Depredación sobre el erizo diadema aff. antillarum en blanquizales de las Islas Canarias

Experimental studies were carried out to determine the effects of predation on populations of the sea urchin Diadema aff. antillarum in barren grounds at the Canary Islands. The studied urchin populations were dominated by small to medium sized individuals (24-38 mm) and were variable in space. Tethering experiments showed that predation rates on D. aff. antillarum were very low and no differences were found between sites. Predation was found to be most intense on juveniles ( 40 mm were not preyed upon whatsoever. We have experimentally demonstrated that there is an absolute predator ‘escape size’ of around 40 mm for D. aff. antillarum individuals in barren grounds. Predation rates obtained for juveniles show that a sufficient number may escape predation and sustain the adult population, maintaining the urchin barren habitat. Recruitment and topographic complexity, rather than predation, seem to determine the structure of urchin populations in barren grounds. We conclude that predation in fished barren grounds of the Canarian Archipelago is not of sufficient magnitude to substantially alter dense urchin populations and cause community-level effects.Se realizaron unos estudios experimentales para valorar el efecto de la depredación sobre las poblaciones del erizo Diadema aff. antillarum, en zonas de blanquizales de las islas Canarias. Las poblaciones de erizos aparecieron dominadas por erizos de tallas pequeñas a medianas (24-38 mm) y resultaron variables en el espacio. Los experimentos de atado mostraron que D. aff. antillarum soporta una presión de depredación muy baja y no se encontraron diferencias entre las estaciones de estudio. La tasa de depredación fue más intensa sobre juveniles (< 20 mm) y adultos de entre 20-30 mm, rango de talla en el que la mayoría de los individuos dejan de tener comportamiento críptico. Los erizos de más de 40 mm de diámetro no fueron depredados en ningún caso. Demostramos experimentalmente la existencia de una talla de escape de D. aff. antillarum frente a la depredación en zonas de blanquizal en torno a los 40 mm. La tasa de depredación obtenida para juveniles indica que un número suficiente debe escapar de la depredación, manteniendo las poblaciones adultas y los blanquizales. Las tasas de reclutamiento y la complejidad topográfica, más que el nivel de depredación, parecen determinar la estructura de las poblaciones de erizos en los blanquizales. Concluimos que la depredación en los fondos rocosos sobreexplotados de las islas Canarias no tiene la magnitud suficiente para alterar substancialmente las densas poblaciones de erizos y causar efectos sobre la comunidad

Farming-up coastal fish assemblages through a massive aquaculture escape event

We investigated the changes on the mean trophic level of fish assemblages across different spatiotemporal scales, before and after a massive escape event occurred off La Palma (Canary Islands), which resulted in the release of 1.5 million fish (mostly Dicentrarchus labrax) into the wild. The presence of escaped fish altered significantly the mean trophic level of fish assemblages in shallow coastal waters. This alteration was exacerbated by the massive escape. A nearby marine protected area buffered the changes in mean trophic level but exhibited the same temporal patterns as highly fished areas. Moreover, escaped fish exploited natural resources according to their total length and possibly, time since escapement. New concerns arise as a “farming up” process is detected in shallow coastal fish assemblages where marine aquaculture is established

Does waste feed from salmon farming affect the quality of saithe (Pollachius virens L.) attracted to fish farms?

Salmon farms attract large amounts of wild fish, which prey on uneaten feed pellets. The modified diet of the wild fish aggregating at salmon farms may reduce the flesh quality of the fish, influencing the local fisheries. We compared the quality of saithe (Pollachius virens) captured near (farm associated—FA) or more than 5 km away (un‐associated—UA) from salmon farms in Norway. The fish were captured during summer, autumn and spring using two commercial fishing methods (jigging and bottom nets). Overall, the fillet quality of FA saithe was good, although it was clearly reduced for almost 10% of the catch. Moreover, the quality of the FA saithe was significantly reduced compared with UA saithe, but the differences were small. Our results also showed that fish caught with jigging had better quality than fish caught with nets, and that fish that died in the nets were of lower quality than fish that were alive after hauling. There was no clear variation among seasons in fillet quality. Although no major and overall differences in quality were found between FA and UA saithe, reduced quality for even a modest proportion of the fish may influence the value of the total catch.The study was funded by the Norwegian Seafood Research Fund through the ProCoEx project (Project number: 900772) and the Norwegian Research Council through the project ‘ECOCOAST’. Kilian Toledo‐Guedes was supported by a grant from Iceland, Liechtenstein and Norway through the EEA Financial Mechanism (ES07‐EEA Grants, 013‐ABEL‐IM‐2013), operated by Universidad Complutense de Madrid, and Juan de la Cierva Program FJCI‐2014‐20100 and IJCI‐2017‐34174 from Ministerio de Ciencia, Innovación y Universidades

Guía de buenas prácticas para la gestión de escapes en acuicultura marina. Vol. I. Prevención

Los escapes en acuicultura son un problema que pueden evitarse con la formación del personal que trabaja en las instalaciones en mar abierto. Este libro proporciona los puntos más importantes que tener en cuenta para prevenir los escapes en acuicultura.Cofinanciado por el Fondo Europeo de Pesca y la Fundación Biodiversidad, del Ministerio de Agricultura, Alimentación y Medio Ambiente

A step towards the validation of bacteria biotic indices using DNA metabarcoding for benthic monitoring

Environmental genomics is a promising field for monitoring biodiversity in a timely fashion. Efforts have increasingly been dedicated to the use of bacteria DNA derived data to develop biotic indices for benthic monitoring. However, a substantial debate exists about whether bacteria‐derived data using DNA metabarcoding should follow, for example, a taxonomy‐based or a taxonomy‐free approach to marine bioassessments. Here, we showcase the value of DNA‐based monitoring using the impact of fish farming as an example of anthropogenic disturbances in coastal areas and compare the performance of taxonomy‐based and taxonomy‐free approaches in detecting environmental alterations. We analysed samples collected near to the farm cages and along distance gradients from two aquaculture installations, and at control sites, to evaluate the effect of this activity on bacterial assemblages. Using the putative response of bacterial taxa to stress we calculated the taxonomy‐based biotic index microgAMBI. The distribution of individual amplicon sequence variants (ASVs), as a function of a gradient in sediment acid volatile sulphides, was then used to derive a taxonomy‐free bacterial biotic index specific for this data set using a de novo approach based on quantile regression splines. Our results show that microgAMBI revealed a organically enriched environment along the gradient. However, the de novo biotic index outperformed microgAMBI by providing a higher discriminatory power in detecting changes in abiotic factors directly related to fish production, whilst allowing the identification of new ASVs bioindicators. The de novo strategy applied here represents a robust method to define new bioindicators in regions or habitats where no previous information about the response of bacteria to environmental stressors exists.This work was partially funded by the project CGL2015-70136-R from the Spanish Ministry of Economy and Competitiveness (MINECO) and the EU ERDF funding program. E.A. and S.C. are supported by funding from a collaboration between KAUST and Saudi Aramco within the framework of the Saudi Aramco –KAUST Center for Marine Environmental Observations. K.T.-G. is supported by Ministerio de Ciencia, Innnovación y Universidades through the Juan de la Cierva Incorporación program (IJCI-2017-34174)

A proxy for carrying capacity of Mediterranean aquaculture

In developing a holistic and innovative approach to determining the carrying capacity in marine finfish aquaculture, we carried out a modified Delphi exercise in which we asked industry experts to identify the factors influencing the production levels of the activity under different scenarios. We disseminated and discussed three rounds of questionnaires in sectoral roundtables and workshops with experts, culminating in the development of a simple formula that adapts production levels to the physical, ecological, social and economic conditions of the activity on the Spanish Mediterranean coast. We used this formula to approach the carrying capacity of the system. Based on the developed model and its theoretical application, we estimated the carrying capacity for floating cages on the Spanish Mediterranean coast at 119,404 t—about 1.2 times the current production level of 96,440 t. We therefore concluded that, subject to the execution of an in-situ validation of the model, the production level of floating nurseries on the Spanish Mediterranean coast could be increased by up to 33.5%.KT-G was funded by a postdoctoral tenure program Juan de la Cierva Formación (FJCI-2014-20100) and Juan de la Cierva Incorporación (IJCI-2017-34174) funded by Spanish National Research Agency. This study was funded by the Projects “Environmental Innovation Measures for the Development and Establishment of Protocols for Carrying Capacity for Aquaculture Sustainability (MIMECCA)”; “Marine Aquaculture Carrying Capacity Applied Models (MACCAM)”; “GLObal change Resilience in Aquaculture-2 (GLORiA2),” supported by the Biodiversity Foundation of the Spanish Ministry for the Ecological Transition and Demographic Challenge, through the Pleamar Program and co-financed by the European Maritime and Fisheries Fund (EMFF). It is also part of the LIFE IP INTEMARES Project “Integrated, innovative and participatory management of the Natura 2000 Network in the Spanish marine environment”. This study forms part of the ThinkInAzul programme and was supported by MCIN with funding from European Union NextGenerationEU (PRTR-C17·I1) and by Generalitat Valenciana (THINKINAZUL/2021/044-TOWARDS)

A Metabolomic Approach To Detect Effects of Salmon Farming on Wild Saithe (Pollachius virens) Populations

A metabolomics approach was used to analyze effects of salmon farming on wild saithe (Pollachius virens) populations. Saithe fish were captured at two salmon farms and at two control locations around the island of Hitra, Norway. Changes in diet seem to drive changes in metabolic status of fishes. The liver and muscle tissues, from the fishes captured around the farm, showed higher levels of lactate and certain amino acids (glutamine, glutamate, and alanine) and lower levels of glucose and choline than the fishes captured in the control locations, far from the farm locations. The higher levels of lactate and amino acids could be related to the facility of obtaining food around the farm and the deficit in choline to the deficit of this nutrient in the salmon feed. At each location the fish were captured with either benthic gill nets and automatic jigging machines, and this feature showed also variations in different metabolites.This research was funded by the Norwegian Seafood Research Fund through the project “Evaluation of actions to promote sustainable coexistence between salmon culture and coastal fisheries, ProCoEx” (Project 900772). K.T.-G. was supported by a grant from Iceland, Liechtenstein, and Norway through the EEA Financial Mechanism

Red de evaluación del potencial en innovación docente del Personal Investigador (PI) en Ciencias Experimentales

El personal investigador (PI) universitario, cuyas tareas son fundamentalmente investigadoras, es un colectivo relativamente pequeño. Se compone del personal investigador en formación (contratados predoctorales), personal contratado con cargo a proyectos (pre o postdoctoral) y los contratados de acceso al sistema español de ciencia y tecnología. Aunque son figuras investigadoras, también se contempla la posibilidad de colaborar en tareas docentes. Nuestra red de innovación docente pretende, mediante la realización de encuestas, valorar el papel del PI en la docencia delas ciencias experimentales y determinar su capacidad para la innovación docente. El PI tiene una alta predisposición a realizar tareas docentes y realizar cursos de formación. Sin embargo su participación en la docencia se suele limitar a la colaboración en clases prácticas cuyo contenido está ya desarrollado, lo cual puede disminuir las posibilidades de que el PI realice innovación docente. En cualquier caso existe una clara predisposición tanto a la mejora mediante la realización de cursos de formación docente, así como a la preparación de material docente innovador. El PI apuesta por un fomento de su participación en tareas docentes, siempre y cuando no influya negativamente en sus tareas de investigación

Potential retention effect at fish farms boosts zooplankton abundance

Coastal aquaculture activities influence wild macrofauna in natural environments due to the introduction of artificial structures, such as floating cages, that provide structural complexity in the pelagic system. This alters the abundance and distribution of the affected species and also their feeding behaviour and diet. Despite this, the effects of coastal aquaculture on zooplankton assemblages and the potential changes in their abundance and distribution remain largely unstudied. Traditional plankton sampling hauls between the farm mooring systems entail some practical difficulties. As an alternative, light traps were deployed at 2 farms in the SW Mediterranean during a whole warm season. Total zooplankton capture by traps at farms was higher than at control locations on every sampling night. It ranged from 3 to 10 times higher for the taxonomic groups: bivalvia, cladocera, cumacea, fish early-life-stages, gastropoda, polychaeta and tanaidacea; 10–20 times higher for amphipoda, chaetognatha, isopoda, mysidacea and ostracoda, and 22 times higher for copepoda and the crustacean juvenile stages zoea and megalopa. Permutational analysis showed significant differences for the most abundant zooplankton groups (copepoda, crustacean larvae, chaetognatha, cladocera, mysidacea and polychaeta). This marked incremental increase in zooplankton taxa at farms was consistent, irrespective of the changing environmental variables registered every night. Reasons for the greater abundance of zooplankton at farms are discussed, although results suggest a retention effect caused by cage structures rather than active attraction through physical or chemical cues