Habitat fragmentation is a major source of biodiversity loss in freshwaters, with rivers around the world fragmented by dams and weirs.

These impoundments restrict connectivity, inhibit fish migrations across ecosystem boundaries, modify gene-flow and impact population sustainability. However, schemes to restore river connectivity can be achieved through either the installation of ‘fish-passes’ on the structures or through removal of the structure. There have, however, been few attempts to quantify the conservation and ecological outcomes for non-salmonid migratory fishes of this reconnection, despite these species facing unprecedented European population declines, such as in European shads Alosa spp. 

The River Severn and Teme is the population stronghold of European shads in western Britain, especially for Twaite shad Alosa fallax but potentially also for Allis shad Alosa alosa. Up to 2021, the lower basin was highly impounded but has now been reconnected through fish passes and weir modifications. However, understanding how reconnection has benefitted the shad populations requires further work to understand the behaviour of spawning adults in and around weirs fitted with passes, the influence of reconnection on spawning distributions and the implication of these on egg, larval and juvenile ecology. 

The PhD builds on work completed on the river and shad population since 2017, with access to historical adult movement data (pre/ post reconnection) as well as the opportunity to collect novel data within the research period using a range of methods, including acoustic telemetry.

Please note: the funding for this course includes waive of tuition fees for 36 months, stipend for 36 months, training costs, and research costs.

Key information

Next start date:

21 September 2026

Location:

Talbot Campus, Bournemouth University

Duration:

Expected submission: 36 months Completion: within 48 months

Entry requirements:

BU PhD Studentships are open to UK, EU and international students.

Candidates for a PhD Studentship should demonstrate outstanding qualities and be motivated to complete a PhD in 4 years. They must demonstrate:

• outstanding academic potential as measured normally by either a 1st class honours degree (or equivalent Grade Point Average (GPA) or a Master’s degree with distinction or equivalent
• an IELTS (Academic) score of 6.5 minimum (with a minimum 6.0 in each component, or equivalent) for candidates for whom English is not their first language and this must be evidenced at point of application.

In addition:

  • Strong candidates are expected to demonstrate strong knowledge and enthusiasm for fish tracking work
  • Candidates are expected to have some experience of fish sampling in the field, with prior experience of fish telemetry methods being desirable but not essential
  • Strong quantitative skills are also essential, including proficiency in R for data analysis.

Deadline for applications: 30 June 2026

Project details

Aim and objectives

The PhD aim to is to overcome the substantial knowledge gaps in the autecology of Alosa spp. in the River Severn, especially the relationship between adult spawning migrations and the ecology and distribution of their progeny.

Objectives:

1. Measure the in-river movements of adult shad around weirs and fish passes to understand their behaviours around these structures, including the extent of pass attraction and passage;
2. Assess the temporal and spatial upstream extents of Alosa spp. in the river in relation to reconnection and spawning hotspots
3. Apply novel telemetry methods (e.g. predation tags) to assess in-river mortality of adult spawners
4. Assess the spawning distribution, egg deposition, larval drift and juvenile Alosa spp. distribution in the river, including assessment of timing and the drift dynamics. 

Academic impact

This research will substantially strengthen current knowledge of how migratory, non-salmonid fishes respond to river reconnection programmes, including both juvenile and adult lifestages, where the fish are now able to access spawning areas for the first time in over 150 years. Novel data should be able to be generated across these different lifestages that enable population responses to reconnection to be measured. This includes data generated using acoustic telemetry at both broad and fine spatial scales, measuring shad movements through fish passes using PIT telemetry, and identification of spawning areas and larval drift. These data will be highly publishable in relevant scientific journals as well as for presenting at relevant international symposia.

Societal impact

The regulation of rivers for flood prevention is a major societal issue, especially given changing precipitation patterns through climate change. Despite best-practice and policy guidance from regulators, pressure continues to build for greater regulation of flows through hard-engineering solutions. However, these are likely to have substantial ecological and conservation consequences, with potential for extirpations of migratory species of European importance due to habitat fragmentation. The opposite approach of allowing rivers to increasingly adopt natural flows and characteristics, with less severe land-use practises in the upper catchment and greater connectivity in the lower reaches, is seen as a viable alternative, with the additional benefit of enabling more sustainability in the populations of threatened migratory species.

This PhD is ideally placed to strongly inform this debate, highlighting the potential conservation and ecological benefits that can accrue from soft-engineering solutions, and so preventing further population declines in threatened species such as European shads. 

Postgraduate research development opportunities

The PhD provides substantial training opportunities, including:

- Fish sampling and telemetry: the research is strongly reliant on the application of telemetry methods to track adult shad, using acoustic and passive integrated transponder (PIT) tags in tracking movements of Alosa spp. through the river (acoustic telemetry) and through fish passes (PIT tags). Training on all aspects of tagging, including implantation, will be provided. Sampling methods for shad eggs, larvae and juveniles will also be developed in the PhD, with full training provided

- Research skills: training will be provided via formal and informal approaches on research skills including literature review, writing scientific publications and presentation skills

- The student will be supported in completed the Animal Procedures Modules 1-4 and so obtain their Home Office personal license for all tagging procedures on live fish

- There will also be opportunities for discussing research results and findings with regulators and policy makers, with significant networking opportunities for the successful candidate.