Aquaculture Impact Mitigation and Lobster Reintroduction, Spain Case Study
Infographic of the Spain demonstration site
Case Study Components
Introduction to the Site
Location: 42.1438 N, 8.4525 W
Observed ecosystem changes
Alteration of benthic communities beneath mussel rafts due to accumulation of organic waste
CLIMAREST Objectives
Support the coexistence of aquaculture with healthy, native marine species
Features of the Ría de Vigo
The Ría de Vigo is located in northwestern Spain
A ría is a coastal landform where a river valley has been flooded by the sea, creating an inlet that is influenced by tidal activity
The Ría de Vigo benefits from upwelling associated with the Canary Current, making it home to Europe's largest mussel aquaculture industry
Map indicating the demonstration site location
Driving Factors and Motivations
The restoration of benthic ecosystems below aquaculture is motivated by the need to create a healthy coexistence between aquaculture activities and the surrounding native marine ecosystems. As mussel farming is essential to the region's economy, it is crucial to find solutions that benefit both farmers and the ecosystem at large.
Aims of restoration efforts
- implement strategically designed reefs to enhance benthic ecosystems beneath aquaculture infrastructure
- reintroduce the Homarus gammarus below mussel farming activities to decrease organic matter accumulation
Assessment Phase
The Ría faces challenges from both natural processes and human activities
Comprehensive management essential for long-term preservation of ecosystems and local economies
Planning and Design Phase
Primary Objective: Mitigate the environmental impacts of mussel aquaculture while maintaining the region's economic and cultural sustainability
Additional objectives
Ecological mitigation
Use an ecological mitigation approach to balance economic, cultural, and environmental factors to modify sedimentary bottoms to support biodiversity
Nature-based nutrient cycling
Utilise nature-based solutions to enhance nutrient recirculation and secondary production
Habitat complexity
Improve habitat complexity to support marine species affected by overfishing and climate change
Restoration techniques
Develop restoration techniques for commercially important invertebrates and fish
Sustainable aquaculture
Explore Integrated Multi-Trophic Aquaculture (IMTA) to repurpose mussel farming waste and improve resource efficiency and sustainability
Permits
Permit authorised by the Xunta de Galicia
- Required for deployment of artificial reefs and restocking of Homarus gammarus
Additional requirements after permitting
- Notifying authorities before release of Homarus gammarus
- Requesting authorisation for diving activities
- Securing guide for transport of Homarus gammarus between hatchery and field sites
Relevant EU regulations
EU Nature Restoration Law
- Sets legally binding targets for restoration of degraded ecosystems
- Member States are required to restore at least 20% of EU land and sea areas by 2030
Habitats Directive (92/43/EEC)
- Requires strict protection and conservation measures for Natura 2000 sites
Marine Strategy Framework Directive (2008/56/EC)
- Mandates achieving Good Environmental Status (GES) of marine waters
Developing Project Protocols
Figure showcasing the three main steps in the demonstration site protocol
Implementation Phase
Implementation Process
Site selection and preparation
- Four sites chosen: two beneath mussel rafts and two control sites not affected by aquaculture
- Sites surveyed using underwater video and sediment analysis to confirm substrate and environmental suitability
- GPS coordinates recorded for precise placement and monitoring
Deployment of artificial reefs
- 3 concrete reefs installed at each site in May 2023
- Reefs installed at 14-16 meter depth, depending on tidal variations
- Each reef contained 5 removable concrete plates, designed for independent sampling without disturbing the entire structure
- Divers, assisted by a research vessel with a crane, lowered and secured structures on seafloor to prevent displacement due to currents
Introduction of Homarus gammarus
- Lobsters measured, tagged with an individual marker, and acclimatised in controlled conditions
- Homarus gammarus introduced into artificial reef sites
- Strategically placed within and around structures ensuring movements and interactions with the habitat could be monitored
Scale and scope of the restoration project
meters squared of intervention area
meters squared of habitat use and aquaulture impact studies
Monitoring and Data Collection Process
Figuring showing the data collection methods used and which ecological indicators were measured.
