Biology subjects

Steenbeek, J.

Publications and source records attributed to Steenbeek, J..

4 recordsLinked to original sources

bioRxiv2023

Identifying and prioritizing demersal fisheries restricted areas based on combined ecological and fisheries criteria: the western Mediterranean

The western Mediterranean basin is a high marine biodiversity area under severe pressure by changing climate and intense human activities. Beyond national jurisdictions, international institutions such as the General Fisheries Commission for the Mediterranean (GFCM) work towards canalizing a regional consensus that fishing practices should evolve to better support the 2030 Agenda for Sustainable Development. In this context, Fisheries Restricted Areas (FRA) are proposed as effective management measures to contribute towards increasing fisheries sustainability in the region that can be considered, under some conditions, as Nature-based Solutions (NbS); however, how to operationalize their framework remains unclear. In this study, based on combined ecological and fisheries criteria, we identify and prioritize six potential priority areas for management (PAMs) in the western Mediterranean Sea. They are specifically aimed at the protection and recovery of Essential Fish Habitats and the conservation of Vulnerable Marine Ecosystems, whilst requiring limited adaptation of fisheries practices due to their relative low fishing pressure. We compare the identified areas to those that are currently under protection, and to areas that have been proposed for protection at the GFCM. Our results show that the FRAs and other spatial management measures introduced in the last years marginally contribute to the protection PAMs in the western Mediterranean region. However, the adoption of FRAs that are currently under discussion at the GFCM could contribute significantly to improve the situation. FRAs could also contribute to operationalize NbS in the western Mediterranean Sea when properly designed and implemented. HighlightsO_LIBased on combined ecological and fisheries criteria, six priority areas for management (PAMs) in the western Mediterranean Sea have being identified, with multiple ecological values and relative low trawling. C_LIO_LICurrent spatial management measures implemented have little contribution on PAMs protection. C_LIO_LIFisheries Restricted Areas currently under discussion at the GFCM can significantly increase the protection level of high priority PAMs. C_LI

ecology↗

bioRxiv2022

Costs and economic impacts of expanding marine protected area systems to 30% coverage

International proposals for marine biodiversity seek to expand marine protected area (MPA) coverage from 8% to 30%, known as 30x30. Quadrupling MPA coverage implies considerably higher MPA system costs and governments need early knowledge of these to inform debate. Ambitious MPA expansion also implies large potential losses or "opportunity costs" for fishers, putting pressure on governments to compromise and permit some fishing inside protected areas (a mixed high/low protection system). Crafting a balanced compromise needs to be informed by model projections of future fisheries outcomes under different protection regimes, climate change scenarios and behavioural adaptations. Here, we develop the first models for management costs at national MPA-system scale. We create scenarios of 30x30 at different compromises around protection strictness. We then examine how both MPA costs and opportunity costs vary with strictness, by simultaneously applying our management cost models and two Marine Ecosystem Models. We find that a no-take (high protection) MPA system could cost just $2 billion/year for the developing world and ~$8 billion overall, but would also create opportunity costs several times larger. A compromise mix of high and medium protection would have much higher MPA costs (e.g. $4.5 billion for the developing world) but much lower opportunity costs, to the point of fisheries actually benefiting in the future. Since lower protection also compromises on biodiversity goals, our results show the trade-offs that political decisions need to consider beyond COP15. More generally, the unusually large opportunity costs show how marine contexts generate very different economic issues from terrestrial ones, by attempting to protect a common pool resource area that envisages no automatic market compensation for income lost to conservation.

ecology↗

bioRxiv2020

Current and potential contributions of the Gulf of Lion Fisheries Restricted Area to fisheries sustainability in the NW Mediterranean Sea

Many commercial species of the world are overexploited resulting in substantial reductions of biomass and ecological changes. Spatial-temporal restrictions of fishing activities are important measures used for the management of marine stocks. However, evidence of whether fishing bans benefit whole ecosystems is still scant. Here, we developed a food-web model approach using the Ecopath with Ecosim (EwE) model representing the Fisheries Restricted Area (FRA) of the Gulf of Lion ecosystem (CoSEGoL model) prior to the establishment of the fisheries restrictions (2006-2008) to characterize the structure and functioning of the ecosystem before and after its establishment. The constructed food-web model was, then, fitted to available time series of data from 2008 to 2016 to verify whether this FRA has contributed to recovery of target demersal species and the demersal community. The fitted model was used to explore alternative future management scenarios to explore feasible management options in order to ensure a full ecosystem recovery under climate change conditions. Both small positive and negative ecosystem changes occurred between prior and after the establishment of the FRA, potentially revealing a lack of protection efficiency and/or enforcement. Scenarios of management options under plausible climate futures revealed possible recovery of targeted species, especially European hake. The study highlighted the importance of considering trophic interactions between predators and prey to identify trade-offs and synergies in fisheries management outcomes and the need to consider both fishing and climate dynamics.

ecology↗

bioRxiv2018

Ensemble projections of global ocean animal biomass with climate change

Climate change is shifting the abundance and distribution of marine species with consequences for ecosystem functioning, seafood supply, management and conservation. Several approaches for future projection exist but these have never been compared systematically to assess their variability. We conducted standardized ensemble projections including 6 global fisheries and marine ecosystem models, forced with 2 Earth-system models and 4 emission scenarios in a fished and unfished ocean, to derive average trends and associated uncertainties. Without fishing, mean global animal biomass decreased by 5% ({+/-}4%) under low and 17% ({+/-}11%) under high emissions by 2100, primarily driven by increasing temperature and decreasing primary production. These climate-change effects were slightly weaker for larger animals and in a fished ocean. Considerable regional variation ranged from strong biomass increases in high latitudes to strong decreases in mid-low latitudes, with good model agreement on the direction of change but variable magnitude. Uncertainties due to differences among ecosystem or Earth-system models were similar, suggesting equal need for model improvement. Our ensemble projections provide the most comprehensive outlook on potential climate-driven ecological changes in the ocean to date. Realized future trends will largely depend on how fisheries and management adapt to these changes in a changing climate.

ecology↗