Chondrichthyan species as by-catch: A review on species inhabiting Turkish waters

Elizabeth Grace Tunka Bengil, Nuri Başusta

Marine School, Girne American University, University Drive, Karmi Campus, Karaoglanoglu, Girne, TRNC, TURKEY
Akdeniz Koruma Derneği, Doga Kent Villaları, 3360 sokak, No.7/16, Urla, Izmir, TURKEY
Fisheries Faculty, Firat University, 23119, Elazig, TURKEY


Chondrichthyan or cartilaginous species, throughout the world, are found among fisheries by-catch. In this study, 52 studies conducted between 1991 and 2018 in Turkish waters were reviewed to assess the status of chondrichthyan species as by-catch. Geographic coverage was grouped as; Black Sea (the number of studies 5), Sea of Marmara (6), Aegean Sea (25), and Levantine Sea (16). Results showed that there were differences in by-catch amounts when sharks, rays and chimaeras were compared according to geographical grouping. When by-catch ratios of listed species were analyzed it showed that almost half of the by-catch was comprised of small spotted catshark, Scyliorhinus canicula (Linnaeus, 1758), followed by blackmouth catshark, Galeus melastomus Rafinesque, 1810. In case of rays, the most common species of by-catch was thornback ray, Raja clavata Linnaeus, 1758, followed by common stingray, Dasyatis pastinaca (Linnaeus, 1758). Among all reported species concerned, 9 were Critically Endangered, 8 Endangered, 7 Vulnerable, 13 Near Threatened, 8 Least concern, 9 were Data Deficient, according to IUCN Red List, corresponding to half of the Turkish cartilaginous fauna. This review aims to provide on the by-catch of cartilaginous species caused by scientific or commercial fisheries activities in the Turkish waters emphasizing on long-needed conservation action plans for future sustainability of these cartilaginous species.

Keywords: Chondrichthyan species, by-catch, Turkish waters, threatened species

pdf-dl icon


Acarlı, D., Ayaz, A. (2015) Using concrete artificial reef as a tool to enrich the new marine habitat in Erdek-Ocaklar Bay (Marmara Sea, Turkey). Fresenius Envir Bull 24(2): 602-609.

Akyol, O., Aydın, I., El Kamel Moutalibi, O., Capapé, C. (2017) Bull ray, Aetomylaeus bovinus (Geoffroy Saint‐Hilaire, 1817) (Myliobatidae) in the Mediterranean Sea and captures of juveniles from Izmir Bay (Aegean Sea, Turkey). J Appl Ichthyol 33(6): 1200-1203.

Akyol, O., Capapé, C. (2014) Distribution of blackchin guitarfish Rhinobatos cemiculus E. Geoffroy Saint-Hilaire, 1817 (Elasmobranchii: Rhinobatidae) with first records from İzmir Bay (Turkey, northeastern Aegean Sea). Turk J Zool 38: 460-465.

Akyol, O., Ceyhan, T., Erdem, M. (2012) Turkish pelagic gillnet fishery for swordfish and incidental catches in the Aegean Sea. J. Black Sea/Mediterr Environ 18(2): 188-196

Amandè, M.J., Ariz J., Chassot E, Delgado de Molina, A., Gaertner, D., Murua, H., Pianet, R., Ruiz, J., Chavance, P. (2010) By-catch of the European purse seine tuna fishery in the Atlantic Ocean for the 2003-2007 period. Aquat Living Resour 23: 353-362.

Avsar, D. (2001) Age, growth, reproduction and feeding of the spurdog (Squalus acanthias Linnaeus, 1758) in the South-eastern Black Sea. Estuar Coast Shelf Sci 52(2): 269-278.

Başusta, N. (1997) Pelagic and Demersal Fish Species Inhabiting Iskenderun Bay. Doctorate Thesis. Institute of Science, Çukurova University (in Turkish).

Başusta, N. (2002) Occurrence of a sawback angelshark (Squatina aculeata Cuvier, 1829) off the Eastern Mediterranean coast of Turkey. Turk J Vet Anim Sci 26: 1177-1179.

Başusta, N. (2016a) Length-weight relationship of sandbar shark Carcharhinus plumbeus (Nardo, 1827) in Iskenderun Bay (North-Eastern Mediterranean Sea).  Rapp Comm int Mer Medit 41: 318.

Başusta, N. (2016b) New records of neonate and juvenile sharks (Heptranchias perlo, Squatina aculeata, Etmopterus spinax) from the north-eastern Mediterranean Sea. Mar Biodivers 46 (2): 525-527.

Başusta, N., Başusta, A. (2015). Additional record of the bluntnose six-gill shark, Hexanchus griseus (Bonnaterre, 1788) from Iskenderun Bay with its morphometric measurements. J Black Sea/Mediterr Environ 21(2): 224-226.

Başusta, N., Demirhan, S. A., Karalar, M., Cekic, M. (2007) Diet of common guitarfish (Rhinobatos rhinobatos l., 1758) in the Iskenderun Bay (northeastern Mediterranean). Rapp Comm int Mer Médit 38: 426.

Başusta, N., Erdem U., Kumlu M. (1998) Two new fısh records for the Turkish seas: round stingray Taenıura grabata and skate stingray Himantura uarnak (Dasyatidae). Isr J Zool 44(1): 65-66.

Başusta, N., Özbek, E. Ö. (2017) New record of giant devil ray, Mobular mobular (Bonnaterre, 1788) from the Gulf of Antalya (Eastern Mediterranean Sea). J Black Sea/Mediterr Environ 23(2): 162-169.

Bayhan, Y. K., Ergüden, D., Cartes, J. E. (2018) Deep sea fisheries in Mersin Bay, Turkey, Eastern Mediterranean: diversity and abundance of shrimps and benthic fish fauna. Acta Zool Bulg 70(2): 259-268.

Bengil, E. G. T. (2018) Genetic Features of Some Cartilaginous Species Inhabiting Aegean and Mediterranean Sea and Bio-ecological Features of Glaucostegus cemiculus (Geoffroy Saint-Hilaire, 1817). Ege University, Institute of Science, PhD Thesis (in Turkish).

Bengil, F., Bengil, E. G., Mavruk, S., Heral, O., Karaman, O. D., Ozaydin, O. (2018) Feeding ecology of four demersal shark species (Etmopterus spinax, Galeus melastomus, Scyliorhinus canicula and Squalus blainville) from the Eastern Aegean Sea. Turk J Fish And Aquat Sci 19(6). doi: 10.4194/1303-2712-v19_6_03

Bilecenoğlu, M. (2008) Conservation and Monitoring Project of Sandbar Sharks (Carcharhinus plumbeus) in Boncuk Bay, Gökova Special Environmental Protection Area. Environmental Protection Agency for Special Areas, Republic of Turkey Ministry of Environment and Forestry, Ankara, 32 pp.

Bilge, G., Filiz, H., Tarkan, A. N. (2010) Length-weight relationship of velvet belly lantern shark Etmopterus spinax (Linnaeus, 1758) in Sigacik Bay (Aegean Sea). Turk J Fish and Aquat Sci 25(1): 1-8 (in Turkish).

Bök, D.T., Göktürk, D., Kahraman, A. E., Alılçı, T. Z., Acun, T., Ateş, C. (2011) Length-weight relationships of 34 fish species from the Sea of Marmara, Turkey. J Anim Vet Adv 10 (23): 3037-3042.

Camhi, M.D., Fowler, S.L., Musick, J.A., Bräutigam, A., Fordham, S.V. (1998) Sharks and Their Relatives: Ecology and Conservation. IUCN/SSC Shark Specialist Group, Gland, Switzerland and Cambridge, UK.

Ceyhan, T., Hepkafadar, O., Tosunoglu, Z. (2010) Catch and size selectivity of small-scale fishing gear for the smooth-hound shark Mustelus mustelus (Linnaeus, 1758) (Chondrichthyes: Triakidae) from the Aegean Turkish coast. Mediterr Mar Sci 11(2): 213-224.

Damalas, D., Vassilopoulou, V. (2011) Chondrichthyan by-catch and discards in the demersal trawl fishery of the Central Aegean Sea (Eastern Mediterranean). Fish Res 108: 142-52.

Demirhan, S. A., Can, M. F. (2007) Length–weight relationships for seven fish species from the southeastern Black Sea. J Appl Ichthyol 23(3): 282-283.

Demirhan, S. A., Engin, S., Seyhan, K., Akamca, E. (2005) Some biological aspects of thornback ray (Raja clavata L., 1758) in the southeastern Black Sea. Turk J Fish and Aquat Sci 5(2): 75-83.

Dereli, H., Tosunoğlu, Z., Göncüoğlu, H., Ünal, V. (2015) Catch per unit effort (CPUE) and catch composition of small-scale fisheries in Gökova Bay. Ege J Fish Aqua Sci 32(3): 135-143.

Dulvy, N.K., Allen, D.J., Ralph, G.M., Walls, R.H.L. (2016) The Conservation Status of Sharks, Rays and Chimaeras in the Mediterranean Sea [Brochure]. IUCN, Malaga, Spain.

Eronat, E.G.T. (2012) Determination of Dietary Features of Chondrichthyes (Cartilaginous Fishes) Species from Central Aegean Sea. Ege University, Institute of Science, Master Thesis (in Turkish).

Eronat, E.G.T., Bizsel, K.C. (2015) Diversity in Fish Fauna of Turkish Seas. DEVOTES-EUROMARINE Summer School “Marine ecosystem services, management and governance: linking social and ecological research” 9-11 June 2015 – Aquarium of Donostia- San Sebastián, Spain.

Eronat, E.G.T., Özaydın, O. (2014) Length-weight relationship of cartilaginous fish species from Central Aegean Sea (Izmir Bay and Sığacık Bay) Ege J Fish Aqua Sci 31(3): 119-125.

Eryilmaz, L. (2003) A study on the fishes of Bozcaada Island (North Aegean Sea). J Black Sea/Mediterr Environ 9(2): 121-137.

Ferretti, F., Morey, G, Serena, F., Mancusi, C., Fowler, S.L., Dipper, F., Ellis, J. (2015) Squatina squatina. The IUCN Red List of Threatened Species 2015: e. T39332A48933059. doi: 10.2305/IUCN.UK.20151.RLTS.T39332A48933059.en. (accessed 12 April 2017).

Filiz, H. (2009) Diet composition of smooth-hound, Mustelus mustelus (Linnaeus, 1758), in Aegean Sea, Turkey. Belg J Zool 139(1): 81-84.

Filiz, H., Bilge, G. (2004) Length–weight relationships of 24 fish species from the North Aegean Sea, Turkey. J Appl Ichthyol 20(5): 431-432.

Filiz, H., Irmak, E., Mater, S. (2005) Occurence of Squatina aculeata Cuvier, 1829 (Elasmobranchii, Squatinidae) from the Aegean Sea, Turkey. Ege J Fish Aqua Sci 22(3-4): 451-452.

Filiz, H., Mater, S. (2002) A preliminary study on length-weight relationships for seven elasmobranch species from North Aegean Sea, Turkey. Ege J Fish Aqua Sci 19(3-4): 401-409.

Filiz, H., Togulga, M. (2002) Commercial elasmobranch species in Turkey’s waters, their Fisheries and Management. İn: Proceedings of IV. National Conference on Turkey’s Coastal and Marine Areas 2: 5-8 (in Turkish).

Guven, O., Kebapcioglu, T., Deval, M.C. (2012) Length-weight relationships of sharks in Antalya Bay, eastern Mediterranean. J Appl Ichthyol 28: 278-279.

Hepkafadar, O. (2008) Research on Fishery and Some Biological Aspects of Smooth-Hound Shark (Mustelus mustelus L., 1758) in Izmir bay. PhD Thesis. Ege Üniversity (in Turkish).

Huse, I., Lokkeborg, S., Soldal, A.V. (2000) Relative selectivity in trawl, longline and gillnet fisheries for cod and haddock. ICES J Mar Sci 57: 1271-1782.

Irtem, E., Kabdasli, S., Azbar, N. (2005) Coastal zone problems and environmental strategies to be implemented at Edremit Bay, Turkey. J Environ Manage 36(1): 37-47.

Ismen, A., Cigdem Yigin, C., Altinagac, U., Ayaz, A. (2009) Length–weight relationships for ten shark species from Saros Bay (North Aegean Sea). J Appl Ichthyol 25: 109-112.

Ismen, A., Ozen, O., Altinagac, U., Ozekinci, U., Ayaz, A. (2007) Weight–length relationships of 63 fish species in Saros Bay, Turkey. J Appl Ichthyol 23(6): 707-708.

IUCN. (2012) IUCN Red List Categories and Criteria: Version 3.1. Second edition. Gland, Switzerland and Cambridge, UK: IUCN. IV 32pp

Kabasakal, H. (2009) On the capture of a large basking shark Cetorhinus maximus (Chondrichthyes: Cetorhinidae) in the Bay of Edremit (northeastern Aegean Sea) Annales Series Historia Naturalis 19(1): 11-16.

Kabasakal, H., Dalyan, C. (2011) Recent records of the bramble shark, Echinorhinus brucus (Chondrichthyes: Echinorhinidae), from the Sea of Marmara. Mar Biodivers 4: doi: 10.1017/S1755267211000108

Kabasakal, H., Kabasakal, O. (2014) Status of angelshark, Squatina squatina (Elasmobranchii: Squatiniformes: Squatinidae) in the Sea of Marmara. Annales Series Historia Naturalis 24(1): 41-46.

Kabasakal, H., Yarmaz, A., Gedikoğlu, S. Ö. (2009) Two juvenile great white sharks, Carcharodon carcharias (Linnaeus, 1758) (Chondrichthyes; Lamnidae), caught in the northeastern Aegean Sea. Annales Series Historia Naturalis 19(2): 127-134.

Kara, A., Sağlam, C., Acarli, D., Cengiz, Ö. (2017) Length-weight relationships for 48 fish species of the Gediz estuary, in İzmir Bay (Central Aegean Sea, Turkey). J Mar Biol Assoc UK. 98(4): 879-884.

Karakulak, F. S., Erk, H., Bilgin, B. (2006) Length–weight relationships for 47 coastal fish species from the northern Aegean Sea, Turkey. J Appl Ichthyol 22(4): 274-278.

Kebapçioglu, T., Özgür, E., Çardak, M., Gökoglu, M., Begburs, C. R. (2010) The status of the demersal fish community in the Gulf of Antalya, Turkey (Levantine Sea). Rapp Comm int Mer Médit 39: 364.

Kettemer, L.E. (2012) Global Estimate of Shark Mortality Induced by Longline Fisheries. Albert Ludwigs Universität Freiburg. PhD Thesis. Albert-Ludwigs-Universität Freiburg. 30 pp.

Jordan, L. K., Mandelman, J. W., McComb, M. D., Fordham, S. V., Carlson, J. K., Werner, T. B. (2013) Linking sensory biology and fisheries bycatch reduction in elasmobranch fishes: a review with new directions for research. Conserv Physiol 1(1). doi: 10.1093/conphys/cot002

Oliver, S., Braccini, M., Newman, S. J., Harvey, E.S. (2015) Global patterns in the by-catch of sharks and rays. Marine Policy 54: 86-97.

Özaydın, O., Uçkun, D., Akalın, S., Leblebici, S., Tosunoğlu, Z. (2007) Length–weight relationships of fishes captured from Izmir Bay, Central Aegean Sea. J Appl Ichthyol 23(6): 695-696.

Özcan, E.I., Başusta, N. (2015). Stomach contents of the lesser spotted dogfish, (Scyliorhinus canicula (Linnaeus, 1758)) inhabiting Northeastern Mediterranean. Ege J Fish Aqua Sci 32 (4): 193-195.

Özbek, E.Ö., Çardak, M., Kebapçıoğlu, T. (2015) Spatio-temporal patterns of abundance, biomass and length-weight relationships of Dasyatis species (Pisces: Dasyatidae) in the Gulf of Antalya, Turkey (Levantine Sea). J Black Sea/Mediterr Environ 21(2): 169-190.

Özbek, E.Ö., Çardak, M., Kebapçıoğlu, T. (2016) Spatio-temporal patterns of abundance, biomass and length-weight relationships of Gymnura altavela (Linnaeus, 1758) (Pisces: Gymnuridae) in the Gulf of Antalya, Turkey (Levantine Sea). J Black Sea/Mediterr Environ 22(1): 16-34.

Özen, Ö., İşmen, A., Özekinci, U., Ayaz, A., Altınağaç, U., Ayyıldız, H., Cengiz, Ö., (2008) Population Dynamics of Economically Valuable Young Fish Species and Fish Biodiversity of Shallow waters of Canakkale. TÜBİTAK TBAG Project 106T123, pp.125 (in Turkish).

Özütemiz, Ş., Kaya, M., Özaydın, O. (2009) A preliminary study on the Length-weight relationship and diet of two species of sharks [Galeus Melastomus Rafinesque, 1810 and Squalus Blainvillei (Risso, 1826)] found in the Siğacık Bay(Aegean Sea), Ege J Fish Aqua Sci 26(3): 211-217 (in Turkish).

Sağlam, H., Bascinar, N.S., (2008) Feeding ecology of thornback ray (Raja clavata Linnaeus, 1758) on the Turkish coast of the south-eastern Black Sea, Mar Biol Res 4(6): 451-457.

Sakalli, A., Yucel, N., Capapé, C. (2016) Confirmed occurrence in the Mediterranean Sea of Mobular japanica (Müller and Henle, 1841) with a first record off the Turkish coasts. J Appl Ichthyol 32(6): 1232-1234.

Saygu, I. (2011) Determination of By-Catch Rays and Their Survival Rates Caught by Demersal Trawl Fishery in Antalya Bay. Akdeniz University. Master Thesis, 92 pp. (in Turkish).

Serena, F. (2005) Field Identification Guide to the Sharks and Rays of the Mediterranean and Black Sea. FAO Species Identification Guide for Fishery Purposes. FAO, Rome, 97 pp.

Torcu, H., Aka, Z. (2000) A Study on the Fishes of Edremit Bay (Aegean Sea) Turk. J Fish and Aquat Sci 24(1): 45-62.

Turan, C., Salihoğlu, B., Özgür Özbek, E., Öztürk, B. (Eds.) (2016) The Turkish Part of the Mediterranean Sea; Marine Biodiversity, Fisheries, Conservation and Governance. Turkish Marine Research Foundation (TUDAV), Publication No: 43, Istanbul, TURKEY.

Türetken, K. F. (2009) Quantitive-qualitive analysis of deep sea fishes around Gökçeada island (Northern Aegean sea). Master Thesis. Institute of Science Istanbul University, (in Turkish).

Wetherbee, B., Grubber, S., Cortés, E. (1990) Food consumption and feeding habits. In: Biology of Sharks and Their Relatives, (eds., Carrier, J., Musick, J., Heithaus, M.), CRC Press, Boca Raton, pp. 239-264.

Yaka, U. (2006) Research and morphological properties of Izmit Bay fishes. Biology Department, Institute of Pure and Applied Sciences, Marmara University, 108 pp. (in Turkish).

Yarmaz, A. (2009) Some biological properties of cartilaginous fish living in Edremit Bay and their vicinity. Balıkesir University, Institute of Science, Department of Biology, Master Thesis (in Turkish).

Yeldan, H., Avşar, D., Manaşırlı, M. (2008) Some biological peculiarities of thornback ray, Raja clavata (Linnaeus, 1758) in the northeastern Mediterranean. Ege J Fish Aqua Sci 25(3): 221-228.

Yıldız, T., Karakulak, F. S. (2017) Discards in bottom‐trawl fishery in the western Black Sea (Turkey). J Appl Ichthyol 33(4): 689-698.

Yücel, N., Sakalli, A., Karahan, A. (2017) First record of the honeycomb stingray Himantura leoparda (Manjaji‐Matsumoto and Last, 2008) (Myliobatoidei: Dasyatidae) in the Mediterranean Sea, confirmed by DNA barcoding. J Appl Ichthyol 33(3): 530-532.