The study aimed at determining the concentration of heavy metals in muscle, liver, and gill tissues of four fish species (Acanthobrama marmid, Capoeta umbla, Capoeta trutta and Chondrostoma regium) collected from five sites in the Karasu River, Erzincan, between July 2019 and January 2020. The relationships between fish size (length and weight) and metal concentrations in the tissues were also investigated using Pearson correlation analysis. Concentrations of Al, Fe, Cu, Mn and Zn were higher than those of other metals in all tissue samples from four fish species. Fe and Al concentrations were very high, while the lowest Co, Cd and Pb concentrations were determined in the muscle, liver and gill tissues. The results of Pearson correlation analysis showed that significant relationships between heavy metal concentrations and fish size (length and weight) were positive (p < 0.01, p < 0.05), except for a few cases. Furthermore, heavy metal concentrations in the edible parts (muscle) of the studied fish species did not exceed the maximum acceptable concentrations (MACs) proposed by national and international food standards and were safe within human consumption limits, except for Cr.

Fish remains popular among the body’s most essential nutrients, as it contains protein and polyunsaturated fatty acids. It is extremely important to choose the fish consumption according to the season and the freshness of the fish to be purchased. It is very difficult to distinguish between non-fresh fish and fresh fish mixed in the fish stalls. In addition to traditional methods used to determine meat freshness, significant success has been achieved in studies on fresh fish detection with artificial intelligence techniques. In this study, two different types of fish (anchovy and horse mackerel) used to determine fish freshness with convolutional neural networks, one of the artificial intelligence techniques. The images of fresh fish were taken, images of non-fresh fish were taken and two new datasets (Dataset1: Anchovy, Dataset2: Horse mackerel) were created. A novel hybrid model structure has been proposed to determine fish freshness using fish eye and gill regions on these two datasets. In the proposed model, Yolo-v5 and Inception-ResNet-v2 and Xception model structures are used through transfer learning. Whether the fish is fresh in both of the Yolo-v5 + Inception-ResNet-v2 (Dataset1: 97.67%, Dataset2: 96.0%) and Yolo-v5 + Xception (Dataset1: 88.00%, Dataset2: 94.67%) hybrid models created using these model structures has been successfully detected. Thanks to the model we have proposed, it will make an important contribution to the studies that will be conducted in the freshness studies of fish using different storage days and the estimation of fish size.

No abstract

Bu çalışma, Karasu Nehri'ndeki fitoplankton kompozisyonunun ve biyolojik çeşitliliğinin mevsimsel ve zamansal değişimlerine odaklanmıştır. Fitoplankton ve su örnekleri Ocak 2019-Temmuz 2019 döneminde iki ayda bir 0,5-8 m derinlikten beş istasyondan toplanmıştır. Dört çeşitlilik indeksi (Shannon-Wiener, Simpson, Margalef ve Menhinick) incelenmiştir. Endeksler arasındaki ilişkiyi yorumlamak için MINITAB 15 yazılımı kullanılmıştır. Ortalama su sıcaklığı, çözünmüş oksijen, pH ve iletkenlik değerleri sırasıyla 19,43 °C, 7,9 mg/l, 8,3 ve 465 mS/cm olarak ölçülmüştür. Bu çalışmada toplam 123 fitoplankton türü tespit edilmiştir. Bu türlerden Bacillariophyta grubuna ait 106 tür, Chlorophyta grubuna ait 10 tür, Cyanobacteri grubuna ait 6 tür ve Euglenophyta grubuna ait 1 tür teşhis edilmiştir. Çalışma boyunca Shannon-Wiener, Simpson Margalef ve Menhinick çeşitlilik indeksleri sırasıyla 1,89 H´, 11,53, 5,12, 0,83 ve 1,44 olarak hesaplanmıştır. Bu çalışma sonucunda fitoplankton çeşitlilik indeks değerleri ile Karasu Nehri’nin su kalitesine bağlı ekolojik durum değerlendirilmesi bir biri ile uyumlu olmadığı tespit edilmiştir. Ancak farklı şehirler için referans koşulların geliştrilmesi endekslerin kullanılabilirliğini artırabilir. Bu nedenle bu çalışmaların devam etmesini ve yaygınlaşmasını öneriyoruz.

In this study, length-weight relationships (LWR) and Fulton's condition factor (K) values of totally 190 Common carp, Cyprinus carpio L., 1758 specimens, captured from Tercan Dam Lake between May 2017-October 2017, were examined. Sex composition was 41.58 % (n=79) female and 58.42 % (n=111) male. Female to male sex ratio of the population was found as 1:0.71. Fork length and weight values of overall, female and male specimens ranged from 11.2-55.5 cm/30.2-2860.5 g, 11.2-55.5 cm/30.2-2860.5 g and 12.7-47.5 cm/44.6-1846.9 g, respectively. K values varied between 1.204 and 4.008. The average value of its was calculated as 2.155±0.041 for females, 2.138±0.046 for males and 2.148±0.030 for overall. The LWR were determined W= 0.0646*FL 2.6613 for females, W=0.0389*FL 2.8103 for males and W=0.0528*FL 2.7202 for overall. The values of b was estimated as 2.66 (females); 2.81 (males); 2.72 in overall. According to b value of LWR, the growth of C.carpio was negatif allometric (b<3, P<0.005). No information currently exists on the LWR of C.carpio in the Tercan Dam Lake, Eastern Anatolia, Turkey. Therefore, this paper is an important contribution to the fisheries management applications.