Age, Growth and Otolith Biometry-Body Length Relationships of Red Bandfish (Cepola Macrophthalma L., 1758) in the Sea of Marmara, Turkey

DergiPark: 714201trkjnatThe age, growth, and the otolith biometry-total length relationships of Cepola macrophthalma (Linnaeus, 1758) were investigated. The individuals were caught with beam trawl in the Sea of Marmara from March 2012 to June 2014. The individual with 51.5 cm total length sampled in this study was recorded as the new maximum size of C. macrophthalma in the Marmara Sea. The length-weight relationship showed negative allometric growth with a 1.36 b value. Otolith length-otolith weight, otolith width-otolith weight, otolith length-total length, otolith width-total length, otolith length-otolith width and total length-otolith weight relationships were found as OW=0.0002*OL2.6377 (R2=0.91), OW=0.001*OWi2.6215 (R2=0.94), O=0.057*TL+3.2087 (R2=0.57), OWi=0.0316*TL+1.8511 (R2=0.55), OWi=0.527*OL+0.2015 (R2=0.86), OW=0.0004*TL+0.0029 (R2=0.58), respectively. Ages were estimated from 80 otolith readings and the minimum and maximum ages observed were 1 and 5 years, respectively. The growth parameters of the von Bertalanffy equation were calculated as L?=61.95 cm, K=0.19 year-1, t0 = -0.05 years. A great majority of the stock (77%) consisted of younger individuals (1-2 age groups). Cepola macrophthalma stock consisted of mainly younger individuals which may indicate that an effective fishing pressure is effective on the stock. Cepola macrophthalma (Linnaeus, 1758)’in yaş, büyüme ve otolit biyometri-total boy ilişkileri araştırılmıştır. Bireyler Mart 2012-Haziran 2014 tarihleri arasında Marmara Denizi'nde algarna ile yakalanmıştır. Bu çalışmada örneklenen 51,5 cm'lik C. macrophthalma bireyinin boyu, Marmara Denizi'nde bu tür için maksimum olarak kaydedilmiştir. Boy-ağırlık ilişkisi denklemine göre büyüme tipi negatif allometrik olarak belirlenmiştir (b=1,36). Otolith boyu-otolith ağırlığı, otolith genişliği- otolith ağırlığı, otolith boyu-total boy, otolith genişliği-total boy, otolit boyu-otolit genişliği, total boy-otolit ağırlığı ilişkileri OW=0,0002*OL2,6377 (R2=0,91), OW=0,001*OWi2,6215 (R2=0,94), OL=0,057*TL+3,2087 (R2=0,57), OWi=0,0316*TL+1,8511 (R2=0,55), OWi=0,527*OL+0,2015 (R2=0,86) OW=0,0004*TL+0,0029 (R2=0,58) olarak hesaplanmıştır. Yaşlar 80 adet otolit okumasından hesaplanmıştır; gözlemlenen en küçük ve en büyük yaşlar sırasıyla 1 ve 5’tir. von Bertalanffy denklemine göre hesaplanan büyüme parametreleri değerleri L?=61,95 cm, K=0,19 yıl-1, t0 = -0,05 yıl olarak belirlenmiştir. Stoğun büyük çoğunluğu (%77) genç bireylerden (1-2 yaş grubu) oluşmaktadır. Marmara Denizi’nde C. macrophthalma stoğunun daha çok genç bireylerden oluşması stokların av baskısı altında olduğunu düşündürmektedir.

Karadeniz' in Türkiye kıyılarındaki mezgitin (Merlangius merlangus euxinus) populasyon dinamiği parametreleri üzerine bir ön çalışma

Karadeniz'in Türkiye kıyılarında yayılış gösteren mezgitin (Merlangius merlangus euxinus) yaş-boy verileri kullanılarak bazı populasyon parametreleri tespit edilmiştir. Boyca ortalama yıllık büyüme oranı 3.7 cm olarak bulunmuştur. Maksimum yaş dişiler için IX, erkekler için VI olarak tespit edilmiştir. Mevsimsel salınımlı von Bertalanffy boyca büyüme parametreleri; L„=39.1 cm, K = 0.15, to = -1.05, C=0.23, tj=0.48 olarak saptanmıştır. Erkek ve dişilerin büyüme oranları arasında farklılık olduğu; dişilerin erkeklerden daha hızlı büyüdükleri ve daha büyük maksimum boya ulaştıkları saptanmıştır. Toplam ölüm ve bileşenleri; Z=1.63, M = 0.39 ve F = 1.24 olarak belirlenmiştir. Trolle avlanabilecek en yüksek biyokütle değerinin, Doğu Karadeniz'de trol avcılığına kapalı bölge olan Çaltı Burnu-Sarp arasındaki alanda olduğu bulunmuştur. Trol avlarında en bol bulunan türün mezgit olduğu belirlenmiştir.Some population parameters of the whiting (Merlangius merlangus euxinus) distributed along the Turkish Black Sea coast, were determined by using age-length data. The mean annual growth rate in length was found to be 3.7 cm. The maximum age group was determined as IX for females and VI for males. The seasonalized von Bertalanffy growth parameters in length were estimated to be $L_\infty$=39.1 cm, K = 0.15 $year^-1$, to = -1.53 year, C=0.23, $t_s$=0.48. There was a difference in growth rate between male and female fish. The females grow faster than males and reach a greater maximum length. Total mortality and its components were Z=1.63, M = 0.39 and F = 1.24. The highest trawlable biomass was found in the region between Çaltı Cape and Sarp which is an area closed to trawl fishing in the eastern Black Sea. In the trawl catches, the whiting was the dominant fish

Karadeniz'in Türkiye kıyılarında bir ayrışım fonksiyonu kullanarak Mezgit Merlangius merlangus euxinus stoklarının morfometrik ve meristik ayırımı

Stock differentiation studies of whiting, Merlangius merlangus euxinus, from the Turkish Black Sea coast were carried out using morphometric and meristic characters and applying the generalised distance of Mahalanobis. Fifteen morphometric measurements, together with eleven meristic characters, were used in the analyses. Insufficient differences (P>0.01) in general phenotypic and genotypic characteristics implied the existence of a single unit stock. Samples taken in different periods showed lower similarity than those taken in the same periods.Stock differentiation studies of whiting, Merlangius merlangus euxinus, from the Turkish Black Sea coast were carried out using morphometric and meristic characters and applying the generalised distance of Mahalanobis. Fifteen morphometric measurements, together with eleven meristic characters, were used in the analyses. Insufficient differences (P>0.01) in general phenotypic and genotypic characteristics implied the existence of a single unit stock. Samples taken in different periods showed lower similarity than those taken in the same periods

The Biology and population parameters of the whiting (Merlangius merlangus euxinus Nordmann) in the Turkish Coast of the Black Sea

Ph.D. - Doctoral Progra

Population Structure of the Tub Gurnard (Chelidonichthys lucerna Linnaeus, 1758) in Türkiye Coasts Using Otolith Chemistry and Shape Analysis

Chelidonichthys lucerna is an economically important demersal species. It is under excessive fishing pressure and yields from fisheries are in decline in Türkiye. Information about the species' population structure and habitat connections is limited. In this study, otolith chemistry and shape analyses of 160 individuals captured between February 2020 and December 2020, in the four main fishing grounds of Türkiye coasts (Black Sea/Ordu, Marmara Sea/Bandırma, Aegean Sea/Foça, Mediterranean Sea/Mersin) were investigated. Otolith morphology and chemistry (Li:Ca, Na:Ca, Mg:Ca, Mn:Ca, Fe:Ca, Co:Ca, Ni:Ca, Cu:Ca, Zn:Ca, Sr:Ca, Ba:Ca , Pb:Ca, K:Ca, P:Ca) of the individuals with similar length range (19-25 cm, TL) were evaluated by univariate and multivariate statistical analyses. The overall combination of otolith elemental chemistry and morphology techniques revealed the highest re-classification success (75%-90%) of samples to their original location and the existence of significant differences among sampling regions. When otolith shape analysis and otolith chemistry were evaluated together, linear discrimination function analyses fully discriminated C. lucerna individuals from the four sampling regions (Black Sea, Marmara, Aegean, Mediterranean). Moreover, the results of the analyses revealed that there were habitat connections among individuals from the Sea of Marmara and Aegean Sea and that the Black Sea and the Mediterranean Sea were isolated regions in terms of C. lucerna stocks. The shape and chemical signatures suggest that C. lucerna is apparently not a single stock-unit in the Turkish coasts and that these fish stocks should be managed separately for fisheries purposes

A study on plastic materials accumulation in the south-eastern Iskendurun Bay

Bu çalışmada, Temmuz 1999-Haziran 2000 tarihleri arasında İskenderun Körfezi'nin güney-doğu kıyılarında trol çekimi yapılarak kaynaklarına göre plastik materyal birikimi araştırılmıştır. 0-50 m derinlik aralığında plastik materyalin aylık dağılımı tanımlanmış ve toplam kütle alan tarama metodu kullanarak hesaplanmıştır.A study on plastic materials accumulation in the the south-eastern iskenderun Bay. In this study, between 1999 July and 2000 June along the south-eastern iskenderun Bay, plastic materials accumulation in relation to their sources were determined by trawling. The distribution of plastic materials in the region down to a depth of 50 was described and total masses calculated applying the swept area method