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    A Hermatophroditic Specimen of Chub Mackerel Scomber japonicus in the Dardanelles, Turkey
    (Medwell Online, 2009) Ozekinci, Ugur; Ayaz, Adnan; Altinagac, Ugur; Cengiz, Ozgur; Öztekin, Alkan
    A hermaphroditic individual of the Chub mackerel, Scomber japonicus, caught in the Dardanelles is described in this study. This specimen is the first record of hermaphroditic Chub mackerel for the Mediterranean Sea.
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    An investigation on ghost fishing of circular fish traps used in Turkey
    (Ege Univ, 2006) Ayaz, Adnan; Ozekinci, Ugur; Altinagac, Ugur; Ozen, Ozcan
    Ghost fishing is an unwanted fishing situation which arises from the continuity of catching fish by the set net and fish traps after being lost in the marine and fresh water. This study was carried out to determine the ghost fishing situation of commercial circle fish traps. In this study, four circular traps were deployed near to a reef area, Karantina Island, Izmir Bay. between November 2002 and March 2003. Traps were observed by daily diving surveys. Depending on fish density, fish learned to escape from the traps' openings or from the bar gaps after the 10th day. Ghost fishing was not observed after the first mount.
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    Bathymetric Distribution, Seasonal Growth and Mortality of the Deep-Water Rose Shrimp Parapenaeus longirostris (Decapoda: Penaeidae) in an Unexploited Stock in Saros Bay, Aegean Sea
    (Medwell Online, 2009) Bilgin, Sabri; Ozen, Ozcan; İşmen, Ali; Ozekinci, Ugur
    To describe the growth, mortality and distribution pattern of the deep-water rose shrimp, Parapenaeus longirostris in an unexploited resource, 301 trawl surveys were conducted between 20 and 465 in water depths from February 2005 to September 2008 in Saros Bay, Aegean Sea. Bathymetrical biomass distribution of the deep-water rose shrimp shown a clear tendency towards the deeper waters with highest biomass estimations exceeding 50 kg h(-1) obtained in water depths between 201 and 300 in. Von Bertalanffy Growth (VBG) parameters were estimated from monthly Carapace Length (CL) frequency distribution data using three different methods: ELEFAN, PROJMAT and SLCA. For the data of this study, the seasonal VBG parameters obtained from ELEFAN was considered to best describe the growth pattern and were estimated as L infinity = 34.7 mm, K = 1.05 year(-1), t(o) = -0.95 year, WP = 0.87 (i.e., November) and C = 0.47 for females and as L infinity = 27.0 mm, K = 1.49 year(-1), t(o) = -0.88 year, WP = 0.35 (i.e., May), C = 0.53 for males. Growth performance index (Phi') was higher in females (Phi' = 3.10) than males (Phi' = 3.03). Instantaneous annual mortality rates (Z), assumed to represent annual natural Mortality rate (M), ranged between 1.19 and 4.73 year(-1) for females and between 0.88 and 3.51 year(-1) for males, depending on the method used for the estimation. The mortality rates estimated with the Seasonal Length Converted Catch Curve (SLCCC) method was the most appropriate one for the Saros Bay stock and was estimated as 1.72 year(-1) for females and as 1.82 year(-1) for males.
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    Defining the reproductive period of the European pilchard ( Sardina pilchardus Walbaum, 1792) in Saros Bay (North Aegean Sea, Turkey)
    (Mekelle Univ, Coll Natural & Computational Sciences, 2024) Cengiz, Ozgur; Ozekinci, Ugur; Oztakin, Alkan
    The European pilchard ( Sardina pilchardus Walbaum, 1792) is one of the main target species of commercial fishery along the Aegean coasts. This work was carried out between July 2014 and June 2015 off Saros Bay (North Aegean Sea, Turkey). The study focuses on determining the reproductive period of the species. The elevated GSI values suggested the spawning period occurred mainly between September and May with a peak in February.
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    Effects of Hanging Ratio on Gill Net Selectivity for Annular Sea Bream (Diplodus annularis) in the Northern Aegean Sea, Turkey
    (Medwell Online, 2010) Ayaz, Adnan; Altinagac, Ugur; Ozekinci, Ugur; Cengiz, Ozgur; Öztekin, Alkan
    This study has been conducted in the North Aegean Sea around the coasts of the Gallipoli peninsula at 3-30 m of water depth between February 2007 and June 2009. In order to test the effect of the hanging ratio on the selectivity, 9 gillnets with 3 different hanging ratios (E = 0.4-0.6) and 3 different mesh sizes (18-20-22 mm) have been made use of. Other than, the hanging ratios and mesh size all other features and specifications of gill nets were identical. Select method was used to fit gillnet selectivity curves. A total of 64 fishery operations have been performed in the study. The lognormal model gave the best fit for all hanging ratios (for hanging ratio (E) = 0.4-0.6, the model deviance = 138.9, 66.19, 56.23, respectively). It was determined that there was no significant selectivity differences among the same mesh size for different hanging ratios. The results showed that there is no effect of hanging ratios on size selectivity of annular sea bream (Diplodus annularis L.) in north Aegean gillnet fishery.
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    Estimation of Economic Losses in Trammel Nets Fisheries Using the Length-weight Relationship
    (Springer Int Publ Ag, 2024) Sen, Yusuf; Ozekinci, Ugur
    Trammel nets are used with nearly five days of soaking time to increase the catching efficiency of demersal fish under the control of commercial fishers in the Marmara Sea, Turkiye. The long soaking times can be deteriorate or damage individuals of fish species and economic losses. In this situation, the length and weight of fresh individuals can be measured, but damaged individuals can not be measured in length and weight or both. These losses can be revealed by relating of the length-weight relationship. The current study aimed to determine economic losses by estimating the length-weight relationships of known length and weight of fresh individuals, and by calculating the weight of damaged individuals depending on the length-weight relationships. The catching operations with different soaking times were conducted firstly from December 2020 to December 2021 and secondly from the winter and spring seasons of 2022 in the Marmara Sea, Turkiye. A total of 654 individuals of all species were caught and 185 of them were determined to be damaged. This shows that 30% of those caught were damaged individuals. The total weight of the damaged individuals was calculated to be 91.3 kg. The damaged fish were caught with a total of 2000 m trammel nets and it was determined that they caused an economic loss of 355.3 USD. When we consider the decline and overexploitation of fish stocks, these economic losses and damaged individuals with long soaking times for trammel nets are significant. So, the negative effects of long soaking times on catchable stocks should be evaluated by fisheries managers, and the long soaking times of trammel nets should be regulated for sustainable fisheries.
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    Gear characteristic of gillnet and trammel net used in Dardanelles Region and problems of fishermen
    (Ege Univ, 2006) Ozekinci, Ugur; Cengiz, Ozgur; Butuner, Sefa
    Dardanelles is one of the important fishing areas. In this area, there are 1065 registered fishing boats, %3.2 of these are purseseine and trawl boats, %96.8 of these are other fishing boats which are used for small-scale fishing activities (angling and gillnet trammel net boats). In this study, questionnaire was made with gillnet and trammel net fishermen's. According to the questionnaire results, in Dardanelles region, gillnets, trammel nets (naming as Marya nets) and Stacked trammel nets were determinated as 4.5%, 5.3%, and 90.2%, respectively. Technical plan of nets, used in this area, was drawn and fishermen's problems were presented.
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    Ghost fishing by monofilament and multifilament gillnets in Izmir Bay, Turkey
    (Elsevier, 2006) Ayaz, Adnan; Acarli, Deniz; Altinagac, Ugur; Ozekinci, Ugur; Kara, Ali; Ozen, Ozcan
    To investigate and compare ghost fishing by monofilament and multifilament gillnets, six monofilament and six multifilament experimental gillnets (each 33 m long) were deployed at two locations, set at various depths between 9 and 14 m in Izmir Bay (eastern Aegean Sea). The gillnets were monitored every other day by divers. Each captured fish or crustacean was tagged to enumerate the total catch. The experimental gillnets at one location (three monofilaments and three multifilaments) were lost after the 42nd day. At the other location, ghost fishing continued for 106 days by the monofilament gillnets and for 112 days by the multifilament gillnets. A total of 29 species (22 fish, 5 crustacean, 1 cephalopod, and I gastropod) were captured by the ghost gillnets at the two locations. In addition, 17 specimens of the endangered species Pinna nobilis were killed during the study. Weekly fish catch rates of both gillnet types declined exponentially. Repeated-measures analyses of variance revealed that the total catch rates of fish in the monofilament gillnets were significantly higher (P < 0.05) than those in the multifilament gillnets. After six months of deployment, the effective fishing areas of the monofilament and the multifilament gillnets decreased by 55 and 63%, respectively. One year after deployment, all the multifilament gillnets had completely collapsed; one monofilament gillnet had disintegrated and totally lost its fishing ability whereas the other two monofilament gillnets were excessively colonized by biota and the nets were about to collapse. (c) 2006 Elsevier B.V. All rights reserved.
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    Gillnet Selectivity for Bluefish (Pomatamus saltatrix, L. 1766) in Canakkale Strait, Turkey
    (Central Fisheries Research Inst, 2013) Acarli, Deniz; Ayaz, Adnan; Ozekinci, Ugur; Öztekin, Alkan
    To determine the selectivity of gill nets with 22, 23, 25 and 28 mm nominal mesh size (bar length) for bluefish (Pomatamus saltatrix, L. 1766), the study was conducted at three different stations between 20 and 30 m water depths at Canakkale Strait, Turkey, between February 2007 and April 2012. Gill net with 22, 23, 25 and 28 mm mesh size (bar length) each having same twine thickness (210 denier / 3) and 100 mesh depth vertically were rigged for this purpose. The fish samples were obtained by drive-in fishery method during winter season. The SELECT method was used in determining selectivity parameters. By comparing the deviances of five different models of SELECT method, lognormal model gave the best fit. The modal lengths of the gill nets with 22, 23, 25, and 28 mm mesh size were estimated 22.24, 23.25, 25.27 and 28.30 cm, respectively. The results of the trials indicated that minimum gill net mesh size for this fish should use larger than 25 mm
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    Gillnet selectivity for bogue boops boops caught by drive-in fishing method from Northern Eagean Sea, Turkey
    (2009) Ayaz, Adnan; Kale, Serkan; Cengiz, Ozgur; Altinagac, Ugur; Ozekinci, Ugur; Öztekin, Alkan; Altin, Aytac
    This study was carried out in six different stations in the Northern Aegean Sea between February-May 2008. In the study, the three different fishing nets which were intensively being used by the region fishermen, the net height of which was 105 meshes and the mesh sizes of which were 44, 46 and 50 mm. In the operations performed with the drive-in fishing method, 5867 and 740 kg fish pertaining to the total 30 species were caught and 4791 were got from bogue being the target species. This value composes of approximately 82% of the total catching. SELECT method was used to fit gill net selectivity curves. Log normal model gave the best fit for the bogue selection. It was observed that modal length and spread values increased as far as the net mesh grew. It was determined that the length groups of bogue individuals we got in our study were quite above the first reproduction length. For this reason, it was seen that the gillnets used in the region did not create fishing pressure over the population. © Medwell Journals, 2009.
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    Gillnet Selectivity for Bogue Bopps boops Caught by Drive-in Fishing Method from Northern Eagean Sea, Turkey
    (Medwell Online, 2009) Ayaz, Adnan; Kale, Serkan; Cengiz, Ozgur; Altinagac, Ugur; Ozekinci, Ugur; Öztekin, Alkan; Altin, Aytac
    This study was carried out in six different stations in the Northern Aegean Sea between February-May 2008. In the study, the three different fishing nets which were intensively being used by the region fishermen, the net height of which was 105 meshes and the mesh sizes of which were 44, 46 and 50 mm. In the operations performed with the drive-in fishing method, 5867 and 740 kg fish pertaining to the total 30 species were caught and 4791 were got from bogue being the target species. This value composes of approximately 82% of the total catching. SELECT method was used to fit gill net selectivity curves. Log normal model gave the best fit for the bogue selection. It was observed that modal length and spread values increased as far as the net mesh grew. It was determined that the length groups of bogue individuals we got in our study were quite above the first reproduction length. For this reason, it was seen that the gillnets used in the region did not create fishing pressure over the population.
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    Hook Selectivity for Bluefish (Pomatomus saltatrix Linneaus, 1766) in Gallipoli Peninsula and Canakkale Strait (Northern Aegean Sea, Turkey)
    (Ankara Univ, Fac Agr, 2018) Öztekin, Alkan; Ayaz, Adnan; Ozekinci, Ugur; Kumova, Can Ali
    This study was conducted to determine the selectivity of the hooks used for bluefish (Pomatomus saltatrix Linneaus, 1766) in the Gallipoli Peninsula and the Dardanelles between 2006 and 2009 fishing seasons (November to September). Bluefish were fished with hooks sized 1, 1/0, 2/0, 3/0, 4/0 and in sum; 1210 bluefish were caught. The hook no 2/0 caught the highest number of fish (344 fish, 20.43%) and the hook no 1 caught the least (35 fish, 2.89%). Length frequency distribution of bluefish, which were caught with different hook sizes, was used in SELECT method and according to the results; the normal scale model gave the best fit for selectivity. The normal scale model was used to calculate model length (ML) and spread value (SV) of each hook size. Model length and spread value were found as follows; 19.18 cm ML and 4.44 SV for hook no. 1; 21.88 cm ML, 5.07 SV for hook no 1/0; 24.14 cm ML, 5.59 SV for hook no. 2/0; 27.02 cm ML, 6.26 SV for hook no. 3/0; 28.19 cm ML, 6.53 SV for hook no. 4/0, respectively. Because the minimum landing size (MLS) for bluefish has been stipulated as 20.0 cm (TL) in the Turkish Fishery Regulations, the use of hook no. 2/0 or bigger hook sizes can be recommended for fishing of bluefish.
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    Length-weight relationship of Eriphia verrucosa (Forskal, 1775) (warty crab) in Canakkale Strait
    (Ege Univ, Fac Fisheries, 2018) Ozekinci, Ugur; Acarli, Deniz
    This study was carried out between April 2016 and March 2017 in order to determine length-weight relationship of Eriphia verrucosa (Forskal, 1775) in canakkale Strait. In the study, 598 individuals were sampled by using skin diving techniques as 239 female (39.97%) and 359 male (60.03%). The carapace width (CW) of the all individuals, males and females was calculated as 55.03 +/- 0.52mm, 56.55 +/- 0.75mm and 52.76 +/- 0.63mm, respectively. The mean weights of the individuals (W) were measured as 90.48 +/- 03.37g and 62.44 +/- 02.16g respectively for male and female. Relationship between CW and W of warty crab individuals were expressed as W=0.0003CW(3.1083 )(R-2 =0.9158) for all individuals, W=0.0002CW(3.163) (R-2 =0.9223) for male and W=0.0001CW(2.6995) (R-2 =0.8427) for females. According to the calculated b value, positive allometry was determined for all individuals and males, negative allometry was determined for female individuals.
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    Length-weight relationships of 26 fish species caught by longline from the Gallipoli peninsula, Turkey (northern Aegean Sea)
    (Cahiers De Biologie Marine, 2016) Öztekin, Alkan; Ozekinci, Ugur; Daban, Ismail Burak
    Length-weight relationship parameters were presented for 26 fish species from the Gallipoli peninsula, Turkey. Samples were caught in depths between 0-400 m by longline between January 2012 and January 2013. The sample sizes, minimum and maximum lengths and weights, length-weight relationships, SE (b), R-2 and growth type were summarized. The values of the exponent b in the length-weight relationship W = aL(b) ranged from 2.522 to 3.336 and the median value was 2.899 (+/- SE = 0.043).
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    Length-Weight Relationships of Thirteen Flatfishes (Pisces: Pleuronectiformes) from Saroz Bay (North Aegean Sea, Turkey)
    (Medwell Online, 2009) Ozekinci, Ugur; Cengiz, Oezguer; İşmen, Ali; Altinagac, Ugur; Ayaz, Adnan
    In this study, length-weight relationships of 13 flatfish species, belonging to the families of Bothidae, Citharidae, Cynoglossidae, Scophthalmidae and Soleidae, from Saroz Bay (North Aegean sea, Turkey) were presented.
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    Monofilament gillnet selectivity parameters for European chub (Leuciscus cephalus L.1758) in Atikhisar Reservoir, Canakkale, Turkey
    (Asian Network for Scientific Information, 2007) Ozekinci, Ugur; Altinagac, Ugur; Ayaz, Adnan; Cengiz, Ozgur; Ayyildiz, Hakan; Kaya, Hasan; Odabasi, Deniz
    Selectivity parameters of gillnets used for fish catching are very important for fisheries management in lakes. The main purpose of the present study was to estimate the selectivity parameters of monofilament gill nets mesh size of 56, 64 and 72 mm (stretched mesh size) used for European chub (Leuciscus cephalus L.1758) in Atikhisar Reservoir, Canakkale, Turkey. The indirect method proposed by Holt was used for the estimation of the selectivity parameters. The common selection factors and common standard deviation of monofilament gill nets were determined as 4.25 and 2.37, respectively. For sustainable fisheries of european chub, the minimum mesh size of monofilament gill nets must be greater than 47 mm stretched mesh size. © 2007 Asian Network for Scientific Information.
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    Occurrence of the Scavenger Crustaceans Natatolana neglecta (Hansen, 1890) (Isopoda: Cirolanidae) and Scopelocheirus hopei (Costa in Hope, 1851) (Amphipoda: Scopelocheiridae) on Bento-pelagic Fish Species in the Turkish Straits System
    (Inst Zoology, Bas, 2022) Mulayim, Aysegul; Ates, A. Suat; Sen, Yusuf; Ozekinci, Ugur; Acar, Secil
    The scavenger crustaceans Natatolana neglecta (Hansen, 1890) (Isopoda: Cirolanidae) and Scopelocheirus hopei (Costa in Hope, 1851) (Amphipoda: Scopelocheiridae), along with several other peracarid crustaceans, were recorded on demersal fish species in the Turkish Straits System. Samples were collected on (in) Raja clavata, Chelidonichthys lucerna, Trachurus sp., Scorpaena scrofa, Merluccius sp., Solea solea and Squalus acanthias captured by trammel nets at depth of 50 m on 26(th) January 2021. Natatolana neglecta, Scopelocheirus hopei and Nebalia abyssicola Ledoyer, 1997 are new for the fauna of the Turkish Straits System.
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    Postmucilage biodiversity of shallow water fish assemblages: A case study in the Marmara Sea, Turkey
    (Tubitak Scientific & Technological Research Council Turkey, 2023) Daban, Ismail Burak; Sen, Yusuf; Ayaz, Adnan; Altinagac, Ugur; Öztekin, Alkan; Ozekinci, Ugur; İşmen, Ali
    A dense mucilage event occurred between November 2020 and August 2021 in the Marmara Sea, Turkey. In this study, the aim was to understand the effect of mucilage on coastal fish biodiversity. For this purpose, juvenile and small-sized adult fish species were sampled with an experimental beach seine at 12 equally-spaced stations around the Marmara Sea between November 2021 and April 2022. In total, 34 species belonging to 19 families were sampled. Approximately 70% of the total fish abundance were Atherina boyeri Risso, 1810, Chelon auratus (Risso, 1810) and Chelon saliens (Risso, 1810). Highest abundance was detected from S5 (Marmara Ereglisi) and S11 (Florya) comprising 17.3% and 14.2% of total abundance, respectively. Maximum species richness was found at S4 (Erdek) and S12 (Yalova Tigem), with 21 and 18 species, respectively. The highest biodiversity indexes were seen at S4, S8 (Karacabey floodplain area) and S12, whereas the lowest biodiversity index was found at S9 (Buyukcekmece). S4 and S8 should be monitored and protected by fisheries management authorities due to being nursery and protection areas for the Sea of Marmara. When the biomass and biodiversity of the coastal fish assemblages were compared with previous studies conducted before the mucilage event, it can be said that mucilage did not adversely affect recruitment success.
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    REPRODUCTIVE BIOLOGY OF THE SPOTTED FLOUNDER, CITHARUS LINGUATULA (ACTINOPTERYGII: PLEURONECTIFORMES: CITHARIDAE), FROM SAROS BAY (NORTHERN AEGEAN SEA, TURKEY)
    (Wydawnictwo Akad Rolniczej W Szczecinie, 2014) Cengiz, Ozgur; İşmen, Ali; Ozekinci, Ugur
    Background. Understanding the reproduction of the spotted flounder, Citharus linguatula (Linnaeus, 1758), has been considered a major step toward understanding its population dynamics, especially, in the northern Aegean Sea. So, the presently reported study aimed to study the reproductive biology of C. linguatula and provided the first data of its fecundity. Materials and methods. This study was carried out between September 2006 and September 2008 in Saros Bay (Northern Aegean Sea, Turkey), which had been closed to trawl fishing since 2000. The gonadosomatic index, length at maturity (L-50), and absolute fecundity were analysed. Results. The elevated GSI values observed, suggested the spawning period was from September to November. The length at maturity (L-50) was at 15.0 cm TL for females and 14.0 TL cm for males. The relations between the absolute fecundity and total length, total weight, and age of the spotted flounder females were estimated as F-a = 0.1878TL(3.29), F-a = 58.515TW + 36.453, and F-a = 887.59A - 389.43, respectively. Conclusion. The identification of reproductive strategy is necessary to obtain a better understanding of its biology.
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    Selectivity of Fishhooks Used in Blotched Picarel (Spicara maena) in Artisanal Fishery in Dardanelles
    (Medwell Online, 2009) Altinagac, Ugur; Kara, Aydin; Ozekinci, Ugur; Ayaz, Adnan; İşmen, Ali; Altin, Aytac; Begburs, Cenkmen R.
    In the study, selectivity of two different types of (short and long shanked but same gap sized) fishhooks used in Blotched Picarel (Spicara maena) in artisanal fishery were determined in Dardanelles. In the calculation of selectivity parameters of fishhooks Holt method was used. The trials were carried out in 3 different regions in the Dardanelles between 12.09.2006-01.16.2008. For hooks gap size of which are 6.10, 7.60 and 9.05 mm, for long shanked hook the optimum catching length was determined as 13.21, 16.46 and 19.60 cm, respectively and for short shanked hook the optimum catching length was determined as 12.69, 15.81 and 18.83, respectively.