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The current study examined the effect of environmental, operational, temporal and catch-related variables on the discard quantities of four species subject to the EU landing obligation (Merluccius merluccius , European hake, HKE; Parapenaeus longirostris , deep-water rose shrimp, DPS; Mullus barbatus , red mullet, MUT; Trachurus trachurus , horse mackerel, HOM) caught in Italian and Greek bottom trawl fisheries. Generalized Additive Models were applied to discards per unit of effort of each species in seven study areas distributed over different sub-divisions of the Mediterranean Sea (Western Mediterranean: (i) Ligurian Sea and Northern Tyrrhenian Sea, (ii) Southern and Central Tyrrhenian Sea; Central Mediterranean: (iii) Southern Adriatic Sea, (iv) Western Ionian Sea; Eastern Mediterranean: (v) Eastern Ionian Sea, (vi) Central and South Aegean Sea, (vii) Crete) and were able to explain 21–96% of the deviance. Geographic coordinates and depth were included as significant covariates in the majority of the final models, showing that discards are affected by bathymetric preferences of the species and sizes, local patterns in productivity and/or possible existence of nursery grounds. Discard rates were higher at the shelf break for HKE and DPS, slightly shallower for HOM, while MUT discards occurred mainly in waters <100 m depth. Positive relationships between discards and volume of catches and negative ones between discards and the mean length (especially for HKE) highlighted the effect of the catch characteristics as well as fishers' discarding behaviour. Interannual effects seemed to be related to trends in species abundance and recruitment success, while seasonal patterns were usually linked to the recruitment period and/or seasonal fishing intensity. The length of the vessel, vessel age and haul duration were significant in few cases, but there were no common patterns across all regions/species. Overall, the results showed that discarding in Mediterranean bottom trawl fisheries is affected by a large number of variables that should be taken into account for a more effective mitigation of unwanted catches. • Modeled effect of environmental, operational, temporal, catch variables on discards. • Geographic coordinates and depth were major contributors. • Temporal patterns were mainly species-specific. • Discards are affected by catch composition and volume and fishers' behaviour. • Multiple factors should be considered for more effective management of discards. [ABSTRACT FROM AUTHOR]

Small‐scale driftnets (SSDs) have been historically used in the Mediterranean without major environmental concern. The introduction of large‐scale driftnets caused unwanted catches of protected species. Specific regulations were therefore issued in European waters, culminating in a proposed moratorium on SSDs. This study aimed to characterise the SSD fishery targeting anchovy (menaide), evaluating its environmental sustainability, economic performance and social relevance. In 2013, a survey by interviews, logbooks and observers on board assessed the order of magnitude of this fishery in terms of fishing capacity and activity, volume of landings and revenues. The menaide fleet consisted in 60 vessels <12 m overall length, moored in little harbours in southern Italy. These nets are highly selective: the target species, European anchovy, Engraulis encrasicholus (L.) and sardine, Sardina pilchardus (Walbaum), dominates the catches, while discards are negligible. The anchovies caught are of high quality and large size; the high prices support fish processing by local factories. Moreover, the results of a SWOT analysis demonstrated that replacing SSDs with a semi‐industrial fishery, like purse seining, would increase impacts on the ecosystem, and a loss of socio‐economic opportunities for several coastal villages. These findings support the option of keeping SSDs operating, in the framework of specifically oriented management measures. [ABSTRACT FROM AUTHOR]

Minimizing the probability of discards is an important step in mitigating environmental impacts of fishing activities and maximizing economic gains from fish stocks. Although several discard models have been recently developed, current approaches are still unable to robustly adjust to different circumstances (e.g. fishery target species, geographical location), and lack a closer interaction with stakeholders. Here, we present a novel approach consisting of a modular Bayesian model, which can incorporate any relevant explanatory variable, independently of data availability. The relationships between the variables and discard rates are initially delineated by stakeholders through surveys, and included to the model as priors. The priors are then used together with observed data for estimating posterior distributions of discard probability. We test this approach in two study areas at the Mediterranean Sea: the Ligurian and Tyrrhenian Seas in Italy, and the Greek part of the Aegean Sea. For each site, we evaluated the model for estimating discards from bottom trawl fishery associated with European minimum conservation reference size regulations, as well as discards caused by the low economic value of catches. [ABSTRACT FROM AUTHOR]