Environmentally sustainable creel fisheries (based at Heriot Watt Orkney campus)

About the Project

Marine regions around the world encounter similar ecological challenges linked to fishing activities, including those arising from fisheries that use passive or static gear such as traps. Passive gear fisheries (e.g., creels) are often deemed sustainable compared to mobile bottom towed gear fisheries, as they are associated with lower fuel use and seabed damage [1]. However, passive gears are often specifically associated with some other challenges (e.g. [2]). These challenges include impacts on marine biodiversity through bycatch of unwanted species or juvenile individuals (see, for example, [3]), pollution and other negative effects associated to gear losses [4].

Even though these challenges are often discussed in the scientific literature (for example [6 - 9]), many issues remain unresolved and often lacking sufficient scientific information. One such example is creel fisheries targeting crustaceans such as lobster (Homarus gammarus) and brown crab (Cancer pagurus). This fishery is widely practiced in the UK and faces a number of sustainability challenges.

Aims of this project: This PhD project will focus on creel fisheries in Orkney and will examine approaches on how to improve creel fisheries for environmentally sustainable marine resource use. This aim will be addressed by systematically assessing the key issues in typical creel fisheries targeting brown crab and lobster in Scotland. The scientific objectives to be addressed during a 3.5-year PhD period would include assessing:

• (Q1) ecological effects of creel fisheries on the species compositions caught using creels in these marine areas (with special focus on current bycatch rates),
• (Q2) technical improvements to reduce bycatch rates of juvenile individuals of the target species and non-target species bycatch in these creel fisheries,
• (Q3) extent of gear loss in this fishery and the associated risk of ghost fishing from derelict creels, and
• (Q4) potential modifications in creel design (e.g. adaptations from other fisheries) which may lead to reductions in ghost fishing and thus improve environmental sustainability.

This PhD research will contribute to practical applications in creel fisheries, for example through collaboration with the Orkney Fisheries Association, to enhance their sustainability. Furthermore, the candidate will develop networking skills and disseminate the results in international forums. The results will inform future teaching activities.

The practical approach planned during this PhD project would consist of the following activities.

First, the project would aim to estimate fisheries effect on the marine environment (Q1). The candidate will assess catch compositions focussing on observed bycatches of juvenile individuals and non-target species in creels in the existing fisheries, including data collection, monitoring the catches and using video recording analysis.

Furthermore, the candidate will use ghost fishing estimations (Q3) based on summarizing earlier results in different trap gear fisheries based on (i) systematic literature review studies on ghost fishing rates and (ii) local interviews estimating gear loss rates. This approach will follow the one outlined, for example, in Rijkure et al. 2024 [10].

The second set of practical work will be conducted in a laboratory where the candidate will assess the morphology of target species and assess which technical modifications in creels (e.g. escape gaps / windows) and their sizes would fit best for excluding bycatch while retaining catches of target species (e.g., [11]). These results would aim to provide an insight into technological changes needed for improvements based on video recordings during the first part of the experiments (Q2 and Q4).

The final stage would include pilot experiments assessing the new modifications such as specifically modified escape panels or plates using degradable components, limiting ghost fishing (Q2 and Q4).