Atlantic salmon survival at sea: temporal changes that lack regional synchrony

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Atlantic salmon survival at sea: temporal changes that lack regional synchrony

Spatial and temporal synchrony in abundance or survival trends can be indicative of whether populations are affected by common environmental drivers. In Atlantic salmon (Salmo salar), return rates to natal rivers have generally been assumed to be affected primarily by shared oceanic conditions, leading to spatially synchronous trends in mortality. Here, we investigated the existence of parallel trends in salmon sea survival, using data on migrating smolts and returning adults from seven Canadian populations presumed to share feeding grounds. We analysed sea survival, using a Bayesian change-point model capable of detecting nonstationarity in time series data. Our results indicate that while salmon have experienced broadly comparable patterns in survival, finer-scale temporal shifts are not synchronous among populations. Our findings are not consistent with the hypothesis that salmon populations consistently share the same mortality-related stressors in the marine environment. Although populations may have shared greater synchrony in survival patterns in the past, this synchrony may be breaking down. It may be prudent to direct greater attention to smaller-scale regional and population-level correlates of survival.publishedVersio

Estudio mineralógico, textural y físico-mecánico de morteros de cal hidráulica curados en distintas condiciones de humedad relativa

This work focuses on the chemical-mineralogical, textural and physical-mechanical properties of hydraulic lime mortars made with siliceous and calcareous aggregate. Mortars were cured at 60% and 90% of relative humidity, so as to assess the variability of mortar petrophysical properties in the hardened state due to the moisture conditions. The final aim was to determine the most adequate moisture conditions to be maintained during application and hardening of hydraulic mortars intended for repair interventions. We found out that using a calcareous aggregate and curing mortar at 90% of relative humidity give place to better textural and mechanical properties. However, these characteristics mostly depend on the maximum size of the aggregate grains, which should be smaller than 6 mm, in order to avoid the occurrence of mechanical discontinuities in the mortar.En este trabajo se han estudiado las propiedades químico-mineralógicas, texturales y físico-mecánicas de morteros de cal hidráulica elaborados con áridos silíceo y calcítico. Estos morteros se han curado al 60% y 90% de humedad relativa, con el fin de evaluar las eventuales diferencias en las propiedades petrofísicas de los morteros una vez endurecidos y así establecer cuál de los dos ambientes es recomendable durante la aplicación y fraguado de morteros de cal hidráulica destinados a obras de restauración. Se ha encontrado que el uso de un árido de composición calcítica y el curado al 90% de humedad relativa dan lugar a morteros hidráulicos con mejores características texturales y propiedades mecánicas. De todas formas, estas características dependen principalmente del tamaño máximo del árido empleado, que debería ser inferior a 6 mm para evitar discontinuidades mecánicas en el mortero

Population productivity of shovelnose rays: inferring the potential for recovery

Copyright: This is an open access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication. There is recent evidence of widespread declines of shovelnose ray populations (Order Rhinopristiformes) in heavily fished regions. These declines, which are likely driven by high demand for their fins in Asian markets, raises concern about their risk of over-exploitation and extinction. Using life-history theory and incorporating uncertainty into a modified Euler-Lotka model, the maximum intrinsic rates of population increase (rmax) were estimated for nine species from four families of Rhinopristiformes, using four different natural mortality estimators. Estimates of mean rmax, across the different natural mortality methods, varied from 0.03 to 0.59 year-1 among the nine species, but generally increased with increasing maximum size. Comparing these estimates to rmax values for other species of chondrichthyans, the species Rhynchobatus australiae, Glaucostegus typus, and Glaucostegus cemiculus were relatively productive, while most species from Rhinobatidae and Trygonorrhinidae had relatively low rmax values. If the demand for their high-value products can be addressed then population recovery for some species is likely possible, but will vary depending on the species

Maximum Intrinsic Rate of Population Increase in Sharks, Rays, and Chimaeras: The Importance of Survival to Maturity

The maximum intrinsic rate of population increase rmax  is a commonly estimated demographic parameter used in assessments of extinction risk. In teleosts, rmax can be calculated using an estimate of spawners per spawner, but for chondrichthyans, most studies have used annual reproductive output b instead. This is problematic as it effectively assumes all juveniles survive to maturity. Here, we propose an updated rmax equation that uses a simple mortality estimator which also accounts for survival to  maturity: the reciprocal of average lifespan. For 94 chondrichthyans, we now estimate that rmax values are on average 10% lower than previously published. Our updated rmax estimates are lower than previously published for species that mature later relative to maximum age and those with high annual fecundity. The most extreme discrepancies in rmax values occur in species with low age at maturity and low annual reproductive output. Our results indicate that chondrichthyans that mature relatively later in life, and to a lesser extent those that are highly fecund, are less resilient to fishing than previously thought

Estudio mineralógico, textural y físico-mecánico de morteros de cal hidráulica curados en distintas condiciones de humedad relativa

This work focuses on the chemical-mineralogical, textural and physical-mechanical properties of hydraulic lime mortars made with siliceous and calcareous aggregate. Mortars were cured at 60% and 90% of relative humidity, so as to assess the variability of mortar petrophysical properties in the hardened state due to the moisture conditions. The final aim was to determine the most adequate moisture conditions to be maintained during application and hardening of hydraulic mortars intended for repair interventions. We found out that using a calcareous aggregate and curing mortar at 90% of relative humidity give place to better textural and mechanical properties. However, these characteristics mostly depend on the maximum size of the aggregate grains, which should be smaller than 6 mm, in order to avoid the occurrence of mechanical discontinuities in the mortar.En este trabajo se han estudiado las propiedades químico-mineralógicas, texturales y físico-mecánicas de morteros de cal hidráulica elaborados con áridos silíceo y calcítico. Estos morteros se han curado al 60% y 90% de humedad relativa, con el fin de evaluar las eventuales diferencias en las propiedades petrofísicas de los morteros una vez endurecidos y así establecer cuál de los dos ambientes es recomendable durante la aplicación y fraguado de morteros de cal hidráulica destinados a obras de restauración. Se ha encontrado que el uso de un árido de composición calcítica y el curado al 90% de humedad relativa dan lugar a morteros hidráulicos con mejores características texturales y propiedades mecánicas. De todas formas, estas características dependen principalmente del tamaño máximo del árido empleado, que debería ser inferior a 6 mm para evitar discontinuidades mecánicas en el mortero.This study was financially supported by the Spanish research group RNM179 of the Junta de Andalucía, by the research project MAT-2012-34473 and by the Institute of Conservation and Restoration of Cultural Heritage of the CICOP foundation (ICON-CICOP)

Delay model for the dynamics of information units in the digital environment

The digital revolution has transformed the exchange of information between people, blurring the traditional roles of sources and recipients as active and passive entities. To study this, we build on a publicly available database of quotes, organized as units of information flowing through media and blogs with minimal distortion. Building on this, we offer an innovative interpretation of the observed temporal patterns through a minimal model with two ingredients: a two-way feedback between sources and recipients, and a delay in the media’s response to activity on blogs. Our model successfully fits the variety of observed patterns, revealing different attention decays in media and blogs, with rebounds of information typically occurring between 1 and 4 days after the initial dissemination. More important perhaps, the model uncovers a functional relationship between the rate of information flow from media to blogs and the decay of public attention, suggesting a simplification in the mechanisms of information exchange in digital media. Although further research is required to generalize these findings fully, our results demonstrate that even a bare-bones model can capture essential mechanisms of information dynamics in the digital environment

Trends in marine survival of Atlantic salmon populations in eastern Canada

Declines in wild Atlantic salmon (Salmo salar) abundance throughout the north Atlantic are primarily attributed to decreases in survival at sea. However, comparing trends in marine survival among populations is challenging as data on both migrating smolts and returning adults are sparse and models are difficult to parameterize due to their varied life histories. We fit a hierarchical Bayesian maturity schedule model to data from seven populations in eastern Canada to estimate numbers of out-migrating smolts, survival in the first and second year at sea, and the proportion returning after 1 year. Trends in survival at sea were not consistent among populations; we observe positive, negative, and no correlations in these, suggesting that large-scale patterns of changes in marine survival are not necessarily representative for individual populations. Variation in return abundances was mostly explained by marine survival in the first winter at sea in all but one population. However, variation in the other components were not negligible and their relative importance differed among populations. If salmon populations do not respond in a uniform manner to changing environmental conditions throughout their range, future research initiatives should explore why.publishedVersio

ESTRATIGRAFÍA DEL NEÓGENO SUPERIOR AL SUR DE LA CUENCA TUMACO (PACÍFICO COLOMBIANO): LA FORMACIÓN CASCAJAL, PROPUESTA DE REDEFINICIÓN LITOESTRATIGRÁFICA

The stratigraphic knowledge of the sedimentary fill of the Tumaco onshore fore-arc basin is relatively poor. Previous works are based on the study of seismic lines and wells for hydrocarbon exploration with minor emphasis on the surface segments. We present a detailed study of the late Miocene - Pliocene rocks that outcrop in the southern Tumaco basin. New stratigraphicdata from the ANH-Tumaco 1-ST-S well represent the most complete and best preserved sections for this time interval. This information is integrated with new data from descriptions of ~200 m of stratigraphic sections visited in the coastal cliffs of the Tumaco bay and the Patia river. The detailed descriptions of these locations following parameters from stratigraphic codes allow us to propose the use of the term Cascajal Formation to refer to volcanoclastic rocks of Messinian – Zanclean age. This succession, with an estimated thickness of up to 405 m, is composed mainly of thick lenticular and undulated layers of sandstones and conglomerates, with an important volcanic input. Minor interbedded mudstones and muddy sandstones are present too. Locally, ichnofossils, bivalves, gastropods, foraminifera, echinoderms, crustaceans and well-preserved plant remains were preserved, interpreted as formed in a deltaic system influenced by volcanism.  El conocimiento estratigráfico del relleno sedimentario del segmento onshore de la cuenca de ante-arco Tumaco es poco conocido y los trabajos existentes se fundamentan en el estudio de líneas sísmicas y pozos para la exploración de hidrocarburos, haciendo poco énfasis en las unidades más superficiales. Se presenta el estudio detallado de las rocas del Mioceno superior – Plioceno expuestas en el sector sur de la cuenca Tumaco. Los nuevos datos estratigráficos del pozo ANH-Tumaco 1-ST-S representan la sección más completa y mejor preservada de este intervalo de tiempo. Se integró esta información con nuevos datos de ~200 m de secciones estratigráficas levantadas en afloramientos de los acantilados de la bahía de Tumaco y del río Patía. A partir de la descripción detallada de estas localidades, y siguiendo los parámetros de los códigos estratigráficos, se propone emplear el término Formación Cascajal para referirse a las rocas volcanoclásticas de edad Messiniense parte superior a Zancliense. Esta sucesión con un espesor observado de hasta 405 m está conformada principalmente por gruesos estratos lenticulares y ondulados de arenitas y conglomerados, con alto contenido de detritos volcánicos, en menor proporción, interestratificaciones de lodolitas y arenitas lodosas, localmente con icnofósiles y fósiles de bivalvos, gasterópodos, foraminíferos, equinodermos, crustáceos y restos de plantas bien conservadas, depositados en un ambiente de sedimentación deltaico influenciado por vulcanismo. &nbsp

ESTRATIGRAFÍA DEL NEÓGENO SUPERIOR AL SUR DE LA CUENCA TUMACO (PACÍFICO COLOMBIANO): LA FORMACIÓN CASCAJAL, PROPUESTA DE REDEFINICIÓN LITOESTRATIGRÁFICA

The stratigraphic knowledge of the sedimentary fill of the Tumaco onshore fore-arc basin is relatively poor. Previous works are based on the study of seismic lines and wells for hydrocarbon exploration with minor emphasis on the surface segments. We present a detailed study of the late Miocene - Pliocene rocks that outcrop in the southern Tumaco basin. New stratigraphicdata from the ANH-Tumaco 1-ST-S well represent the most complete and best preserved sections for this time interval. This information is integrated with new data from descriptions of ~200 m of stratigraphic sections visited in the coastal cliffs of the Tumaco bay and the Patia river. The detailed descriptions of these locations following parameters from stratigraphic codes allow us to propose the use of the term Cascajal Formation to refer to volcanoclastic rocks of Messinian – Zanclean age. This succession, with an estimated thickness of up to 405 m, is composed mainly of thick lenticular and undulated layers of sandstones and conglomerates, with an important volcanic input. Minor interbedded mudstones and muddy sandstones are present too. Locally, ichnofossils, bivalves, gastropods, foraminifera, echinoderms, crustaceans and well-preserved plant remains were preserved, interpreted as formed in a deltaic system influenced by volcanism.  El conocimiento estratigráfico del relleno sedimentario del segmento onshore de la cuenca de ante-arco Tumaco es poco conocido y los trabajos existentes se fundamentan en el estudio de líneas sísmicas y pozos para la exploración de hidrocarburos, haciendo poco énfasis en las unidades más superficiales. Se presenta el estudio detallado de las rocas del Mioceno superior – Plioceno expuestas en el sector sur de la cuenca Tumaco. Los nuevos datos estratigráficos del pozo ANH-Tumaco 1-ST-S representan la sección más completa y mejor preservada de este intervalo de tiempo. Se integró esta información con nuevos datos de ~200 m de secciones estratigráficas levantadas en afloramientos de los acantilados de la bahía de Tumaco y del río Patía. A partir de la descripción detallada de estas localidades, y siguiendo los parámetros de los códigos estratigráficos, se propone emplear el término Formación Cascajal para referirse a las rocas volcanoclásticas de edad Messiniense parte superior a Zancliense. Esta sucesión con un espesor observado de hasta 405 m está conformada principalmente por gruesos estratos lenticulares y ondulados de arenitas y conglomerados, con alto contenido de detritos volcánicos, en menor proporción, interestratificaciones de lodolitas y arenitas lodosas, localmente con icnofósiles y fósiles de bivalvos, gasterópodos, foraminíferos, equinodermos, crustáceos y restos de plantas bien conservadas, depositados en un ambiente de sedimentación deltaico influenciado por vulcanismo. &nbsp