Research Profile | Samantha Slisarenko | MSc Marine Science & Climate Change

The effects of climate variability on a top pelagic predator assessed through stable isotope and stomach content analyses
14th March 2023

Describe your MSc project?

The Atlantic bluefin tuna is a highly migratory species widely distributed in the Atlantic Ocean, providing a significant source of food and revenue for local communities. However, despite its significance, the impact of climate variability on Atlantic bluefin tuna populations remains to be seen, particularly with regard to phenology or the timing of seasonal events such as spawning and migration. This project aimed to explore the impact of shifting oceanographic conditions on Atlantic bluefin tuna, using the species as a representative for related changes. The study employed a combination of meta-analysis and field-based research, utilising stable isotope and stomach content analysis, and involved the participation of local fishermen. The focus was on phenology – the timing of life cycle events such as migration, feeding, and reproduction – and how changing ocean conditions could affect these behaviours. The results offer a crucial understanding of the effects of climate variability on Atlantic bluefin tuna populations and the role of local communities in monitoring and preserving these critical species.
The findings of this study can inform future research and conservation efforts aimed at preserving Atlantic bluefin tuna populations and their habitats. By understanding the impact of climate variability on the timing of life cycle events, it is possible to predict future changes in the populations of these species and implement appropriate management and conservation measures. Furthermore, the involvement of local communities in the research process has emphasised the importance of community-based approaches in marine conservation and management.

What type of research has it involved and what skills have you learned?

My research consisted of a combination of desk-based meta-analyses and experimental fieldwork. I have expanded my skillset by learning new techniques in statistical analysis, systematic literature review methods, and field-based sample collection. These skills have given me a deeper insight into data interpretation, research methodology, and sample collection in different settings.
Firstly, I conducted a meta-analysis of global tuna studies to assess the impact of environmental changes using PRIMER statistical analyses. This component of my thesis involved collecting and synthesising data from multiple studies on tuna diets from various locations worldwide. The data was processed using PRIMER to visualise patterns and relationships in response to changes in climate conditions. This information provided essential insights into the effects of environmental variables on Bluefin tuna’s diet and foraging behaviour.
Secondly, I collected and analysed field samples to study the diet of locally caught Bluefin tuna. The samples were obtained during the open tuna season through the assistance of local recreational fishing fleets in Gibraltar. I recorded morphometrical data to assess the relative health and feeding behaviours of fish in the region; The stomach contents were then analysed using established methodologies for fish diet analysis. I also prepared collected tissues for stable isotope analysis to determine the carbon and nitrogen levels in the collected tissues. These tests will provide insight into the diet and foraging behaviours, particularly the prey sources and trophic levels, of the Bluefin tuna caught in the Gibraltar region. Many of the samples collected during my MSc project are still awaiting analysis results, and I am eager to uncover the details revealed through these tests. My ongoing PhD research will involve using new experimental techniques to answer my research questions fully.

Why should the public know about this project?

The Mediterranean region is expected to have intensified responses to climate change and environmental variability, with impacts that transcend the management of large game catch. Beyond public stakeholders involved in the fisheries sector, the details of my project may be used as a proxy to predict the general effects of climate change that shape oceanic processes, which considerably impact the ecosystem services derived from the sea. By tracking the discoveries made, new information on our changing systems can be publicly available.
Given the importance of commercial and recreational fisheries for multiple regional stakeholders, the ability to predict and monitor effects on key fish stocks is crucial. Sharing data between scientific and public stakeholders is necessary to ensure that new knowledge and findings are accessible to different groups and that misinformation between groups is dispelled. Public engagement with and input to ongoing research will allow this project to continue to monitor Bluefin tuna in Gibraltar to ensure monitoring and sustainable management are enhanced and sustained.

What is the wider impact of your research?

The wider impact of research that assesses the phenology and health of Atlantic bluefin tuna in the Mediterranean is significant as it provides valuable insights into the effect of changing environmental conditions on the populations of this important species. The findings of such research can inform the management of Atlantic bluefin tuna populations, helping to ensure their sustainability and the protection of this vital food source for local communities.
In addition, studying the phenology and health of Atlantic bluefin tuna in the Mediterranean can also provide valuable information on the broader impact of climate change on marine ecosystems. The differences observed in the populations of this species can serve as an indicator of the health of the entire ecosystem, providing an early warning of the potential impact of climate change on other species in the region.
Furthermore, such research can contribute to developing effective conservation and management strategies, including identifying key areas for protection and developing sustainable fishing practices. By improving our understanding of the impact of climate change on Atlantic bluefin tuna, this research can help to ensure the long-term survival of this species, which is critical for both the health of the ecosystem and the livelihoods of local communities.

Comments from Head of School

Sam’s research hopes to shed light on the diet on feeding preferences of Atlantic Bluefin whilst migrating within the Straits of Gibraltar. Working with the local angling community is crucial to understanding tuna ecology and behaviour. As such, we would like to thank Charlie Carreras and the angling community for engaging with the University, welcoming Sam and contributing to scientific research.
 Sam has travelled from Canada for her Master’s degree, and due to her academic prowess, she has been retained as a Graduate Researcher and Teaching Assistant. She assists the School of Marine and Environmental Science in the delivery of teaching and learning whilst undertaking her PhD.
– Dr Awantha Dissanayake, Head of School (Marine & Environmental Sciences)
  • Postgraduate
    MSc

    Master in Marine Science & Climate Change

    Designed and delivered by expert academics and scientists, this full or part-time interdisciplinary programme blends theoretical study with practical, field-based work. You will cover specialist subject areas and gain the skills required to tackle the complex issues associated with the sustainable development of marine ecosystems.[...]

    1 Year

    No Placement option

    Full Time

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