Introduction:
The biodiversity crises , habitat degradation along with a rapidly increase use of marine areas are major challenges worldwide and especially within the EU. The associated start of implementation of the EU Nature restoration regulation in aquatic environments fuels the discussion on suitable measures . These urgent requirements and rapidly progressing demands also affect aquaculture operations and cannot ignored by them. Offshore m ulti-use projects are currently developing concepts and testing different solutions to find and push useful measures. Nature inclusive design (NID) and artificial reefs (AR), have raised significant attention, as being a potential valuable marine ecosystem management tool, compensating human induced habitat destruction and its consequences for marine wildlife. However, a positive impact for the environment, can only be ascertained to very few installations. Missing concepts, i nsufficient data of sound experimental design, quantifiable objectives, monitoring strategy and data accessibility or analysis are the main reasons why the vast AR/NID-installations are not reliable to demonstrate an impact due to recent metadata analysis studies (Paxton et al., 2020). While this research gap has been increasingly acknowledged in recent years, st ill only a few approaches addressed the missing points for an objectively successful AR/NID-installation. Due to the ongoing expansion of marine infrastructure and offshore wind industry the pressure on habitat situation is growing but also new options arise for potentially novel installation opportunities and multi-use efforts. Within the offshore multi-use project ULTFARMS a concept with a filter-based approach has been developed and applied based on proven installations to conceptualize a species- and site-specific AR/NID-installation. The results of first tests in offshore conditions provided invaluable technical insights for future upscaled scenarios. A novel, in-house developed attachment technique, enables a non-disruptive, flexible positioning of add-ons for both existing and future offshore infrastructure, such as monopiles.
Methodology:
The filter approach concept builds on three sequential steps, containing multiple interrelated aspects (non-hierarchical) found in literature (see figure 1)
1. Background analysis:
The ULTFARMS Baltic Sea German offshore pilot, the research platform has been investigated before the design phase to deliver the baseline for habitat developments , cumulative human pressures, historic record of past species abundances and the current status of populations . To be an effective management tool, NID installations must employ SMART objectives prior to the installation as specific, measurable, achievable, realistic and time-bound (Higgins et al. 2022) . The dramatic decline of fish populations has been identified as one of the most obvious negative changes for this area . Therefore, this restoration measure focuses to provide lost habitat for juvenile fish .
2. Design, concept & monitoring
A total of 42 studies have been selected, to fine-tune the site- and species-specific design. While there are limitations in predictability recent studies found good correlation between specific design requirements and population development. Fish diversity has proven to be enhanced via the provision of three-dimensional habitat that incorporates a wide range of microhabitat sizes and types (Taira et al., 2024).
3. Assessment
Stationary underwater cameras fulfil a range of requirement for offshore monitoring as very low maintenance schedules, automatic self- cleaning, continuous data over a longer period of time for monitoring fish and options for AI based automatic species identification.
Results & discussion:
Throughout this pilot-scale deployment, substantial amounts in both quantity and quality of fish assemblages have been observed in and around the installation. The data show a first proof of effectiveness of this NID-installation, the technical and logistical feasibility of a novel attachment technique within an existing windpark . Future experimentally sound studies shall incorporate the above-mentioned filter approach to implement, site- and species-specific AR/NID-installations.
Based on these transferable results of a modular, flexible and scalable NID design tested on an existing offshore monopile future upscaled scenarios for numerous offshore windparks are feasible.
References:
Higgins E, Metaxas A, Scheibling RE (2022) A systematic review of artificial reefs as platforms for coral reef research and conservation. PLoS ONE 17(1): e0261964. https://doi.org/10.1111/1365-2664.14644