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Discard mortality of European anchovy (Engraulis encrasicolus) and European pilchard (Sardina pilchardus) was investigated during commercial purse seine fishing operations off İzmir Bay, Turkey. In total, 6703 anchovy and 2545 sardine individuals were observed for seven days in five survival experiments carried out from March to October 2019. Only in March, fish cages were used and observed by divers. In the other trials, fish were observed in holding tanks; dead fish were collected and any surviving fish were fed. In the study, we compared the mortality of sorted and unsorted fish. The GLM model for European anchovy demonstrated a highly significant category effect (p, Türkiye Bilimsel ve Teknolojik Araştırma Kurumu, TÜBİTAK, This study was a part of project 118O317 funded by TÜBİTAK (Scientific and Technological Research Council of Turkey).

By catch is a serious conservation challenge for the fisheries whose viability is increasingly under threat. To approach maximum by catch reduction with minimum loss of targeted catch, fisheries need to have information on the environmental and anthropogenic factors in multi species seas like the Mediterranean. In this study, we used generalized additive models (GAM) to by the catch ratio of purse seine fishery to determine the effects of environmental variables. The data were collected during each fishing trip in the 2018-2019 fishing season that covers the time period between September 1st and April 15th. There were 26 species (66.216 mt in total) recorded as by catch and the rates of by catch species in the total by catch amount varied between 0.001% and 23.1%. In terms of habitat of by catch species, the total ratios of benthopelagic, demersal and pelagic species were 52%, 28% and 20%, respectively. Significant interactions observed indicate that the fluctuations in by catch ratios differed by depth and sea surface temperature, whereas the quarters of year and the moon phases were not found to affect by catch ratios significantly., Scientific and Technological Research Projects Funding Program (TUBITAK) [118O317], This work was supported by the Scientific and Technological Research Projects Funding Program (TUBITAK - Project No: 118O317)

WOS:000463960800004; International audience; We examined growth rates and reproductive characteristics of Sardinella aurita off Senegal and other coastal areas over a 20 year period (1995-2014) to determine how they relate to variations in environmental characteristics of coastal waters. Based on fish length-frequency data and a coastal upwelling index, we found that S. aurita recruitment tends to occur during the periods of most intensive upwelling (March-April off Senegal). Peak reproduction corresponds to periods of low sea-surface temperature (in February or March). The sex ratio was remarkably consistent during the 30 year study period and so was not affected by environmental changes. We hypothesise that S. aurita takes advantage of the higher zooplankton productivity that occurs in coastal waters when upwelling brings nutrient-rich water to the surface (i.e., it increases its growth rate and accumulates energy reserves for spawning). Growth performance appears to be strongly dependent on environmental conditions. The timing of spawning seems to occur when food (zooplankton) is most available for supplying the energy requirements needed by adults for spawning and early development of larvae. Environmental changes seem to have a significant effect on S. aurita growth and reproduction, which endorses their high phenotypic plasticity.

The study of small pelagic fish by hydroacoustic methods in the Mediterranean Sea began in the Adriatic in the 1950’s. Since 2009, internationally coordinated, extensive, regular surveys have been conducted in the framework of the MEDIAS - Mediterranean International Acoustic Surveys – action, under the EU Data Collection Framework, to provide inputs for the management of small pelagics, particularly European anchovy (Engraulis encrasicolus) and European sardine (Sardina pilchardus). The surveys cover EU Mediterranean waters and monitor the distribution and abundance of small pelagic species using a common protocol. The hydroacoustic surveys, historically conducted by each Country separately, have since been standardized and harmonized. This is a review of the evolution of the surveys from the beginning up to the present and discusses the future prospects. It reports the historical time series of anchovy, sardine and other small pelagics in different areas and describes the spatial and temporal distribution of small pelagic species in decadal maps of the major areas of their distribution in the European Mediterranean Sea. Furthermore, it discusses the use of MEDIAS data for stock assessment purposes, the collection of auxiliary information for an ecosystem-based management approach, the need for further standardization and future challenges.

International audience; The avoidance reaction by fish in front of an approaching vessel is a major source of bias in direct biomass assessment and ecological studies based on fisheries acoustics data. An experiment was carried out to compare echosounder data obtained using a small speedboat and a research fisheries vessel generating significant higher noise above conventional reduced-noise standard. The results show that there was no significant difference between the individual fish target strength distributions, and the numbers of schools recorded by both boats, these schools having similar areas and perimeters. However, the schools detected by the noisier vessel were significantly deeper, and unexpectedly had a significantly higher energy level. These findings suggest that noise-reduced vessels trigger a different vessel avoidance reaction. The noise-reduction standard is not sufficient to reduce avoidance behavior. It is also to take into consideration the ambient noise, which could impair perception of the platform by the fish, and the probability that the acoustic stimuli could be less important than visual perception under some local conditions. The paper introduces the concept of partial avoidance and presents a conceptual diagram of the strength of the avoidance reaction. Last, it is not recommended, because of noise reasons, that vessels routinely used for pelagic stock assessment surveys be changed. Indeed standardized time series, which could be disrupted when switching to a new vessel, are more important than the hypothetical gain from change to quieter vessels. Obviously, all long-term surveys must change vessels; best practice will be to estimate the vessel effect before any change to avoid disrupting the time series and/or perform vessel intercalibration surveys.

WOS:000449553500016; International audience; Small pelagic fish occupy a significant component of the food supply in West Africa and are vitally important for the nutritional needs of local people. The bonga shad (Ethmalosa fimbriata Bowdich, 1825) is the third most-exploited of the small pelagic species fished from coastal waters of Senegal (after Sardinella aurita and S. maderensis) and is routinely consumed by Senegalese people. Bonga shad fishing is practised mainly by artisanal fishermen and of great importance to the Senegalese economy and food security in the region. Our study was designed to examine population dynamics of bonga shad to support the development of fishery management options that may improve the livelihoods of artisanal fishermen. The current rate of exploitation (E = 0.8) suggests that the bonga shad in Senegal is over-fished. In addition, we describe seasonal variability in recruitment and biomass of bonga shad along the Senegal coast, its downward trend in landings over a 17-y study period, and its decline (18%) in maximum size over a 63-y period. We attribute the declines to an increase in fishing pressure and/or changes in local climate. To reverse the effects of overexploitation of the bonga shad stock, it will be necessary to drastically reduce fishing effort, apply and enforce regulatory restrictions on the capture, sale and processing of juveniles, and prohibit seiners and monofilament nets in the fishery.

WOS:000407178900006; International audience; The objective of this study was to assess the effect of environmental variations on the abundance of Sardinella aurita and Sardinella maderensis in Senegalese waters in the upwelling system. Monthly data indicating the abundance of sardinella were first estimated from commercial statistics, using Generalized Linear Model from 1966 to 2011. Abundance indices (AIs) were then compared with environmental indices, at the local scale, a Coastal Upwelling Index (CUI) and a coastal Sea Surface Temperature (SST) index, and on a large scale, the North Atlantic Oscillation (NAO), the Atlantic Multidecadal Oscillation (AMO) and the Multivariate El Nino Southern Oscillation Index (MEI), using correlations and times series analyses. The results showed that the abundance of sardinella is determined by a strong seasonal pattern and inter-annual fluctuations. The abundance of S.aurita peaked in spring and in autumn, whereas that of S.maderensis peaked in the warm season (July-September). The trend of the sardinella abundance was significantly correlated with the CUI, especially in autumn and spring. Interannual fluctuations of S.maderensis and S.aurita abundance are, respectively, driven by the precocity and the duration of the upwelling season that is attributed to distinct migration patterns. Both sardinella species also respond with a delay of around 4years to the winter NAO index and the autumn CUI, and the AMO index, respectively, both related to migration patterns. The wide variations in sardinella biomass are caused by variations in environmental conditions, which should be considered in the implementation of an ecosystem-based approach in sardinella stocks management.

Fishery management is a complicated task that often results in overfishing, overcapacity, and low profits for the industry. The management of shared fish stocks is particularly problematic, especially if national authorities pursue different objectives. Multi-species fisheries add further complexity to the problem. It is no accident that management tools frequently used in Northern Europe, such as total allowable catches and individual quotas, are not applied in the Mediterranean Sea, where more target species are caught simultaneously. However, the European Commission intends to introduce a market-based driver for a strong, profitable fishing industry by phasing in transferable fishing concessions. This management approach is new for the Mediterranean, and it requires in-depth examination at institutional, legal, and economic levels. In this paper, after a review of the institutional setting, the economic perspective was analyzed by estimating the production function for the Italian small pelagic fishery in the Adriatic Sea. With the addition of Croatia to the European Union, the Adriatic Sea can become a Mediterranean communal exclusive fishing area. The results indicate that output measures such as total allowable catches and individual quotas should not cause serious discarding problems for this multi-species fishery Gestión regional de pesquerías multiespecíficas basada en stocks compartidos y derechos de propiedad: un caso Mediterráneo. – El manejo de la pesca es una tarea difícil que con frecuencia tiene como resultado la sobreexplotación de los recursos, la sobrecapitalización de las pesquerías y la baja rentabilidad de la industria pesquera. El manejo de los stocks compartidos es particularmente problemático, especialmente cuando las autoridades públicas persiguen objetivos diferentes. Las pesquerías multiespecíficas aumentan la complejidad del problema. No es accidental que instrumentos de manejo utilizados con frecuencia en el Norte de Europa, como los Totales Admisibles de Capturas (TACs) y las Cuotas Individuales, no sean aplicadas en el mar Mediterráneo, donde se capturan varias especies objetivo simultáneamente. De otro lado, la Comisión Europea piensa introducir un incentivo de mercado para favorecer el sector pesquero y hacerlo más fuerte y rentable, a través de la introducción paulatina de concesiones de pesca transferibles. Este modo de manejo es nuevo para el Mediterráneo, y requiere un análisis detallado a nivel institucional, legal y económico. En este artículo, además de una reseña del contexto institucional, analizamos la perspectiva económica estimando la función de producción para la flota pelágica italiana del mar Adriático. Con la inclusión de Croacia en la Unión Europea, el mar Adriático podría convertirse en una zona de pesca exclusiva comunitaria del Mediterráneo. Los resultados indican que las medidas de control sobre la producción, como los TACs y las Cuotas Individuales, no ocasionarían serios problemas de descarte para este tipo de pesqueria.

Despite long-term investigations of the Adriatic Sea in general and extensive research on sardine and anchovy as ecologically and economically important fish species, knowledge concerning their spawning ecology, precisely their possible spawning grounds, is still incomplete. Therefore, two scientific surveys (January, July 2012) were performed, as target species spawn during different periods of the year (sardine - October to April (Sinovčić et al., 2007) and anchovy - April to September (Zorica et al., 2013)). Throughout these surveys, standard vertical plankton tows were made during the daylight at 72 stations in January and 60 stations in July using a WP2 sampler (mouth opening, 0.255 m2; mesh size, 0.200 mm). WP2 net was put vertically down during the calm sea to a depth of 100 m or to 5 m above the seabed in relatively shallow marine area (less than 100 m). Plankton samples were preserved in 4% buffered formalin and transported to the laboratory where they were analysed. Throughout ichtyoplankton analysis of samples collected during the winter survey a total of 506 sardine eggs and 348 larvae were sorted out. The mean sardine egg and larval abundance in the analysed period at positive stations was 57.8 +/- 77.4 eggs/m2 and 29 +/- 25.85 larvae/m2, with peaks of 396 eggs/m2 and 108 larvae/m2 at positive sampling stations. Concerning the summer survey and anchovy early life stages from obtained samples 1489 anchovy eggs and 1036 larvae were isolated. Average abundance of anchovy eggs and larvae was 145.26 +/- 201.27eggs/m2 and 115.11+/- 162.32 larvae/m2, respectively. The highest values of mentioned parameters at positive stations were 800 eggs/m2 and 952 larvae/m2. According to obtained results and their processing within Ocean Data View (odv.awi.de), revile that both species during 2012 spawn above the whole continental shelf and the areas of higher early life stages abundance overlap.

Integrated information from different parts of the Mediterranean Sea was used to model the spatial and temporal variability of the distribution grounds of the sardine population. Acoustic data from the North Aegean Sea (Eastern Mediterranean), the Adriatic Sea (Central Mediterranean), the Sicily Channel (Central Mediterranean) and Spanish Mediterranean waters (Western Mediterranean) were analysed along with satellite environmental and bathymetric data to model the potential habitat of sardine during summer, autumn and early winter. Generalized additive models were applied in a presence−absence approach. Models were validated in terms of their predictive ability and used to construct maps exhibiting the probability of sardine presence throughout the entire Mediterranean basin as a measure of habitat adequacy for sardine. Bottom depth and sea surface temperature were the environmental variables that explained most of the data variability. Several areas along the Mediterranean coastline were indicated as suitable habitat for sardine in different seasons. An expansion of these areas over the continental shelf, up to 100 m depth, was consistently noticed from summer to winter. This was attributed to the horizontal movements of sardine related to spawning (i.e. winter period) and the peculiarities of the Mediterranean Sea where areas favouring growth, feeding and spawning processes tend to be localised and prevent a long range, offshore migration as opposed to large upwelling ecosystems. Moreover, within the study period, a positive relationship between the extent of sardine preferred habitat and landings was revealed for both summer and winter seasons throughout the entire Mediterranean Sea, Sí