Minimising discards while taking revenue into account : spatio-temporal assessment of catches in an artisanal shrimp trawl fishery in Peru

Funding: Newton Fund (414695818); University of St Andrews Impact and Innovation 2021; Fondo Nacional de Desarrollo Científico Tecno 2018-222.Around 4.2 million tonnes of fish and other species, some of which are of conservation concern, are discarded every year in bottom trawl fisheries. This study focusses on a small-scale shrimp trawl fishery located in northern Peru that operates with high level of discards which causes conflict with other local fishers. Despite trawling being an illegal activity within the 5NM off the coast, this fishery has been operating in these inshore areas for over 40 years because it sustains the well-being of hundreds of fishers. This study aimed to identify the factors that affect the spatio-temporal variation in catches in order to propose recommendations that can be adopted by fishers to minimise their impact on the ecosystem while still providing economic opportunities. The spatial distributions of shrimp, main commercial species and discards were modelled over time using hierarchical generalised additive models. Strong spatio-temporal variation was observed for all catch components and moon phase affected commercial species and discards differently. The results show that, to reduce the environmental impacts of this fishery in the short-term, the fishing area could be divided into north and south and that fishing activities should be limited to the southern area in the autumn. Other recommendations rely on temporal closures during the week of the first quarter of the moon phase. Finally, considering the institutional weaknesses in monitoring, control and surveillance, we suggest that the only realistic approach to reduce the fishery's environmental impacts in the short-term is to foster the willingness of fishers to adopt responsible fishing practices. Yet, long-term solutions will require comprehensive co-management efforts.Publisher PDFPeer reviewe

Incorporating Biotic Information in Species Distribution Models: A Coregionalized Approach

In this work, we discuss the use of a methodological approach for modelling spatial relationships among species by means of a Bayesian spatial coregionalized model. Inference and prediction is performed using the integrated nested Laplace approximation methodology to reduce the computational burden. We illustrate the performance of the coregionalized model in species interaction scenarios using both simulated and real data. The simulation demonstrates the better predictive performance of the coregionalized model with respect to the univariate models. The case study focus on the spatial distribution of a prey species, the European anchovy (Engraulis encrasicolus), and one of its predator species, the European hake (Merluccius merluccius), in the Mediterranean sea. The results indicate that European hake and anchovy are positively associated, resulting in improved model predictions using the coregionalized model.Postprin

Identifying the best fishing-suitable areas under the new European discard ban

The spatial management of fisheries has been repeatedly proposed as a discard mitigation measure. A number of studies have assessed the fishing suitability of an area based on units of by-catch or discard per unit effort. However, correct identification of fishing-suitable areas should assess biomass loss with respect to the benefits. This study therefore, proposes the analysis of by-catch ratios, which do represent benefit vs. loss and are standardized to a wide range of effort characteristics. Furthermore, our study proposes the use of two ratios: the proportion of total unwanted biomass out of the total catch as an indicator of the overall ecological impact, and the proportion of unwanted but regulated species biomass as a proxy for the economic impact on fishers resulting from the new European discard ban that prohibits the discard of regulated species. These discard ratios are modelled by means of a Bayesian hierarchical model, specifically, a spatio-temporal beta regression model, which has several advantages over the traditional arcsine transformation. Results confirm the standardizing capacity of by-catch ratios across vessels and identify at least two economically fishing-suitable areas where discards ratios are minimized by reducing unwanted catch

Modeling discards in Trawling Mediterranean Northern Alboran Sea Fishery

Target and Bycatch species metrics estimated from fishery-dependent data were explored to assess their use in governance of habitat conservation in respect to fisheries. Fishing data collected by onboard observers in otter-trawl boats between 2011 and 2012 at monthly sampling frequency in the Alboran Sea (Western Mediterranean) were used to build maps of sensitivity to fishing stress. Maps were drawn by means kriging interpolation techniques of biomass and abundance (Catch Per Unit of Effort, CPUE) in kilogram and number per fishing hour of blue whiting (Micromesistius poutassou), European hake (Merluccius merluccius), and red mullets (Mullus barbatus and Mullus surmuletus) target species, seabreams (Pagellus acarne, Pagellus bogaraveo, and Pagellus erythrinus), and mackerels (Trachurus mediterraneus, Trachurus trachurus, and Trachurus picturatus) bycatch species and Bogue (Boops boops) bycatch discarded species. Modelling discards by means Generalised Additive Models (GAMs) use environmental (sea surface temperature and chlorophyll-a from satellite data and NAO climatic index); spatial (latitude, longitude, depth and port) and temporal (season, haul duration, moon phase), as well as technical (boat length and power) explanatory variables. The main causes of discards, for both target and bycatch species, are associated to the seasonality of the recruitment and the changes on the spatial distribution of habitat preferences along their ontogeny. Environmental variables did not reveal significant effects, showing that operational oceanography standard products must be not enough to assess discards, and therefore products providing information on specific ecological processes to discards must be designed with this purpose. In Bycatch species, such as sea breams, mackerels and bogue, discards were also highly dependent of the port and boat (fleet/boat strategies, power, etc, and market preferences). The higher discards corresponded to these bycatch pelagic or bentho-pelagic species. Keywords: Discards, Otter-trawl fisheries, fishery conservation, operational oceanography, spatial modelin

Long-term coexistence between the macroalga Caulerpa prolifera and the seagrass Cymodocea nodosa in a Mediterranean lagoon

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Tuning the Magnetic Anisotropy of Lanthanides on a Metal Substrate by Metal–Organic Coordination

Taming the magnetic anisotropy of lanthanides through coordination environments is crucial to take advantage of the lanthanides properties in thermally robust nanomaterials. In this work, the electronic and magnetic properties of Dy-carboxylate metal–organic networks on Cu(111) based on an eightfold coordination between Dy and ditopic linkers are inspected. This surface science study based on scanning probe microscopy and X-ray magnetic circular dichroism, complemented with density functional theory and multiplet calculations, reveals that the magnetic anisotropy landscape of the system is complex. Surface-supported metal–organic coordination is able to induce a change in the orientation of the easy magnetization axis of the Dy coordinative centers as compared to isolated Dy atoms and Dy clusters, and significantly increases the magnetic anisotropy. Surprisingly, Dy atoms coordinated in the metallosupramolecular networks display a nearly in-plane easy magnetization axis despite the out-of-plane symmetry axis of the coordinative molecular lattice. Multiplet calculations highlight the decisive role of the metal–organic coordination, revealing that the tilted orientation is the result of a very delicate balance between the interaction of Dy with O atoms and the precise geometry of the crystal field. This study opens new avenues to tailor the magnetic anisotropy and magnetic moments of lanthanide elements on surfaces.The ALBA synchrotron is acknowledged for providing beam time at BOREAS beamline (proposal number 2015091454). This project has received funding from the European Research Council (ERC, grant 766555) and Marie Sklodowska-Curie Actions (MSCA, project 894924) under the European Union's Horizon 2020 research and innovation programme. This work has been financed by the Spanish Ministerio de Economía, Industria y Competitividad (projects FIS2016-78591-C3-1-R, RTI2018-097895-B-C42, MAT2016-78293-C6-2-R, MAT2017-85089-C2-1-R, and PID2019-107338RB-C65); the Comunidad de Madrid (Projects S2013/MIT-2850, P2018/NMT4321, and S2018/NMT-4367); the European Regional Development Fund (ERDF) under the program Interreg V-A España-Francia-Andorra (Contract No. EFA 194/16 TNSI); and “Severo Ochoa” Programme for Centres of Excellence in R&D (grants SEV-2016-0686, and SEV-2017-0706)

Nanoscale properties of self-assembled and laterally nanostructured surface systems

Las microscopías de campo cercano en general (SPM) y la microscopia de fuerzas (SFM) en particular, se han convertido en una poderosa herramienta en nanotecnología, ya que permiten tanto caracterizar como manipular las superficies de los materiales en la nanoescala. En el presente trabajo de investigación se han estudiado las propiedades morfológicas, mecánicas, electrostáticas y de conducción de sistemas autoensamblados y nanoestructurados que incluyen películas delgadas orgánicas y superficies inorgánicas mediante estas técnicas de SPM, SFM y microscopía de efecto túnel (STM), en condiciones de ambiente controlado. Nos centramos principalmente en el uso de técnicas de SFM en modos de operación de contacto, dinámico, microscopía de fuerzas de fricción (FFM), conductividad con SFM (CSFM) y microscopía de sonda Kelvin (KPFM). El manuscrito de la tesis está organizado del siguiente modo: en el capítulo 1 se exponen las motivaciones del trabajo y en el capítulo 2 se hace una pequeña introducción al concepto de autoensamblado y a los sistemas nanoestructurados en los sistemas bajo estudio, películas delgadas orgánicas y superficies inorgánicas. En el capítulo 3 se introducen las distintas técnicas y procedimientos experimentales. Se explican las características generales del SPM, haciendo particular hincapié en los modos de operación de SFM empleados. En el mismo capítulo se explican los procedimientos empleados para el crecimiento de películas delgadas orgánicas, incluyendo los métodos químicos de solución molecular, la litografía "microcontact printing" ( μCP) y la deposición de moléculas orgánicas por haces moleculares (OMBD). En el capítulo 4 investigamos el impacto de la estructura supramolecular de las capas orgánicas autoensambladas (SAMs) en las propiedades morfológicas, electrostáticas y de conducción de superficies funcionalizadas. Con este propósito y para poder realizar un análisis comparativo basado en el uso de referencias in-situ, estudiamos la SAM formada por dos fases supramoleculares de la misma molécula CH3(C6H4)2(CH2)4SH) (BP4) coexistiendo en la superficie Au(111). Mostramos como la organización supramolecular (estructura interna de la película orgánica) es un factor decisivo que determina las propiedades de la superficie y demostramos como la técnica FFM puede emplearse, por ejemplo, para diferenciar dominios moleculares de distinta orientación cristalina. Además, gracias al uso combinado del STM y CSFM en medidas de transporte electrónico, interpretamos la diferencia en la altura aparente medida por una u otra técnica en películas orgánicas inhomogéneas. En el capítulo 5 estudiamos las propiedades de la superficie SrTiO3 (001) nanoestructurada. La nanoestructuración en este caso viene dada por la coexistencia de las dos posibles terminaciones, TiO2 y SrO, lateralmente diferenciadas, que empleamos como plantilla para la adsorción selectiva de SAMs. Demostramos que la molécula de ácido esteárico (con funcionalidad COOH) se adsorbe selectivamente en la superficie TiO2 y estudiamos el impacto de su adsorción sobre las propiedades mecánicas y electrostáticas de la superficie. Así, describimos las principales características de la superficie SrTiO3 (001) nanoestructurada, la adsorción de la SAM en la superficie TiO2 y discutimos el impacto de esta adsorción en las propiedades de la superficie. Finalmente, en el capítulo 6 presentamos dos efectos inducidos por la punta del SFM susceptibles de usarse para la manipulación local y controlada de películas orgánicas. Mostramos el crecimiento de multicapas de pentaceno inducido mecánicamente y un efecto de pelado de capas moleculares al aplicar voltajes entre una punta conductora y materiales moleculares conductores, un efecto a tener en cuenta en el diseño de futuros dispositivos en electrónica molecular.The present work lies within the scope of the morphological, mechanical, electrostatic and conductive characterization of self-assembled and nanostructured systems, including organic thin films and inorganic surfaces. Scanning probe microscopy (SPM) techniques, in general, and scanning force microscopy (SFM), in particular has become one of the most powerful tools in nanotechnology because they offer the combined capability of surface properties characterization and manipulation of material surfaces in the nanoscale. In this work we make use of SPM techniques, both SFM and scanning tunneling microscopy (STM), under controlled ambient conditions for the characterization and manipulation of different self-assembled and nanostructured systems. We mainly focus on the use of SFM in contact, dynamic, friction force microscopy (FFM), conductive scanning force microscopy (CSFM) and Kelvin probe force microcopy (KPFM) operating modes for such a purpose. The thesis is organized in the following way: the motivations for this work are presented in chapter 1, and a short introduction to the self-assembled concept and nanostructured systems in organic thin films and inorganic surfaces is done in chapter 2. Chapter 3 introduces the fundamental description of the experimental techniques and procedures used. The main experimental characterization SPM techniques are introduced and a particular attention is devoted to explain the different SFM techniques used. In the same chapter, the growth techniques of organic thin film are explained, including, the solution based methods, the soft lithography μ-contact printing (μCP) and the organic molecular beam deposition (OMBD). In chapter 4 we investigate the influence of the supramolecular structure of self-assembled monolayers (SAMs) into the morphological, mechanical, electrostatic and conductive properties of a functionalized surface. For this purpose we study the CH3(C6H4)2(CH2)4SH) (BP4) molecule SAM on the Au(111) surface presenting two different coexisting supramolecular arrangements. We show how the supramolecular order of the SAM is a decisive factor influencing the nanoscale properties of the surface and also demonstrate how FFM can be employed to differentiate SAM domains with different orientation. In addition, based on electron current measurements, the combined use of STM and CSFM allows us interpreting the differences in apparent height as measured by one or the other technique in non-homogeneous organic layers. In chapter 5 we study the properties of the nanopatterned SrTiO3 (001) surface and explore its use as template for the selective adsorption of SAMs. We find that stearic acid molecules (containing a COOH headgroup) selectively chemisorb on the TiO2 surface. This fact allows us to investigate SAMs adsorption influence on the mechanical and electrostatic properties of this oxide surface. We address the main characteristics of the nanopatterned SrTiO3 (001) surface and we describe the selective adsorption of SAMs on the TiO2 surface, discussing how this influences the local mechanical and electrostatic properties of the surface. Finally, in chapter 6 we present two different tip-induced effects which can be use to manipulate organic thin film materials. We address the mechanical induced growth of pentacene molecular layers, a phenomena that can be used as a local nanolithography approach for nanostructuration. And we also provide a way for peeling a layered organic molecular material when a voltage is applied between the conducting system and the conducting probe of the SFM, which is important to take into account for the design of organic electronic devices