence de syndromes comportementaux dĂšs les premiers stades de vie, que lâichtyophagie ne se mettait pas en place au mĂȘme Ăąge chez tous les individus et que celle-ci Ă©tait liĂ©e Ă la personnalitĂ©. Nos rĂ©sultats montrent, Ă©galement, que le cannibalisme chez les premiers stades de vie du sandre serait liĂ© Ă la mise en place dâune ichtyophagie prĂ©coce et non Ă une personnalitĂ© particuliĂšre. On peut en dĂ©duire que le cannibalisme ne repose pas, au cours du dĂ©veloppement, sur les mĂȘmes caractĂ©ristiques individuelles que lâichtyophagi
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