12 February 2025.- Aquaculture finfish species must constantly adapt to changing environmental conditions, while their diets fluctuate due to socioeconomic factors and ingredient availability. Furthermore, climate change increases their exposure to shifting environmental factors, emerging pathogens, and pollutants.
These challenges can compromise fish welfare, affecting not only the animals’ health but also the economic profitability and environmental sustainability of aquaculture production.
The study of innovative strategies to enhance fish welfare in aquaculture can contribute to the sustainability and development of the sector.
Master’s thesis in marine aquaculture
Valery Ravelo recently earned her official master’s degree ‘University Master in Marine Aquaculture’ upon completing and presenting her thesis ‘Improvement of Seabass Welfare (Dicentrarchus labrax) with Adaptogens and Environmental Enrichment’, focusing on innovative approaches to enhance fish welfare.
The results of this work were presented at the National Aquaculture Congress 2024, organised by the Spanish Aquaculture Society in Las Palmas de Gran Canaria, and AQUA 2024, co-organised by the European Aquaculture Society and the World Aquaculture Society in Copenhagen.
Reflecting on her experience, Ravelo commented:
‘’During the second year of the master’s, my scientific progress grew exponentially. I specialised in animal welfare in aquaculture, gaining in-depth knowledge, while refining my technical expertise and research skills. This experience helped me to grow academically and professionally, enabling me to present my findings at national and international congresses - an incredibly enriching opportunity”.
The work was conducted under the supervision of Dr Daniel Montero Vítores, professor of the University of Las Palmas de Gran Canaria (ULPGC), and Dr Silvia Torrecillas Burriel, researcher in aquaculture health and nutrition of the Institute of Agrifood Research and Technology (IRTA), of the Government of Catalonia.
Environmental enrichment and cannabidiol
The main objective of Ravelo’s research was to assess how environmental enrichment using microbubbles and adaptogens such as cannabidiol, individually or in combination, can affect the welfare of European seabass juveniles.
The study analysed different performance indicators such as final growth, weight gain, specific growth rate, and feed conversion factor. Additionally, a confinement stress test was conducted to examine survival rates and blood parameters related with stress response, such as cortisol levels. The research also analysed stress-related gene expression in different regions of the brain, including the telencephalon, the hypothalamus and the pituitary gland.
Strategies to improve seabass welfare
Results showed that environmental enrichment using microbubbles significantly improved growth parameters such as weight gain, final weight, specific growth rate, and feed conversion factor, whereas cannabidiol did not have any negative effects on fish growth.
Concerning welfare parameters, these strategies improved survival rates and reduced stress levels in fish.
About the author
Valery Ravelo holds a degree in Biological Sciences from the Complutense University of Madrid, focusing on the environment. She went on to specialise in aquaculture and completed the International Master in Marine Aquaculture jointly organised by CIHEAM Zaragoza and ULPGC.
Her areas of research include the diversification of strategies to enhance animal welfare, particularly the use of functional additives, essential oils, and natural extracts to improve the general state of fish health. She is currently pursuing this line of research in her doctoral work at the ECOAQUA Institute of the ULPGC.