J Appl Ichthyol. 2018;34:1131–1135. wileyonlinelibrary.com/journal/jai | 1131 © 2018 Blackwell Verlag GmbH 1 | INTRODUCTION Champsodon nudivittis is a common fish species of the Indo‐ West Pacific Ocean (Indonesia, Madagascar, Papua New Guinea, Philippines and Australia: Nemeth, 1994; Yearsley, Last, & Hoese, 2006; Froese & Pauly, 2011). Champsodontids are bottom dwellers in as much as they appear commonly in trawls. It is likely that they perform vertical migrations, shuttling between the seafloor and near‐surface waters. Champsodon nudivittis was reported for the first time in the northeastern Mediterranean Sea on 18 January 2008 (Çicek and Bilecenoglu, 2009), captured by a trawl at 50 m depth. The other records of this exotic species were from the Red Sea and off Ashdod (Goren, Stern, Galil, & Diamant, 2011), Finike Bay (Erguden & Turan, 2011), the Gulf of Antalya (Gökoğlu, Ünlüsayın, Balcı, Özvarol, & Çolak, 2011), off‐shore the western coast of Rhodes Island (Kalogirou & Corsini‐Foka, 2012), Ekincik Bay and Fethiye Bay (Filiz, Akcinar, & Irmak, 2013), between Maden Island and Kucukkuyu, Edremit Bay in March and April 2014 (Torcu Koc, Erdogan, & Sarıgöl, 2015). Nemipterus randalli is also a widespread fish species of the west‐ ern Indian Ocean and can be considered as a Lessepsian migrant. First record of this species in the northeastern Mediterranean Sea was in Iskenderun Bay in July 2007 (Bilecenoglu & Russell, 2008). Further records in Turkish coastal waters were from the Antalya Bay on February 2008 (Gökoğlu, Güven, Balci, Çolak, & Golani, 2009), Iskenderun Bay between November 2007 and October 2008 (Erguden, Turan, Gurlek, Yaglioglu, & Gungor, 2010), north of the Sedir Island in Gokova Bay during September 2011 (Gülşahin & Kara, 2013), and between September 2012 and April 2014 in the Gulf of Antalya (Innal et al., 2015). Both of these migratory species are spreading rapidly. Their oc‐ currence in the Levantine basin of the Mediterranean is now com‐ mon and their abundance much higher than previously reported, thereby attracting the interest of fishermen and scientists. Recent otolith science indicate that otolith specialization in com‐ position can be allocated to certain areas or conditions (annual age, effects of local environments on otolith microstructure, and element chemistry). These influences indicate that otoliths may be used for highly diverse applications. A review on otolith studies before 2005 was presented by Campana (2005); at that time only about 4% of oto‐ lith papers dealt with their chemistry. Some papers feature the ele‐ ment composition of otoliths [e.g., trace element content influenced by Received: 25 November 2017 | Accepted: 16 May 2018 DOI: 10.1111/jai.13761 ORIGINAL ARTICLE Otolith chemistry of Champsodon nudivittis (Ogilby, 1895) and Nemipterus randalli (Russell, 1986) in Iskenderun Bay, Turkey Sevil Demirci 1 | Ayşe Özyılmaz 1 | Abdullah Öksüz 2 | Rafet S. Nadir 3 | Emrah Şimşek 1 1 Department of Marine Technology, Faculty of Marine Science and Technology, Iskenderun Technical University, Iskenderun, Hatay, Turkey 2 Department of Nutrition & Dietetics, Faculty of Health Sciences, Necmettin Erbakan University, Selçuklu, Konya, Turkey 3 Department of Fishing and Fish Processing, Faculty of Aquaculture, Recep Tayyip Erdoğan University, Rize, Turkey Correspondence Sevil Demirci, Faculty of Marine Science and Technology, Iskenderun Technical University, Hatay, Turkey. Email: sevil.demirci@gmail.com Abstract The study objective was to investigate the chemical composition of otoliths of two Lessepsian fish migrants, namely, Champsodon nudivittis and Nemipterus randalli, which thrive in the Iskenderun Bay, Turkey. The study specifically investigated the age structure and explored differences in chemical otolith composition in relation to age. Samples were collected using a traditional Mediterranean bottom trawl (mesh size 44 mm) at depths of 45 to 90 m. A total of 78 Champsodon nudivittis (size range, 6.0 to 14.0 cm) and 60 Nemipterus randalli (size range, 6.1 to 17 cm) were captured in May 2012. Age readings were carried out (sectioning technique). Additionally, the concentrations of Na, K, Li, and Ca were determined using flame photospectrometry. The results revealed that the concentrations of Na (5.70 mg/g) and K (4.45 mg/g) in otoliths of Nemipterus randalli were predominant elements after Ca (128.71 mg/g). The concentration of Li in otoliths was also statistically different in the two species. This study contributes to the knowledge of the otolith chemistry in the two Lessepsian fish species now living in the same (but new) geographical region.