Westcountry Rivers Trust

Abstract Acoustic telemetry is a powerful tool for understanding spatial and temporal fish movements in complex freshwater systems but determining appropriate sample sizes for measuring individual variability in movement metrics is challenging. Here, the movements of 170 common bream Abramis brama were measured over two years in the highly connected River Bure wetland system, eastern England. Analyses of seasonal and spatial movement patterns revealed higher movement metrics in winter versus summer, with the extent of movements measured enabled by the high lateral connectivity of this wetland system, with bream often occupying the numerous off-channel lentic habitats present. Power analyses were then applied to this relatively large dataset to assess how changes in tagged fish number influenced the individual variability in the movement metrics. Although retaining 95% of the movement variability required relatively large samples, using 60 individuals retained 90% of individual variability, with only 20 fish needed to retain 80%. These results emphasise the importance of high connectivity in wetlands to enable potadromous fish to access key functional habitats in all seasons. It also reveals relatively small sample sizes in acoustic telemetry can capture much of the movement variability measured across larger numbers of tagged fish.

A global existential and interlocking environmental, climate and cooperation/equity polycrisis is being faced, which increasingly impacts and is impacted by water and land systems. As a result, transformations in response are gaining increasing traction. Advances in approaches to visualising and communicating how innovations and changes in landscape features enable shifts, transformations and transitions are more crucial than ever before. Visions help focus the actions, collaboration and alignment of multiple actors in working towards a common purpose, whilst also entering people’s consciousness at the deep level of values, transforming beliefs and consequently, thinking and action. They give direction to effort and pull on transformational innovation. The evidence-based ‘Water Visions Visualisation Platform’ presents an innovative and accessible way to illustrate, communicate and support future water visioning and strategising at the landscape scale based on composite paradigms, scenarios, horizons and concepts. Plausible visions of the future are envisioned, illustrated, narratively described and qualitatively assessed, as well as connected with real-world examples and resources through the interactive platform. This paper outlines the co-creation methodology, the architecture and the initial co-development of the platform, as well as a preliminary evaluation of its efficacy through literature-based criteria and the sharing of the platform with stakeholders.

The rivers of southern England and northern France which drain into the English Channel contain several genetically unique groups of trout (Salmo trutta L.) that have suffered dramatic declines in numbers over the past 40 years. Knowledge of levels and patterns of genetic diversity is essential for effective management of these vulnerable populations. Using restriction site-associated DNA sequencing (RADseq) data, we describe the development and characterisation of a panel of 95 single nucleotide polymorphism (SNP) loci for trout from this region and investigate their applicability and variability in both target (i.e., southern English) and non-target trout populations from northern Britain and Ireland. In addition, we present three case studies which demonstrate the utility and resolution of these genetic markers at three levels of spatial separation:(a) between closely related populations in nearby rivers, (b) within a catchment and (c) when determining parentage and familial relationships between fish sampled from a single site, using both empirical and simulated data. The SNP loci will be useful for population genetic and assignment studies on brown trout within the UK and beyond.

Abstract There are few reliable data sets to inspire confidence in policymakers that soil organic carbon (SOC) can be measured on farms. We worked with farmers in the Tamar Valley region of southwest England to select sampling sites under similar conditions (soil type, aspect and slope) and management types. Topsoils (2–15 cm) were sampled in autumn 2015, and percentage soil organic matter (%SOM) was determined by loss on ignition and used to calculate %SOC. We also used the stability of macroaggregates in cold water (WSA) (‘soil slaking’) as a measure of ‘soil health’ and investigated its relationship with SOC in the clay‐rich soils. %SOM was significantly different between management types in the order woodland (11.1%) = permanent pasture (9.5%) > ley‐arable rotation (7.7%) = arable (7.3%). This related directly to SOC stocks that were larger in fields under permanent pasture and woodland compared with those under arable or ley‐arable rotation whether corrected for clay content ( F = 8.500, p < .0001) or not ( F = 8.516, p < .0001). WSA scores were strongly correlated with SOC content whether corrected for clay content (SOC adj R 2 = .571, p < .0001) or not (SOC unadj R 2 = 0.490, p = .002). Time since tillage controlled SOC stocks and WSA scores, accounting for 75.5% and 51.3% of the total variation, respectively. We conclude that (1) SOC can be reliably measured in farmed soils using accepted protocols and related to land management and (2) WSA scores can be rapidly measured in clay soils and related to SOC stocks and soil management.

There are high aspirations for environmental water quality targets in the UK, but requirements for significant growth in agricultural production to meet both food security objectives and provide viable livelihoods for farmers make these hard to achieve. Significant water quality challenges are related to nutrients, pesticides, pharmaceuticals, pathogens, sediments and habitat alteration. To facilitate the challenges posed, there is a need for predictive, spatially distributed models to be developed that encompass the key aspects of agriculture and water management in order to inform future policy and organizations with an interest in land management. Additionally, there needs to be recognition from policy makers that different solutions are needed in different agri‐water systems and that it often takes many years or decades for policies to have a sustained water quality impact. Long‐term support for research infrastructure and the scientific skills base is required to enable measurement and data analysis necessary to inform decision making. Farmers need clearly articulated information on the issues and potential solutions on which to make informed management decisions regarding water. There are existing solutions to some problems and this knowledge needs to be effectively disseminated with appropriate incentives for implementation to have maximum impact. Greater collaboration between researchers, industry, and policy makers, with the necessary framework to deliver effective joint working, is urgently needed. There is also a need for a wider societal understanding of the land–water system and the various ways in which society pays (and might pay in the future) for the real value of water. WIREs Water 2017, 4:e1201. doi: 10.1002/wat2.1201This article is categorized under: Water and Life > Stresses and Pressures on Ecosystems Science of Water > Water Quality

This study focuses on temporal changes in Atlantic salmon (Salmo salar) populations from the vulnerable periphery of the species range (northern Spain). Using microsatellite markers to assess population structuring and introgression of exogenous genes in four different temporal samples collected across 20 years, we have determined the relative weights of climate and stocking practices in shaping contemporary regional population genetic patterns. Climate, represented by the North Atlantic Oscillation Index, was identified as the main factor for determining the level of population genetic differentiation. Populations within the region have become homogenized through gene flow enhanced by straying of adult salmon from natal rivers and subsequent interchange of genes among rivers due to warmer temperatures. At the same time, and in line with documented changes in stock transfer strategies, evidence of genetic introgression from past stock transfers has decreased throughout the study period, becoming a secondary factor in erasing population structuring. The ability to disentangle the effects of climatic changes and anthropogenic factors (fisheries management practices) is essential for effective long-term conservation of this iconic species. We emphasize the importance of evaluating all factors which may be linked to stocking practices in vulnerable species, particularly those sensitive to climate change.

BackgroundAnadromous migratory fish species such as Atlantic salmon (Salmo salar) have significant economic, cultural and ecological importance, but present a complex case for management and conservation due to the range of their migration. Atlantic salmon exist in rivers across the North Atlantic, returning to their river of birth with a high degree of accuracy; however, despite continuing efforts and improvements in in-river conservation, they are in steep decline across their range. Salmon from rivers across Europe migrate along similar routes, where they have, historically, been subject to commercial netting. This mixed stock exploitation has the potential to devastate weak and declining populations where they are exploited indiscriminately. Despite various tagging and marking studies, the effect of marine exploitation and the marine element of the salmon lifecycle in general, remain the "black-box" of salmon management. In a number of Pacific salmonid species and in several regions within the range of the Atlantic salmon, genetic stock identification and mixed stock analysis have been used successfully to quantify exploitation rates and identify the natal origins of fish outside their home waters - to date this has not been attempted for Atlantic salmon in the south of their European range.ResultsTo facilitate mixed stock analysis (MSA) of Atlantic salmon, we have produced a baseline of genetic data for salmon populations originating from the largest rivers from Spain to northern Scotland, a region in which declines have been particularly marked. Using 12 microsatellites, 3,730 individual fish from 57 river catchments have been genotyped. Detailed patterns of population genetic diversity of Atlantic salmon at a sub-continent-wide level have been evaluated, demonstrating the existence of regional genetic signatures. Critically, these appear to be independent of more commonly recognised terrestrial biogeographical and political boundaries, allowing reporting regions to be defined. The implications of these results on the accuracy of MSA are evaluated and indicate that the success of MSA is not uniform across the range studied; our findings indicate large differences in the relative accuracy of stock composition estimates and MSA apportioning across the geographical range of the study, with a much higher degree of accuracy achieved when assigning and apportioning to populations in the south of the area studied. This result probably reflects the more genetically distinct nature of populations in the database from Spain, northwest France and southern England. Genetic stock identification has been undertaken and validation of the baseline microsatellite dataset with rod-and-line and estuary net fisheries of known origin has produced realistic estimates of stock composition at a regional scale.ConclusionsThis southern European database and supporting phylogeographic and mixed-stock analyses of net samples provide a unique tool for Atlantic salmon research and management, in both their natal rivers and the marine environment. However, the success of MSA is not uniform across the area studied, with large differences in the relative accuracy of stock composition estimates and MSA apportioning, with a much higher degree of accuracy achieved when assigning and apportioning to populations in the south of the region. More broadly, this study provides a basis for long-term salmon management across the region and confirms the value of this genetic approach for fisheries management of anadromous species.