Vulnerable marine ecosystems (VMEs) are considered biodiversity hotspots in the deep sea, but are also characterised by a high vulnerability to disturbance and a low recovery potential. Habitats formed by corals and sponges are examples of such hotspots Various species within these broad taxonomic groups form habitats known as Coral gardens, Cold-water coral reefs, and Deep-sea sponge aggregation that are on the OSPAR list of Threathened and/or declining habitats. The NovasArc project has contributed to a more detailed classification of these habitat types which can be used to provide a more specific management advice. Damage to VMEs represents a threat to biodiversity, not only locally but probably also on broader scales since the VME can be regarded as species pools for many species that also live in other habitats. Various ecosystem functions are associated with the VMEs, including biodiversity support, nutrient cycling, carbon sequestration, nursery grounds and preferred habitat for commercial fish species. Avoiding damage to these fragile ecosystems has great effects on seabed integrity (Descriptor 6, MSFD) and the quality of life below water (UN sustainable development goal # 14).
Norway, Iceland and the Faroes have EEZs/EFZ within Nordic Seas where fisheries are very important economically and culturally. The long history of intense fishing pressure on the shelves and slopes in these waters has resulted in considerable damage to VMEs. To further alleviate damage to VMEs, it is important to pinpoint those areas that are at most risk to fishing pressure. Given the lack of bona fide observations from many locations of VMEs, species distribution models can serve as a good approach to predict distribution of the suitable locations of VME indicator species. To evaluate the likely disturbance of VMEs, the footprint of both mobile and static bottom fishing gears can be overlapped with the predicted distribution of suitable VME habitats. In this manner, it is possible to identify areas where there is a high probability of finding thriving VMEs. Such information is of vital importance to inform managers about those areas on the seafloor that are of high ecological value and further damage to these would thus impair the goods and services they deliver, e.g., habitat provision and hotspots of raised biodiversity and productivity.
In NovasArc, the spatial distribution of VMEs within Norwegian, Icelandic and Faroese waters were predicted by using habitat suitability modelling based on an extensive aggregated dataset of the occurrence of indicator species and environmental factors. The risk of bottom trawling to VMEs was evaluated at four different levels of fishing intensity (proportion of a grid cell that is swept by trawl each year) ranging from low (>0–0.1) to high (>2). Furthermore, areas that had a relatively high degree of suitability above the threshold level (0.8) were indicative of optimal condition for the particular habitat that is being modeled. This enabled identification of important areas for VMEs and also evaluation of the risk of bottom fishing to these habitats. To date, NovasArc has predicted the distribution of eleven VMEs and generated estimates of the area at risk from bottom fishing for these. This co-operation has resulted in successful data and knowledge sharing of VMEs and fishing effort. This accomplishment is relevant for good management and sustainable use of resources that will not only be beneficial on national level of VMEs but can be assessed more beneficially for the ecosystem’s connectivity and integrity on larger scale. The Nordic Seas are expected to be facing a range of new pressures in the decades to come. Pressures related to climate change are likely to influence benthic ecosystems in general, and VMEs in particlular, through direct or indirect mechanisms. Climate driven ice retreat will invite a range of other pressures to marine seafloor ecosystems in addition to fisheries, including vessel traffic and seafloor resource extraction. The combination of several pressures, including those caused by fishing and climate change, may compromise the resilience of VMEs to a larger extent than experienced before.
The NovasArc project is funded by The Nordic Council of Ministers – Nordic Working Group for Oceans and Coastal Areas) (NHK) and the main focus of NovasArc has been to improve the knowledge on the distribution of VMEs and assess the risk of bottom fishing activities to these. In the next phase of the NovasArc, the influence of climate scenarios will also be evaluted. This means that new spatial distribution models for VMEs will be run with predictor data representing different Shared Socioeconomic Pathways (SSP) scenarios.
The current report delivers three products. Firstly, we compare predictions of VME distributions with new observations, and update the predictions to produce spatially-explicit estimates of the predictive uncertainty. The outputs of the earlier models have been updated and validated.
Secondly, we discuss how the model output could be used in the development of criteria and indicators relevant to management of benthic habitats including the Good Environmental Status descriptors 1 and 6: Biodiversity and Seafloor Integrity, in the Marine Strategic Framework Directive, and the OSPAR common indicator “Physical damage of predominant and special habitats”.
Thirdly, we explore the relevance of our results against the Performance Indicator Scores used in the requirements for Marine Stewardship Council (MSC) Fisheries Standard for sustainable fisheries.