Population recovery is a key goal for conservation, but our understanding of how genetic and phenotypic variation, including local adaptation, emerges in recently recolonised or recovering systems is limited. This complicates the conservation of fitness-related traits that support resilience and long-term population viability. We employed single nucleotide polymorphism markers, geometric morphometrics and acoustic telemetry to...

Riverine barriers can have significant negative impacts on the spawning migrations of anadromous fishes, with barriers of low passage efficiency limiting access to upstream spawning areas. Even fish that pass a barrier can be negatively affected via migration delays and energetic costs. The spawning migrations of 74 twaite shad Alosa fallax were tracked at two head-of-tide weirs on a bifurcated channel in the River Severn’s up...

This investigation compared the spatial ecology and population dynamics of brown trout Salmo trutta L. between reservoirs with (impact; Langsett Reservoir) and without (control; Grimwith Reservoir) barriers to fish movements into headwater tributaries, and the effectiveness of a fish pass intended to remediate connectivity. Passive integrated transponder (PIT) telemetry revealed that fish that emigrated from Langsett and Grimw...

Anthropogenic barriers are widely known to negatively impact the spawning migrations of anadromous fishes, by delaying or preventing passage upstream. Although the impacts of barriers on emigrating post‐spawned adults are less well studied, they could potentially impact the fitness and subsequent return rates of iteroparous species. In this study, passive acoustic telemetry was used to track the emigrations of 53 twaite shad A...

There is limited knowledge of how philopatry influences the spatial ecology of iteroparous anadromous species during their spawning migrations, but this knowledge is important in understanding population responses to interventions such as river reconnection. Here, acoustic telemetry was applied to twaite shad Alosa fallax and hybrids ( n = 184) during their freshwater spawning migration, enabling quantification of philopatry a...

Reversing the negative impacts that anthropogenic habitat fragmentation has on animal movement is a key goal in the management of landscapes and conservation of species globally. Accurate assessment of measures to remediate habitat fragmentation, such as fish passage solutions in rivers, are imperative but are particularly challenging for territorial species, which are less likely to leave their existing home range, or populat...

The timing of entry into freshwater by mature anadromous fishes is an important component of their migration phenology. In iteroparous anadromous species, identifying the migration cues that influence the timing of entry into freshwater, and annual variability in these timings, is important in assessing the extent of individual repeatability. Here, passive acoustic telemetry tracked 71 twaite shad Alosa fallax (‘shad’) returni...