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    Öğe
    Determination of some population dynamical parameters of Squalius cappadocicus Ozulug & Freyhof, 2011 for Melendiz River (Konya Endorheic Basin)
    (Ege Univ, Fac Fisheries, 2020) Secer, Burak; Comertpay, Umut; Sungur, Sevil; Cicek, Erdogan
    The aim of this study was to determine population parameters of Squalius cappadocicus in Melendiz River. A total of 357 specimens, collected 2016 June-2017August. Age of the specimens ranged from 0th to 5th age groups and dominant age group was found I (30,53%) followed by 0th (% 28,29) and 2nd (%20,44) age groups. Total length varied from 2.6-24.5 cm with the mean of 11.27 +/- 3.88 cm, total weight ranged from 0.44 to 202.99 with the mean of 23.57 +/- 25.32 g. Length-weight relationship were estimated W=0.0120*L-2.9882. Estimated population parameters were calculated as L-infinity: 44.21 cm, k: 0.098, t(0): -1.47, empty set': 2.28 and K: 1.13 for the population. Mortality and exploitation rates estimated as Z: 0.37, M: 0.32, F: 0.05 and E: 0.13, respectively. These values suggested that there is no over fishing pressure on the population.
  • [ X ]
    Öğe
    Modeling the spatial distribution of the ctenophore Mnemiopsis leidyi A. Agassiz, 1865 in the Black Sea using a fuzzy rule-based system
    (Inst Oceanografiju I Ribarstvo, 2022) Poorbagher, Hadi; Birinci-Ozdemir, Zekiye; Eagderi, Soheil; Cicek, Erdogan
    Species distribution models can predict species occurrences in areas where no data is available by finding relationships between occurrences and environmental parameters. In this study, we applied a fuzzy rule-based system to model the spatial distribution of Mnemiopsis leidyi in the Black Sea and predict the probability of its presence throughout the sea. Six variables were used as predictors, including water turbidity, organic and inorganic particulate carbon, photosynthetically active radiation, light absorption by phytoplankton, sea surface temperature, and chlorophyll-a concentration. The results revealed a 0.807 accuracy of the model based on the confusion matrix. The results also showed that photosynthetically active radiation and sea surface temperature were the most important predictors shaping the distribution of this species. The findings also showed that the northern Black Sea was with the highest probability of presence, especially in Ukraine and Russia's coastal areas. In the coastal areas of Turkey, the highest presence probability was found near Rize, Trabzon, Ordu, and from Sinop to Zonguldak. Therefore, continuous monitoring of the Turkish coastal area is crucial to better understanding the effects of climate change and anthropogenic influences on the further distribution patterns of this invasive ctenophore in the southeastern Black Sea.