Search

Copyright of Ege Journal of Fisheries & Aquatic Sciences (EgeJFAS) / Su Ürünleri Dergisi is the property of Ege Journal of Fisheries & Aquatic Sciences (EgeJFAS) / Su Urunleri Dergisi and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Fishing activities have always been a dangerous profession and numerous factors have a direct or indirect impact on the health, safety, and working conditions of fishermen. The present study aims in order to reveal the risk factors affecting the occupational health and safety of smallscale fishermen in Lake Erçek (Van, Turkey). Data were obtained from fishermen by survey between March 2022 and May 2022 and evaluated using the" L type matrix" method. "Having no training in occupational health and safety (OHS)" and "Fatigue from irregular and long working hours" are the important risk factors that affect the working conditions of fishermen. This study will make a significant contribution to the work efficiency of the fishermen and the planning to be made in the following processes, by making a risk analysis in terms of occupational health and safety before the possible increase in the number of fishermen in Lake Erçek (Van, Turkey). [ABSTRACT FROM AUTHOR]

Copyright of Türkiye Jeoloji Bülteni is the property of TMMOB JEOLOJI MUHENDISLERI ODASI and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study presents an analysis of the single-channel high-resolution shallow seismic reflection data from Lake Erçek, eastern Anatolia, to provide key information on the deformational elements, on the fault patterns and on the overall tectonic structure of the Lake Erçek Basin. High-resolution seismic data reveal major structural and deformational features, including N-S trending normal faults and W-E trending reverse faults bounding the Lake Erçek Basin, basement highs and folded structures along the marginal sections of the lake. The N-S trending normal faults asymmetrically control the steep western margin and the gentle eastern deltaic section, while the W-E trending reverse faults appear at the northern and southern margins. The N-S trending normal faults, half-graben structure, and the gradual thickening of sediments in the Erçek Basin toward the fault scarps strongly suggest an extensional tectonic regime resulting from an N-S compression. The Erçek Basin is an extension-controlled depocenter; it is a relatively undeformed and flat-lying deep Basin, forming a typical example of the half-graben structure. The N-S trending normal faults appear to be currently active and control the lake center and the E-delta section, resulting in subsidence in the lake floor. In the N- and S-margins of the lake, there is evidence of folding, faulting and accompanying block uplifting, suggesting a significant N-S compressional regime that results in the reverse faulting and basement highs along the marginal sections. The folding and faulting caused strong uplift of the basement blocks in the N- and S- margins, subsequently exposing the shelf and slope areas. The exposed areas are evident in the erosional unconformity of the surface of the basement highs and thinned sediments. The tilted basement strata and subsequent erosion over the basement block highs suggest prominent structural inversion, probably long before the formation of the lake. New high-resolution seismic data reveal the fault patterns and structural lineaments of the Lake Erçek and provide strong evidence for an ongoing extension and subsidence. The present study provides new structural insights that will support future tectonic and sedimentary studies and the development of strategies related to active earthquake faults and major seismic events in the region of Lake Erçek. [ABSTRACT FROM AUTHOR]

In this study, we analysed the source mechanisms and faulting pattern of the aftershocks in the Lake Erçek area, Eastern Anatolia, during the 2011 Van event ( Mw 7.1). The fault plane solutions of the aftershocks were used to derive a stress tensor acting around Lake Erçek. The estimated seismological parameters (focal mechanism solutions, stress tensor, and fault focal analyses) were integrated with field surveys and high resolution seismic reflection data so as to better understand the main faulting patterns and deformational features which are the causatives of the observed geomorphological features within and around Lake Erçek. The focal parameters of the 56 aftershocks with magnitude range 3.5 ≤ Mw ≤ 5.5 were obtained using the regional broadband seismic data from the network of Kandilli Observatory and Earthquake Research Institute (KOERI) through the Centroid Moment Tensor (CMT) inversion of locally observed broadband-waves. The implications for the lateral variation of the stress field in the lake area were based on information derived from integration of seismicity and stress tensor inversion results. The major outcomes of our analyses were as follows: (a) The maximum principal stress axis is close to horizontal and aligned in NNW-SSE direction, the minimum compressional stress axis is close to vertical and aligned in an ENE-WSW direction, the intermediate stress axis is close to horizontal and is parallel to the strike of the ruptured fault plane, while the stress ratio is ( R = 0.6); (b) the lake basin is mostly deformed by dip-slip faults (dips ≥ 45–60°) in and along its margins where the various folds, basement highs with eroded surfaces and several low-angle normal faults are evident; (c) the majority of the aftershocks have reverse-thrust mechanism with some strike-slip components in the Lake Erçek area (N- and S-margins). Strike-slip and normal faulting events are also evident (E- and W-margins, respectively); (d) the normal and reverse mechanisms with some strike-slip component are mostly confined in the upper crust (0–15 km), compatible with NS-striking normal and WE-striking reverse faults in the marginal sections of the lake; (e) the WE-striking reverse faulting in the N- and S-margins seems to have the seismic potential to generate destructive earthquakes in the lake area; (f) the tectonic implications of the regional stress field and ongoing deformation processes in the lake are defined and supported by field observations and seismic reflection data. The result of these analyses reveals N-S compression/W-E extension in the lake and also the collisional/compressional regime taking place in a region of Lakes Van and Erçek. [ABSTRACT FROM AUTHOR]

Pearl mullet (Alburnus tarichi Güldenstädt, 1814) is an endemic fish species living in the Lake Van basin. Lakes Van and Erçek are soda lakes which have alkaline and brackish properties. Pearl mullet migrate to freshwater streams surrounding these lakes for spawning and return back to the lake environment after reproduction. Migration takes places from the lakes into freshwater streams and the fish are exposed to 2 different environmental conditions. The aim of this study was to assess erythrocyte osmotic fragility, a test providing information about the membrane stability of erythrocytes and the physiological strength of erythrocytes against physicochemical stress, during spawning migration. For this purpose, blood samples were collected into EDTA containing tubes from fish sampled from Lake Erçek and a freshwater environment pouring into the lake (Memedik Stream). Erythrocyte osmotic fragility was performed on the collected blood samples. The results indicated a significant increase in erythrocyte osmotic fragility at 0.4 and 0.5% NaCl concentrations for freshwater stream samples. It can be concluded that the increased erythrocyte osmotic fragility in the freshwater environment was causally related to physicochemical changes. Further research can be conducted on physiological mechanisms that cause this observed change in erythrocyte fragility which is an indicator of membrane stability. [ABSTRACT FROM AUTHOR]