Seascape connectivity of European anchovy in the Central Mediterranean Sea revealed by weighted Lagrangian backtracking and bio-energetic modelling

Ecological connectivity is one of the most important processes that shape marine populations and ecosystems, determining their distribution, persistence, and productivity. Here we use the synergy of Lagrangian back-trajectories, otolith-derived ages of larvae, and satellite-based chlorophyll-a to identify spawning areas of European anchovy from ichthyoplanktonic data, collected in the Strait of Sicily (Central Mediterranean Sea), i.e., the crucial channel in between the European and African continents. We obtain new evidence of ecosystem connectivity between North Africa and recruitment regions off the southern European coasts. We assess this result by using bio-energetic modeling, which predicts species-specific responses to environmental changes by producing quantitative information on functional traits. Our work gives support to a collaborative and harmonized use of Geographical Sub-Areas, currently identified by the General Fisheries Commission for the Mediterranean. It also confirms the need to incorporate climate and environmental variability effects into future marine resources management plans, strategies, and directives

Transitivity and Difunctionality of Bisimulations

International audienceBisimilarity and observational equivalence are notions that agree in many classical models of coalgebras, such as e.g. Kripke structures. In the general category $Set_{F}$-coalgebras these notions may, however, diverge. In many cases, observational equivalence, being transitive, turns out to be more useful.In this paper, we shall investigate the role of transitivity for the largest bisimulation of a coalgebra. Passing to relations between two coalgebras, we choose difunctionality as generalization of transitivity. Since in $Set_{F}$ bisimulations are known to coincide with $\bar{F}-$ simulations, we are led to study the notion of $L-$ similarity, where L is a relation lifting

Coalgebraische Similarität

Bereits bekannt erhält jeder Funktor genau dann schwache Pullbacks, wenn jede Kongruenz eine difunktionale Bisimulation ist. In Kapitel 3 fanden wir äquivalente Aussagen für die schwache Kerpaarerhaltung und die Urbilderhaltung. Ausserdem definierten wir eine Funktorabänderung, die wir Urbildbereinigung nannten. Der resultierende Funktor erhält Urbilder. Die Idee war inspiriert von der Transformation, so dass daraus ein gesunder Funktor entsteht. Der Urbilder erhaltende Funktor hat auch den Vorteil, dass seine Unterfunktoren genau die Urbilder erhaltende Unterfunktoren des ursprünglichen Funktors sind. In Kapitel 4 zeigten wir, dass die monotonen trennbaren Boxen eine korrekte und vollständige Modallogik liefern. Interessant ist, dass die Urbild-Bereinigung des allgemeinen Nachbarschaftsfunktors einen Funktor liefert, der schwache Pullbacks erhält

Larval fish community composition and distribution of the central-southern Mediterranean under summer and winter conditions

Background. The Gulf of Gabès supports an important fishery which is characterized by a great diversity of fish species. Despite this importance, there has been no attempt to examine the whole larval fish assemblage in this area. The aim of this study was to investigate the larval fish communities during summer and winter seasons in the Gulf of Gabès. Materials and methods. Two multidisciplinary surveys were carried out aboard the R/V Hannibal in 2009. A total of 80 and 70 stations were sampled during winter and summer surveys, respectively. Stations were arranged in a regular sampling grid of 10 × 10 nautical miles. Ichthyoplankton was sampled by oblique tows with a Bongo net of 60 cm mouth diameter, fitted with 335 µm mesh nets. Zooplankton dry weight was obtained by drying aliquots of the zooplankton sample in an oven at 60ºC, for 72 hours. Results. In summer 34 taxa representing 24 families, were collected, whereas in winter 35 taxa, representing 16 families, were collected. Larval fish communities were dominated by small pelagic species: sardinella and anchovy in summer and sardine in winter. The results also highlight the Gulf of Gabès as an important spawning ground for many large and medium pelagic fishes, both highly migratory (Thunnus thynnus) and resident species (Auxis rochei, Euthynnus alletteratus). The summer/winter differences observed in species composition and abundance of the larval fish communities reflected the seasonality in fish species spawning in the Mediterranean Sea, likely influenced by the highly contrasting environmental conditions between seasons. Thus, the seasonal changes in the hydrographic conditions of the Gulf of Gabès result in different scenarios that provide suitable spawning environments for a variety of fishes, allowing them to share the Gulf as spawning habitat. Conclusion. The Gulf of Gabès is an important fish spawning area for demersal, small pelagic, medium pelagic, and large pelagic (tunas). Larval species composition differed considerably between summer and winter surveys

Copper-mediated aromatic radiofluorination revisited: Efficient production of PET tracers on a preparative scale

© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Optimization of lubricants for silica micromotors

International audienc

Preliminary 2017 stock assessment results for the eastern and Mediterranean Atlantic bluefin tuna stock

Compared to 2014, the present assessment differs on several respects. During the 2017 data preparatory meetings, number of changes have been presented, among which the revision of the task I and task II statistics, the selection of the indices of abundance. In particular, this led to completely revisit the catch at age matrix. As a consequence, previous model specifications could not be used anymore. Whereas the 2014 assessment updated the catch and abundance index data up to 2013 and used the same model specifications as in the 2012 stock assessment, the present assessment present a complete revisitation of these. VPA2-Box was used to estimate the stock status, using a broad spectrum of settings. The resulting models were tested and compared on the basis of their diagnostics, so that the best models could be identified. In particular, different scenarios for Fratio, variance scaling for indices, recruitment constraints and vulnerability were tested. This document will serve as a basis for the 2017 EBFT stock assessment.En comparación con 2014, la presente evaluación difiere en varios aspectos. Durante la reunión de preparación de datos de 2017, se presentaron varios cambios, entre ellos la revisión de las estadísticas de Tarea I y Tarea II y la selección de los índices de abundancia. En particular, esto condujo a reexaminar completamente la matriz de captura por edad. Como consecuencia, las especificaciones previas del modelo ya no pudieron utilizarse. Mientras que la evaluación de 2014 actualizaba los datos del índice de abundancia y de captura hasta 2013 y utilizaba las mismas especificaciones del modelo que en la evaluación de stock de 2012, la evaluación actual presenta una completa revisión de ellas. Se utilizó el VPA2-Box para estimar el estado del stock, utilizando una amplia gama de ajustes. Se probaron los modelos resultantes y se compararon basándose en sus diagnósticos, para poder identificar los mejores modelos. En particular, se probaron diferentes escenarios para Fratio, varianza escalada para los índices, restricción del reclutamiento y la vulnerabilidad. Este documento servirá como base para la evaluación del stock de atún rojo del Atlántico este de 2017.La prospección aérea francesa en el golfo de León proporciona un importante índice independiente de la pesquería para la evaluación del stock de atún rojo del Atlántico este (EABFT, Thunnus thynnus). El presente documento recuerda la metodología empleada para la prospección y proporciona la actualización del índice para el año 2021, que muestra un ligero descenso respecto a 2020, que fue el año con el valor más elevado hasta la fecha, pero ocupa el tercer puesto en cuanto al valor más alto. Lo que confirma la tendencia al alza de los últimos años