Saros Bay Research Articles

The Maximum Length Record of the White Seabream (Diplodus sargus Linnaeus, 1758) for the Aegean Sea

A single specimen of Diplodus sargus with 40.5 cm in total length and 1000.00 g in total weight was caught off İbrice Bight (Saros Bay) with handline by a commercial fisherman on 25 June 2018. The mentioned sizes are the maximum length and weight values of the species for the Aegean Sea and the other Turkish coasts; however, it is the second-largest length ever reported in the Mediterranean Basin.

The Maximum Length Record of the Blackspot Seabream (Pagellus bogaraveo Brünnich, 1768) for the Entire Aegean Sea and Turkish Territorial Waters

The maximum length, weight, and age information of organisms in an ecosystem, moreover, the first records of migrated exotic species are essential in terms of the basis for the studies on population dynamics, stock assessment, and biological activities. Therefore, the recording of such data may be necessary for scientific databases and new related studies. The Blackspot seabream (Red seabream - Pagellus bogaraveo), which belongs to the Sparidae family, is an important seafood which is marketed fresh and frozen around the Mediterranean and the Aegean seas. Nowadays, this species has high prices depending on market demands in domestic markets as a result of overfishing and is also cultured in northern Spain. It is classified as “Near Threatened Species” in the red list due to its decreasing population trend by the IUCN. A single specimen of the Blackspot seabream with 30.7 cm in total length and 390.00 g in total weight, which was angled in the Saros Bay with a handline by a fisherman on February 08, 2019, was obtained from a fishmonger in Çanakkale. Even though there are bigger individuals in the North-east Atlantic probably depending on polar and/or deep-sea gigantism, the mentioned measurement is the proven maximum total length of this species for the Aegean Sea up to the time.

Determining the hook selectivity of bottom longline used for European hake (Merluccius merluccius, L. 1758) in Saros Bay (northern Aegean Sea, Turkey)

This study was carried out at Saros Bay, between June 2011 and July 2013 to determine hook selectivity of bottom longlines used on European hake (Merluccius merluccius, L. 1758) fishing. Throughout the study thick type in 6, 7, 8 and 9 sized flat hooks were used between 150 to 400 m depth. 36 fishing operations were carried out and 222 fish were caught by using 7200 hooks in total. Depending on the size of hooks number 8 was the most efficient hook that has caught 114 fish and number 6 was the least efficient one that has caught only 14 fish. The SELECT method is used in the determination of the selectivity parameters. Bi model has given the best fit according to selectivity analysis of five different models. Optimum catching lengths were found 60.09 cm for 6 number hook 51.45 cm for 7 number hook 46.43 cm for 8 number hook 40.11 cm for 9 number hook, respectively in Bi Model model. Minimum size limit for European hake is 25 cm in Turkey. Considering the minimum size limit, use of hooks with gapes larger than number 9 hook (11.75 mm) used in this study is suggested.

The Confirmed Occurence of Serpent Eel Ophisurus serpens in Saros Bay (Northern Agean Sea), Turkey

Abstract One mature female specimen of serpent eel Ophisurus serpens (Linnaeus, 1758) was caught by long line by a professional fisherman at a depth of about 45 m from Ece Bight, Saros Bay, north Aegean Sea on 15 February 2016. The species was previously reported without any morphometric and meristic characters from Saros Bay. Some biological characters, such as age and diameters of otolith and oocytes, are also given. In this study, the detailed morphomeristic features, which can contribute to the taxonomic studies of serpent eel from Turkish Seas, are presented.

Genetic characterization of the invasive Blue crab, Callinectes sapidus (Rathbun, 1896), in the Black Sea

Blue crab, Callinectes sapidus (Rathbun, 1896), is a commercially important crab species native to the Western Atlantic Ocean. Callinectes sapidus has invaded the Mediterranean Sea in 1930s and spread rapidly. It has become widely distributed and has been moving through adjacent basins including the Black Sea. In this study, mitochondrial 16S rRNA and COI sequences were generated for individuals captured from the Black Sea for the genetic characterization of the population for the first time. Additionally, available sequences of C. sapidus from their native and introduced populations were included in the analysis to evaluate phylogenetic affinities and the most probable origin of the population in the Black Sea. The Black Sea specimens were clustered with the sequences from the Northwest Atlantic Ocean on the basis of 16S rRNA sequence analysis and with those from the Northwest Atlantic Ocean and the Levantine Sea on the basis of COI sequence analysis. The Caribbean Sea and the Southwest Atlantic Ocean sequences were clustered together. Notable genetic divergence was observed between the populations of the Black Sea and the Levantine Sea. The present C. sapidus population in the Black Sea is most probably a result of the migration from the Aegean Sea (Saros Bay), where C. sapidus has established a stable, reproductively successful population. Patterns of the haplotype diversity and maximum likelihood trees indicate that the invasive population of C. sapidus in the Black Sea possibly originated from the Northwest Atlantic Ocean. Genetic divergence between populations of the Black Sea and the Levantine Sea were attributed to the limited sample size from the Black Sea.

Saros Körfezi Ağ Dalyan Balıkçılığı Üzerine Bir İnceleme

Çalışma Saros Körfezinde bulunan ağ dalyanların av verimleri, tür boy kompozisyonları ve ağ planlarının incelenmesi amacıyla Nisan 2019 – Eylül 2019 tarihleri arasında gerçekleştirilmiştir. Dalyanlara karadan ulaşım olmadığı için, dalyanların lojistik ihtiyaçları beşyol köyü sınırları içinde yer alan Ece Limanından yapılmaktadır. Çalışmada Ece limanına gidilerek dalyan sahipleri ile görüşmeler ve dalyanlardan gelen balıkların boy ölçümleri yapılmıştır. Sezon başlamadan önce dalyanda kullanılan ağların teknik planları incelenerek Türkiye’de ilk defa planlarının çizimi yapılmıştır. Çalışmada, 2019 balıkçılık sezonunda Saros Körfezi'nde incelenen 3 adet ağ dalyanda 9 familyaya ait 12 türün yakalandığı belirlenmiştir. İncelenen Ağ dalyanların av verimleri Arifağa taşları mevkii için 53,9 kg/gün, Bozburun mevkii için 52,6 kg/gün ve Mersinlik bölgesi için 43,2 kg/gün olarak hesaplanmıştır. Araştırma sonucunda, Saros Körfezi'nde dalyanların yaptığı avcılığın yasal boy altı balıkları önemli derecede yakalamadığı görülmüştür. Ek olarak, sonuçlar Saros Körfezi'ndeki dalyanlarının ağ yapılarının modernize edilmesi gerektiğini ortaya koymuştur. * Bu çalışma İsmail ÇALIŞKAN’ın yüksek lisans tezinden üretilmiştir.

An Observation About Maximum Size Record of Blotched Picarel (Spicara maena Linnaeus, 1758) from Northern Aegean Coasts of Turkey

Maximum length and weight are important parameters and they are commonly used in life history studies and fishery science. Therefore, it is important to regularly bring up to date the maximum size of commercially important species. The accurate estimates of the maximum size of fish in a population are important issues. Because the parameters related to maximum length, weight and age in fish communities within an ecosystem are constantly used in population dynamics and stock estimation studies, recording of such data is vital for determining the life history of fish. In this connection, a single specimen of blotched picarel (Spicara maena) with 20.3 cm in total length and 159.00 g in total weight was caught off Saros Bay (Northern Aegean Sea, Turkey) with handline at 20 m water depth by a commercial fisherman on October 20, 2019. Its length and weight were the maximum size of Spicara maena for Saros Bay.

Maximum Size Record of Sharpsnout Seabream (Diplodus puntazzo Walbaum, 1792) for Saros Bay, Northern Aegean Sea

A single specimen of Diplodus puntazzo with 34.6 cm in total length and 550.00 g in total weight was caught off İbrice Bight (Saros Bay) with handline (hook (Mustad 496) size 1 and 0.40 mm monofilament line-diameter) by fisherman on May 25, 2016. Its total length and weight were the maximum observed values for the species in the Saros Bay, Northern Aegean Sea.

Weight-Length Relationships with Maximum Length Record of Striped Sea Bream (Lithognathus mormyrus Linnaeus, 1758) for Turkish Seas

Bu çalışma Ocak 2018-Aralık 2018 tarihleri arasında Saros Körfezi’nde (Kuzey Ege Denizi, Türkiye) yürütülmüştür. Maksimum boya sahip bir adet mırmır balığı (35.2 cm toplam boy ve 400.00 gr toplam ağırlık) 15 Aralık 2018 tarihinde balıkçılar yardımıyla fanyalı ağlarla yakalanmıştır. Tüm bireyler için ağırlık-boy ilişkisi W = 0.0335TL2.68 olarak hesaplanmıştır. Bu çalışmanın amacı Türkiye denizleri için türün maksimum boy kaydını sunmaktadır.

Some reproductive characteristics of the blotched picarel <i>Spicara maena</i> (Perciformes: Centracanthidae) from Saros Bay, Northern Aegean Sea, Turkey

This study was carried out, monthly, in the Saros Bay (Northern Aegean Sea, Turkey) between January 2015 and December 2015. The gonadosomatic index (GSI) and absolute fecundity (Fa) of the blotched picarel (Spicara maena) were analyzed . GSI values suggested the spawning period of S. maena was from April to June. The relations between the absolute fecundity and total length (TL), total weight (TW) and age (A) of the blotched picarel females were estimated as Fa= 287.52TL1.40, Fa= 153.33TW + 6,680.9 and Fa= 2,407.5A + 5,289.6, respectively. The present study contributes to the reproductive biology of S. maena by reporting the first data about the fecundity of the species for the Aegean Sea.

Saros Körfezi’ndeki (Kuzey Ege Denizi, Türkiye) Kupes Balığının (Boops boops Linnaeus, 1758) Üreme Zamanı ve Ağırlık-Boy İlişkisinin Belirlenmesi

Bu çalışma Ocak 2014-Aralık 2015 tarihleri arasında Saros Körfezi’nde yürütülmüştür. Türün üreme zamanı gonadların aylık ağırlık değişimleri dikkate alınarak GSI (Gonadosomatik indeks) = (Gonad Ağırlığı / Vücut ağırlığı - Gonad Ağırlığı) × 100 eşitliğinden, ağırlık-boy ilişkisi ise W = aLb denklemi kullanılmak suretiyle elde edilmiştir. Üreme zamanının Mart ve Mayıs ayları arasında olduğu gözlemlenmiştir. Dişi bireyler için ağırlık-boy ilişkisi W = 0.0085TL3.11, erkek bireyler için W = 0.0095TL3.07 olarak hesaplanmıştır.

Age, Growth and Reproduction of Silvery Pout (Gadiculus argenteus Guichenot, 1850) in the Saros Bay (Northeastern Aegean Sea)

The age, growth and reproduction of Silvery Pout (Gadiculus argenteus), caught in the Bay of Saros (Northeastern Aegean Sea) between April 2005 and September 2008, were investigated. The total length and weight of the G. argenteus ranged from 5.5 cm to 16.8 cm in total length (TL) and from 1.6 g to 30.7 g in weight. The length-weight relationships were estimated W = 0.011*TL2.924.Age data derived from otoliths readings were used to estimate the growth parameters of the von Bertalanffy equation. The population growth parameters for G. argenteus were estimated as L∞ = 14.97 cm, K = 0.28 year−1 and t0 = −1.69 year. The maximum age was 5 years. The data on maturity stages indicated that length at 50% maturity (L50) were 8.94 cm TL for G. argenteus. Monthly values of the gonadosomatic index indicated that reproduction period of G. argenteus was determined between December and March.

Agglutinated vs. calcareous foraminiferal assemblages as bathymetric proxies: Direct multivariate tests from modern environments

Benthic foraminiferal assemblages, used widely as paleoenvironmental indicators, can potentially provide numerical estimates of relative water depth. The quality of this bathymetric proxy was tested here directly using onshore-offshore transects across two present-day marine basins: (1) Saros Bay (northern Aegean Sea), with sampling sites ranging from 15 to 500 m water depth; and (2) Marmara Sea (between Black Sea and Aegean Sea), with sampling sites ranging from 15 to 350 m water depth. For both marine basins, multivariate ordinations of calcareous and agglutinated foraminifera demonstrated that samples varied predictably in faunal composition along regional depth gradients. The multivariate ordination scores and water depthwere highly and positively correlated in all cases: r2 = 0.74 (Saros Bay, agglutinated foraminifera), r2 = 0.67 (Saros Bay, calcareous foraminifera), r2 = 0.68 (Marmara Sea, agglutinated foraminifera), and r2 = 0.96 (Marmara Sea, calcareous foraminifera). Comparably robust relationships between ordination scores and water depth were observed when data were pooled across basins and/or foraminiferal type. These results suggest that both agglutinated and calcareous benthic foraminifera provide robust quantitative proxies of water depth. Multivariate ordinations based on agglutinated foraminiferamay potentially yield numerical estimates of water depth in the geological record and provide a quantitative environmental framework for paleontological and stratigraphic interpretations.

Different Test Forms and Numerous Apertures of Cibicidella variabilis (d’Orbigny) from The Turkish Coast of Eastern Aegean Sea

In the last ten years, morphological abnormalities and colored tests have been observed in benthic foraminifera specimens collected from Aegean and Southwestern coasts of Turkey. Specific morphological abnormalities show distinct distribution patterns, suggesting the need for special environmental conditions facilitating the development of such abnormalities. Physical and chemical parameters have been proposed to be responsible for these morphological changes. The benthic foraminifera, Cibicidella variabilis (d’Orbigny) specimens have been collected from different locations on the East Aegean coast of Turkey. Some of them, especially those from Dikili Bay, were found to have variable number of apertures, ranging from one to five. These apertures not structurally, but positionally differ. The abundance of certain test forms in specific locations draws attention. The aim of this study is to determine the possible causes of this aberrant morphology observed in tests of Cibicidella variabilis (d’Orbigny).Cibicidella variabilis (d’Orbigny) shows a wide distribution range on the Aegean coast of Turkey, and has been found in Saros Bay, Gökçeada, Bozcaada, Çanakkale, Edremit Bay, Dikili Bay, Çandarlı Bay, Karaburun Peninsula, Kuşadası, Güllük Bay, Gulf of Gökova, Gulf of Datça, and Marmaris Bay. But, the individuals collected from Gulf of Edremit, Dikili Bay, Çandarlı Bay, Gulf of Gökova, and Gulf of Datça were morphologically different than those collected from the rest of the regions. The variation in the number of apertures, as well as their positions were typical in these samples. Besides, the variations in the shape of the tests observed in adult individuals, but not in juveniles indicates that some environmental factors, which were specific to these regions, might have been involved in this unusual test development. The submarine springs caused by the tectonic activities are typical of the Aegean Sea. It is well documented that these kinds of springs change the characteristics of the surrounding habitat and its fauna. Therefore, it is possible that some of the trace elements, which are abundant in hot spring waters, may be related with the abnormal test morphology observed in our samples. On the other hand, it is also possible that, not only the chemical and physical conditions of the surrounding water, but also its biological properties may affect the test development.

Source constraints using ground motion simulations.

We study the source characteristics of the 9 August 1912, Mw 7.4, Mürefte (Ganos) earthquake that ruptured the Ganos Fault in the westernmost segment of the North Anatolian Fault. We apply the stochastic method for finite-faults in order to simulate strong ground motion acceleration using different fault geometries in terms of therupture initiation and the length of the fault. A first-order approximation of the site effect variation is achieved following an empirical approach based on the topography gradient as a proxy for site-effect. The simulated ground motions, which are calculated at phantom stations, over a grid covering the area of study, satisfactorily produce the regions which were more severely shaken during the 1912 event. We simulate ground motions using a conservative fault length of 50 km (one land segment) which is able to explain the location of the surface ruptures but is not able to reproduce the surface extent of strong shaking. We then use a longer fault ofapproximately 120 km, extending to Saros Bay in the west and to Marmara Sea in the east. The synthetic peak ground acceleration values, indicate a segmented nature of the fault, have at least two patches of strong shaking and significantly predict the observed macroseismic intensities of the 1912 earthquake. Further constrain in our modelling is posed by surface ruptures, with small releasing andrestraining structures and 1.5–5.5 m right-lateral offsets, that have been previously measured by others, at 45 sites of the on-land ~50-km-long fault section.

A Study on Heavy Metal Content of Sardine (Sardina Pilchardus) Caught in the Dardanelles

Sardine (Sardina pilchardus) is one of the most important species among Turkish fisheries and is broadly distributed along Turkey’s Saros Bay waters. In this study, the amount of heavy metal content of sardine, which is a fish abundantly consumed and caught in the Dardanelles has been determined between November and December of 2013. The effects of heavy metals, which are found especially in fisheries, on human health and on the environment arouse great interest. Toxic contaminants particularly such as lead, cadmium and mercury are found in the water as a result of industrial and agricultural activities and mining. The high concentration of these metals affects not only aquatic environments but also fish species negatively. In this research, the amount of heavy metal in two sardine samples (R1/R2) taken from Çanakkale fish market is analyzed. ICP-AES (Inductively Couple Plasma Atomic Emission Spectroscopy) is used in the analysis for Zn, Cr, Cd, Pb, Fe, Cu, and Ni. According to the results obtained, the average heavy metal amount of the two samples are found at the levels: 47,81001 for Zn, 0,163543 for Cr, 0,047545 for Cd, ND for Pb, 19,60705 for Fe, 1,385225 for Cu and 0,174258 for Ni. Pb is below the limits of the detection of ICP device, and no figures have been obtained. Other obtained figures have been observed to be below the acceptable amount in comparison to the figures of EPA standards.

Harbour porpoises in the Aegean Sea, Eastern Mediterranean: the species’ presence is confirmed

Results are presented from the first systematic visual and acoustic line-transect survey for harbour porpoises in the Thracian Sea, northern Aegean Sea. During the vessel survey, undertaken in summer 2013, porpoises were observed on nine occasions and detected acoustically 16 times, with a total of 21 distinct encounters recorded. Harbour porpoises were encountered in three discrete blocks: north of the Island of Thasos, Greece; south and west of the city of Alexandroupolis, Greece; and in Saros Bay, Turkey. Saros Bay exhibited the highest relative acoustic encounter rate of harbour porpoises, and porpoises were observed visually there on two occasions 14 days apart, in small groups, one of which included a mother-calf pair. A comprehensive review of stranding records is also presented. The three areas identified as harbour porpoise habitat in this study coincide with the highest number of recorded stranded animals. This paper is the first to report free-swimming harbour porpoises in the Aegean Sea since 1993, and the first time ever in Turkish Aegean waters. Now that the presence of harbour porpoises has been documented, international cooperation towards long term monitoring and management measures are urgently required in order to conserve this vulnerable population.

Saros Körfezi'nin (Kuzey Ege Denizi) kıyısal sularında ağ dalyan balıkçılığının av kompozisyonu

Set net (fixed stake trap) fisheries are performed according to traditional methods in the coastal waters of Saros Bay, North Aegean Sea (Turkey). These fisheries systems are the gear which is passively constructed for catching fish in shallow waters with sandy–muddy substrates. We studied the fish species caught by four set nets between April and August (set net fishing season) in 2010 – 2012. In total, 37 fish species belonging to 22 families were captured from the study areas. Clupeidae (45.65%), Carangidae (16.51%) and Sparidae (13.24%) were determined as dominant families, and the total catch amount of dominant species, Sardina pilchardus (27.18%), Sardinella aurita (18.47%) and Trachurus mediterraneus (16.42%), comprised 62.07% of the total catch. Species diversity (H′log2) and evenness (J′) index values calculated for all set nets were 0 – 1.566 and 0 – 0.999, respectively. This study provides some general information about the status of set net fisheries as well as the diversity and abundance of the species caught from the set nets.

A case study in natural coastline of Enez–Kesan districts by using natural threshold analysis

Study area takes place in coastal line of Enez–Kesan districts starting from Dalyan Lake region which was also legally declared as wetland conservation zone of Maritza basin. In this study, nearly 56 km of coastal development in Enez – Kesan, located northern part of Saros Bay, is evaluated according to the ecological threshold analysis. Despite the ecological and socio-cultural importance of the region, transformation of the ecological quality is getting more noticeable. Mapping of Morphological structure are performed from General Directorate of Soil and Water surveys including Slope, Erosion and Land Use Capability Classification data. Furthermore, anthropogenic effects (industrial and residential zones etc.) and natural areas (forestry, wetlands etc.) are determined using SPOT 5 imagery acquired in 2006. The methodology involves covering the study area with grids and potential land evaluation charts. These charts are assessed by “Usage Value Analysis for Supporting Method of Planning” and obtain total usage value of the lands. Adverse effects on natural potential lands depending on current land use at the study zone appraised for strategic environmental assessment. Study is aimed to analyze development dynamics and natural thresholds affected by physical geography in coastal line of Enez – Kesan districts including also wetlands, natural areas. Study indicates proposals according to the landscape assessments. Additionally, legal tools applied on the study area are provided to pose the effects of legal impediments and to establish the question of law.

Age, growth, and reproduction of Dentex maroccanus (Actinopterygii: Perciformes: Sparidae) in the Saros Bay (north Aegean Sea)

In the Mediterranean, sea breams (Sparidae) are represented by 22 species belonging to 10 genera (Arculeo et al. 2003), of which 14 species are also found in the north Aegean Sea (Ismen et al. unpublished**). The Morocco dentex, Dentex maroccanus Valenciennes, 1830, is an important demersal commercial sparid species inhabiting depths ranging from 20 to 500 m and can be found throughout the Mediterranean (absent in the Adriatic), especially in the areas featuring gravel or rubble bottoms. Morocco dentex ecologically prefers deep and highersalinity waters. This species is distributed in the southern and eastern Mediterranean (Maravelias et al. 2007) and the Atlantic (Bay of Biscay to Gulf of Guinea) (Froese and Pauly 2014). The major studies on the Morocco dentex in the Mediterranean have been carried on its western basin and concerned the age, growth, feeding, reproduction, and distribution (Nguyen and Wojciechowski 1972, Mennes 1985, Lamrini and Bouymajjane 2002, Chemmam-Abdelkader et al. 2004, Maravelias et al. 2007). In the Aegean Sea (Saros Bay), a basin of the eastern-central Mediterranean, the sparids represent important components of the demersal fish stock and are generally caught by trawl, long line, and trammel nets. There is currently no information concerning the age, growth, and reproduction of this species or regarding the state of stocks in the Aegean Sea. Aspects concerning to the length–weight relation have been investigated, but these studies did not provide any population relations (Karakulak et al. 2006, Ceyhan et al. 2009). As far as we know, this is the first report that provides a comprehensive picture of population parameters (length–weight relation, age, growth, reproduction, fecundity, first maturity length) of Dentex maroccanus, with the aim of generating sufficient information to improve future stock management and sustainable fishing. ACTA ICHTHYOLOGICA ET PISCATORIA (2014) 44 (4): 295–300 DOI: 10.3750/AIP2014.44.4.03