Skip to main content Accessibility help

Unsustainable harvest of water frogs in southern Turkey for the European market

  • Kerim Çiçek (a1), Dinçer Ayaz (a1), Murat Afsar (a2), Yusuf Bayrakcı (a1), Çiğdem Akın Pekşen (a3), Oğuzkan Cumhuriyet (a1), İlhan Bayram İsmail (a1), Melodi Yenmiş (a1), Erdal Üstündağ (a4), Cemal Varol Tok (a5), C. Can Bilgin (a6) and H. Reşit Akçakaya (a7)...


Frogs have been harvested from the wild for the last 40 years in Turkey. We analysed the population dynamics of Anatolian water frogs (Pelophylax spp.) in the Seyhan and Ceyhan Deltas during 2013–2015. We marked a total of 13,811 individuals during 3 years, estimated population sizes, simulated the dynamics of a harvested population over 50 years, and collated frog harvest and export statistics from the region and for Turkey as a whole. Our capture estimates indicated a population reduction of c. 20% per year, and our population modelling showed that, if overharvesting continues at current rates, the harvested populations will decline rapidly. Simulations with a model of harvested population dynamics resulted in a risk of extinction of > 90% within 50 years, with extinction likely in c. 2032. Our interviews with harvesters revealed their economic dependence on the frog harvest. However, our results also showed that reducing harvest rates would not only ensure the viability of these frog populations but would also provide a source of income that is sustainable in the long term. Our study provides insights into the position of Turkey in the ‘extinction domino’ line, in which harvest pressure shifts among countries as frog populations are depleted and harvest bans are effected. We recommend that harvesting of wild frogs should be banned during the mating season, hunting and exporting of frogs < 30 g should be banned, and harvesters should be trained on species knowledge and awareness of regulations.

  • View HTML
    • Send article to Kindle

      To send this article to your Kindle, first ensure is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about sending to your Kindle. Find out more about sending to your Kindle.

      Note you can select to send to either the or variations. ‘’ emails are free but can only be sent to your device when it is connected to wi-fi. ‘’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.

      Find out more about the Kindle Personal Document Service.

      Unsustainable harvest of water frogs in southern Turkey for the European market
      Available formats

      Send article to Dropbox

      To send this article to your Dropbox account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your <service> account. Find out more about sending content to Dropbox.

      Unsustainable harvest of water frogs in southern Turkey for the European market
      Available formats

      Send article to Google Drive

      To send this article to your Google Drive account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your <service> account. Find out more about sending content to Google Drive.

      Unsustainable harvest of water frogs in southern Turkey for the European market
      Available formats


Corresponding author

(Corresponding author) E-mail


Hide All

Supplementary material for this article is available at



Hide All
Abdulali, H. (1985) On the export of frog legs from India. Journal of the Bombay Natural History Society, 2, 347375.
Akçakaya, H.R. (1991) A method for simulating demographic stochasticity. Ecological Modelling, 54, 133136.
Akçakaya, H.R. (2013) RAMAS Metapop: Viability Analysis for Stage-structured Metapopulations. Version 6.0. Applied Biomathematics, Setauket, USA.
Akçakaya, H.R., Mills, G. & Doncaster, C.P. (2007) The role of metapopulations in conservation. In Key Topics in Conservation Biology (eds Macdonald, D.W. & Service, K.), pp. 6484. Blackwell, Oxford, UK.
Akin, Ç. & Bilgin, C.C. (2010) Preliminary Report on the Collection, Processing and Export of Water Frogs in Turkey. (Presented to KKGM). ODTÜ, Ankara, Turkey. [in Turkish]
Akin, Ç., Bilgin, C.C., Beerli, P., Westaway, R., Ohst, T., Litvinchuk, S.N. et al. (2010) Phylogeographic patterns of genetic diversity in eastern Mediterranean water frogs were determined by geological processes and climate change in the Late Cenozoic. Journal of Biogeography, 37, 21112124.
Alford, R.A. & Richards, S.J. (1999) Global amphibian declines: a problem in applied ecology. Annual Review of Ecology, Evolution and Systematics, 30, 133165.
Altherr, S., Goyenechea, A. & Schubert, D. (2011) Canapés to Extinction — the International Trade in Frogs’ Legs and its Ecological Impact. A report by Pro Wildlife, Defenders of Wildlife and Animal Welfare Institute (eds), Munich, Germany, and Washington, DC, USA.
Armstrong, P., Young, C. & McKeown, D. (1990) Ethyl chloride and venepuncture pain: a comparison with intradermal lidocaine. Canadian Journal of Anaesthesia, 37, 656658.
Baker, S.E., Cain, R., van Kesteren, F., Zommers, Z.A., D'Cruze, N. & Macdonald, D.W. (2013) Rough trade: animal welfare in the global wildlife trade. BioScience, 63, 928938.
Boone, M.D. & Bridges, C.M. (2003) Effects of carbaryl on green frog (Rana clamitans) tadpoles: timing of exposure versus multiple exposures. Environmental Toxicology and Chemistry, 22, 26952702.
Carpenter, A.I., Dublin, H., Lau, M., Syed, G., McKay, J.E. & Moore, R.D. (2007) Over-harvesting. In Amphibian Conservation Action Plan (eds Gascon, C., Collins, J.P., Moore, R.D., Church, D.R., McKay, J.E., & Mendelson, J.R.), pp. 2631. IUCN, Gland, Switzerland, 21–31.
Chan, H.K., Shoemaker, K.T. & Karraker, N.E. (2014) Demography of Quasipaa frogs in China reveals high vulnerability to widespread harvest pressure. Biological Conservation, 170, 39.
Chan, H.K., Zhang, H., Yang, F. & Fischer, G. (2015) Improve customs systems to monitor global wildlife trade. Science, 348, 291292.
Çiçek, K. (2009) Population Dynamics of Rana macrocnemis Boulenger, 1885 (Anura:Ranidae) inhabiting Uludağ (Bursa). MSc thesis, Ege University, İzmir, Turkey.
Çiçek, K., Mermer, A. & Tok, C.V. (2011) Population dynamics of Rana macrocnemis Boulenger. 1885 at Uludağ. Western Turkey (Anura: Ranidae). Zoology in the Middle East, 53, 4160.
Cooch, E.G. & White, G.C. (2017) Program MARK: a Gentle Introduction. 1082 pp. [accessed 13 November 2018].
Cormack, R.M. (1964) Estimates of survival from the sighting of marked animals. Biometrika, 51, 429438.
Daszak, P., Berger, L., Cunningham, A.A., Hyatt, A.D., Green, D.E. & Speare, R. (1999) Emerging infectious diseases and amphibian population declines. Emerging Infectious Diseases, 5, 735748.
Daszak, P., Cunningham, A.A. & Hyatt, A.D. (2003) Infectious disease and amphibian population declines. Diversity and Distributions, 9, 141150.
Franke, J. & Telecky, T.M. (2001) Reptiles as pets: an examination of the trade in live reptiles in the United States. Journal of International Wildlife Law and Policy, 4, 315317.
Gerson, H. (2012) International trade in Amphibians: a customs perspective. Alytes, 29, 103115.
Gibbons, J.W., Scott, D.E., Ryan, T.J., Buhlmann, K.A., Tuberville, T.D., Metts, B.S. et al. (2000) The global decline of reptiles, déjà vu amphibians. BioScience, 50, 653666.
Gilbert, M., Bickford, D., Clark, L., Johnson, A., Joyner, P.H., Keatts, L.O. et al. (2012) Amphibian pathogens in Southeast Asian frog trade. EcoHealth, 9, 386398.
Goode, M.J., Swann, D.E. & Schwalbe, C.R. (2004) Effects of destructive collecting practices on reptiles: a field experiment. Journal of Wildlife Management, 68, 429434.
Gratwicke, B., Evans, M.J., Jenkins, P.T., Kusrini, M.D., Moore, R.D., Sevin, J. et al. (2010) Is the international frog legs trade a potential vector for deadly amphibian pathogens? Frontiers in Ecology and the Environment, 8, 438442.
Holsbeek, G., Mergeay, J., Hotz, H., Plötner, J., Volckaert, F.A.M. & De Meester, L. (2008) A cryptic invasion within an invasion and widespread introgression in the European water frog complex: consequences of uncontrolled commercial trade and weak international legislation. Molecular Ecology, 17, 50235035.
Houlahan, J.E., Findlay, C.S., Schmidt, B.R., Meyer, A.H. & Kuzmin, S.L. (2000) Quantitative evidence for global amphibian population declines. Nature, 404, 752755.
Jolly, G.M. (1965) Explicit estimates for capture–recapture data with both death and immigration stochastic model. Biometrika, 52, 225247.
Karesh, W.B., Cook, R.A., Bennett, E.L. & Newcomb, J. (2005) Wildlife trade and global disease emergence. Emerging Infectious Diseases, 11, 10001002.
Kats, L.B. & Ferrer, R.P. (2003) Alien predators and amphibian declines: review of two decades of science and the transition to conservation. Diversity and Distributions, 9, 99110.
Kiesecker, J.M., Blaustein, A.R. & Belden, L.K. (2001) Complex causes of amphibian population declines. Nature, 410, 681684.
Klemens, M.W. & Thorbjarnarson, J.B. (1995) Reptiles as a food source. Biodiversity and Conservation, 4, 281298.
Kriger, K.M. & Hero, J.M. (2009) Chytridiomycosis, amphibian extinctions and lessons for the prevention of future panzootics. EcoHealth, 6, 610.
Kürüm, V. (2015) Statistics of Frog Trade in Turkey. Republic of Turkey Ministry of Agriculture and Forestry General Directorate of Fisheries and Aquaculture, Ankara, Turkey. [in Turkish]
Kusrini, M.D. (2005) Edible frog harvesting in Indonesia: evaluating its impacts and ecological context. MSc thesis, School of Tropical Biology, James Cook University, Australia.
Ministry of Food, Agriculture and Livestock (2016) Bulletin 4/1. [accessed 1 January 2019]. [in Turkish]
Mohneke, M. (2011) (Un)sustainable use of frogs in West Africa and resulting consequences for the ecosystem. MSc thesis, Mathematisch-Naturwissenschaftliche Fakultät, Humboldt-Universität zu Berlin, Berlin, Germany.
Musing, L., Norwisz, M., Kloda, J. & Kecse-Nagy, K. (2018) Wildlife Trade in Belgium: an Analysis of CITES Trade and Seizure Data. TRAFFIC and WWF, Cambridge, UK.
Otis, D.L., Burnham, K.P., White, G.C. & Anderson, D.R. (1978) Statistical inference from capture data on closed animal populations. Wildlife Monographs, 62, 3135.
Pavajeau, L., Zippel, K.C., Gibson, R. & Johnson, K. (2008) Amphibian Ark and the 2008 year of the frog campaign. International Zoo Yearbook, 42, 2429.
Plötner, J. (2005) Die westpaläarktischen Wasserfrösche: von Märtyrern der Wissenschaft zur biologischen Sensation. Laurenti-Verlag, Bielefeld, Germany.
Plötner, J. & Ohst, T. (2001) New hypothesis of the western Palearctic water frog complex (Anura: Ranidae). Mitteilungen aus dem Zoologischen Museum in Berlin, 77, 521.
Plötner, J., Uzzell, T., Beerli, P., Akın, Ç., Bilgin, C.C., Haefeli, C. et al. (2010) Genetic divergence and evolution of reproductive isolation in eastern Mediterranean water frogs. In Evolution in Action. Case Studies in Adaptive Radiation, Speciation and the Origin of Biodiversity. Special Volume from the SPP 1127 “Radiations – Genesis of Biological Diversity” of the DFG (ed. Glaubrecht, M.), pp. 373403. Springer, Heidelberg, Berlin, Germany.
Polishchuk, D., Gehrmann, R. & Tan, V. (2012) Skin sterility after application of ethyl chloride spray. Journal of Bone & Joint Surgery, 94, 118120.
Raghavendra, K., Sharma, P. & Dash, A.P. (2008) Biological control of mosquito populations through frogs: opportunities and constrains. Indian Journal of Medical Research, 128, 2225.
Reynolds, R.E., Shaffer, T.L., Renner, R.W., Newton, W.E. & Batt, B.D.J. (2001) Impact of the conservation reserve program on duck recruitment in the U.S. Prairie Pothole Region. Journal of Wildlife Management, 65, 765780.
Scheffers, B.R., Oliveira, B.F., Lamb, I. & Edwards, D.P. (2019) Global wildlife trade across the tree of life. Science, 366, 7176.
Schlaepfer, M.A., Hoover, C. & Dodd, C.K. Jr (2005) Challenges in evaluating the impact of the trade in amphibians and reptiles on wild populations. BioScience, 55, 256264.
Seber, G.A.F. (1965) A note on the multiple recapture census. Biometrika, 52, 249259.
Smith, M. & Green, D. (2005) Dispersal and the metapopulation paradigm in amphibian ecology and conservation: are all amphibian populations metapopulations? Ecography, 28, 110128.
Smith, R.K., Meredith, H. & Sutherland, W.J. (2018) Amphibian conservation. In What Works in Conservation 2018 (eds Sutherland, W.J., Dicks, L.V., Ockendon, N., Petrovan, S.O. & Smith, R.K.), pp. 965. Open Book Publishers, Cambridge, UK.
Sodhi, N.S., Koh, L.P., Brook, B.W. & Ng, P.K.L. (2004) Southeast Asian biodiversity: an impending disaster. Trends in Ecology and Evolution, 19, 654660.
Stuart, S.N., Chanson, J.S., Cox, N.A., Young, B.E., Rodrigues, A.S.L., Fischman, D.L. et al. (2004) Status and trends of amphibian declines and extinctions worldwide. Science, 306, 17831786.
Török, Z. (1999) Ghid pentru descrierea ariilor de importanţă herpetofaunistică din România. Probleme de Ecologie Teoretică şi Aplicată în România – Direcţii Actuale, No. 2. Editura Aves, Tulcea, Romania.
Tüik (Turkish Statistical Institute) Fisheries Statistics (2018) Turkish Statistical Institute, Ankara, Turkey. [accessed 1 January 2019].
Warkentin, I.G., Bickford, D., Sodhi, N.S. & Bradshaw, C.J.A. (2008) Eating frogs to extinction. Conservation Biology, 23, 10561059.
White, G.C. & Burnham, K.P. (1999) Program MARK: survival estimation from populations of marked animals. Bird Study, 46, 120138.
White, G.C., Anderson, D.R., Burnham, K.P. & Otis, D.L. (1982) Capture–Recapture and Removal Methods for Sampling Closed Populations. Los Alamos National Laboratory Rep. LA-8787-NERP, Los Alamos, USA.
Worm, B., Barbier, E.B., Beaumont, N., Duffy, J.E., Folke, C., Halpern, B.S. et al. (2006) Impacts of biodiversity loss on ocean ecosystem services. Science, 314, 787790.


Type Description Title
Supplementary materials

Çiçek et al. supplementary material
Çiçek et al. supplementary material

 Word (930 KB)
930 KB

Unsustainable harvest of water frogs in southern Turkey for the European market

  • Kerim Çiçek (a1), Dinçer Ayaz (a1), Murat Afsar (a2), Yusuf Bayrakcı (a1), Çiğdem Akın Pekşen (a3), Oğuzkan Cumhuriyet (a1), İlhan Bayram İsmail (a1), Melodi Yenmiş (a1), Erdal Üstündağ (a4), Cemal Varol Tok (a5), C. Can Bilgin (a6) and H. Reşit Akçakaya (a7)...


Altmetric attention score

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed.