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Öğe Age, Growth and Reproduction of the Thornback ray, Raja clavata (Linnaeus, 1758) in the Waters Off Gökçeada (the Northern Aegean Sea)(Springer Science and Business Media Deutschland GmbH, 2023) Yığın, Cahide Çiğdem; Cabbar, Koray; İşmen, Ali; Daban, İsmail Burak; Arslan İhsanoğlu, MukadderIn this study, the age, growth, maturity, and reproductive biology parameters of 262 Raja clavata, which were collected monthly from commercial trawlers off Gökçeada between February 2019 and February 2020, were estimated. The individuals comprise of 55.7% females and 44.3% males. The length of the females ranged between 23-84.2 cm (Disc width: 13.5-55.8 cm) and 11.2-74 cm (Disc width: 8-48.9 cm) for males. For age determination, age readings were performed on the vertebrae of 255 Raja clavata specimens (43.5% female, 56.4% male). The calculated von Bertalanffy growth parameters were estimated to be L∞= 93.04 cm, K=0.17 years-1, to=0.48 years for males, and L∞=102.46 cm, K=0.16 years-1, t0 =0.72 years for females. The minimum and maximum ages of the thornback rays ranged from 1 to 10 years. The first sexual maturity length of the population was measured to be L50 =57.7 cm in males, and L50 =66.1 cm in females.Öğe Analysis of Demersal Fish Fauna off the Sea of Marmara, Turkey(Çanakkale Onsekiz Mart Üniversitesi, 2021) Daban, İsmail Burak; İşmen, Ali; Şirin, Murat; Yığın, Cahide Çiğdem; Arslan İhsanoğlu, MukadderDemersal fish fauna of the Sea of Marmara, Turkey was determined by bottom trawl surveys between March 2017-December 2018 at 34 stations with the monthly samplings. During the study, a total of 61 teleost and 12 cartilaginous fish species belonging to 42 families were sampled. The target, bycatch and discard rates of CPUE were determined as 13.40%, 69.64% and 16.95%, respectively. In total, 53.9% of the CPUE was stemmed from Trachurus trachurus. Mustelus mustelus, Raja clavata, Merluccius merluccius and Merlangius merlangius had the highest CPUE with a mean of 77.63, 71.86, 71.72 and 72.68 kg/km2, respectively. The highest biodiversity was observed in the southwestern part of the Marmara Sea. With increasing depth, the species number of the teleost fish decreased, whereas the species number of the cartilaginous fish increased. The mean CPUE values of the economical demersal fish species were lower in comparison to those reported from other regions in Turkey. Evidence suggests fish stocks with shallower distribution is under heavier threat against fishing pressure. Since commercial trawling is banned in the Sea of Marmara, beam trawl fishery can be considered as the major threat to demersal fish stocks in the region.Öğe Çardak Lagün’ü Balıkçılığının Genel Durumunun Değerlendirilmesi(Mersin University Mersin Üniversitesi, 2025) İşcan, Samet; Daban, İsmail Burak; Şen, Yusuf; Öztekin, Alkan; Arslan İhsanoğlu, Mukadder; Acar, Seçil; İşmen, AliÇardak lagünü ve çevresindeki balıkçılık faaliyetlerinin genel durumunun değerlendirmesi ve lagünün ticari av kompozisyonu hakkında bilgi sahibi olmak için, lagün içi ve yakın çevresinde balıkçılık faaliyetleri ger-çekleştiren balıkçılar ile Mayıs 2024 ile Mayıs 2025 tarihleri arasında anket yöntemiyle araştırma gerçekleşti-rilmiştir. Ruhsatlı ve ruhsatsız 23 tekne sahibi ve 2 amatör balıkçı ile yüz yüze gerçekleştirilen görüşmeler so-nucunda oluşturulan anketlerde, balıkçıların sosyoekonomik yapısı ve av gücü ile lagünün ticari av kompo-zisyonu ve yönetimsel sorunlar değerlendirilmiştir. Balıkçıların sosyo-ekonomik açıdan %80’nin evli olduğu, yaşlarının ortalamasının 53,7 ± 2,3 (32 ile 81 yaş arası) olduğu, %52’sinin ortaokul mezunu olduğu, %72’sinin sosyal güvencesinin bulunduğu, tekne sahiplerinden %65’inin ek gelir için farklı işlerde çalıştığı, %70’inin 20 yıldan fazla balıkçılık tecrübesine sahip olduğu ve %74’ünün 2 çocuk sahibi olduğu belirlenmiş-tir.Av gücü değerlendirildiğinde, balıkçıların sahip oldukları teknelerin %74’ünün 6,9 m ve daha küçük boyda, %61’inin 15 hp motor gücünden düşük güçte ve %60,8’inin 20 yaşından büyük olduğu tespit edilmiş-tir. Balıkçıların %73,9’unun tayfa çalıştırmadığı, %52,2’sinin sadece uzatma ağları ile avlandığı, %47,8’inin 12 ay balıkçılık yaptığı ve %65’inin lagün dışında avlandığı belirlenmiştir. Ticari av kompozisyonu değerlen-dirildiğinde 13 farklı kemikli ve 3 farklı kıkırdaklı balık türünün lagün içerisinde bulunduğu ve yıllık ortalama kişi başı av miktarının 250 kg’dan az olduğu, en fazla yakalanan türlerin kefal türleri (Mugilidae spp.), levrek (Dicentrarchus labrax) ve lüfer (Pomatomus saltatrix) olduğu belirlenmiştir. Son 10 yılda lagün içerisindeki bolluğu azalan ve/veya tamamen yok olan türlerin durumu sorulduğunda, balıkçılar kefal türleri, kalkan (Scophthalmus maximus), uskumru (Scomber scombrus), levrek ve lüfer gibi türlerin bolluğunda ciddi azal-malar olduğunu ifade etmişlerdir. Yönetimsel sorunlar değerlendirildiğinde, lagün içi av baskısının azaltılması açısından dönem içi belirli bir aralıkta kapalı sezon uygulanmasının faydalı olacağı, balıkçılar tarafından bil-dirilmiştir. Lagünde sığlaşmanın ve bataklık alanların en büyük sorunlarından olduğu ve lagün içerisinde ya-sadışı balıkçılık faaliyetlerinin de görüldüğü bildirilmiştir. Sonuç olarak, balıkçıların beyanlarına göre aşırı av-cılık, kirlilik, sığlaşma gibi olumsuz etkenlerin Çardak Lagünü balıkçılığını olumsuz etkilediği anlaşılmaktadır. Mevcut sorunların daha iyi anlaşılabilmesi için bilimsel örneklemelere dayalı tespitlerin gerçekleştirilmesi, çö-züm önerilerinin geliştirilmesi için ise balıkçıların da paydaş olarak katılacağı kurumlar arası işbirliklerinin hayata geçirilmesi önerilmektedir.Öğe Length-Weight and Otolith Morphometry Relationships of Hoplostethus mediterraneus Cuvier, 1829 from the Saros Bay, Northern Aegean Sea(Springer Int Publ Ag, 2025) İşmen, Ali; Yığın, Cahide Ciğdem; Öz, Melike İdil; Arslan İhsanoğlu, MukadderThe relationship between total length (TL) and total weight (TW) and the morphometric relationships of the otolith between total length and otolith length (OL), total length and otolith weight (OW) and otolith length and otolith weight of Hoplostethus mediterraneus were examined in Saros Bay, North Aegean Sea, T & uuml;rkiye. The samples were collected with commercial trawls in Saros Bay from September 2006 to September 2008. A total of 970 specimens were caught at depths of 100-500 m. The average value of fish length was 11.86 +/- 0.14 cm (4.0-22.1 cm), and weight 32.2 +/- 1.0 g (0.83-148.75 g). Otolith size was measured with a minimum of 4.31 mm and a maximum of 12.88 mm. The relationships between TL and TW, OW and OL, OL and TL, OW and TL and OW and OL were determined as TW = 0.010*TL3.10 (r2 = 0.99), OW = 0.0004*OL2.64 (r2 = 0.99), OL = 0.055*TL + 0.564 (r2 = 0.98), OW = 0.0002*TL2.38 (r2 = 0.98), and OW = 0.0004*OL2.64 (r2 = 0.99). The high correlation coefficients (r(2) values) demonstrate the reliability of the established equations, offering a robust framework for estimating the size and weight of this species based on otolith measurements. This study provides crucial insights into the growth patterns and morphometric relationships of Hoplostethus mediterraneus, which can be used to enhance fishery management and conservation efforts in Saros Bay.Öğe Marmara denizi'nde parapenaeus longirostris (Lucas, 1846)'in populasyon yapısı, bolluk ve av oranlarının zamansal-alansal değişimleri(Çanakkale Onsekiz Mart Üniversitesi, Lisansüstü Eğitim Enstitüsü, 2017) Arslan İhsanoğlu, Mukadder; İşmen, AliIn this study, temporal and spatial changes of catch per unit effort (CPUE-kg/h), stock amount (biomass-kg/km2), population structure of Parapenaeus longirostris, and current situation of the stocks, effects of beam trawl were determined in the Sea of Marmara. Samples were obtained by beam trawls monthly between October 2011-July 2014 and population parameters; size distributions, length-weight relationships, condition factor, growth-mortality parameters and sex rates were determined. The catch per unit effort value (CPUE) and abundance index of deep water pink shrimp were found 8,5 kg/h and 1545 N/h in the Sea of Marmara. The highest CPUE values were estimated region 2 (10,1 kg/h) and region 6 (15,1 kg/h). The lowest value was in region 5 (3,4 kg/h). According to depth contours, catch per unit effort values were determined as 8.8 kg/h in 50-100 m, 7 kg/h in ≥100 m. Biomass of the species was found 354 kg/km2 in the Sea of Marmara. The maximum value of biomass were in Tekirdag and Silivri and the lowest value was in the Yalova. 36288 individuals were measured, total length (TL), carapace length (CL) and weight (g) values were found as 34-175 mm (107 mm), 8-41 mm (22.6 mm), 0,2-28,9g (6,1g), respectively. Carapace length-weight relationship was calculated as W=0.0022*CL2.52. Growth parameters were determined as L∞=199,5 mm, k=0,47, t0=-0,5 in total length, L∞=36,8 mm, k=0,37, t0=-0.69 y in carapace length. Total mortality, natural mortality, fishing mortality and exploitation rates were found 1,60, 0,61, 0,99 and 0,62, respectively. Male-female ratio was found as 1:1,3.Öğe Population Structure, Age, Growth and Reproduction Biology of Piper Gurnard, Trigla lyra (Linnaeus, 1758) in the Sea of Marmara, Turkey(Springer Int Publ Ag, 2024) Şirin, Murat; Daban, İsmail Burak; Arslan İhsanoğlu, Mukadder; İşmen, Ali; Yığın, Cahide ÇiğdemThis study describes the biomass, age, growth, mortality and reproduction biology of piper gurnard, Trigla lyra. Individuals were obtained with monthly trawl surveys between March 2017 and December 2018 from 34 stations located in the Sea of Marmara, Turkey. Mean Catch per unit effort (CPUE-kg/h) and stock amounts (biomass kg/km(2)) were calculated as 0,62 kg/h and 8,54 kg/km(2), respectively. The age interval was determined as between I and VIII. Von Bertalanffy growth parameters were determined as L infinity = 59.92 cm, K = 0.21 per year and t0 = -0.36 for females and L infinity = 78.53 cm, K = 0.13 per year and t0 = -0.41 for males. The total mortality (Z) was determined as 0.55 t(-1). The natural mortality (M) and fishing mortality (F) were estimated as 0.36 t(-1) and 0.19 t(-1). The exploitation rate was determined as 0.35 t(-1). The length at first maturity (L50) was calculated as 32.7 cm TL for females and 25.2 cm TL for males. The spawning period of T.lyra was determined between December and April and peaked in March.Öğe Reproductive Biology of Bogue, Boops boops Linneaus, 1758 in the Aegean Sea and Sea of Marmara, Türkiye(Istanbul Univ Press, 2025) Şen, Yusuf; Daban, İsmail Burak; Arslan İhsanoğlu, Mukadder; Ayaz, Oğuzhan; Özekinci, UğurBogue (Boops boops Linnaeus, 1758) is one of the most economic and common species in Türkiye. The bogue individuals were obtained monthly from the commercial catches of gillnet fisheries from May to August 2024 and purse seine fisheries from September 2024 to April 2024 around the Northern Aegean Sea and Southwest Sea of Marmara, Türkiye. The 378 total individuals consisted of 176 females, 201 males and 1 unspecified in the Aegean Sea. The 370 total individuals consisted of 214 females, 154 males and 2 individuals unspecified in the Sea of Marmara. The female:male ratio was calculated as 0.9:1.0 in the Aegean Sea and 1.4:1.0 in the Sea of Marmara. The total length and weight of individuals varied from 10.6 to 28.6 cm (17.52±0.15) and 8.1 to 236.86 g (54.20±2.43) in the Aegean Sea, respectively, and the total length was 10.8 to 28.5 cm (17.92±0.18) and the weight was 13.08 to 399.88 g (76.54±3.14) in the Sea of Marmara. The positive allometric growth was found for females, males and all sexes in both seas. The first maturity length was determined as 12.2 cm TL for females, 15.8 cm TL for males in the Aegean Sea, whereas it was 12.8 cm TL for females, 15.1 cm TL for males in the Sea of Marmara. The reproductive period is estimated between January and May in the Aegean Sea, while February to May in the Sea of Marmara. The total fecundity varied between 2770-85112 (mean:20021±2027) in the Sea of Marmara, while it was 2740-309457 (mean:42834±9194) in the Aegean Sea. As results of this study, some differences were determined in sex ratio, spawning period, and fecundity from the reproductive characteristics between the Sea of Marmara and Aegean Sea. Due to the limited scientific data on the reproductive biology of B.boops in Türkiye, the results of the present study should contribute to the strategic assessment, management, and sustainability of B.boops.Öğe Reproductive biology of Penaeus kerathurus (Forskal, 1775) (Decapoda: Penaeidae) in the Sea of Marmara, Turkey(De Gruyter Open Ltd, 2021) Arslan İhsanoğlu, Mukadder; Daban, İsmail Burak; İşmen, Ali; Cabbar, Koray; Yığın, Cahide ÇiǧdemOne of the economically important species is Penaeus kerathurus (Forskål, 1755), which is widespread in the Mediterranean ecosystem. This paper presents results of research on reproductive biology of Penaeus kerathurus in the Sea of Marmara. A total of 1404 specimens were dissected to determine the maturity stages, reproduction time, and length at first reproduction. The female-to-male ratio was 1:0.9. A high percentage of mature females was determined in April, May and July. Moreover, the value of the gonadosomatic index (GSI) decreased after July. The spawning period was observed between April and July, and its intensity increased in July. The carapace length at first sexual maturity was determined to be 39 mm.Öğe Some biological aspects of White seabream, Diplodus sargus (Linnaeus, 1758) from the northeastern Aegean Sea, Turkiye(Ege Univ, Fac Fisheries, 2024) Daban, İsmail Burak; İşmen, Ali; Arslan İhsanoğlu, Mukadder; Daban, İsmail BurakIn the study, the age, growth, mortality parameters and length-weight relationship parameters of Diplodus sargus (white seabream) collected by a small-scale fisherman between August 2020 and July 2021 along the northeastern coast of Aegean Sea (Turkiye coast), were investigated. D. sargus had a range of total length and weight from 14.3 cm to 36.7 cm and from 50.5 g to 836.5 g, respectively. The length-weight relationships (LWRs) were calculated as W=0.02368*L-2.881 for females, W = 0.01847*L-2.959 for males and W = 0.01989*TL2.936 for both sexes. Using data from fish scales, the maximum age was determined to be 11 years. von Bertalanffy growth parameters have been calculated as follows L-infinity=39.01 cm TL, K=0.13 year(-1), and t(0)= -2.58 year for both sexes combined. Total (T), natural (N) and fishing (F) mortalities were defined as Z: 0.83 year-1, M: 0.33 year(-1) and F: 0.50 year(-1) for both sexes combined. The exploitation rate (E) was calculated as 0.70, 0.44 and 0.60 for females, males and combined, respectively.
