Research Profile | Elly Clay | Marine Science & Climate Change

Octopus Hotels - artificial dens to increase habitat availability for Octopus vulgaris in Gibraltar’s waters.
15th November 2022

Describe your MSc project?

My research project aimed to increase the abundance of Octopus vulgaris in Gibraltar through repurposing artisanal clay fishing pots into artificial dens to increase habitat availability for Octopus vulgaris in Gibraltar. Octopus vulgaris are threatened by unregulated fishing activity and habitat degradation. Shelter is extremely important for Octopus vulgaris as they spend a high proportion of time within dens which provide refuge from predators, as well as an area to feed, mate, and spawn.
Increasing habitat availability provides increased dens for juvenile settlement, and dens to mate and spawn and therefore can contribute to increasing the abundance of Octopus vulgaris.
My research project was successful in increasing habitat availability for Octopus vulgaris as the artificial dens were occupied by octopus which was evident from direct observations of Octopus vulgaris occupancy, as well as midden and den formations. Occupancy of the artificial dens increased by 75 % from 19 days post den deployment to 27 days post den deployment and has continued increasing post data collection, and Octopus vulgaris have been observed mating in the artificial dens.
This project provides a low-cost nature-based solution to increasing habitat availability, and abundance, of Octopus vulgaris. The use of clay material to create the dens, as opposed to plastic, which is implemented in many fishing and artificial den projects, is crucial in increasing habitat availability without introducing more plastic pollution to the marine environment. Repurposing artisanal clay fishing pots into artificial dens for Octopus vulgaris is easy to implement, low cost and doesn’t have a negative impact on the community or the environment.

Video credits to Bianca Daniell

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

My field research methods included Baited Remote Underwater Video (BRUV) surveys which I used to assess the abundance of Octopus vulgaris as well as scuba diving surveys to obtain footage of artificial den occupancy, followed by precision in analysing large volumes of video and imagery data. Skills in planning and implementing scientific research in the field were essential to organise the efficient deployment of the artificial dens, BRUV surveys and scuba diving surveys.
My research projected also involved desk-based skills including conducting a literature review, scientific report writing, data analysis, SWOT analysis, developing an infographic and visual representations of data such as maps and diagrams.

Why should the public know about this topic?

The topic of my research is important for the public as octopus is a popular food source in Europe and other regions of the world. Still, as Octopus vulgaris is not a threatened species under the ICUN categorisation, it is often overlooked and not included in fishing quotas and restrictions. Assessments of stocks of O. vulgaris in Gibraltar, and other regions, are often not conducted, leaving O. vulgaris vulnerable to overexploitation from fishing. In Gibraltar, fishing is a popular recreational activity, so it is important to ensure fishing stocks are not depleted to unsustainable levels. To ensure healthy supplies of octopus, increased and enforced fishing regulations are necessary measures that must be taken. 
My research in introducing artificial dens offers a solution to increase the abundance of octopus that can run alongside fishing activities if the artificial dens are left undisturbed, preventing the requirement for complete fishing bans and enforcements that may be the only option should stocks be overexploited. In addition to the threats faced by octopus from fishing, they are also at risk from habitat degradation due to introduction of human infrastructure, storms, and removal of natural materials such as shells, therefore the introduction of these artificial dens provides additional habitat availability. 
The use of clay material in creating artificial dens is also beneficial for the public, as well as the environment, as this avoids using plastic which could increase plastic pollution in the local marine environment. 
Octopus also play an important role in maintaining healthy marine ecosystems exerting influence on the abundance of their prey organisms, such as crabs, as well as predatory organisms such as dolphins. Octopus are also a charismatic marine organism that are often viewed favourably by the public and are of interest to scuba divers and snorkellers creating an attractive marine experience, relevant for tourism and local recreation. 

What is the wider impact of your research?

My research project can be applied across the globe to any region where octopus are threatened from overfishing and/or habitat degradation. This is a low-cost method, that is easily introduced, with little ongoing costs, and therefore is easily replicated in other regions. The use of clay, as opposed to plastic, is crucial as this prevents contributing to plastic pollution in the marine environment. My project can also be adapted and used for continued research to gain further understanding of the social behaviours of Octopus vulgaris, prey consumption and spawning behaviours to increase understanding of Octopus vulgaris in Gibraltar and other regions. My project can also assist in raising awareness of the importance of Octopus vulgaris in Gibraltar’s marine waters and educating the community in the importance of sustainable fishing.

Comments from Head of School

Elly’s project builds on a simple idea of repurposing flowerpots for use as shelters for octopus as a nature-based solution. By increasing habitat availability, the pots could be potentially used as a simple but cost-effective method of increasing octopus abundance. Octopus are a very charismatic organism and often a talking point among divers but also both ecologically and economically important – within the Iberian Peninsula and the wider Mediterranean, octopus is frequently on the menu in seafood restaurants.
By employing these artificial dens, a more sustainable fishery could be employed, ecotourism (e.g. diving) benefits could be derived, as well as a method of boosting populations within Marine Protected Areas and in particular, No Take Zones.
We are very proud of Elly and her hard work and with rapid occupancy of these dens within 20 days – the impact of this work is clear to see.
Next time you are diving and see these pots at Camp Bay with an octopus or evidence of an octopus (e.g. shells), take a photo and share on social media and tag UniGib and/or email us at
  • 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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