COMU Journal of Marine Sciences and Fisheries

102-115

Authors: Serap Pulatsü1*, Dijar Latifi2

In this study, four tributaries (Başpınar, Gölcük, Sukesen and Yavrucak Creeks) of Mogan lake under anthropogenic pressure and declared as a Special Environmental Protection Area were investigated with the following goals: a) Determination of the variations in potentially toxic element concentrations (Cr, Ni, Cu, Zn, As, Cd, Hg, Pb) in the creek waters between different months (December 2002, February 2023, April 2023), b) Calculation of potentially toxic elements indexes (Heavy Metal Pollution Index-HPI and Heavy Metal Evaluation Index-HEI) in terms of irrigation water quality, based on international and national values, c) Determination of the potential ecological risk (PER) status of the creeks in terms of irrigation water quality, d) Comparison of potentially toxic element concentrations with the environmental quality standard values specified in the current “Turkish Surface Water Quality Regulation”. According to the findings; a) In terms of overall potentially toxic element levels, the creeks are ranked as follows: Başpınar Creek> Sukesen Creek>Gölcük Creek>Yavrucak Creek. The heavy metal As was identified as having the highest contribution to metal pollution and the potentially toxic element concentrations in all creeks in February and April were found to be higher compared to that in December, b) The HPI value was found to be less than 15 for all months and creeks, with the highest HPI value of 13.21 calculated in Başpınar Creek in February, c) The HEI values were found to be less than 10 (ranging from 0.02 to 0.84), indicating a low level of potentially toxic element pollution according to this index, d) In terms of irrigation water quality, all creeks exhibited a low level of PER, with the highest PER value of 13.54 belonging to Başpınar Creek, e) The detected potentially toxic element concentrations in all four creeks did not exceed the maximum EQS values provided. In this context, it has been determined that the potentially toxic element levels in creek waters, due to anthropogenic activities, are not currently causing significant pollution. However, it is noted that Başpınar Creek is at a higher risk compared to other creeks. Furthermore, because of the ongoing anthropogenic activities in the basin, long-term metal monitoring studies are important in terms of the sustainability of Lake Mogan.

124-136

Authors: Gürkan Salih Karabacak1*, Mehmet Cengiz Deval2

This study analyses a highly damaging and prevalent fishing practice of trawl infringements, which is one of the crucial components of IUU fishing in Turkish waters. The raw data gathered from the Turkish Coast Guard Command (TURCG), covered 2012 – 2014 period. Data covered a total of 1040 trawl infringements, with considerable differences in trawling violations among the seas surrounding Türkiye; the Black Sea, the Sea of Marmara, the Aegean Sea, and the Mediterranean Sea. With respect to trawling infringements, the Sea of Marmara (37%) and Istanbul Strait (15%) were the hot points. The most common infringement type was trawling in a closed area (43%) and when combined with the rate of infringements on trawling during the closed season (10%), these violations accounted for 53% of spatio-temporal infringements. Regarding illegal trawling by vessel type, trawl vessels had a 44% share and non-trawlers had a share of 56%, of which included infringements by other type of fishing vessels (46%) and non-fishing vessels (10%). It was also found that infringement by vessels smaller than 12 meters in length had a share of 46%. These vessels (known as "şebeke" in Turkish), trawl illegally using small types of nets and gears in coastal waters without giving any obvious indication of fishing activity. The results of this study will be useful to policy-makers, practitioners and scientists to successfully combat trawling infringements by providing information on distribution, intensity and methods of trawl violations.

147-157

Authors: Melis Yılmaz1*, İlknur Ak2

This study aims to investigate the influence of three different dichromatic LED light sources and varying photoperiod durations on the mineral content and trace element compositions in cultivated Gongolaria barbata under controlled culture conditions. During the experiment, red-blue (RB), blue-green (BG), red-green (RG) and fluorescent lights were examined at 16:16, 12:12, and 8:16 Light: Dark (L:D) photoperiods, and at 150 μmol photon m-2 s-1 intensity of light in all treatments. The elemental compositions of the thallus samples were analyzed for Mg, Ca, K, Na, P, Zn, Mo, Cu, Mn, Cr, Co, Cd, Fe, and As.. Our results showed that macro element and trace element compositions significantly varied among different experimental groups. Regarding the order of abundance, macroelements were ranked as follows: K > Na > Ca > Mg > P. Meanwhile, trace elements followed this order: As > Zn > Mn > Cr > Co > Cu > Cd > Mo > Fe. Among the experiment groups, the highest value of the macro elements was recorded as 1041.3±22.2 mg kg-1 for K, and the lowest value was 26.61±0.02 mg kg-1 for the P. Among the trace elements, for As, the highest value was recorded as 1339.86±5.27 µg kg -1, and the lowest was determined at 1.93±0.04 mg kg-1 for the Fe. The findings highlight that LED lighting conditions can significantly influence the elemental composition of G. barbata.

166-177

Authors: Cansu Metin Hacisa*, Taçnur Baygar

In the present study, the potential of waste fish scales for obtaining a valuable bioactive material was evaluated. Acid soluble collagen from golden grey mullet (Chelon auratus) scales was isolated and characterized successfully. Proximate composition, denaturation temperature, Sodium dodecyl sulphate gel electrophoresis (SDS-PAGE), amino acid composition, Scanning electron microscopy and Energy dispersive X‑ray spectroscopy (SEM-EDS), Fourier transform infrared spectrophotometer (FTIR), Thermogravimetric analysis (TGA), antioxidant and antimicrobial activity analyses were performed for the extraction of collagen and extracted collagen was compared with commercial collagen. As a result, an alternative and useful source for mammalian collagen for the industrial applications like food and cosmetics was extracted from the fish scale waste material, which may help mitigate the management of natural wastes or environmental problems.

15-23

Authors: Muhammet DEMİR

In recent years, the fisheries sector, which has developed rapidly in Turkey as well as all over the world, has become an important sector in the province of Van. In this study, the share and importance of fisheries with respect to capture fisheries and aquaculture in the province of Van has been investigated. Data indicated that during the period 2013-2021, the province of Van had the following share with respect to inland fisheries production: 2.23% of trout farms, 3.00% of inland fishing vessels, 1.67% of inland water resources where restocking programs have been undertaken, 28.43% of inland fisheries, 2.14% of trout culture, 2.44% of restocked fish and 7.65% of total inland fisheries production. The province of Van ranks 1st in terms of inland capture fisheries. With better management practices, both inland capture fisheries and aquaculture production may be increased.

33-43

Authors: İbrahim GÜR, Sevim POLAT

Proximate and bioactive compounds (total phenolic, flavonoid, chlorophyll-a and total carotenoid contents) of three brown seaweeds (Dictyota dichotoma, Padina pavonica, Stypopodium schimperi) and a red seaweed (Jania rubens) from the north-eastern Mediterranean Sea (İskenderun Bay) were investigated seasonally at three sampling sites. Seasonal variations were found for all of the parameters studied. The highest ash content was in J. rubens (77.7%) in the spring. The results showed that J. rubens is a rich source with respect to mineral content. D. dichotoma had the highest crude protein content, whereas S. schimperi contained the most lipids. Phenolics ranged between 34.6 - 107.0 mg GAE/g dw. The highest total phenolics were found in S. schimperi in the summer, and the lowest in P. pavonica in the spring. The flavonoid contents (9.05-10.6 mg QE/g dw) were higher in brown seaweeds than that in the red seaweed. Moreover, chlorophyll-a and carotenoids levels were highest in D. dichotoma (4.53 and 2.83 mg/g, respectively) during the autumn. The results revealed that the biochemical composition of the examined seaweeds showed significant changes depending on the species, location and seasons.

56-69

Authors: Mayurdan GADHAVİ, Zahra MAKDA, Dudhagara DARSHİTA, Shiyani JENİSHA, Shabanam SAİYAD

Marine molluscs are economically very important and they are exploited by men for various purposes since the prehistoric times. Manufacture of ornaments is an age-old industry in the south and south-east India and molluscs as an ornament or souvenir are still in high demand. Although there is plenty of literature on the trade and economy of ornamental shells, exploitation of ornamental molluscs is less studied and limited to regions in the south and south-east India. The ornamental molluscs is widely traded in pilgrims places like Dwarka, Somnath and all along the coast of Gujarat, and with the exception of Turbinella pyrum (the chank shell), there is no literature available on ornamental mollusc taxonomy, utilization and trade in Gujarat. This is the first study on ornamental molluscs from Gujarat. We have reviewed the available literature on ornamental molluscs of India and established a comprehensive checklist as there is no checklist available for ornamental molluscs of India. A total 136 species were recorded as ornamental molluscs in India. Of these shells, 118 species were listed by reviewing the literature and 33 ornamental molluscs were added from on-site observations in which 18 species were recorded for the first time from the study area. A total of 11 species among the 136 species were protected under wildlife protection act 1972. Different use of ornamental species was studied and classified accordingly. With respect to families, the majority of contributions were from Cypraeidae (7 species) followed by Muricidae (3 species), Turbinellidae (2 species), Strombidae (2 species) and Cardiidae (2 species). The major source of ornamental imports was from south India with some souvenirs collected from nearby intertidal areas and sold by local vendors as whole shells. Due to the extensive trade of ornamental shells, there is a need to study the degree of exploitation of ornamental molluscs in India, particularly in Gujarat.

76-82

Authors: Şebnem TOLASA YILMAZ

Today discard and fish species with low economic value as well as by products generated during fish processing are in Turkey and around the world contain protein, fatty acids, vitamins and minerals that are very beneficial for human health. It is possible to evaluate these stocks as a functional food, which cannot be used effectively as human food, with using innovative formulation strategies in the form of cryostabilized minced meat blocks. However oxidation of lipids and proteins especially during frozen storage causes quality losses. Antioxidants are widely used to prevent the lipid oxidation and cryoprotectants to delay protein denaturation. Due to the possible toxicity and carcinogenic effects of synthetic additives, the interest in using natural ingredients is increasing day by day. For this reason it is important to stabilize the minced fish blocks during frozen storage which are processed with natural cryoprotectants and antioxidants.

90-94

Authors: Ruhay ALDIK, Fikret ÇAKIR

In this study, 75 chub mackerels that were caught in the Canakkale Strait in Türkiye between October to December, 2019, were examined for the presence of parasites. The length and weight of all fish were measured and the external body area, oral cavity, nostrils, fins, and gills were examined. Gill samples were examined under a stereomicroscope and all suspicious findings were preserved in 99.99% ethanol. The mean length and weight of fish were 24.84±0.39cm and 146.01±7.16 gr, respectively. It was determined that the collected parasite is Grubea cochlear, a monogenic helminth belonging to the Mazocraeidea family. The chub mackerel, in which the specimen of G. cochlera was isolated among the gill filaments, was a female with a total length of 18.5 cm and a weight of 49.80 gr. This finding of Grubea cochlear isolated from the gills of chub mackerel is the first record of this species in this region.