Etude socio-économique et technologique de la production du poisson fermenté et séché (Guedj) au Sénégal

Cette étude aborde les aspects socio-économiques et technologiques relatifs à l’un des maillons très important de la pêche maritime qui est la transformation du poisson en guedj ou poisson fermenté et séché. En effet, une enquête diagnostique menée à travers trois zones de production au Sénégal (Dakar, Thiès et Fatick), combinée aux données de la bibliographie et des entretiens avec les acteurs, ont permis de faire ressortir un certain nombre d’enjeux. L’étude a montré que cette activité assurée à 80% par des femmes, génère beaucoup d’emplois et de revenus, que le prix de vente fluctue entre 1000 et 3500 frs CFA.kg-1 et par conséquent qu’une grande productrice peut gagner en moyenne jusqu’à 400000 frs CFA par mois. Cependant, malgré son importance économique, elle est confrontée à d’énormes difficultés liées à la manutention, au manque d’infrastructures et de stockage adéquates et aux techniques de transformation rudimentaires utilisées. Par ailleurs, l’analyse physicochimique et microbiologique réalisée sur des échantillons prélevés dans les sites de production et de vente laisse apparaître la nécessité d’appliquer rigoureusement les bonnes pratiques de fabrication et d’hygiène afin d’améliorer la qualité sanitaire du guedj, qui fait de plus en plus l’objet de demande du marché extérieur.Mots clés : Guedj, poisson fermenté, méthode traditionnelle, étude de filière, qualité, Sénégal

Український фольклорний анекдот як гуманiтарна цiннiсть та гуманiстичний iдеал: перспективи вивчення

Кирчiв Р.Ф. Етюди до студій над українським народним анекдотом. Львiв: Інститут народознавства НАН України, 2008. 268 c

Analysing environmental and fishing effects on a short-lived species stock: the dynamics of the octopus Octopus vulgaris population in Senegalese waters

Short-lived species are extremely dependent on the seasonal and interannual variability of environmental conditions, and determining their stock status is  often difficult. This study investigates the effects of environmental  variability and fishing pressure on the stock of octopus Octopus  vulgaris in Senegalese waters over a 10-year period from 1996 to 2005. Monthly catches-at-age were estimated based on catch-at-weight data and a  polymodal decomposition constrained by a given growth curve. Octopus recruitments and fishing mortalities were then estimated using a catch-at-age analysis performed on a monthly basis. Yield and biomass per recruit were  simulated using a Thompson and Bell model and used to generate a diagnostic of the fishery’s impacts. Results indicate that the high interannual and seasonal variability of the octopus stock biomass is linked to the spring recruitment event, the annual intensity of which was significantly correlated with the coastal upwelling index and sea surface temperature. Yield per recruit varied  seasonally but remained almost unchanged from one year to the next. Even when catches vary strongly according to recruitment, the octopus stock appears to be consistently fully exploited, or slightly overexploited in some years. In this context of environmental variability, usual indicators such as the maximum yield per recruit, and the related fishing mortality and spawning potential ratio, remain useful for fisheries management purposes. Keywords: environment, fishery, indicators, population dynamics, Senegal, stock assessment, West AfricaAfrican Journal of Marine Science 2011, 33(2): 209–22

Changes in the trophic structure, abundance and species diversity of exploited fish assemblages in the artisanal fisheries of the northern coast, Senegal, West Africa

International audienceThis work investigates the effects of changes in both fishing pressure and the environment on the trophic dynamics, abundance and diversity of species in the artisanal commercial fisheries off the northern coast of Senegal. Using artisanal commercial fishing data (provided by the Centre for Oceanographic Research of Dakar-Thiaroye [CRODT] in Senegal), we identify changes in the catch per unit effort, mean trophic level, biomass trophic spectrum and species diversity between two fishing periods (1990-1999 and 2000-2009). Decreases in mean trophic level, the biomass of high trophic level species and indices of species diversity between 1990 and 2009 were observed in commercial catches. These decreases were then related to changes in fishing pressure, fishing strategy and the combined effects of fishing and environmental factors (as derived from satellite observations). This paper helps to better inform the management of fisheries resources by providing decision makers with more effective biological indicators that incorporate the effects of fishing pressure and environmental change and that are applicable at local, regional and global scales

How warm is too warm for the life cycle of actinopterygian fishes?

We investigated the highest constant temperature at which actinopterygian fishes can complete their lifecycles, based on an oxygen supply model for cleavage-stage eggs. This stage is one of the most heat-sensitive periods during the lifecycle, likely reflecting the exhaustion of maternally supplied heat shock proteins without new production. The model suggests that average eggs would not develop normally under a constant temperature of about 36 °C or higher. This estimate matches published empirical values derived from laboratory and field observations. Spermatogenesis is more heat sensitive than embryogenesis in fishes, so the threshold may indeed be lower, at about 35 °C, unless actinopterygian fishes evolve heat tolerance during spermatogenesis as in birds. Our model also predicts an inverse relationship between egg size and temperature, and empirical data support this prediction. Therefore, the average egg size, and hence hatching size, is expected to shrink in a greenhouse world but a feeding function prohibits the survival of very small hatchlings, posing a limit to the shrinkage. It was once suggested that a marine animal community may be sustained under temperatures up to about 38 °C, and this value is being used, for example, in paleotemperature reconstruction. A revision of the value is overdue. (199/200