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Numair Masud

Dr Numair Masud


Reasearch Associate

School of Biosciences

Sir Martin Evans Building, Museum Avenue, Cardiff, CF10 3AX


I am passionate about understanding how various anthropogenic stressors impact fish welfare and crucially testing whether intervention strategies to help improve fish welfare and their environment really works. Understanding and potentially improving fish welfare has been a slow endeavour, with the knowledge that fish can neurologically respond to pain only being discovered in 2003. This neglect of fish welfare has contributed to the 'silent extinction' of many fish species, with freshwater species in particular facing higher extinction rates than any other group of vertebrates on the planet. Using an interdisciplinary approach has meant I have been able to understand how a broad range of anthropogenic factors, including plastic pollution, eutrophication, aquaculture feeds and even infectious disease treatments impact fish welfare.  

Key research interests:

  • - Impact of anthropogenic factors on fish behaviour, physiology and disease resistance
  • - Developing infectious disease prevention and control strategies











Latest Research Project

Plastic fish: assessing the scale, chemical properties, and biological effects of petrochemical plastics and bioplastics on aquaculture fish  

This project has two broad aims: use cutting edge polymer analysis to investigate the scale, and biochemical properties of plastic polymers within aquaculture and investigate the impacts of a subset of these common plastics and associated chemical additives on fish health. Specific objectives:

1)    Plastic survey: identify and quantity plastic contamination in UK freshwater aquaculture facilities. 

2)    Petrochemical plastics: determine the chemical adsorption and desorption capacity of microplastics in relation to plasticisers, thermal stabilisers, and aquatic toxins as well as understanding their impacts on aquaculture fish growth, metabolism, disease resistance and underlying molecular mechanisms. 

3)    Biobased plastics: determine the degradability, adsorption, and desorption capacity of biobased plastics (i.e., bioplastics) compared with petrochemical plastics within aquaculture environments and their biological impacts on fish health. 

Broad Research Themes

Aquaculture: with our industry partner Adisseo-Nutriad, I have investigated how fortified feeds impact disease resistance in fish. In developing and testing fortified feeds, aquaculture is addressing preventative and control strategies that replaces the traditional approach of chemical treatments.

Ornamental trade: my research has focussed on how various stressors including, transport stress, enrichment deprivation and noise pollution impact fish physiology, behaviour, and disease resistance. With fish being the most populous pets in western households, such primary research offers insights into how neglected stressors might be impacting fish welfare. Techniques used include behavioural analysis, respirometry and experimental parasitology.

Ecosystems: using an interdisciplinary approach, I investigate how various ecosystem pollutants such as microplastics and herbicides impact freshwater fish welfare. Here, I have drawn on various techniques including NMR spectroscopy, transcriptomic analysis, and experimental parasitology.

Line manager

Professor Jo Cable


  • Freshwater ecology
  • Aquaculture and fisheries stock assessment
  • Fish pests and diseases
  • Polymers and plastics