Life-history, ecology and fisheries of cephalopods in the western Mediterranean

Abstract: Cephalopods constitute an important faunistic group in marine ecosystems, representing keystone elements in marine food webs. Additionally, they are an important fishing resource, and their contribution to worldwide fishery landings has been rising significantly over the last decades. In the Mediterranean Sea, several local short-term studies on cephalopod abundance and distribution exist, but few integrate longer time scales and larger areas. The present thesis work combines large-scale, long-term studies on cephalopods community composition, diversity and abundance (Part I) with small-scale, local case studies around the Balearic Islands (Part II). First, a community analysis was conducted at the whole Mediterranean scale in order to describe the present status and reveal possible differences between the western and the eastern Mediterranean sub-basins (Chapter 2). The aim was to compare assemblage structures between sub-basins together with the influence of large-scale environmental gradients on species composition. While basins did not differ significantly in cephalopod species composition, relative species contributions varied. Cephalopods are very sensitive to environmental changes, and adapt quickly due to their short life cycle and typically seasonal semelparity impeding generation buffering. Therefore sea surface temperature (SST) and chlorophyll a (Chl a) were hypothesised and documented as important drivers of cephalopod assemblages. While their importance differed between sub-basins, depth was confirmed as the most important factor structuring cephalopod communities. At the same spatial scale, cephalopod diversity was analysed during two decades (Chapter 3). Results revealed the absence of clear longitudinal or latitudinal gradients in cephalopod diversity, combined with no distinct temporal trends over the last twenty years. Besides, temporal changes in diversity varied between various Mediterranean sub-regions. Location, depth, SST and productivity regime resulted to influence diversity. To assess whether environmental variability impacts cephalopod populations at species level, the influence of SST and surface primary production on the spatial structuring and the population dynamics of two commercially important cephalopod species was investigated (Chapter 4). Although Octopus vulgaris and Illex coindetii exhibit contrasting life history traits and inhabit different habitats, long-term abundance trends and synchronic behaviour of their populations was similar, and population sub-structuring across the Mediterranean Sea were revealed. In consistency with former chapters, SST and Chl a regimes were shown to be significant drivers of distribution patterns and inter-annual abundance fluctuations. The motivation for the second part of the thesis was fuelled by the present situation in the Mediterranean Sea, where cephalopod stocks are presumably overexploited, but where their ad- hoc assessment and management is far from being implemented. To contribute to existing knowledge of the current situation in the Balearic Sea, a case study on cuttlefish fishery, life-history and population dynamics was conducted using short-term and intra-annual data (Chapter 5). Possible drivers of cuttlefish abundance fluctuations were analysed, revealing significant influences of SST and local climatic variability. While the study provided a complete view of the intrinsic and extrinsic drivers of cuttlefish population fluctuations in the Balearic Sea, the next step was applying stock assessment techniques to cuttlefish and squid fisheries of this area (Chapter 6). Being the first application of depletion methods to Mediterranean cephalopod stocks, the study combined information of those two fisheries with the evaluation of this stock assessment method for short life cycle species. Results uncovered existing problems and suggested that the current sampling scheme under the EU-Data Collection Framework is inadequate for cephalopods in view of the assessment´s data requirements. Consequently, a modification of the existing scheme was proposedResumen: Los cefalópodos constituyen un grupo faunístico importante en los ecosistemas marinos, representando elementos clave en la estructura y dinámica de las redes tróficas. Además, son un importante recurso pesquero y su contribución a los desembarcos pesqueros mundiales se ha incrementado significativamente en las últimas décadas. En el Mar Mediterráneo existen varios estudios locales sobre la abundancia y distribución de cefalópodos, pero pocos integran escalas temporales largas y áreas extensas. Esta tesis combina estudios sobre la estructura de la comunidad, la diversidad y la abundancia de cefalópodos a gran escala espacio-temporal (Parte I) con estudios a escala local alrededor de las Islas Baleares (Parte II). En primer lugar, se realizó un análisis de la comunidad de cefalópodos a escala de todo el Mediterráneo para describir el estado actual y determinar posibles diferencias entre las sub- cuencas occidental y oriental (Capítulo 2). El objetivo fue comparar la estructura de las comunidades faunísticas entre estas dos sub-cuencas y analizar la influencia de gradientes ambientales a gran escala sobre la composición específica. Aunque no se observaron diferencias significativas en la composición específica, las contribuciones relativas de las diferentes especies variaron entre ambas cuencas. Debido a su corto ciclo vital y estrategia reproductiva semélpara, los cefalópodos son muy sensibles a los cambios ambientales, adaptándose a ellos con relativa rapidez. Se esperaba, por tanto, que factores ambientales como la temperatura superficial del mar (SST) y el contenido de clorofila a (Chl a) fueran factores importantes en la estructuración de las comunidades de cefalópodos. Si bien su importancia difirió entre las dos sub-cuencas, se confirmó que la profundidad era el factor estructural más importante en dichas comunidades. Se analizaron también cambios en la diversidad específica de las comunidades de cefalópodos a escala de todo el Mediterráneo durante los últimos 20 años (Capítulo 3). Los resultados no mostraron ninguna tendencia temporal ni espacial (latitud, longitud) clara y homogénea en la diversidad. Las únicas tendencias temporales observadas variaron entre diferentes sub-regiones, siendo la posición geográfica, profundidad, SST y productividad los principales factores determinantes de estas tendencias. Para confirmar la importancia de la variabilidad ambiental a nivel específico, se analizó la influencia de la SST y la producción primaria en la estructura espacial y la dinámica poblacional de dos especies de cefalópodos de importancia comercial (Capítulo 4). Aunque Octopus vulgaris e Illex coindetii exhiben diferentes estrategias vitales y viven en diferentes hábitats, las tendencias temporales a largo plazo en su abundancia y el comportamiento sincrónico de sus poblaciones fueron similares, observándose sub-poblaciones temporalmente persistentes a lo largo de todo el Mediterráneo. En consonancia con los capítulos anteriores, la SST y Chla resultaron ser factores significativos en la definición de patrones de distribución y fluctuaciones interanuales de la abundancia. La segunda parte de la tesis estaba motivada por la situación actual de los cefalópodos en el Mar Mediterráneo, donde no existen medidas de evaluación y gestión específica para este grupo y algunas de sus poblaciones se encuentran sobreexplotadas. Para contribuir al conocimiento de la situación actual en el Mar Balear, se analizó la pesquería, ciclo vital y dinámica poblacional de la sepia utilizando series temporales intra-anuales (Capítulo 5). El análisis de diferentes factores ambientales reveló que la SST y la variabilidad climática local influían significativamente en las fluctuaciones de abundancia de la especie. En un trabajo posterior (Capítulo 6) se aplicaron técnicas de evaluación de stocks a las pesquerías de sepia y calamar de las Islas Baleares utilizando datos procedentes de la EU Data Collection Framework (DCF). Hasta donde sabemos, este trabajo constituye la primera aplicación de los Lesly-Delury Depletion Methods a stocks de cefalópodos del Mediterráneo. Los resultados demostraron que el esquema actual de muestreo de la DCF es inadecuado para la evaluación de cefalópodos y se proponen posibles modificacionesResum: Els cefalòpodes constitueixen un grup faunístic important als ecosistemes marins, essent elements clau a les xarxes tròfiques. A més, són importants recursos pesquers i la seva contribució als desembarcs pesquers mundials s’ha incrementat en les últimes dècades. representant al voltant del 30% de la captura desembarcada a nivell mundial. Al Mar Mediterrani existeixen varis estudis locals sobre l’abundància i distribució de cefalòpodes, però pocs integren escales temporals llargues i àrees extenses. Aquesta tesi combina estudis sobre la composició de la comunitat, la diversitat i l’abundància de cefalòpodes a gran escala espaciotemporal (Part I) amb estudis a escala local al voltant de les Illes Balears (Part II). En primer lloc, es va realitzar un anàlisi de les comunitats de cefalòpodes a escala de tot el Mediterrani per descriure l’estat actual i determinar possibles diferències entre les sub-conques occidental i oriental (Capítol 2). L’objectiu fou comparar l’estructura de les comunitats faunístiques entre sub-conques i analitzar la influència de gradients ambientals a gran escala sobre la composició específica. Tot i que no s’observaren diferències significatives en la composició específica, les contribucions relatives de les diferents espècies variaren entre sub-conques. Degut al seu cicle vital curt i estratègia reproductiva semèlpara els cefalòpodes són molt sensibles als canvis ambientals, adaptant-se a ells amb relativa rapidesa. S’esperava, per tant, que factors ambientals com la temperatura superficial del mar (SST) i el contingut de clorofil•la a (Chla) fossin factors importants en l’estructuració de les comunitats de cefalòpodes. Si bé la seva importància va diferir entres les dues sub-conques, es va confirmar que la profunditat era el factor estructural més important en aquestes comunitats. S’analitzaren també canvies en la diversitat específica de les comunitats de cefalòpodes a escala de tot el Mediterrani durant els últims 20 anys (Capítol 3). Els resultats no mostraren cap tendència temporal ni espacial (latitud, longitud) clara i homogènia en la diversitat. Les úniques tendències temporals observades variaren entre diferents sub-regions, essent la posició geogràfica, profunditat, SST i productivitat els principals factors determinants d’aquestes tendències. Per tal de confirmar la importància de la variabilitat ambiental a nivell específic, es va investigar la influència de la SST i la producció primària en l’estructuració espacial i la dinàmica poblacional de dues espècies de cefalòpodes d’importància comercial (Capítol 4). Tot i que Octopus vulgaris i Illex coindetii tenen característiques vitals diferents i viuen en hàbitats diferents, les tendències temporals a llarg plaç en la seva l’abundància i el comportament sincrònic de les seves poblacions va ser similar, observant-se sub-poblacions temporalment persistents al llarg del Mediterrani. En consonància amb els capítols anteriors, la SST i Chla resultaren ser factors significatius en la definició de patrons de distribució i fluctuacions interanuals de l’abundància. La segona part de la tesi estava motivada per la situació actual dels cefalòpodes al Mar Mediterrani, on no existeixen mesures d’avaluació i gestió específica per aquest grup i algunes de les seves poblacions es troben sobre-explotades. Per contribuir al coneixement de la situació actual al Mar Balear, es va analitzar la pesqueria, cicle vital i dinàmica poblacional de la sípia utilitzant sèries temporals intra-anuals (Capítol 5). L’anàlisi de diferents factors ambientals va revelar que la SST i la variabilitat climàtica local influïen significativament en les fluctuacions d’abundància de l’espècie. En un treball posterior (Capítol 6) s’aplicaren tècniques d’avaluació d’stocks a les pesqueries de sípia i calamar de les Illes Balears utilitzant dades procedents de la EU Data Collection Framework (DCF). Fins on sabem, aquest treball constitueix la primera aplicació dels Lesly-Delury Depletion Methods a stocks de cefalòpodes del Mediterrani. Els resultats demostraren que l’esquema actual de mostratge de la DCF és inadequat per a l’avaluació de cefalòpodes i es proposen posibles modificacion

GROMACS Stochastic Dynamics and BAOAB are equivalent configurational sampling algorithms

Two of the most widely used Langevin integrators for molecular dynamics simulations are the GROMACS Stochastic Dynamics (GSD) integrator and the splitting method BAOAB. We show that the GROMACS Stochastic Dynamics integrator is equal to the less frequently used splitting method BAOA. It immediately follows that GSD and BAOAB sample the same configurations and have the same high configurational accuracy. Our numerical results indicate that GSD/BAOA has higher kinetic accuracy than BAOAB

Path probability ratios for Langevin dynamics -- exact and approximate

Path reweighting is a principally exact method to estimate dynamic properties from biased simulations - provided that the path probability ratio matches the stochastic integrator used in the simulation. Previously reported path probability ratios match the Euler-Maruyama scheme for overdamped Langevin dynamics. Since MD simulations use Langevin dynamics rather than overdamped Langevin dynamics, this severely impedes the application of path reweighting methods. Here, we derive the path probability ratio $M_L$ for Langevin dynamics propagated by a variant of the Langevin Leapfrog integrator. This new path probability ratio allows for exact reweighting of Langevin dynamics propagated by this integrator. We also show that a previously derived approximate path probability ratio $M_{\mathrm{approx}}$ differs from the exact $M_L$ only by $\mathcal{O}(\xi^4\Delta t^4)$, and thus yields highly accurate dynamic reweighting results. ($\Delta t$ is the integration time step, $\xi$ is the collision rate.) The results are tested and the efficiency of path-reweighting is explored using butane as an example

Reading books in the second half of life: What correlations are there with aspects of quality of life and health?

This DZA Aktuell is intended to provide an initial contribution on book reading and possible positive correlations with health-related aspects in the second half of life. In addition to differentiations according to age, gender and educational status, correlations between the volume of reading and emotional well-being (positive affect), subjective health and cognitive performance are presented. Key messages: The average number of books read has remained largely stable over the last 20 years. People between the ages of 46 and 85 read an average of eight to nine books a year between 2008 and 2021, compared to just seven in 2002. Around two-fifths of people in the second half of life are avid readers, reading at least 6 books a year. A good quarter of all respondents, on the other hand, do not read at all. A differentiation by education and gender clearly shows that highly educated people and women are particularly likely to be avid readers. In 2021, around half belonged to the group of avid readers, but also a good quarter of respondents with a low level of education. However, reading has nothing to do with age. All age groups read roughly the same amount. Over 85 per cent of avid readers reported positive feelings. Among non-readers, this proportion was significantly lower at 72 per cent to 79 per cent. Almost two thirds of avid readers rate their health as good or very good. Among non-readers, on the other hand, there are roughly as many people with poor as good subjective health. In the cognition test conducted in 2017, 96 per cent of avid readers scored well. This was only the case for around 89 per cent of non-reader

Life-history, ecology and fishery of Sepia officinalis in the western Mediterranean

Cephalopods constitute important resources for different Mediterranean fisheries such as trawl, artisanal and recreational fleets. Cuttlefish (Sepia officinalis) has been caught there from ancient times on and holds an important seasonal artisanal fishery in the Balearic Islands (western Mediterranean). This fishery takes advantage of the reproductive migration to coastal waters of large, mature individuals, even though the species is also taken by bottom trawlers throughout the year. In this study we used data from the following sources to analyze different aspects of cuttlefish biology, ecology and fishery in the western Mediterranean: 1) monthly biological and size samplings of individuals caught by artisanal boats (2007-08); 2) size samplings on board ofcommercial bottom trawlers (2001-11); 3) biological and size samplings on spring scientific surveys (2001-11); and 4) official fishery statistics from 1965 to the present. The main objectives of this study are twofold. First, use all this information to generate a comprehensive insight on the life cycle of this species linking ecology and life-history traits to seasonal fishery trends. Secondly, analyze interannual variations on landings and the relationship with different environmental parameters (e.g. moon, temperature, climatic indices). Biological (N=950 individuals) and size frequency samplings were used to estimate different species and population parameters such as length-weight relationships, sex- ratio, population structure and dynamics, gonadosomadic index and fecundity. The vast majority of individuals caught by the artisanal fishery between January and July were sexually mature, which confirms the reproductive migration to coastal waters during spring. The clear seasonal trend observed in cuttlefish landings also tallies with this migration, since catches show a marked peak in March-April. Although landings display a sawtooth like pattern from 1965 to 2011 with historical maximums in 1991 and 2005, there is a general increasing trend with time, especially from mid-1990

Microtubular Gas Diffusion Electrode Based on Ruthenium-Carbon Nanotubes for Ambient Electrochemical Nitrogen Reduction to Ammonia

The drawback of the energy-intensive Haber-Bosch process promotes the research and development of alternative ammonia (NH3) synthesis approaches. The electrochemical nitrogen (N2) reduction reaction (eNRR) may offer a promising method to produce NH3 independent of fossil-fuel-based hydrogen production. However, the low solubility and the low-efficiency mass transport of N2 in aqueous electrolytes are still among the challenges facing the feasibility of eNRR. Herein, we demonstrate a microtubular ruthenium-carbon nanotube gas diffusion electrode (Ru−CNT GDE), for the first time, applying it to electrochemical NH3 synthesis in an H-type cell under ambient conditions. The highest reported Ru-catalyzed NH3 yield rate of 2.1×10−9 mol/cm2 s and high faradaic efficiency of 13.5 % were achieved, showing the superior effect of Ru−CNT GDEs on the eNRR performance. This work provides a new approach for the design and fabrication of self-standing catalyst-loaded GDEs for eNRR. © 2020 The Authors. ChemElectroChem published by Wiley-VCH Gmb

The use of Depletion methods to assess Mediterranean cephalopod stocks under the current EU Data Collection Framework

Fuelled by the increasing importance of cephalopod fisheries in Europe, scientists and stakeholders have demanded their assessment and management. However, little has been done to improve the data collection under the EU Data Collection Framework (DCF) in order to analyse cephalopod populations. While the DCF allows member states to design flexible national sampling programmes, it establishes the minimum data requirements (MDR) each state is obliged to fulfil. This study was performed to investigate whether such MDR currently set by the DCF allow the application of depletion models (DMs) to assess European cephalopod stocks. Squid and cuttlefish fisheries from the western Mediterranean were used as a case study. This study sheds doubt on the suitability of the MDR to properly assess and manage cephalopod stocks by means of DMs. Owing to the high plasticity of life-history traits in cephalopod populations, biological parameters should be estimated during the actual depletion period of the fished stocks, rather than performing triennial sampling as established by the DCF. In order to accurately track the depletion event, the rapid growth rates of cephalopods implies that their populations should be monitored at shorter time scales (ideally weekly or biweekly) instead of quarterly as specified by the DCF. These measures would not require additional resources of the ongoing DCF but a redistribution of sampling efforts during the depletion period. Such changes in the sampling scheme could be designed and undertaken by the member states or directly integrated as requirements.This study was performed under the Data Collection Framework (cofunded by the EU and the Spanish Institute of Oceanography, IEO) and the CONFLICT project (CGL2008-958; funded by the Spanish Ministry of Science and Innovation). SK was financed by an IEO-FPI grant (2011/11)Peer Reviewe

miR-34a-5p as molecular hub of pathomechanisms in Huntington's disease

Background Although a pivotal role of microRNA (miRNA, miR) in the pathogenesis of Huntington’s disease (HD) is increasingly recognized, the molecular functions of miRNAs in the pathomechanisms of HD await further elucidation. One of the miRNAs that have been associated with HD is miR-34a-5p, which was deregulated in the mouse R6/2 model and in human HD brain tissues. Methods The aim of our study was to demonstrate interactions between miR-34a-5p and HD associated genes. By computational means we predicted 12 801 potential target genes of miR-34a-5p. An in-silico pathway analysis revealed 22 potential miR-34a-5p target genes in the KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway “Huntington’s disease”. Results Using our high-throughput miRNA interaction reporter assay (HiTmIR) we identifed NDUFA9, TAF4B, NRF1, POLR2J2, DNALI1, HIP1, TGM2 and POLR2G as direct miR-34a-5p target genes. Direct binding of miR-34a-5p to target sites in the 3’UTRs of TAF4B, NDUFA9, HIP1 and NRF1 was verifed by a mutagenesis HiTmIR assay and by determining endogenous protein levels for HIP1 and NDUFA9. STRING (Search Tool for the Retrieval of Interacting Genes/Proteins) analysis identifed protein–protein interaction networks associated with HD like “Glutamine Receptor Signaling Pathway” and “Calcium Ion Transmembrane Import Into Cytosol”. Conclusion Our study demonstrates multiple interactions between miR-34a-5p and HD associated target genes and thereby lays the ground for future therapeutic interventions using this miRNA

Insights into Male Androgenetic Alopecia: Differential Gene Expression Profiling of Plucked Hair Follicles and Integration with Genetic Data

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