Fishing effort alternatives for the management of demersal fisheries in the western Mediterranean

Abstract

Management alternatives based on fishing effort for the demersal fisheries in the western Mediterranean were tested, with the novelty of examining management alternatives at temporal scales smaller than one year. Nine scenarios were considered on the basis of input control: decrease in the number of fishing days, which may correspond to cessation of activity of vessels or lower activity of the fleet; and implementation of seasonal closures of one-, two- and three-month duration in winter, spring, summer and autumn. The approach is based on a multispecies and multigear bioeconomic model. We selected a total of ten species (Merluccius merluccius, Nephrops norvegicus, Mullus barbatus, Mullus surmuletus, Parapenaeus longirostris, Lophius piscatorius, Lophius budegassa, Aristeus antennatus, Phycis blennoides and Lepidorhombus boscii) and seven fleets, defined as a combination of fishing gear (bottom trawl, entangling nets and longline) and fleet segment. A similar decrease in F is achieved with a 20% reduction of fishing effort (days) or with two- to three-month closures. Maximum Sustainable Yield (MSY) for all stocks would be achieved only with such a drastic reduction of fishing effort ( > 80% of fishing days by the end of the five years of simulation) that, in practice, its application can be considered unrealistic, since it would represent a very low activity of all fishing fleets over the year.

Persistence of Biogeochemical Alterations of Deep‐Sea Sediments by Bottom Trawling

“…These results reveal that, although a 2‐months seasonal trawling closure could allow fish stocks to rebuild (Martín et al., 2019), it is insufficient to restore the quantity and quality of organic matter in sediments of deep‐sea trawling grounds. Indeed, with sedimentation rates of 0.37–0.85 cm yr −1 (Table ), a trawling break of 2 months would only allow the accumulation of approximately 0.05–0.15 cm of sediment, which cannot lead to measurable recoveries in these disturbed environments.…”

“…These results reveal that, although a 2-months seasonal trawling closure could allow fish stocks to rebuild (Martín et al, 2019), it is insufficient to restore the quantity and quality of organic matter in sediments of deep-sea trawling grounds. Indeed, with sedimentation rates of 0.37-0.85 cm yr −1 (Table S3) Relative difference in concentrations of organic matter compounds in trawled cores versus untrawled cores during the different sampling periods for bulk concentrations (a), after normalizing for fine-grained sediment (b), and after normalizing for OC contents (c).…”

Bioeconomic Analysis of the EU Multiannual Management Plan for Demersal Fisheries in the Western Mediterranean. Spanish Fisheries as a Case Study

“…The West Med MAP goal suggests that the MSY level of the most vulnerable stock should be achieved by 2025. However, this goal requires a drastic reduction in fishing mortality, such that its application in practice would be unrealistic (Maynou, 2014;Martín et al, 2019), because it will require an 80% reduction in fishing time. Moreover, the reduction in fishing time established in the West Med MAP is insufficient to achieve F MSY levels in 5 years, and more time would clearly be necessary to reach MSY levels.…”

“…or technical measures (e.g., selectivity, catchability). It has been used in various studies of GSA06 Maynou, 2014Maynou, , 2019Sola and Maynou, 2018b;Martín et al, 2019) and in other areas of the Mediterranean Sea (Merino et al, 2007;Silvestri and Maynou, 2009;Maravelias et al, 2014). MEFISTO is a free software that can be downloaded at http://mefisto2017.wordpress.com/.…”

Evidence for spatiotemporal shift in demersal fisheries management priority areas in the western Mediterranean

“…The socioeconomic models by Sola et al (2020) suggest that the maximum sustainable yield level of vulnerable stocks should be achieved soon. However, this goal requires 80% reduction of fishing effort following the current spatial planning, which in practice seems to be unrealistic (Martín, Maynou, Garriga-Panisello, Ramírez, & Recasens 2019; Maynou 2014).…”