35 research outputs found
Time scale evolution of avipoxviruses
AbstractAvipoxviruses are divided into three clades: canarypox-like viruses, fowlpox-like viruses, and psittacinepox-like viruses. Several molecular clock and demographic models available in the BEAST package were compared on three avipoxvirus genes (P4b, cnpv186 and DNA polymerase genes), which enabled to determine that avipoxviruses evolved at a rate of 2â8Ă10â5substitution/site/year, in the range of poxviruses previously reported evolution rates. In addition, the date of mean time of divergence of avipoxviruses from a common ancestor was extrapolated to be about 10,000â30,000years ago, at the same period as modern poxvirus species. Our findings will facilitate epidemiological investigations on avipoxvirusesâ spread, origin and circulation
Climate change in the Bay of Biscay: Changes in spatial biodiversity patterns could be driven by the arrivals of southern species
Climate change and fisheries
International audienceThere is considerable evidence that Mediterranean marine species have been shifting their ranges, migration patterns, seasonal activities and periodicities, abundances, growth and mortality rates, and consequently their trophic interactions in response to climate change and variability. These responses may ultimately have significant consequences for ecosystem productivity, biodiversity and functioning and hence for the overall goods and ecosystem services they provide, especially the production of living resources (Kirby & Beaugrand 2009,Doney et al. 2012). Climate change is an additional pressure on marine ecosystems that are already subject to many anthropogenic disturbances such as fishing activities. This is especially true in the Mediterranean Sea, where a series of human impacts co-occur and interact (Coll et al. 2010, Micheli, Halpern, et al. 2013). The consequences of climate change for marine resources need to be evaluated in this context and research and management need to take interactions between fishing, other human impacts, and climate into account (Brander 2010, Perry etal. 2010). This chapter thus has three aims: (i) to investigate the synergy between climate and fishing (a major human impact on Mediterranean marine ecosystems) and, using some examples from the Mediterranean Sea, to highlight how these two factors interact, from the individual to the ecosystem scale, (ii) to assess and quantify the consequences of climate change for the composition of fishery catches in the Mediterranean Sea, and (iii) to address the consequences of climate change for the management tools and strategies implemented in the region
Rearing performances and environmental assessment of sea cage farming in Tunisia using life cycle assessment (LCA) combined with PCA and HCPC
ISI Document Delivery No.: GD0MXTimes Cited: 1Cited Reference Count: 51Abdou, Khaled Lasram, Frida Ben Rais Romdhane, Mohamed Salah Le Loc'h, Francois Aubin, Joel'Institut de Recherche pour le Developpement' (JEAI GAMBAS project); LabexMerThe authors would like to acknowledge valuable financial support from the 'Institut de Recherche pour le Developpement' (JEAI GAMBAS project). This study was also partially funded by 'LabexMer'.Springer heidelbergHeidelbergThe present study aims to understand the influence of rearing practices and the contributions of production phases of fish farming to their environmental impacts and determine which practices and technical characteristics can best improve the farms' environmental performance. Another objective is to identify the influence of variability in farming practices on the environmental performances of sea cage aquaculture farms of sea bass and sea bream in Tunisia by using principal component analysis (PCA) and hierarchical clustering on principal components (HCPC) methods and then combining the classification with life cycle assessment (LCA). The approach consisted of three major steps: (i) of the 24 aquaculture farms in Tunisia, 18 were selected which follow intensive rearing practices in sea cages of European sea bass (Dicentrarchus labrax) and gilthead sea bream (Sparus aurata) and then a typology was developed to classify the studied farms into rearing practice groups using HCPC; (ii) LCA was performed on each aquaculture farm and (iii) mean impacts and contributions of production phases were calculated for each group of farms. Impact categories included acidification, eutrophication, global warming, land occupation, total cumulative energy demand and net primary production use. Results revealed high correlation between rearing practices and impacts. The feed-conversion ratio (FCR), water column depth under the cages and cage size had the greatest influence on impact intensity. Rearing practices and fish feed were the greatest contributors to the impacts studied due to the production of fish meal and oil and the low efficiency of feed use, which generated large amounts of nitrogen and phosphorus emissions. It is necessary to optimise the diet formulation and to follow better feeding strategies to lower the FCR and improve farm performance. Water column depth greatly influenced the farms' environmental performance due to the increase in waste dispersion at deeper depths, while shallow depths resulted in accumulation of organic matter and degradation of water quality. Cage size influences environmental performances of aquaculture farms. Thus, from an environmental viewpoint, decision makers should grant licences for farms in deeper water with larger cages and encourage them to improve their FCRs. This study is the first attempt to combine the HCPC method and the LCA framework to study the environmental performance of aquacultural activity. The typology developed captures the variability among farms because it considers several farm characteristics in the classification. The LCA demonstrated that technical parameters in need of improvement are related to the technical expertise of farm managers and workers and to the location of the farm
Diversity of avipoxviruses in captive-bred Houbara bustard
Implementation of conservation breeding programs is a key step to ensuring the sustainability of many endangered species. Infectious diseases can be serious threats for the success of such initiatives especially since knowledge on pathogens affecting those species is usually scarce. Houbara bustard species (Chlamydotis undulata and Chlamydotis macqueenii), whose populations have declined over the last decades, have been captive-bred for conservation purposes for more than 15 years. Avipoxviruses are of the highest concern for these species in captivity. Pox lesions were collected from breeding projects in North Africa, the Middle East and Central Asia for 6 years in order to study the diversity of avipoxviruses responsible for clinical infections in Houbara bustard. Molecular and phylogenetic analyses of 113 and 75 DNA sequences for P4b and fpv140 loci respectively, revealed an unexpected wide diversity of viruses affecting Houbara bustard even at a project scale: 17 genotypes equally distributed between fowlpox virus-like and canarypox virus-like have been identified in the present study. This suggests multiple and repeated introductions of virus and questions host specificity and control strategy of avipoxviruses. We also show that the observed high virus burden and co-evolution of diverse avipoxvirus strains at endemic levels may be responsible for the emergence of novel recombinant strains
Seasonal variability of living benthic foraminifera from the outer continental shelf of the Bay of Biscay
International audienc
Mise en place dâun modĂšle dâaspergillose aviaire et recherche de biomarqueurs dâune infection Ă Aspergillus fumigatus chez la dinde (Meleagris gallopavo)
National audienc