Emma Ocaña | Preliminary study into the presence and sightings distribution of the Atlantic blue crab (Callinectes sapidus, Rathbun, 1896) in Gibraltar’s coastal waters.

MSc in Environmental Science & Climate Change

Image of Emma Ocaña | Preliminary study into the presence and sightings distribution of the Atlantic blue crab (Callinectes sapidus, Rathbun, 1896) in Gibraltar’s coastal waters.

Research Project Overview

“My MSc project focussed on investigating the presence and distribution of sightings of the invasive Atlantic blue crab (Callinectes sapidus) in the coastal waters of Gibraltar. The study employed a mixed-method, non-invasive approach combining direct field surveys with citizen science data and stakeholder engagement. This was the first systematic evaluation of C. sapidus in the region, aiming to fill critical knowledge gaps, support early detection and inform evidence-based marine management strategies. The research also included a comprehensive literature review of the species’ spread and impact across the Mediterranean and southern Iberian waters, contextualising the local findings within a broader regional invasion framework.”

  • Primary Supervisor: Dr Awantha Dissanayake
  • Secondary Supervisor: Dr Jaime Davies
  • Advisor: Stephen Warr (Department of the Environment, Sustainability, Climate Change and Heritage (DESCCH)

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

This was an interdisciplinary research project incorporating marine ecology, conservation policy, citizen science and stakeholder analysis. It involved:

  • Ecological fieldwork, including BRUVs (Baited Remote Underwater Video) and timed swim surveys
  • Systematic literature review following PRISMA guidelines
  • Citizen science coordination, including public engagement campaigns, media communications and data verification
  • Statistical and spatial analysis using R Studio and QGIS
  • Stakeholder perception research via survey design and analysis

I developed key skills in:

  • Scientific writing and critical review
  • Quantitative and qualitative data analysis
  • Field equipment operation and non-invasive marine monitoring techniques
  • Public engagement and science communication
  • Project management, including ethical approvals, safety planning, and stakeholder coordination

Were there any partners/stakeholders on your project?

Yes, the project engaged multiple stakeholders such as the Department of Environment, Sustainability, Climate Change and Heritage (DESCCH) which provided historical sighting records and distributed the stakeholder survey. The Nautilus Project, a local NGO which provided important historical data and supported the citizen science data collection through its NEMO reporting platform. Additionally, local marine users such as divers, fishers, open water swimmers, and conservation volunteers contributed observations and survey responses for this project. Lastly, media partners like Gibraltar Broadcasting Corporation (GBC) and The Gibraltar Chronicle helped raise public awareness on the projects aims, encouraging engagement and promoting citizen science.

Why should the public know about this topic?

The introduction of invasive species like the blue crab poses a serious threat to marine biodiversity, fisheries, and local economies. Understanding and addressing biological invasions is essential for:

  • Safeguarding native species and ecosystems
  • Preventing socio-economic losses to fisheries
  • Empowering communities to contribute to early detection and rapid response

This project showed that citizen participation significantly increases detection rates and that public engagement can be a powerful tool in environmental monitoring and management.

What is the wider impact of your research?

This research contributes to the early detection and monitoring of invasive species in a geopolitically and ecologically strategic region — the Strait of Gibraltar. Its broader impact includes:

  • Providing a model for low-cost, scalable monitoring in areas with limited baseline data
  • Supporting compliance with national and international biodiversity frameworks (e.g., CBD, EU Invasive Alien Species Regulation)
  • Informing policy and conservation management for invasive species in marine protected areas
  • Raising public awareness and building local capacity for environmental stewardship through citizen science
  • Contributing to regional data gaps, particularly in underrepresented areas like Gibraltar within Mediterranean invasion research

Keywords

Callinectes sapidus; marine invasive species; Mediterranean Sea; Gibraltar; citizen science; early detection; BRUV surveys; marine monitoring; stakeholder engagement; invasive species management.