Temporal single-cell atlas of full-length Huntington's disease mouse model defines stage-specific signatures of corticostriatal dysfunction.

The critically endangered European eel () population has declined by more than 90% over the past half-century. Eel have been negatively impacted by multiple stressors that include overfishing, habitat loss, pollution, shifts in oceanic currents, non-native parasites and river infrastructure. Moving fish can be impeded by man-made structures, such as dams and weirs, or entrained at water intakes, e.g. at hydropower and pumping stations. Furthermore, compared to other species, eel may be at greater risk of injury and mortality, e.g. from blade strike and grinding during passage through turbines and pumps due to their elongated body morphology, leading in some cases to 100% mortality (e.g.. Concerns related to the migratory delay, injury and mortality of European eel at river infrastructure has led to the development of environmental impact mitigation technologies, such as bespoke eel passes and screens. These have largely focused on the upstream migrating juveniles (glass eel and elver) (e.g.. and downstream moving adults (silver-phase eel) (e.g.), even though eel spend the vast majority of their life (e.g. more than two decades, inhabiting the freshwater environment during their resident yellow-phase, during which they encounter river infrastructure during both upstream and downstream exploratory movements. Nevertheless, knowledge gaps on the movement behaviour of this life stage remain (see. To minimise the negative impact of river infrastructure on eel there is a need to consider the entire lifecycle, rather than concentrate only on the active migratory life stages. Therefore, greater understanding of the value of environmental impact mitigation strategies that target yellow-phase eel is also needed. Physical and mechanical fish screens traditionally installed at water intakes can themselves negatively impact the target species they were designed to protect. For example, eel become impinged and suffocate on the screen surface if the water velocities at the face exceed burst swimming capabilities, preventing escape (e.g.. for silver-phase European eel). Further, whilst the efficiency of screens designed to guide silver-phase European eel to bypass routes can be high in other cases it was as low as 0%, delaying migration and increasing energetic expense and predation risk. To better protect eel at water intakes there is a need to reduce risks of impingement on screens and enhance the efficiency of guidance. Improved efficacy of physical fish screens may be achieved by integrating behavioural stimuli (e.g. light, bubbles, acoustics) that induce avoidance in the target species (e.g.. To achieve this for eel, however, there is a need to identify the most appropriate cue(s) that may be used as a deterrent or as part of a combined physical-behavioural screening system.