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Small-scale fisheries (SSFs) constitute a substantial component of European fisheries and have a high socioeconomic importance, especially for remote insular areas. Traps produce catches of high quality and value, associated with limited bycatch and low habitat impact. Long-standing trap SSFs in both the Mediterranean and the Atlantic showcase the potential of such SSFs to support remote fishing communities; however, trap SSFs remain relatively understudied. Here, we investigate the spatial and temporal dynamics of a Greek trap SSF targeting Plesionika narval (Fabricius, 1787) in the eastern Mediterranean, by means of Generalized Additive Models fitted on fishers’ logbook data from 2005 to 2014. The dynamics of both catch per unit effort (CPUE) and profits suggest a pronounced seasonality for this fishery, while there are also signs of local overexploitation in the traditional fishing grounds. Additionally, small vessels (< 12 m) report higher CPUEs than larger vessels. Our results point to management measures that could improve the sustainability of this valuable SSF, such as changes in the spatial and temporal allocation of fishing effort, and in fleet composition. The insights gained from this study are relevant to other localized trap SSFs and illustrate the socioeconomic potential of such fisheries for remote fishing communities. [ABSTRACT FROM AUTHOR]

In the Mediterranean Sea, the dominant type of fisheries is small-scale. Coastal communities remain dependent on fisheries for their income, some of them with limited potential for economic diversification. The top-down micro-management regime has proven ineffective to secure ecological and social sustainability as it lacks flexibility and adaptation to local and regional conditions. This paper explores the advantages of using a participatory approach and a bio-economic model to develop management scenarios in a high value small-scale shrimp trap fishery in Greece. Seeking active stakeholder involvement throughout the management process advanced the identification of management measures aiming at MSY, with high levels of acceptance from stakeholders. It also increased transparency and legitimacy of the proposed management measures and could be considered as a first step towards co-management and regionalization. The participatory approach undertaken could promote compliance and facilitate the transition to sustainable fishing, ensuring the viability of coastal communities and, thus, social sustainability. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

We investigate long-term changes in the Mediterranean marine resources driving the trawl fisheries by analysing fishers’ perceptions (Traditional Ecological Knowledge, TEK) throughout the Mediterranean Sea during the last 80 years. To this end, we conducted an extended set of interviews with experienced fishers that enabled us to classify species (or taxa) as ‘decreasing’ or ‘increasing’ both in terms of abundance, as well as average size in the catch. The aspect that most clearly emerged in all the investigated areas over time was the notable increase of fishing capacity indicators, such as engine power and fishing depth range. Atlantic mackerel, poor cod, scorpionfishes, striped seabream, and John Dory demonstrated a decreasing trend in the fishers’ perceived abundance, while Mediterranean parrotfish, common pandora, cuttlefish, blue and red shrimp, and mullets gave indications of an increasing temporal trend. Although, as a rule, trawler captains did not report any cataclysmic changes (e.g. extinctions), when they were invited to estimate total catches, a clear decreasing pattern emerged; this being a notable finding taking into account the steep escalation of fishing efficiency during the past century. The overall deteriorating status of stocks in most Mediterranean regions calls for responsible management and design of rebuilding plans. This should include historical information accounting for past exploitation patterns that could help defining a baseline of fish abundance prior to heavy industrial fisheries exploitation. [ABSTRACT FROM AUTHOR]

Abstract: Fish-habitat associations were investigated for twenty-five non-commercial demersal species in the Aegean Sea (eastern Mediterranean) using Generalized Additive Modeling techniques. Fishery related abundance indices, derived from experimental bottom trawl surveys, were linked to various habitat variables: substrate characteristics, area, season, depth, temperature and salinity. Depth was the most important factor for all species. Eleven species showed decreasing abundance with depth, while the remaining species were more abundant in specific depth zones either on the continental shelf or in the upper continental slope. Most species were associated with specific substratum characteristics such as the dry weight percentage of sand-gravel and the carbonate content. The dry weight percentage of sand-gravel in the sediments was selected as a predictor of the relative abundance of most (twenty three) species. Seasonal patterns in the relative abundance of species were observed, related in most cases to the seasonal differentiation of temperature. The effect of temperature was more pronounced in summer and autumn, when a marked thermocline is observed, while it was much less intense in winter. For most of the species, the preferable habitat was identified, that contributes valuable information for the successful implementation of an ecosystem approach to fisheries management. [Copyright &y& Elsevier]

Generalized additive models (GAMs) were applied to investigate the influence of spatial (subarea), temporal (season) and environmental variables (substrate characteristics, depth, temperature and salinity) on the relative abundance of 27 demersal species of commercial importance in the Aegean Sea. Twelve species exhibited decreasing population density with increasing depth, whereas the abundance of the remaining species peaked at intermediate depths. Most of the species were mainly distributed on the continental shelf and upper continental slope. The dry weight percentage of sand in the sediment was included as an important predictor in the best models of all species with a lifecycle closely related to the substrate (flatfish, skates, gurnards, mullets, anglers, scorpionfish) and in most benthopelagic species (seven of 12). The weight percentage of carbonates in the sediment was also included in the best models of most species (19 of 27). Seasonal patterns in the relative abundance of species were observed, related in most cases to the seasonal differentiation of temperature and salinity gradients. During the period of water stratification (summer and autumn) the influence of temperature or salinity on fish abundance was always greater than during the period of vertical mixing (winter). The present results are discussed in the light of fostering the current perception as to factors influencing the spatiotemporal distribution of fish, which is a prerequisite for the sustainable exploitation of commercial stocks. [ABSTRACT FROM AUTHOR]

Univariate and multivariate autoregressive integrated moving average (ARIMA) models were used to model and forecast the monthly pelagic production of fish species in the Mediterranean Sea during 1990–2005. Autocorrelation (AC) and partial autocorrelation (PAC) functions were estimated, which led to the identification and construction of seasonal ARIMA models, suitable in explaining the time series and forecasting the future catch per unit of effort (CPUE) values. Univariate and multivariate ARIMA models satisfactorily predicted the total pelagic fish production and the production of anchovy, sardine, and horse mackerel. The univariate ARIMA models demonstrated a good performance in terms of explained variability and predicting power. The current findings revealed a strong autoregressive character providing relatively high R2 and satisfactory forecasts that were close to the recorded CPUE values. The present results also indicated that the multivariate ARIMA outperformed the univariate ARIMA models in terms of fitting accuracy. The opposite was evidenced when testing the forecasting accuracy of the two methods, where the univariate ARIMA models overall performed better than the multivariate models. The observed seasonal pattern in the monthly production series was attributed to the intrinsic nature of the pelagic fishery. As anchovy, sardine, and horse mackerel represent main target species in the Mediterranean pelagic fishery, the findings of the present study provided direct support for the potential use of accurate forecasts in decision making and fisheries management in the Mediterranean Sea. [ABSTRACT FROM AUTHOR]

The seasonal distribution of Morocco dentex ( Dentex maroccanus) was investigated in relation to ocean environmental conditions in the NE Mediterranean Sea. Data were collected during a 2-yr period (1996–1997) of quasi-synoptic seasonal sampling using demersal trawl surveys. The study revealed evidence for the existence of environmental relationships and temporal habitat associations of Morocco dentex. The sea-bottom salinity, the water depth (through its interaction with bottom salinity) and the spatial location appeared to be key determinants of distribution. There was a strong consistency in the pattern and significance of the observed relationships across all seasons. The present results provided direct support for a preferential seasonal aggregation of Morocco dentex in specific geographic and bathymetric regions of the study area. In all four seasons, these favourable regions were found to be relatively stable and distinct, had the highest catch-per-unit-effort index, and were located over shallower grounds (50–70 m) having bottom salinity around 39.1. The current findings also indicated that, throughout the year, the species was confined below the thermocline and avoided the deeper waters (>80 m). Morocco dentex ecological preferences for certain sea-bottom salinities, water depth zones and hydrographic regimes were suggested to contribute to the processes governing differential settlement to preferred grounds. [ABSTRACT FROM AUTHOR]

Complex natural systems, spanning from individuals and populations to ecosystems and social-ecological systems, often exhibit abrupt reorganizations in response to changing stressors, known as regime shifts or critical transitions. Theory suggests that such systems feature folded stability landscapes with fluctuating resilience, fold-bifurcations, and alternate basins of attraction. However, the implementation of such features to elucidate response mechanisms in an empirical context is scarce, due to the lack of generic approaches to quantify resilience dynamics in individual natural systems. Here, we introduce an Integrated Resilience Assessment (IRA) framework: a three-step analytical process to assess resilience and construct stability landscapes of empirical systems. The proposed framework involves a multivariate analysis to estimate holistic system indicator variables, non-additive modelling to estimate alternate attractors, and a quantitative resilience assessment to scale stability landscapes. We implement this framework to investigate the temporal development of the Mediterranean marine communities in response to sea warming during 1985-2013, using fisheries landings data. Our analysis revealed a nonlinear tropicalisation of the Mediterranean Sea, expressed as abrupt shifts to regimes dominated by thermophilic species. The approach exemplified here for the Mediterranean Sea, revealing previously unknown resilience dynamics driven by climate forcing, can elucidate resilience and shifts in other complex systems.

Predicting the occurrence of keystone top predators in a multispecies marine environment, such as the Mediterranean Sea, can be of considerable value to the long-term sustainable development of the fishing industry and to the protection of biodiversity. We analysed fisheries independent scientific bottom trawl survey data of two of the most abundant cartilaginous fish species (Scyliorhinus canicula, Raja clavata) in the Aegean Sea covering an 11-year sampling period. The current findings revealed a declining trend in R. clavata and S. canicula abundance from the late '90 s until 2004. Habitats with the higher probability of finding cartilaginous fish present were those located in intermediate waters (depth: 200-400 m). The present results also indicated a preferential species' clustering in specific geographic and bathymetric regions of the Aegean Sea. Depth appeared to be one of the key determining factors for the selection of habitats for all species examined. With cartilaginous fish species being among the more biologically sensitive fish species taken in European marine fisheries, our findings, which are based on a standardized scientific survey, can contribute to the rational exploitation and management of their stocks by providing important information on temporal abundance trends and habitat preferences.