10 research outputs found

    The Introduction of a Marine Species Atherina boyeri into Bayramiç Reservoir, Çanakkale

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    This study reports the first recorded instance of Atherina boyeri (Risso, 1810) in the Bayramiç Reservoir, located on the Karamenderes Stream. Since 2005, ichthyological researches have been carried out in the Bayramiç Reservoir by various researchers, but none of them have noted the existence of A. boyeri in this reservoir. In the field studies conducted between May 2016 and July 2017, a total of 98 A. boyeri specimens was caught. In these samplings, a 70 m long and 2 m wide beach seine net with 10 mm a mesh size was used. Although a small number of A. boyeri was caught during the first observation in October 2016, more individuals were observed in July 2017. The fork length of the A. boyeri observed was between 2.7-8.8 cm and the weight ranged between 0.06-4.31 g. The bimodal length distribution of the specimens indicates that there have been multiple incidents of adult specimens entering the reservoir and that these individuals have given birth to new offspring. The translocation of A. boyeri into the Bayramiç Reservoir might have been due to unauthorized introduction by fishermen or through illegal release by anglers as fish bait. However, the distribution map of A. boyeri in inland waters in Turkey shows significant overlap with the migration routes of big waterfowl. The waterfowl might partially be responsible for the spread of the adult specimens across short distances

    Strandings of loggerhead (Caretta caretta) and green (Chelonia mydas) sea turtles along the eastern Mediterranean coast of Turkey

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    Ozdilek, Sukran Yalcin/0000-0001-8264-7606; Turkozan, Oguz/0000-0001-6889-7908; Kacar, Yasemin/0000-0002-8682-9228; Sonmez, Bektas/0000-0002-8190-409XWOS: 000320354200002Data on strandings of dead loggerhead (Caretta caretta) and green (Chelonia mydas) turtles were collected from the eastern Mediterranean coast of Turkey during the nesting seasons between 2002 and 2009. A total of 276 strandings were recorded (142 C. caretta and 128 C. mydas). The curved carapace length (CCL) of C. caretta ranged from 12.6-85 cm (mean 63.50 +/- 1.06 cm). The CCL of C. mydas ranged from 20-93 cm with a mean of 40.97 +/- 1.41 cm. 2.4% and 31.7% of the loggerheads were oceanic stage small juveniles (= 70 cm CCL), respectively. Of the green turtles, 33.3% (= 85 cm CCL) were small juveniles and adults, respectively. The source populations of these turtles could become identified with genetic mixed stock analysis

    Report of the Joint EIFAAC/ICES/GFCM Working Group on Eels (WGEEL)

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    The Joint EIFAAC/ICES/GFCM Working group on eels (WGEEL) met in a split meeting from 4–8 September (online) and 25 September–02 October 2023 (hybrid meeting) in Helsinki, Finland, to provide the scientific basis for the ICES advice on fishing opportunities and conservation aspects for the European eel and address requests from EIFAAC and GFCM.WGEEL assessed the state of the European eel and its fisheries, collated and analysed biometric data, reviewed the implementation of the WKFEA (Workshop on the future of eel advice) roadmap, examined available recruitment data from coastal and marine habitats, reported on any updates to the scientific basis of the advice, new and emerging threats or opportunities, including developments in the Mediterranean region.After high levels in the late 1970s, the recruitment declined dramatically in the 1980s and remains low. Compared to 1960–1979, the recruitment in the “North Sea” was 0.4% in 2023 (provisional) and 0.7 % in 2022 (final). In the “Elsewhere Europe” index series was 8.8 % in 2023 (provisional) and 11.3% in 2022 (final). For the yellow eel data series, recruitment for 2022 was 9% (final). Time-series from 1980 to 2023 show that glass eel recruitment remains at a very low level, with an historical minimum value in the North Sea.Silver eel time series have been analysed to identify patterns in abundance trends. These analyses are exploratory and have enabled us to test certain statistical methods and their limitations for analysing temporal series on silver eels. Although they give us an initial idea of trends in silver eel abundance, their results should be treated with caution. In fact, several problems have been identified and these points need to be improved in order to be able to interpret the results. The trend of reported commercial landings shows a long-term continuing decline, from a level of around 10,000 t in the 1960s, reported commercial landings have now dropped to 2028 (glass eel + yellow eel + silver eel) in 2022. The commercial glass eel fishery in 2022 was 60.1 t and 53.6 t in 2023. Reported landings from yellow and silver eel commercial fisheries (Y, S, YS) add up to 2914 t in 2021 and 2437 t in 2022. Spain was the only country allowing a recreational catch of glass eel, with landings estimated at 0.72 t in 2022 and 1.32 t in 2023. Reported recreational landings for yellow and silver eel combined were 240 t for 2021 (11 countries reporting) and 249 t for 2022.Progress with regards to the ‘road map’ developed within WKFEA was evaluated. The returns from the three questionnaires distributed by WKSMEEL to WGEEL members were summarised. In relation to the progress of the WKFEA roadmap, item 1; the inclusion of biological data is advanced with biometry data included in the annual data call. Item 2 relates to the reconstruction of the landings data and a workshop will take place in December 2023. Items 3 and 4 are also in progress, the Spatial database and Model for Eel (WKSMEEL) workshop was held in June 2023 with a follow up workshop planned for October 2023. A questionnaire for 3 topics (electrofishing, hydrographic network, and river obstructions & hydropower) was circulated to WGEEL members in August 2023. Of the 21 countries who responded, a large majority carry out electrofishing, have available hydrographic networks and hold some information of obstructions to migration. However, it was recognised that considerable effort and resources will be required before the available data could be collated
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