Steph Bradbeer

Steph Bradbeer


2016-present. PhD Student at the Univerity of Leeds, NERC Case Partner PhD working with the Environment Agency. Project focusing on preventing the spread of invasvie species in the environment through development and employment of biosecurity protocols.  Projects include testing of biosecurity protocols to determine effectiveness on a range of freshwater invasive invertebrate and plant species and developing a novel assessment to determine stakeholders' level of awareness of biosecurity vectors. Supervisors: Dr Alison Dunn (Biological Sciences), Dr Claire Quinn (Earth & Environment), Trevor Renals (Environment Agency).

2015-2016. Masters by Research at the University of Bristol. Assessing the extent of hybridisation between invasive and native Oreochromis spp. in Tanzania, determining if Oreochromis species and/or hybrids can be identified based on morphometric variables and assessing relative growth of invasive and native Oreochromis species.  Project supervisor: Dr Martin Genner.

2011-2015. BSc Biological Sciences (with a year Study abroad) at the University of Exeter (Montana State University, USA). Final year project: Effect of different Zebrafish (Danio rerio) breeding chambers in relation to embryo output, embryo viability and fish health. Supervisors: Prof Charles Tyler, Dr Gregory Paull.

Research interests

Improving the efficiency and effectiveness of biosecurity protocols to prevent the spread of invasive species in the environment.

The presence of invasive species in the environment causes significant environmental, ecological and social impacts. These species are accidentally spread on a range of vectors such as boats and sporting equipment, which in the absence of biosecurity protocols can result in introductions of invasive species in previously uninvaded locations. Biosecurity aims to remove invasive species from these vectors to prevent introductions and spread, however in part due to the array of potential vectors there are gaps in our knowledge of effective and efficient biosecurity which my PhD aims to tackle in part. Focusing on the freshwater environment, my research aims to test both novel and currently employed biosecurity practices to identify appropriate recommendations for stakeholders.

Engaging stakeholders with employing biosecurity protocols in a range of activities.

Whilst the development of biosecurity protocols is imperative, this must be coupled with the practical application of protocols for stakeholders working in the environment. Developing the understanding of how to practically engage with stakeholders and increase knowledge transfer is essential to prevent invasive species spread. Within my PhD, this chapter focuses on understanding the impacts of training to enhance individuals' understanding of potential vectors of invasive species and the need to employ biosecurity.

Understanding the impacts of invasive species on native populations

Stemming from research completed during my Masters by Research at the University of Bristol, I have been involved with work aiming to identify the extent of spread and quantify the impacts of introduced aquaculture fish, Oreochromis spp. in Tanzania, in particular, Nile tilapia (Oreochromis niloticus).

Main focus involves assessing the extent of hybridization between invasive and native tilapia species in northern Tanzania, using microsatellite markers to identify purebred individuals and any possible hybrids. Morphometric analysis then quantified if pure-bred and/or hybrids are identifiable based on visual inspection of individuals, therefore identifying if hybrids are possible to identify in the field in the absence of genetic studies or if there is the possibility of them going undetected. I have assessed the relative growth of sympatric invasive and native tilapia fish to infer relative competitiveness of invaders and importance for fisheries production.


Bradbeer et al. 2018. Limited hybridization between introduced and critically endangered indigenous tilapia fishes in northern Tanzania. Hydrobiologia.

Schechonge et al. 2018. Widespread colonisation of Tanzanian catchments by introduced Oreochromins tilapia fishes: the legacy from decides of deliberate introduction. Hydrobiologia.  

Schechonge et al. 2018. Losing cichlid fish biodiversity: genetic and morphological homogenization of tilapia following colonization by introduced species. Conservation Genetics


  • 2016-present. PhD; University of Leeds
  • 2015-2016. Masters by Research; University of Bristol
  • 2011-2015. BSc Biological Sciences (with Year Study); University of Exeter (Montana State University