
Taner yıldızIstanbul University · Faculty of Aquatic Sciences
Taner yıldız
PhD
eDNA method in fish market for monitoring fisheries,
fishing effort calculation by AIS data
About
112
Publications
36,522
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
595
Citations
Introduction
Fisheries management
Additional affiliations
December 2008 - present
Publications
Publications (112)
The Sea of Marmara (SoM) holds significant importance for both local and regional fisheries due to its characteristic as a semi-enclosed sea on the migratory route of small and medium pelagic fish. While this area sees active fishing with numerous small-scale vessels and approximately 150 purse seiners, there has been a noticeable absence of resear...
Objective
In this study, we applied shape analysis to differentiate two Red Mullet Mullus barbatus stocks in the western Black Sea and assessed the generalized linear model (GLM) for age prediction based on otolith dimensions and weight.
Methods
Sagittal otoliths from 259 fish were collected by commercial bottom trawl vessels in İğneada and Şile,...
Over the past two decades, environmentally harmful fishing subsidies, particularly capacity-enhancing ones, have posed significant threats to marine fish stocks worldwide, including the Mediterranean Sea. Despite the global attention paid to harmful fishing subsidies, studies focusing on their impacts in specific regions, especially in the Mediterr...
Present study deals with the species compositions of trawl haulings performed between December 2014 and September in the eastern part of the Sea of Marmara. As a result of 177 trawl operations, totally 88 species belonging to 7 taxonomic groups were encountered. Osteichthyes were represented by 42 species, Chondrichthyes by 11 species, Crustacea by...
From 2010 to 2014, a seasonal study on round goby (Neogobius melanostomus) population dynamics was undertaken in the Southeastern Black Sea and Western Black Sea (Sakarya Shelf and Thrace littoral region). The population of N. melanostomus was highest (mean 23.8 kg/km²) in the coastal shelf regions where there is large river discharge, compared to...
Despite not being included in Türkiye's official fisheries statistics, dolphinfish have been actively targeted by anglers and spearfishers, as evidenced by citizen science data reviewed in this study. Given the absence of commercial fishing and organized sport fishery, social media records were assessed to gauge the fishing activity around this spe...
The silver-cheeked toadfish (Lagocephalus sceleratus) is an invasive species of highest concern. Its population must be controlled to mitigate its negative impacts on marine ecosystems, fishers, fisheries and human health. This study thoroughly investigates the biology, diet and catchability of the L. sceleratus stock from Finike, Turkey from March...
Understanding the dynamics of pelagic fish fluctuations is crucial to ecosystem well-being and sustainable fishery. Here, inter-and intra-annual landing dynamics of small and medium pelagic fish were delineated between 2000 and 2022 in the landlocked Sea of Marmara. Time series of environmental variables and fisheries landings were analyzed for the...
Skates and rays, which are widely encountered in the by-catch of fisheries activities from the Sea of Marmara and banned for sale by regulation, are species that are discarded if caught. For this reason, in our study, we aimed to determine the bioactive potentials of these species, considered fishing waste, by investigating the skin secretions and...
The highly toxic orange-spotted toadfish Torquigener hypselogeneion (Bleeker 1852) [conspecific Torquigener flavimaculosus Hardy & Randall, 1983] is now a very common invasive fish in the Eastern Mediterranean. Its small size, well under 20 cm, may have concealed the danger it represents, and little is known about its biology or ecology. Here, the...
Fisheries are of immense importance to Mediterranean countries, for protein, employment and livelihoods. Studies addressing the factors affecting fish price dynamics are of interest to examine their drivers as prices often dictate target fisheries. This study investigates fish market prices in relation to landings and fish sizes from Türkiye's larg...
Various studies have recently been carried out to assess the condition of the Sea of Marmara's ecosystem and fish stocks. In this section, i) The results obtained from these studies are synthesized to reveal the ecosystem change and fisheries status; ii) The relationship between the mucilage event and the fisheries, and the status of the important...
Son yıllarda, Marmara Denizi ekosistemi ve balık stoklarının durumunu ortaya koymak için önemli çalışmalar yapılmıştır. Bu bölümde, i) Bu çalışmalardan elde edilen sonuçlar sentezlenerek Marmara Denizi’nin ekosistem değişimi ve balıkçılığının durumu ortaya konmuş, ii) Marmara Denizi’nde gerçekleşen müsilaj olayının balıkçılıkla ilişkisi ve bu deniz...
Ecosystem regime shifts can alter ecosystem services, affect human well-being, and trigger policy conflicts due to economic losses and reductions in societal and environmental benefits. Intensive anthropogenic activities make the Sea of Marmara ecosystem suffer from nearly all existing available types of ecosystem pressures such as biological degra...
Purse seiners generally try to maximize their revenues by targeting multiple species,
starting with the most valuable ones available. The technology and capacity of purse seiners can be exceptionally high for the stocks found in the Marmara Sea, Turkey’s only inland sea, due to its small size and nearly totally enclosed nature. Due to their large c...
Considerable by-catch problems have been occurred during deep water pink shrimp targeted commercial beam trawl fishery in the Sea of Marmara. In the study, grid systems were used in order to reduce the untargeted catch and improve the species selectivity. By-catch reduction ratios of beam trawls deployed with and without grid were compared by paral...
The study evaluated to model the growth and reproduction aspects of the hake, Merluccius merluccius, in the Sea of Marmara. On-board sampling was conducted on the commercial beam trawl fishery from February 2016 to January 2017. For the growth trajectories, using monthly length frequency data set, different methods were employed to improve paramete...
Major invasions of Indo-Pacific lionfish (Pterois volitans and P. miles) are underway in the Western Atlantic Ocean and the Mediterranean Sea. While the establishment of lionfish in the Western Atlantic is perhaps the most well-studied marine fish invasion to date, the rapidly expanding invasion in the Mediterranean is more recent and has received...
The stock structure and productivity components (growth, maturity and mortality) of the Black Sea whiting Merlangius merlangus were studied in the western Black Sea for a year. The results aim to improve fisheries management of whiting in the Black Sea. Fresh samples were collected from commercial bottom trawlers between October 2017 and September...
The study deals with the growth pattern, mortality, and reproduction of common sole, Solea solea (Linneaus, 1758), from the Sea of Marmara (Turkey). A total of 580 fish specimens were sampled monthly from October 2017 to September 2018. The total length of all sampled individuals ranged from 11.1 to 29.5 cm, corresponding to ages from 1 to 3 years....
Invasive species pose threats to either human health or inflict ecological and/or economic damage. The silver-cheeked toadfish (Lagocephalus sceleratus), a Lessepsian species, is one of the most harmful species in the Mediterranean Sea, because of its potent neurotoxin, impacts on marine biodiversity, and the increased costs and labor they inflict...
The invasive Rapa whelk, Rapana venosa in the Black Sea presents a complex governance problem posing a diverse set of positive and negative impacts on marine ecosystems as well as on coastal communities. While some marine scientists perceive the Rapa whelk as a fishery to be sustainably managed, others are more concerned about the threats it poses...
The silver-cheeked toadfish (Lagocephalus sceleratus, from the pufferfish family Tetraodontidae) and the Pacific red lionfish (Pterois miles, family Scorpaenidae) have recently invaded the Mediterranean Sea. Lagocephalus sceleratus has spread throughout this entire sea with the highest concentrations in the eastern basin, while more recently, Ptero...
This study aims to reveal how the fishing sector was affected by the sea snot seen in the Sea of Marmara in 2021. For this purpose, an online survey was conducted in the Sea of Marmara and the surrounding provinces. In total 211 commercial or recreational fishers participated in the questionnaire and answered the questions between 30 May and 22 Jun...
The marbled spinefoot, Siganus rivulatus (Forsskål&Niebuhr, 1775) was recorded for the first time in Izmit Bay, Sea of Marmara. One specimen was caught on 30 September 2019 by a small scale fisherman at depth of 25 m. The fish measured 151 mm in total length and weighted of 43.45 g. S. rivulatus is one of the Lessepsian immigrants who entered the M...
In this study, the efficiency of two fishing methods (a) traditional handline commonly used in the Strait of Istanbul and (b) light rock fishing (LRF), which is beginning to spread in recent years, were investigated by monthly sampling between September 2014 and September 2015. One classic handline fishing tackle and one LRF fishing tackle were use...
Seasonal fishery closures, are an input control measure to reduce fishing pressure on spawning stocks in fisheries management. Despite the huge foregone economic losses from such closures, the efficacy of them has yet to be examined in Turkey. This study compares the monthly landed catch distribution for commercial marine species averaged for 12 ye...
Age, growth and reproduction biology of the golden grey mullet, Chelon auratus (Risso, 1810) have been studied in the Istanbul Golden Horn area. Fish length ranged from 13.4–46.8 cm, and age from 1–10 years, respectively. The sex ratio (female:male) was 1:1.08. The length-weight relationship was estimated as W = 0.0127L 2.89 , W = 0.0099L 2.97 and...
This paper updates some information on fish catches from the last dalians (stationary uncovered pound nets) operating off the coast of Istanbul Strait. The data were collected on the weekly basis directly from the owners of the traps. Although the traps have been targeting migratory pelagic fishes during their migration, demersal species have been...
Currently, knowledge of the spatial distribution of European hake Merluccius merluccius in the Sea of Marmara is scarce, particularly regarding the dependency of this fish on biotic or abiotic conditions. A generalized additive model (GAM) was used to model hake abundances in relation to depth, temperature, dissolved oxygen, pH, and spatial locatio...
The Mediterranean and Black Sea host the most intense overfishing and Turkey has the largest commercial fisheries in them (when both seas considered). However, the state of the Turkish fisheries is in critical condition as both the quality (i.e, in number of caught species, value and sizes of fish) and quantity of fisheries catches have been rapidl...
Keywords Whiting Length-weight relation Otoliths Age and growth Mortality Western Black Sea. Abstract The aim of this study was to determine the age and growth, length-weight relationship, sex ratio and mortality rates of the whiting, Merlangius merlangus, in the western Black Sea coast of Turkey. On-board sampling was conducted on the commercial b...
Background. This study is the first attempt to acquire information about growth, age composition, and mortality of European hake, Merluccius merluccius (Linneaus, 1758), in the northern Aegean Sea. In Turkey, the hake is a very important commercial species captured with demersal trawls. Therefore the management of the hake fishery is important for...
The common dolphinfish (Coryphaena hippurus) is an epipelagic, mid-trophic level, highly migratory species distributed throughout the
world’s tropical and subtropical oceans in waters greater than 20�C. Life-history variables, migratory behaviour, and genetic markers have
been used to define major stocks in the central Atlantic Ocean and Mediterran...
This is a correction to:
ICES Journal of Marine Science, fsy174, https://doi.org/10.1093/icesjms/fsy174
Length-weight relationships were estimated for common demersal elasmobranch species in two different fishing
regions - Northeastern Aegean Sea (NEAS) and North Eastern Levantine Sea (NELS) - in the Eastern Mediterranean. All
individuals were collected using bottom trawl fishing vessels from September 2014 to April 2016. Nonlinear models were
used a...
The common dolphinfish (Coryphaena hippurus) is an epipelagic, mid-trophic level, highly migratory species distributed throughout the world's tropical and subtropical oceans in waters greater than 20 C. Life-history variables, migratory behaviour, and genetic markers have been used to define major stocks in the central Atlantic Ocean and Mediterran...
Some biometrical measurements and revision on the occurrences of Pterois miles in the Mediterranean Sea are here presented.
II. INTERNATIONAL FISHERIES SYMPOSIUM
IFSC 2018 / GIRNE – TURKISH REPUBLIC OF NORTHERN CYPRUS /
SYMPOSIUM PROCEEDINGS
The aim of this study was to derive length-weight relations (LWRs) for a wide range of fish species collected
from the narrow continental shelf of the western Black Sea, Turkey which is exploited by the bottom trawl fisheries.
Therefore, the present study describes the length-weight relationships for 24 fish species. A total of 31,553 individuals
c...
In this review, the mechanism of action of poisons and toxic effects of and treatment methods for the same among weever fishes, which are present along the coast of Turkey, were addressed. Weever fish poison is present in the spicule located on the operculum and in the 5 th-8 th dorsal spines located on the first dorsal fin. Weever fish poisoning i...
In this study, the determination of catch composition in bottom trawling and effect of depth was aimed in the
western Black Sea. Data was obtained by 66 bottom trawl hauls during 2012-2013 and 2013-2014 fishing periods in İğneada and Rumeli Feneri fishing regions. A total of 32 species were obtained where the species
composition and catch rates wer...
In this study, the composition and density of marine litter for 50 trawl hauls conducted seasonally between 2015 and 2017 in depths of 40-150 m in the Sea of Marmara were examined.
In this study, which was carried out in 2016 summer season to determine the situation of marine litter in the Black Sea, bottom trawling operations were performed in 20 stations within the scope of Integrated Marine Pollution Monitoring Project (CSB/CEDIDGM-TUBITAK/MAM, 2014-2016).
In this study, the amount of turbot and bonito net lost in a season was determined by surveying the questionnaire with artisanal fishermen in the western Black Sea
The main objective of this study was to analyze the differences and similarities in morphometric characteristics among specimens of juvenile little tunny (Euthynnus alletteratus) that were collected from commercial hand line fisheries of Turkish waters (Eastern Mediterranean Sea).
The study deals with the sexual maturity and reproductive patterns of European hake Merluccius merluccius
(L.) from the Sea of Marmara, Turkey. Totally, 777 specimens were sampled monthly between
October 2014 and September 2015. Total lengths of all sampled individuals ranged from 10.4 cm to 55.3
cm. The sex ratio (♂/♀) was 0.56. A total of 341 ova...
This study deals with the age composition, growth and mortality of European hake Merluccius merluccius (L.) from the Sea of Marmara, Turkey. A total of 777 European hakes were sampled monthly from October 2014 to September 2015. Total lengths of all sampled individuals ranged from 10.4 cm to 55.3 cm. The length–weight relationship for all samples w...
This study attempted to determine certain characteristics of the species caught in the boat seine fishery in the İstanbul Strait during the 2009–2010 fishing season, including catch composition, commercial and nontarget catch ratios, catch per unit effort (CPUE), and the length distributions of commercial species. A survey of 20 boat seine operatio...
Atlantic bluefin tuna (ABFT) fattening activities began in the eastern Mediterranean (Cyprus, Greece, and Turkey) in 2002. The total potential production is estimated at 11,240 tons. However, the actual production fluctuates depending on catch quota. ABFT farming in the region uses traditional methods of catching tuna with purse seiners and transfe...
The aim of this study was to determine the age, growth, length-weight relationship, sex ratio and fishing mortality rates of the red mullet off the western Black Sea coast of Turkey. Age, growth and mortality parameters were estimated for the red mullet, M. barbatus, sampled from commercial landings for the demersal trawl fishery in the western Bla...
No study has been held about the stock assessment of commercial demersal fish species in the western Black Sea waters within last 20 years. In this study, estimations were made about the stocks of commercial fish species such as red mullet, whiting and turbot in the western Black Sea waters which is one of the most important demersal fishing areas...
Illegal trawl activities were evaluated with official records.
This paper presents some biological features of juvenile specimens of Atlantic bluefin tuna, T. thynnus Linnaeus, 1758, in the eastern Mediterranean Sea. A total of 369 specimens were analysed. Juvenile individuals ranged from 12.2 to 46.5 cm. In order to analyse biometry, 11 morphometric characters were analysed. Length-weight relationships of juv...