SEX RATIO, LENGTH AND WEIGHT FREQUENCY OF FRESHWATER CRAYFISH (ASTACUS LEPTODACTYLUS) INHABITING IN ARAS DAM LAKE, IRAN

Year 2014, Volume: 29 Issue: 2, 35 - 47, 20.10.2015

Ali Azari Muzaffer Harlıoğlu , Fereidun Mohebbi Masoud Seidgar

https://doi.org/10.18864/iujfas.39759

Abstract

Freshwater crayfish are one of the important commercially caught aquatic organisms. Their nutritional values are also considerably important. Crayfish are benthic organisms which spends most of their life on the bed of aquatic habitats. In the present study, sex ratio and some biometric characteristics of crayfish (Astacus leptodactylus) inhabiting in Aras dam lake was investigated seasonally between spring 2011 and winter 2012. The mean total length and weight for the crayfish were 106.26±12.9 mm and 38.79±15.5 g, respectively. The results revealed that only a 13.67% of the captured crayfish exceeded than the standard commercial size (120 mm) and only 19.9% of the samples had higher weight than the standard commercial weight (50 grams). The results also revealed that male crayfish slightly dominated in captured samples (male: female, 1.07:1). Under the light of this study, it can be concluded that decreased catch value and crayfish size in comparison to previous studies carried out last decade, A. leptodactylus has a critical condition in Aras dam lake. Therefore, it is thought that further researches on the conservation and improving stocking density of this species in Aras dam lake are urgently required

Keywords

length-weight frequency, sex ratio, crayfish, Astacus leptodactylus, Aras dam lake

ARAS REZERVUAR (İRAN)’INDA YAŞAYAN TATLISU ISTAKOZU (ASTACUS LEPTODACTYLUS)’NUN CİNSİYET ORANI, UZUNLUK VE AĞIRLIK DAĞILIMI

Abstract

Tatlısu ıstakozu (kerevit) ticari olarak avcılığı yapılan önemli krustasea türlerinden biridir. Bu canlıların besin değerleri de oldukça yüksektir. Kerevitler bentik organizmalar olup, yaşamlarının büyük bölümünü su ortamlarının tabanlarında geçirirler. Bu çalışmada, Aras baraj göletinde yaşayan Astacus leptodactylus’un 2011 ilkbaharı ile 2012 kış mevsimleri arasında cinsiyet oranı ve bazı biyometrik özellikleri araştırıldı. Kerevitlerin ortalama toplam uzunluğu ve ağırlığı sırasıyla 106,26±12,9 mm ve 38,79±15,5 g olarak bulundu. Bulgular, yakalanan kerevitlerden sadece %13,67’sinin standart ticari uzunluğun (120 mm) ve %19,9’unun standart ticari ağırlığın (50 g) üzerinde olduğunu gösterdi. Bulgular ayrıca, erkek bireylerin dişi bireylere oranının azda olsa daha yüksek olduğunu gösterdi (erkek: dişi, 1.07:1). Sonuç olarak, bu çalışmada elde edilen bulgular, Aras baraj göletinde daha önceden yapılan çalışmalarla karşılaştırıldığında, A. leptodactylus’un yakalanan miktarında ve yakalanan bireylerin büyüklüğünde azalmanın olduğunu, ortamda yaşayan kerevitin durumunun birkaç yıl öncesine göre daha iyi olmadığını, ortaya çıkarmaktadır. Bu nedenle, Aras baraj göletinde yaşayan A. leptodactylus’un korunması ve stok yoğunluğunun arttırılması için çalışmaların yapılmasının gerektiği düşünülmektedir. 

Keywords

uzunluk ağırlık frekansı, cinsiyet oranı, kerevit, Astacus leptodactylus, Aras baraj gölü

References

• Abele, L.G., (1982). The Fossil Record and Biogeography of Crustacea. Academic Press, New York.
• Ackefors, H., (2000). Freshwater crayfish farming technology in the 1990s: a European and global perspective. Fish and Fisheries 1: 337-359.
• Baradaran naviri, Sh., (2001). Length and weight comparision of A.leptodactylus in Khazar lake and Aras reservoir habitats, Paghohesh and Sazandegi, 52: 94-97.
• Bayrak, M., (1985). Research on fecundity and growth of freshwater crawfish (A. leptodactylus. Esch., 1823) in Morgan Lake. Ph.D. Thesis, Ankara University, Turkey.
• Bowman, T.E. and Abele, L.G., (1982). Classification of the Recent Crustacea. Academic Press, New York.
• Cobb, J. S., and D. Wang., (1985). Fisheries biology of lobsters and crayfishes. Ch. 3. pp. 167-247. In, A. J. Provenzano (ed.), the Biology of Crustaceans. Vol 1. pp 206-208.
• Harlıoğlu M.M., (2004). The present situation of freshwater crayfish, Astacus leptodactylus (Eschscholtz, 1823) in Turkey, Aquaculture, Volume 230, Number 1, pp. 181-187(7).
• Harlıoğlu, M.M., Holdich, D.M., (2001). Meat yields in the introduced crayfish, Pacifastacus leniusculus and Astacus leptodactylus, from British waters., Aquaculture Research, 32, 411-417.
• Holdich, D.M and Lowery, R.S., (1988). An Introdaction. In Freshwater Crayfish (eds: Holdich and Lowery). Croom Helm, London. pp 1-7.
• Karimpour, M., Hossein pour, S.N., (2000). Length structure, sex ratio, and CPUE of A.leptodactylus in Aras reservoir, Iranian Journal of Fisheries Research, 9(1): 49- 64.
• Karimpour, M., Khanipour, A., Taghavi Motlagh, S., (2004). Some biological characteristics of Khazar A.leptodactylus in Anzali port beaches, Iranian Journal of Fisheries Research, 13(1): 129- 148.
• Karimpour, M., (2003). Final project report of stock monitoring of A.leptodactylus in Aras reservoir, Bony Fishes Research Center of the Caspian Sea, Anzali port, pp. 44.
• Karimpour, M., Hosseinpour, S.N., Haghighi, D., (1991). Some studies on freshwater crayfish of Anzali lagon, Iranian Fisheries Organization, pp.22.
• Köksal, G., (1988). Astacus leptodactylus in Europe. In: Freshwater crayfish: biology, management and exploitation, Holdich D.M., Lowery R.S. (Eds.), 365-400, Croom Helm, London.
• Mehraban, H., (1999). Absolute fecundity of lobster, B.S.c. Thesis, National Resources University of Zabol, p. 33.
• Mohammadi, Gh.H., Keivan, A., Vosoghi, Gh.H., Matinfar, A., (2007). The comparision of meristic characteristics of A.leptodactylus leptodactylus in Anzali lagon and Aras reservoir habitats. Pazhohesh and Sazandegi, 75: 171-180.
• Mohsenpour Azari, A., Yahyazadeh, M.Y. Mohebbi, F., Ahmadi, R.,Moniri,Y. Gangi,S., Shiri, S., (2011). Final project report of the study of environmental factors effects of Aras river and its reservoir on growth of freshwater crayfish, Iranian Fisheries Research Organization , p.172.
• Romiantsef, V., (1989). The riverin cray fishes (crabs) of Caspean Sea (in Russian), translated by Holchik, Zh., translated in Persian: Hossein pour, S.N., 1991, Gilan Fisheries Research Center, Anzali port, p.12.
• Starobogatov, Ya.I., (1995). Crustaceans. Inventory of Freshwater Invertebrates in Russia. V.2: 177-180 (in Russian).
• Vladykov, V. D., (1964). Inland Water Fisheries Resources of Iran Especially of the Caspian Sea with Special Reference to Sturgeon. 51. FAO Report, 1818. Rome.
• Westman, K., Pursiainen, M. & Westman, P., (1990). Status of crayfish stocks, fisheries, diseases and culture in Europe. Report of the FAO European Inland Fisheries Advisory Commission (EIFAC) Working Party on Crayfish. Helsinki.
• Wickins, J.F. and Lee, D.O’C., (2002). Crustacean Farming Ranching and Culture. Blackwell Science, Oxford. 446 pp. ISBN 0-632-05464-6.
• Woodland, D.J., (1967). Population study of a freshwater crayfish. Ph.D. Thesis, University of New England, Australia.