A tale of two seas: a meta‐analysis of crustacean stocks in the NE Atlantic and the Mediterranean Sea

Abstract

Meta‐analysis of marine biological resources can elucidate general trends and patterns to inform scientists and improve management. Crustacean stocks are indispensable for European and global fisheries; however, studies of their aggregate development have been rare and confined to smaller spatial and temporal scales compared to fish stocks. Here, we study the aggregate development of 63 NE Atlantic and Mediterranean crustacean stocks of six species (Nephrops norvegicus, Pandalus borealis, Parapenaeus longirostris, Aristeus antennatus, Aristaeomorpha foliacea and Squilla mantis) in 1990–2013 using biomass index data from official stock assessments. We implemented a dynamic factor analysis (DFA) to identify common underlying trends in biomass indices and investigate the correlation with the North Atlantic Oscillation (NAO) index. The analysis revealed increasing and decreasing trends in the northern and southern NE Atlantic, respectively, and stable or slowly increasing trends in the Mediterranean, which were not related to NAO. A separate meta‐analysis of the fishing mortality (F) and biomass (B) of 39 analytically assessed crustacean stocks was also carried out to explore their development relative to MSY. NE Atlantic crustacean stocks have been exploited on average close to FMSY and remained well above BMSY in 1995–2013, while Mediterranean stocks have been exploited 2–4 times above FMSY in 2002–2012. Aggregate trends of European crustacean stocks are somewhat opposite to trends of fish stocks, suggesting possible cascading effects. This study highlights the two‐speed fisheries management performance in the northern and southern European seas, despite most stocks being managed in the context of the European Union's Common Fisheries Policy.

Structured additive distributional regression for analysing landings per unit effort in fisheries research

“…This coincides with the strong increase in the effect on the location parameter which overall translates in a strongly increasing variability. These results are in line with those found by Vasilakopoulos and Maravelias [59] for the whole Mediterranean sea and may, to some extend be a result of fuel prices (or other price changes in resources required), see Guillen and Maynou [23] . -When interpreting the effect of the NAO, it is interesting to compare our results to those of [32] where only temporal variation was considered.…”

Resilience and regime shifts in a marine biodiversity hotspot

“…Data availability for other important stressors, such as fishing pressure, primary production, and planktonic assemblages could have further elucidated the system dynamics. For example, the decreasing trends observed in the majority of the Mediterranean fisheries resources during 1985–2013, especially in thermophilic taxa of high economic value such as Merluccius merluccius and Epinephelus spp., and in vulnerable taxa such as the elasmobranchs, possibly also reflect the overfishing problem in the Mediterranean Sea 41 , 42 . Overfishing could also be partly responsible for the decrease in commercially important, non-thermophilic taxa, such as Solea solea and Palinurus spp., but in that case it is harder to disentangle the effects of fishing and sea warming.…”

Premium small scale: the trap fishery for Plesionika narval (Decapoda, Pandalidae) in the eastern Mediterranean Sea

“…Trap fishing is a fuel efficient and fairly selective fishing activity with minimal habitat impacts and delivers catches of high quality (Suuronen et al, 2012). The preservation and expansion of trap fisheries in the Mediterranean Sea, an area characterized by intense overexploitation of most of its fisheries resources (Vasilakopoulos et al, 2014;Vasilakopoulos & Maravelias, 2016), could help reduce the use of less sustainable fishing gears and practices by the SSFs (e.g. boat/beach seines, trammel nets).…”

“…Demersal crustaceans are among the most valuable species for Mediterranean fisheries (STECF, 2017a). Some of them, such as Norway lobster, Nephrops norvegicus (Linnaeus, 1758), spot-tail mantis shrimp, Squilla mantis (Linnaeus, 1758), blue and red shrimp Aristeus antennatus (Risso, 1816), giant red shrimp Aristaeomorpha foliacea (Risso, 1827) and deepwater rose shrimp Parapenaeus longirostris (Lucas, 1846) are heavily exploited by towed gears throughout the Mediterranean Sea, often above sustainable levels (Vasilakopoulos & Maravelias, 2016). Stocks of these important crustacean species are analytically assessed and relevant management advice is produced by dedicated expert working groups (e.g.…”