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.

109-118

Authors: Abdolsaleh QARANJIKI, Mine KIRKAĞAÇ

In this study, Artemia parthenogenetica was fed with either Spirulina (S), yeast (Y), rice bran (R), oat (O) or their combinations in 10 experimental groups in triplicate for 20 days in laboratory conditions and growth, biomass, feed conversion rate (FCR), specific growth rate (SGR), survival rate, crude protein, crude lipid contents were determined. The highest average body length obtained at the end of the experiment was 2.805±0.003 mm in treatments (S) and (SYR), and the highest average individual dry weight was 23.057 µg in treatment (S). The mean biomass changed between 167.2±0.003 mg and 115.7±0.012 mg. The highest biomass value was 20.9 g/m3 in treatment (S), followed by 20.5 g/m3 in treatment (SYR). The highest FCR was found to be similar in (S) and (Y) with 1.14±0.02. SGR was 1.01±0.001 in all experimental groups. The highest survival rate was in treatment (S), and overall it ranged between 78.22±1.78 - 90.64±0.06%. The highest crude protein contents of Artemia were found in (SR) and (S) and the highest lipid content was found in treatment (O). As a result, it is thought that combinations of by-products such as rice bran and yeast together with microalgae will be economical in the cultivation of Artemia parthenogenetica.

143-149

Authors: Herdem ASLAN

The demand for the roe of Paracentrotus lividus is increasing despite world-wide fisheries bans and the balance of marine ecosystems is disturbed due to this overexploitation. Although not consumed locally, there has been fishing pressure on this species, due to the intense export demand in recent years. For an ecosystem-based sustainable fishery of P. lividus, it is very important to establish the stock status as well as the reproductive biology of this species in Turkish seas. However, studies on the stock information of the species are limited. This study reports preliminary findings on the abundance of P. lividus on the coasts of Gökçeada by using the visual counting technique with SCUBA during the summer of 2012 and 2018. In the study carried out with transects of different lengths, the highest number of individuals was observed on the rocky shores of Laz Bay in 2012 with 4 individuals m-2, between 112-120 m of the Kuzulimanı transect with 5 individuals m-2 in 2018, and between 0-52 m transect of Kokina III in 2018. According to the SACFOR scale, when P. lividus species was observed on the coasts of Gökçeada, it was either common or frequent in terms of abundant. For an effective and sustainable sea urchin management plan, the stock status of the P. lividus species in Turkish waters should be determined immediately.

160-168

Authors: Burhan TAŞLI, Adnan AYAZ

As in every business sector, the safety factor in fishing is too important to ignore. Although there is no deficiencies of equipment and materials in fishing boats, we can say that if the safety issue is not internalized by the employees, the danger continues. In addition, the idea that the safety at sea can only be provided by the equipment on the boat remains missing. Especially the fishermen's ignorance of the navigation restrictions and difficulties in the fishery areas causes a serious danger. The Turkish Straits, which is our field of study, is also the most dangerous and heavily trafficked strait in the world. For this reason, fishermen must be aware of all meteorological, navigational and geographical restrictions. Semi-structured interviews were conducted with the fishermen who navigate the straits to reach the fishery area or use the straits as fishery grounds. As a result of the interview, it was aimed to determine the awareness of safety and navigational safety at sea. With 1 fisherman in Yeniköy Harbor, 1 fisherman in Kumkale Harbor, 2 fishermen in Gallipoli Harbor, 2 fishermen in Şarköy Harbor, 4 fishermen in Hoşköy Harbor, 5 fishermen in Çakılköy Harbor, 5 fishermen in Karşıyaka Harbor and 3 fishermen in Kurşunlu Harbor in Turkey, interviews were held a total of 23 fishermen. The interviews were audio recorded with the permission of the participants and analyzed by content analysis method. As a result of the analysis, it has been determined that the fishermen mostly ignore the safety factor and especially see the safety equipment as an expense item that creates a financial burden. It has been determined that navigational safety awareness is higher than safety awareness at sea. It has been observed that there are no lack of equipment possession, but it is generally equipped with survey reservations.

179-187

Authors: Soner ÇETİNKAYA

In this study, electrolyzed water (EW), which is being used for disinfection in various food production applications, is discussed. Today, research on green production has intensified, aiming to preserve food for a longer time, using fewer chemicals or none, in order to preserve the initial nutritional properties of the food and deliver it to the consumer. In this context, it is an undeniable fact that there is a need to improve existing methods and practices and develop new technologies for the long-term storage of foods without quality losses and health concerns. One of the methods developed for this purpose is the use of electrolyzed water in food disinfection. While the use of electrolyzed water in various stages of the food processing industry creates a relatively new field of application, many studies have focused on its antimicrobial and antioxidant activity. However, studies on the use of this method in the fish processing industry are very limited and need to be developed. Previous studies are mainly related to the antimicrobial properties of electrolyzed water and there are limited studies on the effects of seafood products on storage times (shelf life). However, in light of the studies, it is seen that electrolyzed water has potential uses for the seafood processing industry.

199-202

Authors: Okan AKYOL, Halil ŞEN, Christian CAPAPÉ

In this study, a shoal of bull rays, Aetomylaeus bovinus (E. Geoffroy Saint-Hilaire, 1817), around a sea-cage fish farm in Iskenderun Bay, Turkey is reported. Such an aggregation is probably due to ontogenetic shift but may also be a factor of reproductive process as some pregnant females were observed. The number of individuals recorded, in all more than 25, shows that the species is still present in the area but needs a conservation plan due to its k-selected life-histories and potential for extinction.

11-18

Authors: Sevdan YILMAZ Ekrem Şanver ÇELİK Dilek KAHRAMAN YILMAZ Mehmet Ali KÜÇÜKER

In this study, cyanobacterial communities in mucilage samples collected from three stations in the Dardanelles Strait were analyzed with a metagenomic approach. Mucilage samples were collected at the beginning of June 2021 from three points of the Dardanelles (Station 1: 40°6'42.78"N, 26°23'57.00"E; Station 2: 40°9'8.09"N, 26°24'16.19"E; Station 3: 40°6 '21.62"N, 26°22'41.25"E). The dominant cyanobacteria were Prochlorococcus marinus (39.17%), Synechococcus sp. (20.85%), Lyngbya sp. (12.00%), Trichodesmium erythraeum (7.33%), Aphanocapsa sp. (4.33%) and Leptolyngbya sp. (3.33%), which constituted 87.00 % of the total number of sequences. In this study, cyanobacteria species that can cause harmful algal blooms and have toxic effects on the mucilage structure have been determined. The Marmara Sea and the Dardanelles Strait, which have been affected by serious disturbances, including industrial activities, anthropogenic impacts, tourism and artificial lighting, will never be fully restored to their former ecological state. In addition, cyanobacteria species in the mucilage may cause harmful algal blooms and have toxic effects that threaten the future well-being of coastal populations and ecosystem stability. Thus, the government and local authorities should pay more attention to combating the mucilage.

26-38

Authors: Deniz Anıl ODABAŞI Serpil ODABAŞI Ozan DENİZ Fikret ÇAKIR Belgin ÇAMUR ELİPEK Naime ARSLAN Onur ÖZBEK H. Barış ÖZALP

Caves are laboratories for many disciplines that work in natural sciences including mineralogy, biology, hydrogeology, and archaeology. In this study, bi-monthly samplings were carried out from three sampling locations within and around the Güvercinkaya Cave, a high-altitude cave located in northwestern Turkey, to evaluate the hydrochemical and microbiological properties and the aquatic macroinvertebrates of the cave stream. Some parameters of the water including pH, electrical conductivity, temperature, oxidation-reduction potential, and dissolved oxygen were measured in-situ, while elemental (70 in total) and ionic composition of water were analyzed in the laboratory. Microbiological analyses of the cave stream were examined through analyses of total bacteria, total coliforms, fecal coliforms, fecal Streptococcus, and Escherichia coli. According to the Piper diagram of hydrochemical data, the cave stream had mainly Ca-Mg-HCO3 character, on the other hand, the Schoeller diagram indicated a common water source in Güvercinkaya cave due to the similar components of the main ionic components of the water. As a result of microbiological analysis, fecal contamination was determined, indicating active wildlife in the cave. Additionally, several aquatic macroinvertebrates taxa, Rhynchelmis limosella, Dugesia sp., Gammarus uludagi which have non-troglobiont character were found in the cave stream. Rhynchelmis limosella detected in this study is the first record for the Turkish fauna.

48-55

Authors: Erhan MUTLU Yaşar ÖZVAROL

The present study reports the occurrence of Oceania armata in the Turkish Levantine Sea, and presents evidence to support a hypothesis established to link an increased recent and near-past records of many gelatinous zooplankton species in the Turkish seas, and particularly in the Turkish Levantine Sea to specific Mediterranean basin-scale currents (Atlantic-Ionian Stream and the Mid-Ionian Jet). One worldwide-distributed oceanic cnidarian specimen was collected from the surface water of a location of 36.59002 N and 29.02471 E by a SCUBA diver on January 18, 2019 in the eastern Mediterranean Sea. The hydrozoan specimen was then identified as O. armata and recorded for the first time in the Turkish Mediterranean coast and only second time in the Levant coast after about 30 years. This is the second report of the species from the Turkish waters, and the first report was from the Turkish Aegean coast. Recently, new records of the gelatinous species have increased from the Turkish marine coasts; Sea of Marmara, Aegean Sea, and Levantine Sea. Most of them are distributed in the West Mediterranean Sea, but are also present in the Adriatic Sea (East Mediterranean Sea). In the Mediterranean Sea, one branch of the Atlantic current (Atlantic-Ionian Stream) enters the eastern basin via the Mid-Ionian Jet, linked with the southern Adriatic current. Therefore, it is possible that zooplankton could have entered East Mediterranean by the Atlantic current through West Mediterranean.

67-76

Authors: Tekin DEMİRKIRAN Uğur ÖZEKİNCİ

This study was aimed to determine the effects of different bait types on the efficiency of fyke-nets and traps in catching narrow-clawed crayfish (Pontastacus leptodactylus (Eschscholtz, 1823)). The study was carried out in Atikhisar reservoir, Çanakkale, between July 2020 and March 2021. In the study, 12 traditional fyke-nets (“D” inlet, 5 rigid rings and a leader net) and 12 traps (double inlet) were used. Fyke-nets and traps were rigged with 34 mm stretched mesh that are commonly used in crayfish fishing in Türkiye. Three different bait types including fish, chicken and bread and a control treatment with no bait were allocated to each gear type. Baits were distributed randomly to each gear before fishing trials. The baits were placed in small bags corresponding to 1% of total trap volume. The results of 24 trials showed 68.8% (1940 crayfish) of the total catch was caught with fyke nets and 31.20% (880 crayfish) with traps. The highest average CPUEN values for both trap types were observed in those baited with the chicken meat which were 7.89±1.02 n/fyke net/day and 5.07±0.88 n/trap/day.. The mean length of the crayfish caught by the fyke nets was significantly smaller than those caught by the traps (p<0.05). When the mean CPUE values based on the number of fishing operations were compared, differences were significant for baits other than the chicken meat (p<0.05). These results showed that catching efficiencies of baited fyke-nets and traps were higher (especially chicken meat) than those of unbaited traps than those without bait.

87-93

Authors: Okan AKYOL Tevfik CEYHAN Faik Ozan DÜZBASTILAR Okan ERTOSLUK

This study presents some exotic fish diversity and catch per unit effort values of exotic fish from gillnet fishery along the southern Aegean Sea. Lessepsian puffer fish (Lagocephalus sceleratus), lionfish (Pterois miles), squirrelfish (Sargocentron rubrum), rabbitfish (Siganus sp.) and a blue crab (Portunus segnis) were caught in the Aegean Sea. Rabbitfish and blue crab sell in the fish markets. Seasonally, the average CPUE of exotic fish was calculated to be 0.7 ± 0.3 kg.1000 m-1 in autumn in catch. This value indicated that it was 72 times lesser than the total seasonal CPUE.

98-102

Authors: Seçil ACAR Yusuf ŞEN

Some morphometric and biological characteristics of a European spider crab, Maja squinado (Herbst, 1788) caught off Aksaz region, (Biga, Çanakkale, Türkiye) were investigated. In addition, an epizoic species infesting this M. squinado specimen has been identified. The crab specimen was caught by a commercial fisherman using trammel nets. Carapace length, carapace width and weight of the crab were 15.9 cm, 14.5 cm, and 1109 g respectively. The specimen was an ovigerous female with a calculated fecundity of 3.48x104 eggs. Eggs were in stage 4th of development and covered the whole carapace region. Additionaly, it was observed that the specimen was infested with the epixoic barnacle Octolasmis angulata (Aurivillius, 1894). A total of 46 O. angulata individuals were observed; 32 from the gill lamellae, and 14 from the carapace. This study reports the existence of the epizoic O. angulata on Maja squinado for the first time in Türkiye.

99-106

Authors: Hüseyin Gökhan Aytepe, Orkun Dalyan , Mehmet Pişkin

In this study, the attitudes of fishermen in Çanakkale region towards occupational health and safety measures have been investigated. For this purpose, a questionnaire consisting of 26 questions was conducted in June 2021 with fishermen working in fishing boats registered to Çanakkale Central Port Authority. Data obtained from responses of 103 randomly selected fishermen indicated that 99 participants (96.1%) were male and 63 (61.2%) were married. Fifty-two of the participants (50.5%) were between the ages of 25-35. Only 26 (25.2 %) of the participants received higher education. 55 (53.4%) of the participants had 1-5 years of professional experience. Fishermen between the ages of 19-24, with an associate degree and less than 1 year of professional experience gave more positive answers regarding the occupational health and safety efforts in fishing activities compared to those expressed by the personnel in other groups. There was a significant difference between the occupational health and safety perception and age and professional experience variables in fishing activities. The data obtained indicated insufficient efforts on fishing activities by the authorized public organizations and institutions, docking problems of fishing boats, lack of OHS service in fishing activities. Involvement of fishermen in the planning of fisheries related programs and informing employers about the necessity of mandatory OHS services provided by the Ministry of Labor and Social Security may solve identified problems.

116-129

Authors: Hakkı Dereli , M. Alp Salman, Okan Özaydın , Zafer Tosunoğlu

This study aimed to determine the spatial and temporal variation of species diversity and CPUE in trawl fisheries in the Central Aegean Sea (Sığacık Bay). The study also aimed to evaluate changes in some biometric parameters (mean and frequency of length) depending on the season and depth for three important commercial species (Parapenaeus longirostris, Nephrops norvegicus and Illex coindetii). Monthly trawl samplings were carried out in three depth strata (0-200; 201-400 and 401-600 m) between May 2008 - April 2009. A total of 111 species were identified including 74 Osteichthyes, 13 Chondrichthyes, 18 Cephalopods and 6 Crustaceans. The highest species diversity and catch per unit effort (CPUE) values were obtained at 201-400 m strata. Among these, Osteichthyes had the highest frequency and CPUE values in all strata and seasons. Summer was the season with the highest CPUE in all groups followed by a decrease until winter due to openning of trawl fisheries in the Autumn. The mean carapace length of P. longirostris, the target species in Sığacık Bay trawl fisheries, increased with depth and this species was more abundant at the 201-400 m strata.

159-167

Authors: Arzu Binici , Serap Pulatsü , Nurbanu Bursa

: Sediment dredging (removal), a lake management method, is performed on a regular basis to improve the recreational value of Mogan Lake. The aim of the study is to a) determine heavy metal concentrations (Hg, As, Cd, Cr, Pb, Ni, Cu, and Zn) in the sediment after dredging and make evaluations based on the sediment quality criteria, b) define the potential sources of heavy metals by multivariate analyses, c) shed light on the effectiveness of the dredging in the context of current data. As indicated by the findings from two stations under the influence of mineral processing facilities (station I) and domestic wastewater discharges (station II) taken in May and November, 2020, the mean heavy metal concentrations in the sediment in decreasing order were Cr>Cu>Zn>Ni>Pb>As>Cd>Hg. Cr, Ni, and As levels were found to exceed the probable effect level (PEL) and therefore, the lake sediment was classified as heavily polluted in terms of Cr, Ni, Cu and As. Based on the Spearman’s correlation analysis, Cu-Cd, Zn-Pb, and As-Cd were found to have similar anthropogenic sources. Three main components determined by the principal component analysis also support this result; the differences in heavy metals originating from different anthropogenic sources reflect the environmental pollution diversity and pressure related to the heavy metal accumulation in the lake sediment. Based on our findings, sediment removal in Mogan lake can not be considered as effective intervention. As anthropogenic pollutants persist in the lake basin, sediment should be routinely monitored for heavy metal levels to ensure the lake's sustainable use.

175-186

Authors: Cemil Sağlam , Okan Akyol

The study was carried out monthly between 2014 and 2016 in Akköy Lagoon, Southern Aegean Sea. Experimental beach seine net was used to determine the species diversity in the lagoon. Fishing operations were carried out in triplicate at two different stations. Sea surface temperature (°C), salinity (‰), dissolved oxygen (mg.l-1 ) and pH were measured. Abundance, species richness (S) and Shannon (H) index values were computed to determine species diversity. A total of 1878 fish specimens from 17 species belonging to 9 families were captured by the beach seine net. The Mugilidae family with five species was represented by the highest catch rates among all the families. According to Canonical Correspondence Analysis (CCA), the diversities of fish species were strongly influenced by environmental parameters. Results indicated that Chelon ramada, Mugil cephalus and Chelon saliens were dominant in the winter and autumn and showed positive correlation with DO. Chelon auratus and Sparus aurata were dominant in the spring and Solea solea, Chelon labrosus, Lithognathus mormyrus, Sardina pilchardus, Boops boops, Zosterisessor ophiocephalus, Mullus spp. and Syngnathus spp. were dominant in the summer and showed positive correlation with SST, pH and salinity. Atherina boyeri, Aphanius fasciatus, Blennius spp. and Pomatoschistus spp. were present in all seasons.

197-201

Authors: Melis Yılmaz , Gülen Türker , İlknur Ak

: In this study, the antioxidant activities, total polyphenolic contents of algal extracts from Gongolaria barbata were examined by using ethyl acetate (AcOEt), water(W), and phosphate buffer (PH) as solvents. According to the results, EtOH, W, and PB showed medium antioxidant potential with low IC50 values. The highest total flavonoid content was detected in W (6.91±0.09 mg/g Ext., and PB showed the maximum phenolic content (2.29±0.01 mg GAE/g ext.). The chlorophyll a and total carotenoid contents were detected as 40.5±1.20 and 29.13±1.12 (mg/g DW), respectively. Phycoerythrin was 0.002±0.001 (mg/g DW), while phycocyanin content was found as0.04 ±0.01 (mg/g DW). Our results show that PB could be used as an extraction solvent for determining the antioxidant properties of G. barbata instead of ethanol.

208-234

Authors: İsmail Burak Daban

The teleost fish stocks distributed in Turkish seas are threatened due to overfishing, pollution, global warming and increasing food competition. There is a need to provide scientific knowledge on reproductive traits of commercial species in order to ensure the sustainability of fish stocks. Parameters related to reproductive biology of fishes such as sex ratio, first sexual maturity length, gonadosomatic index, fecundity and reproductive period are rather effective constituents that should be taken into consideration in the decision making process by fisheries managers. In this study, studies on reproductive biologies of teleost fishes from Turkish waters have been reviewed. A total of 177 studies were compiled that focused on 91 species belonging to 41 families. Reviewed data indicated that existing studies focused on certain fishing areas in the Turkish seas and no information were provided on reproductive biologies of some species. In some species, important parameters such as first sexual maturity length, reproductive period, gonadosomatic index and fecundity were not available.