Water security determines social attitudes about dams and reservoirs in South Europe

River barriers affect river dynamics and aquatic biota, altering the entire ecosystem. Nevertheless, dams and reservoirs provide goods like water supply and low-carbon energy that are becoming increasingly critical under current climate change. To know to what extent dams and reservoirs are important to the population, we explored social attitudes towards dams and reservoirs using a face-to-face questionnaire in two regions of contrasting climate and water security in Spain, a country with one of highest densities of dams in Europe. Results (N = 613) revealed a higher support for dams, mediated by the recognition of the services they provide, in the drier Mediterranean Malaga province (Andalusia), than in the wetter Atlantic Asturias province (Bay of Biscay), where water shortages are rare. Awareness of the impacts of the dams was more pronounced in Malaga, coupled with a higher willingness to pay for reconnecting rivers. Social awareness of both impacts and services provided by dams and reservoirs may depend on local climate and water security; different dam acceptance emphasizes the need to involve local citizens in the decision-making processes about water management

SNP analyses and acoustic tagging reveal multiple origins and widespread dispersal of invasive brown trout in the Falkland Islands

Biological invasions are important causes of biodiversity loss, particularly in remote islands. Brown trout (Salmo trutta) have been widely introduced throughout the Southern Hemisphere, impacting endangered native fauna, particularly galaxiid fishes, through predation and competition. However, due to their importance for sport fishing and aquaculture farming, attempts to curtail the impacts of invasive salmonids have generally been met with limited support and the best prospects for protecting native galaxiids is to predict where and how salmonids might disperse. We analysed 266 invasive brown trout from 14 rivers and ponds across the Falkland Islands as well as 32 trout from three potential source populations, using a panel of 592 single nucleotide polymorphisms (SNPs) and acoustic tagging, to ascertain their origins and current patterns of dispersal. We identified four genetically distinct clusters with high levels of genetic diversity and low admixture, likely reflecting the different origins of the invasive brown trout populations. Our analysis suggests that many trout populations in the Falklands may have originated from one of the donor populations analysed (River Wey). The highest genetic diversity was observed in the rivers with the greatest number of introductions and diverse origins, while the lowest diversity corresponded to a location without documented introductions, likely colonized by natural dispersal. High levels of gene flow indicated widespread migration of brown trout across the Falkland Islands, likely aided by anadromous dispersal. This is supported by data from acoustically tagged fish, three of which were detected frequently moving between two rivers ~26 km apart. Our results suggest that, without containment measures, brown trout may invade the last remaining refuges for the native endangered Aplochiton spp. We provide new insights into the origin and dispersal of invasive brown trout in the Falkland Islands that can pave the way for a targeted approach to limit their impact on native fish fauna

Personality profiling may help select better cleaner fish for sea-lice control in salmon farming

Lumpfish (Cyclopterus lumpus) are increasingly being used as cleaner fish to control parasitic sea-lice in salmon farming, but cleaning rates are very variable and not all individuals eat sea-lice, which increases the risk of emaciation and has ethical and practical implications. Selecting good cleaners is a priority to make the industry more sustainable, but there is little information on what behaviours make cleaner fish effective under a commercial setting. We examined variation in lumpfish personalities according to the five-factor personality model that takes into account differences in activity, anxiety (shelter use, thigmotaxis), aggression, sociality, and boldness (neophobia). We then quantified how variation in lumpfish personalities influenced interactions with naïve Atlantic salmon (Salmo salar), without the confounding effects of variation in sea-lice loads. Variation in activity, sociality, aggression and neophobia, but not in anxiety, was repeatable. Neophilic, non-aggressive lumpfish spent more time inspecting salmon than neophobic and aggressive individuals, but salmon fled in the presence of the most active and social individuals, suggesting there may be an optimal cleaner fish personality amenable to artificial selection. The personality screening protocols developed in this study could inform a more efficient use of cleaner fish in salmon farming and reduce the number of individuals required to control sea-lice

Experimental investigation of shallow mixing layers at a river confluence using 3D-PTV

The present study investigates a simplified laboratory model of a river confluence (shallow mixing layer) using 3D-PTV to improve the understanding of the 3-D interaction between the large-scale turbulent motions (Kelvin-Helmholtz instability) and small-scale turbulent motions (Tollmien-Schlichting instability)

Excavaciones en el conjunto funerario de época hispano-visigoda de la Cabeza (La Cabrera, Madrid)

La presencia visigoda en la actual Comunidad de Madrid está ampliamente constatada a través de las innumerables necrópolis conocidas. El pequeño conjunto funerario de la Cabeza, excavado con carácter de urgencia, ofrece una serie de características que le hacen particularmente interesante: número de tumbas, situación geográfica, ubicación topográfica, tipología del conjunto, etc. Tanto por su arquitectura funeraria como, y sobre todo, por el material hallado, hemos fechado el conjunto dentro del siglo VII