In this study, the temporal changes of the trophic state in Lake Mogan were examined to evaluate the results of various rehabilitation approaches, including dredging, over a 30-year period. Water samples were taken from two different points seasonally between May 2022 and February 2023. The Carlson’s Trophic State Index (TSI) was calculated using total phosphorus, Secchi depth and chlorophyll a values, and the trophic status of the lake was estimated. Furthermore, TSI was also calculated using data obtained from previous studies conducted in the lake, and a 34-year change was evaluated based on TSI, OECD, and Turkish Surface Water Regulation (SWQR). In this study, the average TSI value was calculated as 52.46, and the trophic status of the lake was determined as eutrophic. Differences in TSI (AVG) values among the months and sampling points were found statistically significant (p<0.05). Based on the TSI values calculated using data from previous years, it was determined that the trophic status of the lake still maintained a eutrophic level in a 34-year period despite the rehabilitation efforts. A similarity test (Bray-Curtis Similarity Index) applied to the TSI values obtained for different years showed a strong similarity between the values in 2023 and those in 1989. As a result, preparing precautionary plans against eutrophication of Lake Mogan and monitoring the trophic status via TSI is recommended.

This study investigated the morphological characteristics of the body and otoliths of three Sphyraenidae species (Sphyraena flavicauda, S. sphyraena, and S. viridensis) collected from the Benghazi coast, eastern Libya, during winter 2023. Morphometric measurements were recorded from the left side of each specimen, including total length, standard length, head length, eye diameter, snout length, eye height, maximum body height and width, caudal peduncle dimensions, head width, and total weight. Eight morphometric ratios were calculated to evaluate proportional differences among species. The length–weight relationship indicated isometric growth, with b values ranging from 2.39 to 2.68 and condition factors from 0.375 ± 0.00 to 0.531 ± 0.013. Otolith length, height, area, and sulcus features were measured, and indices such as rectangularity, circularity, SAL/OL, OSL/SAL, CUL/SAL, OH/OL%, S index, and relative otolith size were calculated. Significant differences in body and otolith morphometrics were detected among the species, providing reliable markers for identification and supporting Sphyraenidae management in Libyan waters.

Aquatic plants called macrophytes, one of the most important components of aquatic ecosystems, are used in many sectors such as agricultural fertilizer, animal feed, cosmetics industry, pharmaceutical raw material in pharmacology, furniture decoration and human food. In addition to these uses, macrophytes are used as ecological indicators in determining the trophic (productivity; oligotrophic, mesotrophic, eutrophic, etc.) levels of water bodies and monitoring changes in aquatic ecosystems due to the fact that most of them have steady locations, can be seen with the naked eye and are relatively easy to obtain. Macrophytes are essential components of aquatic ecosystems and in this context of streams and rivers. The presence, abundance, community formation and continuity of macrophytes are the best indicators of the health of the ecosystems in which they are found; water quality and pollution, trophy status. For this reason, the EU Water Framework Directive has introduced macrophyte indices as a requirement for the "good ecological status" of water resources. Some studies on macrophyte indices have started in Türkiye. As a result of the researches, it has been revealed that the most appropriate river index calculation system for the waters of our country is the IBMR index. In this study, macrophyte indices used for rivers in the world and in Türkiye were emphasized. It is necessary to develop and use indices specific to our own country in our water resources, to increase the number of field researches on this subject and to expand the area. The aim of this study is to explain the macrophyte indices used for ecological status determination in Europe and Türkiye and to create scientific data for the studies to be carried out in this field by proposing a suitable index model for our country.

This study aimed to characterize fishing and its effect on the functioning of Lake Madarounfa. Surveys were conducted to identify the fishing practices, used gears, the fish stock, and the impacts of fishing activities on the ecosystem. The fish fauna was studied through the catches of artisanal fishermen at four stations from June to December 2023. Twenty-two species belonging to twelve families and nineteen genera were identified. The Cichlidae family, with 4 genera and 4 species, was the most prevalent. Of the 5 fishing gear identified, the gillnet was the most used. A total of 35 tons of fresh fish were produced during the present study. This result showed that the greatest catch per unit effort (CPUE) was found with the cast net (9.72 kg/h). The analysis of the size structures showed a dominance of small individuals. More than 73.97% of individuals were smaller than 18.11±9.25 cm, corresponding to the mean total length of all fish individuals measured during this study. This level of fishing pressure on juveniles could affect the normal recruitment of fish stocks and lead to biodiversity erosion. Due to the intensity of uncontrolled fishing all year, agricultural activities and climate change, the functioning of the ecosystem is greatly disrupted. This constitutes a threat to the sustainability of the ecosystemic services provided by the lake. The findings of this work suggests that to ensure a sustainable fishery management of the lake, it is necessary to establish continuous monitoring and strengthen the enforcement of laws concerning ecosystem protection around this water body.

The continuous development of industry pushes people to search for new resources, and for this reason, the usage areas of Rare Earth Elements (REEs) are increasing day by day. Increasing concentrations of REEs, as a result of increased use, create pollution in the environment and harm living organisms. This pollution interacts with increasing temperature and causes more negative synergistic effects of the pollutant in the environment and in the living body. In this study, sublethal concentration values were determined by literature review and the concentration value was determined as 125 mg/L. In the present study tt was aimed to investigate some oxidative stress and antioxidant responses of Terbium, Lanthanum, Gadolinium and Praseodymium REEs in Dreissena polymorpha at 125 mg/L concentration at 3 different temperatures (16, 18, 20 0C) with biomarkers. For this purpose, 24 and 96 hour experimental trial design was created and 7 D. polymorpha were used in each trial group, and the application experiments were carried out with 3 replications. The samples at the end of the experimental phase were stored at -80 degrees Celsius until they were analyzed. In this study, Superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) enzyme activities and glutathione (GSH) and Thiobarbituric acid (TBARS) level biomarker responses were determined by ELISA test microplate reader. CAYMAN brand SOD (Catalog No 706002), CAT Catalog No 707002) and GPx (Catalog No 703102), GSH (Catalog No 703002) and TBARS (Catalog No 10009055) were used in the study. SPSS 24.0 package program one-way ANOVA (Duncan 0.05) was used for the evaluation of biochemical analyzes. According to the study data, statistically significant decreases were observed in SOD and CAT activities in the oxidative stress responses of REEs on D. Polymorpha with increasing temperature, while there was no significant change in GPx activities. It was determined that there were increases in TBARS levels and decreases in GSH levels. It is thought that the temperature factor, application concentration and application time are effective in the formation of these changes. It can be said that temperature change and pollutants cause oxidative stress in organisms and cause cell damage.

This study aimed to investigate the genetic diversity and structure of rainbow trout (Oncorhynchus mykiss) cultured populations in different provinces of Turkey, based on the cytochrome b (cyt-b) gene region of mitochondrial DNA (mtDNA). Tissue samples were collected from a total of 98 fish (seven fish per province) across 14 provinces, followed by DNA isolation. The mtDNA cyt-b gene region (754 bp) was amplified using PCR. Genetic diversity indices, genetic structure, and phylogenetic analyses were calculated from the cyt-b gene sequence data. The average nucleotide frequencies of the four nucleotides cytosine (C), thymine (T), adenine (A), and guanine (G) were found to be 26.2%, 24.9%, 26.2%, and 22.8%, respectively, with a higher A + T content (51%) compared to G + C content (49%). A total of 645 polymorphic loci were identified across the 14 populations, and 50 distinct haplotypes were defined. Haplotypic diversity ranged from 0.91 to 0.48, while nucleotide diversity (π) varied between 0.26 and 0.00. The highest genetic diversity was observed in the Tokat and Van populations, whereas the lowest was recorded in the Elazığ and Kahramanmaraş populations. AMOVA analyses revealed that 71.1% of the genetic diversity was found between populations, while 28.9% was found within populations. Pairwise FST values ranged from 0.38 to 0.99, with an average FST of 0.71. Phylogenetic analyses indicated that the populations clustered into two main groups, with further sub-groupings within these clusters. Notably, the Kahramanmaraş and Elazığ populations were found to be significantly differentiated from other populations. In conclusion, despite rainbow trout not being a native species in Turkey, the findings of this study indicate that the genetic diversity of the populations is at a good level. However, in order to preserve the genetic diversity of cultured rainbow trout populations and to increase effective population size, it is recommended that breeders engage in fry exchanges and import new rainbow trout specimens to enhance genetic diversity.

The present study aimed to determine the water quality of Susurluk Stream, Çapraz Stream, and Karadere Stream by examining 5207 samples from 14 different stations in two different periods of 2021 (July and September), during which 37 families belonging to 15 order were identified. Physidae was identified as the dominant family for the first sampling period, while Baetidae was dominant for the second sampling period. BMWP Original, BMWP Turkish, BMWP Spanish, and ASPT biotic indices were used to assess the water quality of Susurluk, Çapraz, and Karadere Streams, and the index results were determined for each station for the first and second periods (July and September). Based on these index results, five different water quality categories were identified (Very Poor, Poor, Moderate, Good, Very Good). The obtained data were interpreted using t-tests and correlation analysis with the SPSS 2021 program.

Bu çalışmada, Nisan- Eylül 2023 tarihleri arasında Edremit Körfezi’nde küçük ölçekli balıkçılar tarafından kullanılan av araçlarının teknik ve yapısal özellikleri belirlenerek, av araçlarındaki yıllar içerisindeki değişim tespit edilmiştir. Çalışmada Edremit Körfezi’ndeki Behramkale (Asos), Küçükkuyu, Altınoluk, Güre, Akçay, Burhaniye (Ören), Gömeç, Ayvalık (Merkez) ve Ayvalık (Cunda) bölgelerinde toplam 9 farklı alanda, 399 ticari tekne içerisinden 256 ticari balıkçı ile anket çalışması yapılmıştır. Yapılan anket çalışması neticesinde bölgedeki küçük ölçekli balıkçıların farklı özelliklerde 3 ince ve 4 kalın paragat takımı, 1’er adet karides ağı, zargana ağı, dil ağı, bırakma ağı, bakalyaro ağı, 16 barbun ağı, 3 alamana ağı, 7 voli ağı, 2 köpekbalığı ağı, 4 uskumru-kolyoz ağı, 6 mezgit ağı, 8 kupes ağı ve 17 adet farklı tipte marya ağı kullandığı tespit edilmiştir. Bu çalışmada Edremit Körfez’inde yapılan önceki çalışmalara göre, uzatma ağlarında farklı özelliklerde 32 adet uzatma ağı, 3 adet farklı özellikte paragat takımı tanımlanmıştır. Sonuç olarak Edremit Körfezi’ndeki balıkçılık alanlarında küçük ölçekli balıkçıların kullandığı uzatma ağları ve paragat takımlarının çeşidi artarken, yıllara göre takımların teknik ve yapısal özelliklerinde değişiklikler olduğu belirlenmiştir. Av araçlarındaki bu değişimlerin bölgedeki balık stokları üzerindeki etkilerini ortaya koyan çalışmalar yürütülmelidir.

Terbiyum (Tb), su ortamında yüksek konsantrasyonlarda bulunduğunda sucul organizmalar için toksik hale gelebilen nadir toprak elementi (NTE)’dir. Tatlı su ekosistemindeki Tb toksisitesinin meydana getirdiği oksidatif stres sonuçlarıyla ilgili hala yeterince çalışmalar mevcut değildir. Bu çalışma ile Tb'nin oksidatif stres sonuçlarını değerlendirmek için tatlı su canlısı olan Pontastacus leptodactylus kullanılmıştır. Bu organizmada, 1, 5 ve 25 mg/L konsantrasyonlardaki Tb'nin 24 ve 96. saatte meydana getirdiği oksidatif stres ve antioksidan değişimleri süperoksit dismutaz (SOD), glutatyon peroksidaz (GSH-Px), katalaz (CAT) enzim aktiviteleri ile Tiyobarbitürik asit (TBARS) ve redükte glutatyon (GSH) seviyeleri belirlenmiştir. Sonuçlar ELISA kitleri kullanılarak tespit edilmiştir. Biyobelirteç analizlerin istatatistiksel değerlendirilmesinde SPSS 24.0 paket program tek-yönlü ANOVA (Duncan 0,05) testi kullanılmıştır. Kontrol grubu ile karşılaştırıldığında SOD aktivitesinde önemli bir değişim gözlemlenmezken (p>0,05) CAT ve GPx aktivitelerinde anlamlı azalmalar (p<0,05) gözlemlenmiştir; GSH ve TBARS seviyelerinde ise anlamlı (p<0,05) artışlar gözlemlenmiştir. Çalışma verileri dikkate alındığında canlı organizma vücuduna nüfuz eden Tb ksenobiyotiğinin organizma da oksidatif strese neden olduğu düşünülmektedir.

Çalışmada; ülkemizin balıkçılık konusunda gelişmiş ülkeler seviyesine ulaşabilmesi için lisans düzeyinde eğitim ve öğretim yapan Su Ürünleri Fakültelerinin kurulmasının ilk aşamaları ve 20 Temmuz 1982 tarih, 41 Sayılı Kanun Hükmünde Kararname ile kurulan 6 adet Su Ürünleri Yüksekokulu arasında yer alan, Cumhuriyetimizin kuruluşunun 100. Yılını kutladığımız bu günlerde, 41. Kuruluş yıldönümünü kutlayan Eğirdir Su Ürünleri Fakültesi’nin kuruluş hikayesi anlatılmıştır.