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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.
A study on the catch composition and bycatch of shrimp beam trawl in the Sea of Marmara
(Ege Univ, Fac Fisheries, 2006) Yazici, M. Fatih; İşmen, Ali; Altinagac, Ugur; Ayaz, Adnan
Catch productivity, catch composition, bycatch and discard rates of shrimp beam trawl were investigated between January 2003 and March 2004 in Marmara Sea. A total of 37 species which were captured by beam trawl during survey. The relative abundance in weight, respectively, were 51,3 % arthropoda, 30,9 % fish species, 15,5 % echinodermata, 1,3% mollusc. The deep water pink shrimp (Parapenaus longirostris) formed 50,8 % of the total catch. The length distribution of deep water pink shrimp ranged from 47 mm to 154 mm. Catch productivity in beam trawl fishery was calculated 10,1 kg/h. On average 0,42 kg discard, 0,62 kg incidental catch rate and 1,04 kg by-catch for 1 kg shrimp were estimated from beam trawl fisheries.
An investigation on fyke nets in Canakkale Region
(Ege Univ, 2006) Ayaz, Adnan; Altinagac, Ugur; Cengiz, Ozgur
Fyke nets are type of traps are used in fresh - water such as lake, river and running water, also they are used in shallow water such as sea shore, lagoon, strait and having a current sea. They catch creatures by guiding with wings towards the entrance of the trap. In this study a fyke net has 36 mm mesh size, 6 m length and 1x 1.5 m entrance width was tried in the Dardanelles Strait. This trap was set up to right current and catching efficiency was observed. In the trials with this net, two banded bream (Diplodus vulgaris), rockfishes (Scorpaena sp.), annular sea bream (Diplodus annularis), painted comber (Serranus scriba), stripped mullet (Mullus surmuletus) and conger ell (Conger conger) were trapped. In addition bogue (Boops boops), saddle bream (Oblada melanura) and painted comber (Serranus scriba) were caught from gills by the wing nets.
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.
Comparison of Fish Aggregating Devices (FADs) Having Different Attractors
(Medwell Online, 2010) Altinagac, Ugur; Kara, Ali; Ayaz, Adnan; Acarli, Deniz; Begburs, Cenkmen R.; Öztekin, Alkan
In this study three FAD types, which were being commonly used in small scale fisheries and had different attractors were tried. Attractors such as pyramid, rope and panel types were tied to static FADs. The fish species and densities attracted by them were examined. The samplings were made through visual census, trammel nets and line fishing before and after the deploying of FADs. Any significant difference was not able to be found statistically between the attractors tied to fish aggregating devices. In the result of observation and samplings before and after the deploying of FADs, while 10 fish species belong to 6 families were observed before deployment, 16 fish species belong to 11 families were determined after the deployment of the FADs.
Effect of Hanging Ratio on Selectivity of Gillnets for Bogue (Boops boops, L. 1758)
(Central Fisheries Research Inst, 2015) Kumova, Can Ali; Altinagac, Ugur; Öztekin, Alkan; Ayaz, Adnan; Aslan, Alparslan
This study was conducted between November 2011 - January 2013 on Bogue gill nets in mesh size of 36, 40, 44 and 50 mm targeting bogue (Boops boops, L. 1758), which is used in commercial fishing commonly at Canakkale shores. The bouge nets were rigged in three varying hanging ratios (E = 0.40, E = 0.50, E = 0.60) with the purpose of determining the effect of hanging ratio to selectivity. SELECT (Share Each Lengthclass Catch Total) method was used to fit selectivity curves. Lognormal model gave the best fit for selectivity curve of bogue selection according to the findings obtained from five different curve models (normal location, normal scale, gamma, lognormal, bimodal). According to the lognormal method modal lengths of bogue nets in mesh size of 36, 40, 44 and 50 mm, following findings were obtained; in hanging ratio of 0.4, rigged nets are 18.65, 20.72, 22.80 and 25.90 cm, respectively; in hanging ratio of 0.5, rigged nets are 17.90, 19.89, 21.88 and 24.86 cm, respectively; in hanging ratio of 0.6, rigged nets are 16.98, 18.87, 20.75 and 23.58 cm, respectively. Model lengths of bogue nets that were used in field studies are quite higher than the first reproduction length. The results show that the nets used in research have no pressure on bogue stock. It was determined that the hanging ratio may affects the selectivity with the help of other factors. It is taken into account the hanging ratio together with the other factors affect the selectivity.
Effect of jigs color to catching efficiency in the squid fishing in Turkey
(2006) Altinagac, Ugur
To investigate and compare squid jigs, six squid-jigging experiments were conducted from 1 July 2005 to 30 August 2005 with small scale fishermen. The aim of these experiments was to determine the effects of color of jigs on catch rates and catching efficiency of European squid taken by the hand jigging methods used by small scale fishermen in Turkey. Same types of two different colored red and green jigs were used in per gears in trials. A total of 102 squid were caught by the handline jigging during the study. After six fishing trials 12510.1 g squid were caught totally. 7890.3 g (n:63)of these value was belong to green type of jig and 4619.8 g (n:39) squid were caught by red jigging line. Average catch weight of squids per trial was 2085 g. One way ANOVA revealed that for born jig types no significant relationship (p>0.05) was found between the means of groups. Fishing with squid jigging line is proposed to small-scale fisheries due to high price of squid, low by-catch, no requirements of complex fishing gears and having low cost. And the green types of jigs are found more efficient. © 2006 Asian Network for Scientific Information.
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.
Estimation of spawning stock biomass and spawning areas of sardine, (Sardina pilchardus) with winter time ichthyoplankton sampling in the Sea of Marmara, Turkiye
(Ege Univ, Fac Fisheries, 2024) Daban, Ismail Burak; Sen, Yusuf; Öztekin, Alkan; Ayaz, Adnan; Altinagac, Ugur; İşmen, Ali; Yuksek, Ahsen
The spawning areas and spawning stock biomass of sardine were studied with ichthyoplankton sampling in the winter period from the 32 stations, in the Marmara Sea. The mean fish egg and larvae biomass in a unit area were calculated as 18.4 +/- 5.3 eggs/10 m(2) and 2.5 larvae/10 m(2), respectively. Three main spawning areas were detected as Karacabey Floodplain area, Gonen, and Buyukcekmece estuarine area. The larvae are mostly located in the western part. The batch fecundity of sardine was detected between 2415.9 and 16738.3, with a mean of 6899.8 +/- 255.7 eggs. The sex ratio (R), spawning fraction (S), mortality rate, and daily egg production (Po) were calculated as 0.53, 0.098, 0.62, and 9.25 eggs/m(2) in the Marmara Sea. The spawning stock biomass (B) is estimated at 2998 tonnes in the Marmara Sea. Both ichthyoplankton biomass and spawning stock biomass were found relatively lower. It is recommended to apply stricter management sanctions for the sustainability of sardine stocks.
FIRST RECORD OF AN INVASIVE LESSEPSIAN MIGRANT, LAGOCEPHALUS SCELERATUS (ACTINOPTERYGII: TETRAODONTIFORMES: TETRAODONTIDAE), IN THE SEA OF MARMARA
(Wydawnictwo Akad Rolniczej W Szczecinie, 2015) Irmak, Erhan; Altinagac, Ugur
One specimen of the silver-cheeked toadfish, Lagocephalus sceleratus (Gmelin, 1789), was obtained for first time from the Sea of Marmara, off Gelibolu, by trammel net in October 2008. The morphological features of this species were examined. The presently reported finding also represents the second documented occurrence of a puffer fish in the Sea of Marmara.
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.
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.
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.
Growth performance of bath sponge (Spongia officinalis Linnaeus, 1759) farmed on suspended ropes in the Dardanelles (Turkey)
(Wiley, 2011) Celik, Ihsan; Cirik, Sukran; Altinagac, Ugur; Ayaz, Adnan; Celik, Pinar; Tekesoglu, Haluk; Yilmaz, Harun
Commercial bath sponge population in the Mediterranean has been recently reduced due to diseases and the depletion of natural banks. The commercial supply is far below the demand on the last 1015 years. In this study, we aimed to investigate the farming performance of Spongia officinalis in the Dardanelles. Sponges collected from the Dardanelles cut into pieces of different weight. They were divided into two groups depending on the wet weight ranging from 50 to 150 g (mean weight 102.6 +/- 4.81 g) and from 160 to 360 g (mean weight 235.8 +/- 8.56 g). Three rope systems located parallel to each other with 67 m inter-distance were constructed for the cultivation of sponges. At the end of the study, while small-sized sponges could reach mean wet weight of 120.7 +/- 14.8 g, large-sized sponges reached mean wet weight of 247.6 +/- 22.4 g. Growth rates were estimated 517% at 21st month. The survival rates were found 82% and 88%.
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.
Mass mortality in endangered fan mussels Pinna nobilis (Linnaeus 1758) caused by co-infection of Haplosporidium pinnae and multiple Vibrio infection in canakkale Strait, Turkey
(Taylor and Francis, 2021) Kunili, Ibrahim Ender; Erturk Gurkan, Selin; Aksu, Ata; Turgay, Emre; Cakir, Fikret; Gurkan, Mert; Altinagac, Ugur
Purpose: Pinna nobilis (fan mussel) is one of the most important endemic bivalve molluscs in the Mediterranean and mass mortality events were observed in these mussels in recent years. In this study, we report mass mortalities caused by Haplosporidium pinnae, which has been spreading in the Mediterranean for 3 years, and reached the C¸anakkale Strait, which is the entrance of the Marmara and the Black Sea. Material and methods: Field observations during sampling and subsequent histopathological, biochemical, genetic, and microbiological analyses were carried out. Results: These analyses showed that H. pinnae infection spread among the natural beds of P. nobilis, causing severe tissue damage and oxidative stress. Our phylogenetic analyses suggested that the parasite spread through the Mediterranean much faster than thought. The results showed that vibriosis originating from Vibrio coralliilyticus, Vibrio tubiashii, Vibrio mediterranei, and Vibrio hispanicus, acted together with H. pinnae in infected individuals and caused death. Conclusion: It is highly probable that the spread of H. pinnae to the Sea of Marmara and the Black Sea may occur earlier than expected, and it was concluded that mass deaths were caused by co-infection with H. pinnae and a geographically specific marine pathogen that can infect P. nobilis populations.
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.
Post-Mucilage Distribution, Daily Growth, Mortality, and Hatch Date Timing of Sand steenbras Lithognathus mormyrus (Linnaeus, 1758) Juveniles in the Sea of Marmara
(Istanbul Univ Press, Fac Aquatic Sciences, 2024) Daban, Ismail Burak; Sen, Yusuf; Öztekin, Alkan; Ayaz, Adnan; Altinagac, Ugur; İşmen, Ali; Yuksek, Ahsen
Between 2021-2022, a dense mucilage disaster occurred in the Sea of Marmara in T & uuml;rkiye. Mucilage mostly covered coastal areas, which juvenile fish use for nurseries, growth, and protection. Due to Sand steenbras having been suggested as an environmental bioindicator species for Mediterranean coastal waters, this study attempts to reveal post-mucilage distribution and potential differences on the timing of hatching, daily age, growth, and mortality as revealed by the otolith microstructure. Individuals were sampled using beach seine nets from 12 equally spaced stations along the Sea of Marmara. Its presence and significant abundance in 10 out of 12 stations showed the Sand steenbras to be a common juvenile species for the Sea of Marmara. Hatching occurs between MayJanuary, with peak hatching occurring in October. When considering that the mucilage had completely disappeared from the environment in August, the first set of hatching months can be seen to coincide with the dense mucilage. Thus, Sand steenbras can be considered as able to reproduce under these environmental conditions. The daily age of the Sand steenbras juveniles ranged between 38-235 days, with a mean of 120.3 +/- 1.8 days. The daily growth and mortality rates were also calculated respectively as 0.226 mm/day and 4.11%.
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.
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.

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