Effect of environmental conditions on the seasonal and inter‐annual variability of small pelagic fish abundance off North‐West Africa: The case of both Senegalese sardinella          下载免费PDF全文

Modou Thiaw  Pierre‐Amaël Auger  Fambaye Ngom  Timothée Brochier  Saliou Faye  Ousmane Diankha  Patrice Brehmer 《Fisheries Oceanography》2017,26(5):583-601

The objective of this study was to assess the effect of environmental variations on the abundance of Sardinella aurita and Sardinella maderensis in Senegalese waters in the upwelling system. Monthly data indicating the abundance of sardinella were first estimated from commercial statistics, using Generalized Linear Model from 1966 to 2011. Abundance indices (AIs) were then compared with environmental indices, at the local scale, a Coastal Upwelling Index (CUI) and a coastal Sea Surface Temperature (SST) index, and on a large scale, the North Atlantic Oscillation (NAO), the Atlantic Multidecadal Oscillation (AMO) and the Multivariate El Niño Southern Oscillation Index (MEI), using correlations and times series analyses. The results showed that the abundance of sardinella is determined by a strong seasonal pattern and inter‐annual fluctuations. The abundance of S. aurita peaked in spring and in autumn, whereas that of S. maderensis peaked in the warm season (July–September). The trend of the sardinella abundance was significantly correlated with the CUI, especially in autumn and spring. Interannual fluctuations of S. maderensis and S. aurita abundance are, respectively, driven by the precocity and the duration of the upwelling season that is attributed to distinct migration patterns. Both sardinella species also respond with a delay of around 4 years to the winter NAO index and the autumn CUI, and the AMO index, respectively, both related to migration patterns. The wide variations in sardinella biomass are caused by variations in environmental conditions, which should be considered in the implementation of an ecosystem‐based approach in sardinella stocks management.  相似文献   

Contrasted optimal environmental windows for both sardinella species in Senegalese waters          下载免费PDF全文

Ousmane Diankha  Aliou Ba  Patrice Brehmer  Timothée Brochier  Bamol Ali Sow  Modou Thiaw  Amadou Thierno Gaye  Fambaye Ngom  Hervé Demarcq 《Fisheries Oceanography》2018,27(4):351-365

We investigate Sardinella aurita and Sardinella maderensis recruitment success relative to the variability of oceanographic conditions in Senegalese waters using generalized additive models (GAM). Results show that recruitment of both species is marked by a strong intra‐annual (seasonal) variation with minimum and maximum in winter and summer, respectively. Their interannual variations are synchronous until 2006 (recruitment decreasing), while from 2007 there is no synchrony. The model developed shows that sardinella recruitment variability is closely related to the tested environmental variables in the study area. However, the key environmental variables influencing the recruitment success are different for both species: the Coastal Upwelling Index and the sea surface temperature for S. aurita and S. maderensis, respectively. We report that recruitment success of S. aurita and S. maderensis are associated with distinct ranges of sea surface temperature, upwelling intensity, wind‐induced turbulence, concentration of chlorophyll‐a and north Atlantic oscillation index. Considering food security and socio‐economic importance of both stocks, we recommend that consideration is given to the environmental variability in the small pelagic fish national management plans, particularly in the context of climate change.  相似文献   

A novel spatial and stochastic model to evaluate the within and between farm transmission of classical swine fever virus: II validation of the model     

Martínez-López B  Ivorra B  Ngom D  Ramos AM  Sánchez-Vizcaíno JM 《Veterinary microbiology》2012,155(1):21-32

A new, recently published, stochastic and spatial model for the evaluation of classical swine fever virus (CSFV) spread into Spain has been validated by using several methods. Internal validity, sensitivity analysis, validation using historical data, comparison with other models and experiments on data validity were used to evaluate the overall reliability and consistency of the model. More than 100 modifications in input data and parameters were evaluated. Outputs were obtained after 1000 iterations for each new scenario of the model. As a result, the model was shown to be consistent, being the probability of infection by local spread, the time from infectious to clinical signs state, the probability of detection based on clinical signs at day t after detection of the index case outside the control and surveillance zones and the maximum number of farms to be depopulated at day t the parameters that have more influence (>10% of change) on the magnitude and duration of the epidemic. The combination of a within- and between-farm spread model was also shown to give significantly different results than using a purely between-farm spread model. Methods and results presented here were intended to be useful to better understand and apply the model, to identify key parameters for which it will be critical to have good estimates and to provide better support for prevention and control of future CSFV outbreaks.  相似文献   

Selection of arbuscular mycorrhizal fungal strains to improve <Emphasis Type="Italic">Casuarina equisetifolia</Emphasis> L. and <Emphasis Type="Italic">Casuarina glauca</Emphasis> Sieb. tolerance to salinity     

Pape Ibrahima Djighaly  Mariama Ngom  Daouda Ngom  Valérie Hocher  Dioumacor Fall  Diégane Diouf  Laurent Laplaze  Sergio Svistoonoff  Antony Champion 《Annals of Forest Science》2018,75(3):72

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