Assessment of Scale-Loss to Atlantic Salmon (Salmo Salar L.) Smolts from Passage Through an Archimedean Screw Turbine

The potential for external damage to Atlantic salmon (Salmo salar L.) smolts from passage through an Archimedean screw turbine was tested with controlled field trials at two turbine speeds. Change in external condition of smolts was measured by grading photographs of individual fish for scale-loss before and after the tests. Results were compared between turbine-passed and control smolts. There were no significant differences in proportions of fish with new scale-loss between treatment and control smolts. New scale-loss of between 4 and 30% was seen in 7.46% of turbine-passed smolts, exceeding the prevalence in control smolts by 2.46%. Of these, 1.49% had minor scale-loss of 5-9%. Minor scale-loss was more prevalent for both groups at the faster turbine speed, although differences between treatment and control groups were more apparent at the slower speed

Conservation evo-devo: preserving biodiversity by understanding its origins

Unprecedented rates of species extinction increase the urgency for effective conservation biology management practices. Thus, any improvements in practice are vital and we suggest that conservation can be enhanced through recent advances in evolutionary biology, specifically advances put forward by evolutionary developmental biology (i.e., evo-devo). There are strong overlapping conceptual links between conservation and evo-devo whereby both fields focus on evolutionary potential. In particular, benefits to conservation can be derived from some of the main areas of evo-devo research, namely phenotypic plasticity, modularity and integration, and mechanistic investigations of the precise developmental and genetic processes that determine phenotypes. Using examples we outline how evo-devo can expand into conservation biology, an opportunity which holds great promise for advancing both fields

Session E9: Migration of Atlantic Salmon (Salmo Salar) at Low-Head Archimedean Screw Hydropower Schemes

Abstract: There has been a rapid increase in development of small-scale hydropower schemes across Europe. Such schemes may impact upon migratory fish populations through modification of migration pathways. There is a clear need for scientific evidence to inform guidelines for the design, placement and management of small-scale hydropower schemes for the protection of migratory fish. The proliferation of the Archimedean screw turbine (AST) for lowhead applications is concerning because although these turbines are purported to cause negligible damage to fish passing through them, the available data is limited. The studies presented assess the impacts of low-head AST hydropower schemes on migrating populations of anadromous Atlantic salmon (Salmo salar) in Scotland. Smolts were tracked through an AST hydropower scheme on the river Don using radio tags and passive integrated transponder (PIT) tags. Smolt movements through alternative passage routes were observed using an array of fixed loggers at the hydro scheme. The proportion of radio tagged fish which passed through the turbine was 27% (7/26). The majority of PIT tagged smolts passed through the turbine channel within 27 minutes. Passage behaviour is considered in the context of the scheme’s operation and environmental conditions. Adult fish were tracked using radio and PIT tags at three AST hydropower schemes with distinctive designs and operational regimes: on the middle reaches of the river Don, the upper reaches of the Don, and on the Ettrick water. A mixture of fine-scale radio detection zones and PIT antennas was used to investigate attraction to the competing flows at each of the turbine and fish pass or depleted stretch outflows, and the efficiency and efficacy of the fish pass. Behaviours at these regions are related to the turbine operation, scheme layout and the resulting hydrodynamics at the regions of interest

The active control of acoustic noise in a small enclosure

This thesis describes the theory and implementation of a system for the active control of acoustic noise in a small enclosure ("small" inferring that only a small number of acoustic modes dominate the reverberant field in the en c1osure). The theory for a multichannel active noise control system is developed. A system could consist of a number of detectors and cancellation sources controlling the field at a number of monitor positions. The simplest system comprises a single detector and a single source and is capable of controlling the field at one position. The controller for this system could consist of a pair of electronic filters, one between the detector and the source in parallel with another cancelling the feedback from the source to the detector. It is shown that for any configuration of transducers the required controllers can be realised by repeatedly using the same filter pair as described above. A particular study is made of the active control of reverberant fields. A system was successfully implemented to partially control the reverberant field in a small enclosure (0-5 x 0-6 x 0.7m). This consisted of a single detector microphone and a single control loudspeaker controlling the field at a single monitor microphone. The system was controlled with two finite impulse response filters realised using a Texas Instruments TMS32020 microprocessor accessed via a Ferranti PC360XT personal computer. The first two modes of the reverberant field were successfully attenuated. In summary, the theory for a multichannel controller has been developed and the simplist case tested. The importance of this is that the basic unit of a multichannel controller has been successfully implemented and this unit could be replicated as the basic building block for more complex controllers. This facilitates the implementation of controllers to attenuate the sound field at a number of points in a practical enclosure. <p

Atlantic Salmon and Non-Native Species: Is There an Issue?

The International Union for the Conservation of Nature (IUCN) assert that the spread of Invasive Alien Species (IAS) is, after habitats loss, the second most significant threat to global biodiversity. The most recent global assessment report on biodiversity and ecosystem services carried out by the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) concluded that nearly one fifth of the Earth’s surface is at risk of plant and animal invasions, impacting native species, ecosystem functions and nature’s contributions to people, as well as economies and human health. This paper considers the impact that Invasive Alien Species may have on the survival of wild Atlantic salmon

The Scottish invasion of pink salmon in 2017

No abstract available

RADseq and mate choice assays reveal unidirectional gene flow among three lamprey ecotypes despite weak assortative mating: Insights into the formation and stability of multiple ecotypes in sympatry

Adaptive divergence with gene flow often results in complex patterns of variation within taxa exhibiting substantial ecological differences among populations. One example where this may have occurred is the parallel evolution of freshwater‐resident nonparasitic lampreys from anadromous‐parasitic ancestors. Previous studies have focused on transitions between these two phenotypic extremes, but here, we considered more complex evolutionary scenarios where an intermediate freshwater form that remains parasitic is found sympatrically with the other two ecotypes. Using population genomic analysis (restriction‐associated DNA sequencing), we found that a freshwater‐parasitic ecotype was highly distinct from an anadromous‐parasitic form (Qlake‐P = 96.8%, Fst = 0.154), but that a freshwater‐nonparasitic form was almost completely admixed in Loch Lomond, Scotland. Demographic reconstructions indicated that both freshwater populations likely derived from a common freshwater ancestor. However, while the nonparasitic ecotype has experienced high levels of introgression from the anadromous‐parasitic ecotype (Qanad‐P = 37.7%), there is no evidence of introgression into the freshwater‐parasitic ecotype. Paradoxically, mate choice experiments predicted high potential for gene flow: Males from all ecotypes were stimulated to spawn with freshwater‐parasitic females, which released gametes in response to all ecotypes. Differentially fixed single nucleotide polymorphisms identified genes associated with growth and development, which could possibly influence the timing of metamorphosis, resulting in significant ecological differences between forms. This suggests that multiple lamprey ecotypes can persist in sympatry following shifts in adaptive peaks, due to environmental change during their repeated colonization of post‐glacial regions, followed by periods of extensive gene flow among such diverging populations

Searching for a signal: Environmental DNA (eDNA) for the detection of invasive signal crayfish, Pacifastacus leniusculus (Dana, 1852)

Environmental DNA (eDNA) is a rapid, non-invasive method for species detection and distribution using DNA deposited in the environment by target organisms. eDNA has become a recognised and powerful tool for detecting invasive species in a broad range of aquatic ecosystems. We examined the use of eDNA as a tool for detecting the invasive American signal crayfish Pacifastacus leniusculus in Scotland. Species-specific TaqMan probe and primers were designed for P. leniusculus and a robust quantitative PCR (qPCR) assay and DNA extraction protocol were developed. We investigated the detection capability for P. leniusculus from water samples in a controlled laboratory experiment and determined whether crayfish density (low = 1 crayfish 5.5 L-1 or high = 3 crayfish 5.5 L-1) or length of time in tanks (samples taken at 1, 3 and 7 days) influenced DNA detectability. Additionally, the persistence of DNA was investigated after P. leniusculus removal (samples taken at 1, 3 and 7 days post removal). P. leniusculus DNA was consistently detected during the entire 7-day period and higher density tanks yielded stronger positive results with lower Ct values. After removal of P. leniusculus, there was a rapid and continuous decrease in the detectability of DNA. P. leniusculus DNA could only be detected in high density tanks by the end of the 7-day period, while DNA was no longer detectable in low density tanks after 72 hours. Preliminary field experiments sampled water from three sites in winter and five sites in summer. P. leniusculus was known to be present at two of these sites. P. leniusculus was not detected at any site in winter. However, in summer, positive signals were observed at sites with known P. leniusculus, and at sites where P. leniusculus was believed to be present anecdotally, but not confirmed. All sites where crayfish were believed to be absent were negative for eDNA. Therefore, eDNA represents a promising technique to detect and monitor invasive P. leniusculus, although the presence of detectable amounts of eDNA may be season and location dependent, even where invasive crayfish are known to be present

Genomic underpinnings of head and body shape in Arctic charr ecomorph pairs

Across its Holarctic range, Arctic charr (Salvelinus alpinus) populations have diverged into distinct trophic specialists across independent replicate lakes. The major aspect of divergence between ecomorphs is in head shape and body shape, which are ecomorphological traits reflecting niche use. However, whether the genomic underpinnings of these parallel divergences are consistent across replicates was unknown but key for resolving the substrate of parallel evolution. We investigated the genomic basis of head shape and body shape morphology across four benthivore–planktivore ecomorph pairs of Arctic charr in Scotland. Through genome-wide association analyses, we found genomic regions associated with head shape (89 SNPs) or body shape (180 SNPs) separately and 50 of these SNPs were strongly associated with both body and head shape morphology. For each trait separately, only a small number of SNPs were shared across all ecomorph pairs (3 SNPs for head shape and 10 SNPs for body shape). Signs of selection on the associated genomic regions varied across pairs, consistent with evolutionary demography differing considerably across lakes. Using a comprehensive database of salmonid QTLs newly augmented and mapped to a charr genome, we found several of the head- and body-shape-associated SNPs were within or near morphology QTLs from other salmonid species, reflecting a shared genetic basis for these phenotypes across species. Overall, our results demonstrate how parallel ecotype divergences can have both population-specific and deeply shared genomic underpinnings across replicates, influenced by differences in their environments and demographic histories