Atlantic salmon dynamics in the Foyle catchment (Ireland), a Bayesian approach

Population dynamics is the study of the abundance of a species at different life stages of a species, the interactions between these life stages and sometimes the interactions with other species. Stage-structured modelling is a popular approach for population dynamics studies. This approach examines populations based on their ecology and allows the incorporation of complex dynamic processes. Model outputs are sensitive to the parameter values. It then becomes crucial to accommodate and quantify parameter uncertainty. This is of particular importance when the population of interest is exploited and the risk of over-exploitaion or extinction needs to be assessed. When studying real world examples of populations exploited by fisheries, several additional problems often arise such as: multiple and heterogeneous sources of information (e.g. datasets collected at different spatial and temporal scales), missing observations, life stages of interest not directly observable. The Bayesian framework allows all of these issues to be handled within the general framework. Thus has proven its particular value in studying the dynamics of exploited populations. Indeed, unknown quantities have associated probability distributions reflecting their uncertainty. Dealing with variations in the interactions/processes between life stages or limited and indirect ecological data is also facilitated by Bayesian modelling. In this study, I examined a large Atlantic salmon population located in the Foyle catchment (Ireland). This population has been exploited for several centuries and particularly during the 20th century. This study focused on the period from 1959 to present for which most monitoring data is available from the Loughs Agency (formerly the Foyle Fisheries Comission). The Loughs Agency is responsible for the management of the salmon population. The aim of the agency is “to manage [the] fisheries towards maximum sustainable exploitation for commercial and recreational purposes”. In order to do so, it is important to understand the regulatory mechanisms occurring in the population in order to (i) estimate the number of fish returning to river, i.e. pre-fishery abundances (PFAs), and (ii) to derive standard reference points for assessing the population status with regards to its sustainable exploitation. To this end, a state-space model is implemented within a Bayesian framework. A life stage and spatially structured dynamic model describes the lifecycle of the Main components of Atlantic salmon in the Foyle catchment. Several empirical datasets related to the abundances of the stages at different scales of space and time, over a period of 50 years are brought together. Observations and process errors are taken into account ultimately allowing PFAs to be estimated. A retrospective analysis was also carried out providing insights on the historical status of the population and its exploitation. Geo unit specific abundances of the different states and their associated uncertainty are estimated. The main state of interest is the pre-fishery abundance (PFA), during the time-series considered (1959-2008) the salmon population reached its apex in the mid 1960’s. This was followed by a steep decrease until the mid 1970’s. From then to present, the population followed a slow declining trend with a slight recovery in the mid 1980’s. This decline is shown to be mostly due to a decline of the 0+ juvenile to returning adult survival which is accentuated some years by some overfishing

Effect of substitution on the intramolecular 1,3-dipolar cycloaddition of alkene tethered münchnones

Abstract: A sequence of chemoselective activation of N-acylaminoacids, münchnone generation, intramolecular 1,3-dipolar cycloaddition, and ring opening efficiently generated functionalized polycyclic structures such as cyclopenta[b]pyrroles or zwitterionic bicyclo[4.3.0]nonane or bicyclo[3.3.0]octanes in one operation is given. These zwitterionic species were isolated for the first time and were subsequently reduced to bicyclic aminoalcohols. The effect of the substitution of both the dipolarophile and the münchnone on the intramolecular cycloaddition outcome was examined. It was found that either nonactivated or electron-poor alkenes can react with the münchnone if these alkenes are tethered at position 4 on the münchnone (2, R2 = alkene tether), whereas only an electron-poor alkene at position 2 (2, R3 = alkene tether) could undergo successful cycloaddition. Also, münchnones substituted at position 2 with a phenyl (2, R3 = Ph) showed a dramatic increase in reactivity, whereas a phenyl at position 4 (2, R2 = Ph) had a very limited effect

Medjez II

Ce gisement princeps du faciès « Sétifïen* » joue un rôle majeur dans la caractérisation de la variabilité capsienne de l’Epipaléolithique du Maghreb, observée entre le VIII-Ve millénaire cal BC. On doit à Henriette Camps-Fabrer d’avoir souligné les éléments diagnostics d’une abondante et nouvelle documentation régionale. Recueillie lors de plusieurs campagnes de fouilles (entre 1963 et 1968), cette documentation est conservée à Alger, au CNRPAH. Bien après la première monographie sur le Caps..

The Second ICES/NASCO Workshop on Salmon Mortality at Sea (WKSalmon2; outputs from 2022 meeting) The Second ICES/NASCO Workshop on Salmon Mortality at Sea (WKSalmon2; outputs from 2022 meeting)

ICES, in consultation with the North Atlantic Salmon Conservation Organisation (NASCO), convened a series of workshops to explore how to use biological and environmental data in models to advance the conservation of wild Atlantic salmon (<em>Salmo salar</em> L.) at sea. This workshop set out to consider multiple candidate hypotheses contributing to changes in the temporal patterns of abundance, and agree the priority research questions. No agreement on the development of a set of priority marine mortality hypotheses was reached. This resulted from the recognition of the hierarchical nature of ecosystem controls, and important complexities introduced by evolutionary diversity. An integrated ecological-evolutionary framework was proposed for the evaluation of hypotheses, and to identify key points in space and time. There was an agreed need for the continuation of cooperative initiatives to examine drivers of marine growth change using standardised approaches, and in the evolutionary delineation of stock units. These were seen as productive pathways to significantly enhance understanding of the marine factors impacting species abundance. The workshop recognised that options for developing and testing hypotheses remain constrained by the availability and quality of data, and identified ways to mobilise existing knowledge resources on key aspects of salmon ocean ecology. These focused on the synthesis of physical ocean data and model outputs, involving ocean basin-wide evaluations of available energy from surveys of lower trophic levels, and updating of population-specific biological information. The workshop agreed on the need for a specific call for data from pelagic commercial fisheries, given the broad scale of this activity and potential overlap with salmon migrations. There was also the recognition that Atlantic salmon should be included in the ICES Working Group on Bycatch of Protected Species (WGBYC) Protected, Endangered and Threatened Species list. Much of the work required to mobilise useful data sources was recognised as being outside the scope of existing ICES data calls, or the constituted core work of ICES Working Group on North Atlantic Salmon (WGNAS). Recommendations for the third workshop are for 1. More detailed consideration of how to access the work needed for data mobilisation, and 2. The identification of well-defined, achievable outcomes

The GenTree Dendroecological Collection, tree-ring and wood density data from seven tree species across Europe

The dataset presented here was collected by the GenTree project (EU-Horizon 2020), which aims to improve the use of forest genetic resources across Europe by better understanding how trees adapt to their local environment. This dataset of individual tree-core characteristics including ring-width series and whole-core wood density was collected for seven ecologically and economically important European tree species: silver birch (Betula pendula), European beech (Fagus sylvatica), Norway spruce (Picea abies), European black poplar (Populus nigra), maritime pine (Pinus pinaster), Scots pine (Pinus sylvestris), and sessile oak (Quercus petraea). Tree-ring width measurements were obtained from 3600 trees in 142 populations and whole-core wood density was measured for 3098 trees in 125 populations. This dataset covers most of the geographical and climatic range occupied by the selected species. The potential use of it will be highly valuable for assessing ecological and evolutionary responses to environmental conditions as well as for model development and parameterization, to predict adaptability under climate change scenarios