Age and growth of the common guitarfish (Rhinobatos rhinobatos) were estimated from the north-eastern Mediterranean coast of Turkey. A total of 115 common guitarfish (66 females and 49 males) were sampled. Age determinations were carried out using vertebral sections. Alcian blue dying techniques were used to enhance the visibility of the band on vertebrae. The techniques have been used for the first time on elasmobranchs vertebrae successfully in this study. A total of 97 vertebrae of 115 were visible on the vertebral band in this study. Male and female common guitarfish ranged in age from 1 to 15 and 1 to 24 y respectively. Total length ranged from 42 to 147 cm for females and 39 to 124 cm for males.The relationships between total length (TL) and total weight (TW) were presented as TW ¼ 0.0014*TL 3.1672 (R 2 ¼ 0.98) for females, TW ¼ 0.0012*TL 3.1947 (R 2 ¼ 0.98) for males and TW ¼ 0.0012*TL 3.1915 (R 2 ¼ 0.98) for both sexes. The parameters for von Bertalanffy growth curves were estimated as L inf ¼ 137.70 + 9.38 cm, K ¼ 0.159 + 0.047, to ¼ 2 2.180 + 0.90 for pooled data.

Summary Presented are length–weight relationships for Rhinobatos rhinobatos, Rhinobatos cemiculus, Gymnura altevela, Dasyatis pastinaca, Rhinoptera marginata, Pteromylaeus bovinus, Torpedo nobiliana, Raja miraletus and Raja clavata captured by gillnet, longline and bottom trawl fishing between May 2010 and July 2011 off the east coast of Iskenderun Bay, Turkey.

In this third Collective Article, with fisheries-related data from the Mediterranean Sea, we present the historical length distribution of Lophius budegassa in the catch of commercial trawlers in the Greek seas; length-weight and length-length relationships of five flatfish species (Lepidorhombus boscii, L. whiffiagonis, Platichthys flesus, Pegusa lascaris and Solea solea) from different coastal areas of Turkey (Black Sea and Eastern Mediterranean Sea); growth of settled Polyprion americanus and length-weight relationships of this species and of Deltentosteus quadrimaculatus, Capros aper and three commercially important groupers in the Eastern Mediterranean Sea; the age, growth and mortality of Zosterisessor ophiocephalus in the Eastern Adriatic Sea; the length-weight relationship and condition factor of Atherina boyeri in a Central Mediterranean semi-isolated lagoon, and also the length-weight and length-length relationships of three Alburnus species from different inland waters in Turkey.

This study describes the length-weight relationship (LWR) for Serranus hepatus from Iskenderun Bay, Northeastern Mediterranean, Turkey. A total of 202 individuals were caught from Iskenderun Bay, during the 2015-2016 fishing season. The total length ranged from 5.7-9.5 cm and body weight 2.23-12.19 g. Length-weight relationship was found as the W = 0.0172L 2.9664 (R 2 =0.84, F1,200=21.221, P < 0.001) and SEb= 0.091 (t-test: 32.706 p < 0.01). The types of growth were found isometric growth for all indivuduals of S. hepatus.

In this study, six chondrichthyan species (Raja clavata, Raja miraletus, Raja asterias, Torpedo marmorata, Rhinobatos rhinobatos and Gymnura altavela) were captured for age determination in Iskenderun Bay (North eastern Mediterranean Sea) between May 2010 and January 2012. Age was determined from vertebral sectioned, using four staining techniques, namely Crystal Violet, Silver Nitrate, Safranin O and Alcian Blue. The results from these four techniques were compared to each other, with respect to visibility success on growth rings. Of all four staining techniques, Silver Nitrate staining provided the best optical resolution for growth rings of R. clavata, R. miraletus and R. rhinobatos. For, R. asterias, T. marmorata and G. altavela, however, it provided a lower optical resolution. In fact, four staining technique was also efficient for R. clavata. The most efficient staining techniques were Safranin O in T. marmorata and Alcian Blue in R. rhinobatos. The order of average readability scores for staining techniques was as follows: Silver Nitrate = Safranin O > Crystal Violet = Alcian Blue. A standardized staining methodology that can be used for all species studied, however, has not been achieved.Keywords: Age determination, Cartilaginous Fish, Crystal Violet, Silver Nitrate, Alcian Blue, Safranin O. Keywords: Bazı Kıkırdaklı Balık Türlerinde Yaş Tayininde Kullanılan Boyama Yöntemlerinin Karşılaştırılması ÖzetBu çalışmada altı kıkırdaklı balık türü (Raja clavata, Raja miraletus, Raja asterias, Torpedo marmorata, Rhinobatos rhinobatos and Gymnura altavela) yaş tayini amacıyla Mayıs 2010 -Ocak 2012 tarihleri arasında İskenderun Körfezi'nde yakalanmıştır. Yaş tayini Kristal Viyole, Gümüş Nitrat, Safranin O ve Alsian Mavisi boyama yöntemleri kullanılarak omur kesitlerinden yapılmıştır. Bu dört teknik büyüme halkalarındaki görünürlülük başarısı açısından birbirleriyle karşılaştırılmıştır. Bu dört boyama tekniğinden gümüş nitrat, R. clavata, R. miraletus ve R. rhinobatos türlerinin büyüme halkaları için en iyi görüntü çözünürlüğünü sağlamıştır. R. asterias, T. marmorata ve G. altavela türleri için ise daha düşük görüntü çözünürlüğü vermiştir. Aslında, R. clavata için dört boyama tekniği de etkili olmuştur. R. rhinobatos omurlarındaki büyüme halkalarını belirgenleştirmek için en etkili boyama tekniği Alsian Mavisi ve T. marmorata için ise Safranin O olmuştur. Boyama teknikleri için ortalama okunabilirlik puanları sırası: Gümüş Nitrat = Safranin O > Kristal Viyole = Alsian Mavisi. Bununla birlikte, türlerin hepsinde kullanılabilecek standart bir boyama tekniği bulunamamıştır.