Sex Dependent Catch Efficiency of Fyke Nets for Narrow-clawed Crayfish (Pontastacus leptodactylus): A Case from Eğirdir Lake (Türkiye)

Year 2026, Volume: 41 Issue: 1, 34 - 40, 20.01.2026

Mehmet Cilbiz

https://doi.org/10.26650/ASE.2025.1766136

https://izlik.org/JA46MR69JL

Abstract

The present study aimed to investigate the effects of sex-related morphological differences in crayfish bodies on their escape rates from the fyke net used in fishing. The study, conducted in Eğirdir Lake (Isparta, Türkiye) with a total of 20 fishing operations, utilized commercial crayfish fyke nets equipped with 34 mm diamond mesh size. Statistical differences were determined between the body parts of female and male crayfish within the same length classes among the 1,529 crayfish examined, ranging from 31.80 to 149.00 mm in total length. These observed differences were reflected in the catch comparison results; however, the difference was found to be statistically insignificant. According to the study results, the crayfish fyke nets commonly used in crayfish fisheries in Türkiye, rigged with 34 mm diamond mesh, did not exhibit selectivity based on sex groups. In this context, it is considered that there is no need for any sex-specific regulation in crayfish fisheries in Türkiye.

Keywords

Catch comparison , Eğirdir Lake , inland fisheries , sustainability , small scale fisheries

References

• Abrahamsson SAA (1971). Density, growth and reproduction in populations of Astacus astacus and Pacifastacus leniusculus in an isolated pond. Oikos 22: 373–380. google scholar
• Anonymous. (2024). 6/1 Notification of commercial fish catching regulation in seas and inland water (Notificaiton number 2024/20). Republic of Türkiye, Minister of Agriculture and Rural Forestry, General Directorate of Fisheries and Aquaculture, Ankara. google scholar
• Atilgan, A., Coskan, A., Isler, E., & Oz, H. (2009). Amounts of nitrogen and phosphorus related to agricultural pollution elements in Egirdir Lake. Asian Journal of Chemistry, 21(4), 3107–3116. google scholar
• Aydin, H; Harlioğlu, MM, Deniz, T (2015) "An investigation on the population parameters of freshwater crayfish (Astacus leptodactylus Esch., 1823) in Lake İznik (Bursa)," Turkish Journal of Zoology: 39:4, 16. https://doi.org/10.3906/zoo-1406-6 google scholar
• Balık, İ., Çubuk, H., Özkök, R., & Uysal, R. (2005). Some Biological Characteristics of Crayfish (Astacus leptodactylus Eschscholtz, 1823) in Lake Eğirdir. Turkish Journal of Zoology, 29, 295–300. google scholar
• Bolat, Y. (2001). Eğirdir Gölü Hoyran Bölgesi Tatlı Su İstakozlarının (Astacus leptodactylus Esch., 1823) Populasyon Büyüklüğünün Tahmini Süleyman Demirel Üniversitesi, Fen Bilimleri Enstitüsü. Doktora Tezi.117p. google scholar
• Bolat, Y., & Kaya, M. A. (2016). Determination of growth and reproduction properties of freshwater crayfish (Astacus leptodactylus, Eschscholtz, 1823) in Eğirdir Lake-Türkiye [İn Turkish]. Eğirdir Su Ürünleri Fakültesi Dergisi, 12(1), 11–24. https://doi.org/https://doi.org/10.22392/egirdir.246312 google scholar
• Bolat, Y., Demirci, A., & Mazlum, Y. (2010). Size Selectivity of Traps (Fyke-Nets) of Different Mesh Size on The Narrow-Clawed Crayfish, Astacus leptodactylus (ESCHSCHOLTZ, 1823) (Decapoda, Astacidae) İn Eğirdir Lake, Turkey. Crustaceana, 8(11), 1349–1361. https://doi.org/https://doi.org/10.1163/001121610X536969 google scholar
• Bolat, Y., Mazlum, Y., Demirci, A., & Koca, H. U. (2011). Estimating the population size of Astacus leptodactylus (Decapoda: Astacidae) by mark-recapture technique in Eǧirdir lake, Turkey. African Journal of Biotechnology, 10(55), 11778–11783. google scholar
• Çapkın, K., Cilbiz, M., & Demirol, F. (2023). Bycatch estimation of narrow-clawed crayfish (Pontastacus leptodactylus) in Turkish fyke net fisheries. Fisheries Management and Ecology, 30(2), 171 – 181. https://doi.org/10.1111/FME.12610 google scholar
• Cerbule, K., Jacques, N., Pettersen, H., Ingólfsson, Ó. A., Herrmann, B., Grimaldo, E., Larsen, R. B., Brinkhof, J., Sistiaga, M., Lilleng, D., & Brčić, J. (2021). Bycatch reduction in the deep-water shrimp (Pandalus borealis) trawl fishery with al arge mesh top panel. Journal for Nature Conservation, 61, 126001. https://doi.org/10.1016/j.jnc.2021.126001 google scholar
• Cilbiz, M. (2020). Pleopodal fecundity of narrow-clawed crayfish (Pontastacus leptodactylus Eschscholtz, 1823). Invertebrate Reproduction & Development, 64(3), 208–218. https://doi.org/10.1080/07924259.2020.1762771 google scholar
• Cilbiz, M., & Aydın, C. (2024a). Improving the size selectivity of crayfish fyke-net codend, applying the hexagonal mesh and sorting grid. Marine and Freshwater Research, 75, MF23224. https://doi.org/10.1071/MF23224 google scholar
• Cilbiz, M., & Aydın, C. (2024b). Sorting grid use to reduce catch of undersized narrow-clawed crayfish (Pontastacus leptodactylus Eschscholtz, 1823) in fyke net fisheries. Fisheries Management and Ecology, 31, e12731. https://doi.org/10.1111/fme.12731 google scholar
• Cilbiz, M., Aydin, C., & Herrmann, B. (2022). New codend designs to improve the size selectivity of fyke net for narrow-clawed crayfish (Pontastacus leptodactylus). Aquatic Living Resources, 35, 14. https://doi.org/10.1051/alr/2022014 google scholar
• Cilbiz, M., Aydın, C., & Uzunmehmetoglu, O. Y. (2020). Evaluation of Turkey's crayfish (Pontastacus leptodactylus (Eschscholtz, 1823) Production in National and Global Scale [in Turkish]. Journal of Limnology and Freshwater Fisheries Research, 6(1), 59–74. https://doi.org/http:\10.17216/LimnoFish-561180 google scholar
• Claereboudt, M. R. G., Al-Oufi, H. S., McIlwain, J., & Goddard, J. S. (2007). Relationships between fishing gear, size frequency and reproductive patterns for the kingfish (Scomberomorus commerson Lacépède) fishery in the Gulf of Oman. In Management of Shared Fish Stocks (pp. 56–67). google scholar
• Cobb JS, Wang D (1985). Fisheries biology of lobsters and crayfish. In: Provenzano AJ, editor. The Biology of Crustacea. New York, NY, USA: Academic Press, pp. 167–247. google scholar
• Correia, M. J., Domingos, I., De Leo, G. A., & Costa, J. L. (2021). A comparative analysis of European eel’s somatic growth in the coastal lagoon Santo André (Portugal) with growth in other estuaries and freshwater habitats. Environmental Biology of Fishes, 104(7), 837–850. https://doi.org/10.1007/s10641-021-01123-6 google scholar
• Dakić, L., & Maguire, I. (2016). Year cycle and morphometrical characteristics of Austropotamobius torrentium from two karstic rivers in Croatia. Natura Croatica, 25(1), 87–100. https://doi.org/10.20302/NC.2016.25.5 google scholar
• Demirol, F. (2023). Data-poor stock assessment of Narrow-Clawed Crayfish (Pontastacus leptodactylus) in Keban Dam Lake (Türkiye) Using CMSY Method. Turkish Journal of Fisheries and Aquatic Sciences, 23, TRJFAS22665. https://doi.org/10.4194/TRJFAS22665 google scholar
• Deval, M. C., Bök, T., Ateş, C., & Tosunoǧlu, Z. (2007). Length-based estimates of growth parameters, mortality rates, and recruitment of Astacus leptodactylus (Eschscholtz, 1823) (Decapoda, Astacidae) in unexploited inland waters of the northern Marmara region, European Turkey). Crustaceana, 80(6), 655–665. https://doi.org/10.1163/156854007781360649 google scholar
• Efron, B. (1982). The jackknife, the bootstrap and other resampling plans. SIAM Monograph No. 38, CBSM-NSF Regional Conference Series in Applied Mathematics; SIMA: Philadelphia, PA, USA. https://doi.org/10.1137/1.9781611970319 google scholar
• Fakıoğlu, Y. E., Gökçe, G., Özbilgin, H., Cerbule, K., & Herrmann, B. (2023). Impact of ground gear design on catch efficiency in demersal trawl fishery. Regional Studies in Marine Science, 61, 102852. https://doi.org/10.1016/j.rsma.2023.102852 google scholar
• Herrmann, B., Sistiaga, M. B., Nielsen, K. N., & Larsen, R. B. (2012). Understanding the size selectivity of redfish (Sebastes spp.) in North Atlantic trawl codends. Journal of Northwest Atlantic Fishery Science, 44(1), 13. https://doi.org/10.2960/J.v44.m680 google scholar
• Herrmann, B., Sistiaga, M., Santos, J., & Sala, A. (2016). How Many Fish Need to Be Measured to Effectively Evaluate Trawl Selectivity? PLOS ONE, 11(8), e0161512. https://doi.org/10.1371/journal.pone.0161512 google scholar
• Kassambara, A. (2023). rstatix: Pipe-Friendly Framework for Basic Statistical Tests_. R package version 0.7.2, https://CRAN.R-project.org/package=rstatix. google scholar
• Kirjavainen J, Westman K (1999). Natural history and development of the introduced signal crayfish, Pacifastacus leniusculus, in a small, isolated Finnish lake, from 1968 to 1993. Aquatic Living Resources 12: 387–401. google scholar
• Köksal, G. (1979). Biometric analysis on the freshwater crayfish (Astacus leptodactylus Esch. 1823) wldch ls produced in Turkey - Relationship between the major body components and meat yield. Ankara Üniversitesi Veteriner Fakültesi Dergisi, 26(03.04), 93–114. https://doi.org/10.1501/Vetfak_0000001011 google scholar
• Korkmaz, B., Bolat, Y., & Cilbiz, M. (2023). Length-based Stock Assessment for the Data-poor Crayfish Fishery from the Eğirdir Lake, Turkiye. Turkish Journal of Fisheries and Aquatic Sciences, 23(3), TRJFAS22354. https://doi.org/10.4194/TRJFAS22354 google scholar
• Lomeli, M. J. M., Groth, S. D., Blume, M. T. O., Herrmann, B., & Wakefield, W. W. (2020). The efficacy of illumination to reduce bycatch of eulachon and groundfishes before trawl capture in the eastern North Pacific ocean shrimp fishery. Canadian Journal of Fisheries and Aquatic Sciences, 77(1), 44–54. https://doi.org/10.1139/cjfas-2018-0497 google scholar
• Lomeli, M. J. M., Wakefield, W. W., Herrmann, B., Dykstra, C. L., Simeon, A., Rudy, D. M., & Planas, J. V. (2021). Use of artificial illumination to reduce Pacific halibut bycatch in a U.S. West Coast groundfish Bottom trawl. Fisheries Research, 233, 105737. https://doi.org/10.1016/j.fishres.2020.105737 google scholar
• Momot, W. T., Gowing, H., & Jones, P. D. (1978). The Dynamics of Crayfish and Their Role in Ecosystems. The American Midland Naturalist, 99(1), 10–35. https://doi.org/10.2307/2424930 google scholar
• Ogburn, M. B. (2019). The effects of sex-biased fisheries on crustacean sex ratios and reproductive output. Invertebrate Reproduction and Development, 63(3), 200–207. https://doi.org/10.1080/07924259.2019.1612787 google scholar
• Özseven, A., Akkurt, I., & Günoğlu, K. (2020). Determination of some dosimetric parameters in Eğirdir Lake, Isparta, Turkey. International Journal of Environmental Science and Technology, 17(3), 1503–1510. https://doi.org/10.1007/s13762-019-02569-z google scholar
• Poot-López, G. R., López-Rocha, J. A., González-Salas, C., Guillen-Hernández, S., & Villegas-Hernández, H. (2019). Sex related differences in density, selectivity and vulnerability of the Atlantic blue crab, Callinectes sapidus (Rathbun, 1896), in the southern Gulf of Mexico. Regional Studies in Marine Science, 32, Article 100846. https://doi.org/10.1016/j.rsma.2019.100846 google scholar
• Positteam. (2025). RStudio: Integrated Development Environment for R.Posit Software, PBC, Boston, MA. URL http://www.posit.co/. google scholar
• Reynolds, J., Souty-Grosset, C., & Richardson, A. (2013). Ecological roles of crayfish in freshwater and terrestrial habitats. Freshwater Crayfish, 19(2), 197–218. google scholar
• Şener, E., Varol, S., Şener, Ş., & Davraz, A. (2019). Assessment of the stream network pollution in the Eğirdir Lake Basin (Turkey) using water quality index and multivariate analysis. Mühendislik Bilimleri ve Tasarım Dergisi, 7(2), 352–368. google scholar
• Sainte-Marie, B., Gosselin, T., Sévigny, J. M., & Urbani, N. (2008). The snow crab mating system: Opportunity for natural and unnatural selection in a changing environment. Bulletin of Marine Science, 83:1 (131-161). google scholar
• Simon, T. P., & Samadder, M. A. (2016). Age, growth, and condition of the papershell crayfish Orconectes immunis (hagen 1870) (decapoda: Cambaridae). In Geographic Distribution, Ecological Impact, and Conservation Strategies for North American Crayfish (pp. 139–154). google scholar
• Taylor, C. A., Warren, M. L., Fitzpatrick, J. F., Hobbs, H. H., Jezerinac, R. F., Pflieger, W. L., & Robison, H. W. (1996). Conservation Status of Crayfishes of the United States and Canada. Fisheries, 21(4), 25–38. https://doi.org/10.1577/1548-8446(1996)021<0025:CSOCOT>2.0.CO;2 google scholar
• Williams, A. J., Wakefield, C. B., Newman, S. J., Vourey, E., Abascal, F. J., Halafihi, T., Kaltavara, J., & Nicol, S. J. (2017). Oceanic, latitudinal, and sex-specific variation in demography of a tropical deepwater snapper across the indo-pacific region. Frontiers in Marine Science, 4(DEC), Article 382. https://doi.org/10.3389/fmars.2017.00382 google scholar
• Yüksel, F., Demirol, F., & Gündüz, F. (2013). Leslie Population Estimation for Turkish Crayfish (Astacus leptodactylus Esch., 1823) in the Keban Dam Lake, Turkey. Turkish Journal of Fisheries and Aquatic Sciences, 13, 835–839. https://doi.org/DOI: 10.4194/1303-2712-v13_5_07 google scholar
• Žák, J., Jůza, T., Blabolil, P., Baran, R., Bartoň, D., Draštík, V., Frouzová, J., Holubová, M., Ketelaars, H. A. M., Kočvara, L., Kubečka, J., Mrkvička, T., Muška, M., Říha, M., Sajdlová, Z., Šmejkal, M., Tušer, M., Vašek, M., Vejřík, L.,…Wagenvoort, A. J. (2018). Invasive round goby Neogobius melanostomus has sex-dependent locomotor activity and is under-represented in catches from passive fishing gear compared with seine catches. Journal of Fish Biology, 93(1), 147–152. https://doi.org/10.1111/jfb.13646 google scholar