Estimation of fish composition and catchability coefficient of gillnet in the Shadegan Wetland

Seyed Ahmadreza HASHEMI, Rasoul GHORBANI, Farhad KYMARAM, Seyed Abass HOSSINI, Gholamreza ESKANDARI, Aliakbar HEDAYATI


To estimate the fish composition and catchability coefficient of gillnet, a survey was carried out during April 2011 to March 2012 in the Shadegan Wetland, Khuzestan Province, Iran. Samples were collected from five stations viz., Mahshar, Rogbe, Khorosy, ‍Salmane and Atish. Approximately 4300 fish specimens were measured and depletion method was used for the estimation of Catchability coefficients of gillnet. Mean±SD q value for Leslie model in different season was 0.008±0.006 and its maximum and minimum values were 0.001 (summer) and 0.004 (spring), respectively. Mean±SD q value for Delury model in different seasons was 0.0007±0.0001 and its maximum and minimum values were 0.002 (summer) and 0.0007 (winter), respectively. Mean±SD of q value for Leslie model in different stations was 0.008±0.006 and for Delury model in different station was 0.003±0.001. Mean catchability value of Leslie model was higher than that for Delury model. Using Students t-test, no significant differences between the calculated Leslie and Delury models among the different stations (P>0.05) and different seasons were observed (P>0.05). A comparison of catchability values showed that there are no significant differences among different seasons (ANOVA, F=0.32, P>0.05) and among different stations (ANOVA, F=0.29, P>0.05).


Catchability, Gillnet, Shadegan Wetland, Iran.

Full Text:



Addison, J.T.; Lawler, A.R. & Nicholson, M.D. 2003. Adjusting for variable catchability of brown shrimps (Crangon crangon) in research surveys. Fisheries Research 65: 285–294.

Arreguin-Sanchez, F. 1996. Catchability: a key parameter for fish stock assessment. Journal of Fish Biology 6: 221–242.

Brazner, J.C. 1997. Regional, habitat, and human development influences on coastal wetland and beach fish assemblages in Green Bay, Lake Michigan. Journal of Great Lakes Research 23: 36–51.

Brazner, J.C.; Tanner, D.K.; Detenbeck, N.E.; Batterman, S.L.; Stark, S.L.; Jagger, L.A. & Snarski, V.M. 2005. Regional, habitat, and human development influences on coastal wetland and beach fish assemblages in Green Bay, Lake Michigan. Journal of Great Lakes Research 23 (2): 36–51.

Brouwer, E.; Bobbink, R. & Roelofs, J.G.M. 2002. Restoration of aquatic macrophyte vegetation in acidified and eutrophied lakes: an overview. Aquatic Bulletin 73: 405–431.

Burridge, C.Y.; Pitcher, C.R.; Wassenberg, T.J.; Poiner, I.R. & Hill, B.J. 2003. Measurement of the rate of depletion of benthic fauna by prawn (shrimp) otter trawls: an experiment in the Great Barrier Reef, Australia. Fisheries Research 60: 237-253.

Chapman, D.G. 1961. Statistical problems in dynamics of exploited fisheries populations. Berkeley Symposia. Mathematical and Statistical Probability 4 (1): 153-168.

Cowx, I.G. 1983. Review of the methods for estimating fish population size from survey removal data. Fisheries Management 14: 67–82.

Delury, D.B. 1947. On the estimation of biological populations. Biometrics 3: 145–167.

Francis, R.I.C.C.; Hurst, R.J. & Renwick, J.A. 2003. Quantifying annual variation in catchability for commercial and research fishing. Fishery Bulletin 101: 293–304.

Gulland, J.A. 1964. Catch per unit effort as a measure of abundance. ICES Rapp. Proc. Verb. 155: 8-14.

Hashemi, S.; Eskandary, G. & Ansary, H. 2012. Biomass of fish species in the Shadegan Wetland, Iran. Research Journal of Recent Sciences 1(1): 66-68.

Hashemi, S., Eskandary, G., Ansary, H. & Yooneszadeh, M. 2011. Stock assessment and production of fish species in the Shadegan Wetland, Iran. World Journal of Fish and Marine Sciences 3(6): 502-508.

Hilborn, R. & Walters, C.J., 1992. Quantitative Fisheries Stock Assessment Choice, Dynamics, and Uncertainty. Chapman & Hall, New York.

Houghton, R.G. & Flatman, S. 1980. The exploitation pattern, density-dependent catchability, and growth of cod (Gadus morhua) in the west-central North Sea. ICES Journal 39: 271-287.

Kholfenilsaz, M. 2009. Survey frequency and diversity of planktonic in Shadegan Wetland. Scientific Journal of Marine Biology, Islamic Azad University, Ahvaz Branch 1:1-12.

King, M.G. 2007. Fisheries biology assessment and management. 2nd edition, Blackwell Publishing Ltd. 189-194.

Lee, G.F.; Jones, P.E. & Jones, R.A. 1991. Effects of eutrophication on fisheries. Aquatic Science 5: 287–305.

Leslie, P.H. & Davis, D.H.S. 1939. An attempt to determine the absolute number of rats on a given area. Journal of Animal Ecology 8: 94–113.

Loneragan, N.R.; Wang, Y.G.; Kenyon, R.A.; Staples, D.J.; Vance, D.J. & Healesl, D.S. 1995. Estimating the efficiency of a small beam trawl for sampling tiger prawns Penaeus esculentus and P. semisulcatus in sea grass by removal experiments. Marine Ecology Progress Series 18(2): 139-148.

Lotfi, A.; Ghafari, H.; Behrozirad, B.; Savari, A. & Kawosi, K. 2003. Human activity and their affect in Shadegan Wetland. Counselor Engineering Publisher.

McAllister, M.K.; Hill, S.L.; Agnew, D.J.; Kirkwood, G.P. & Beddington, J.R. 2004. A Bayesian hierarchical formulation of the Delury stock assessment model for abundance estimation of Falkland Islands’ squid (Loligo gahi). Canadian Journal of Fisheries and Aquatic Sciences 61: 1048–1059.

Mitsch, W.J. & Gosselink, J.G. 2000. The value of wetlands: Importance of scale and landscape setting. Ecological Economics 35(1): 25-35.

Olin, M. & Malinen, T. 2003. Comparison of gillnet and trawl in diurnal fish community sampling. Hydrobiologia 506–509: 443-449.

Olin, M.; Rask, M.; Ruuhijärvi, J.; Kurkilahti, M.; Ala-Opas, P. & Ylönen, O. 2002. Fish community structure in mesotrophic and eutrophic lakes of southern Finland: the relative abundances of percids and cyprinids along a trophic gradient. Journal of Fish Biology 60: 593-612.

Quinn, T.J. & Deriso, R.B. 1999. Quantitative Fish Dynamics. Oxford University Press, New York.

Ricker, W.E. 1975. Computation and interpretation of biological statistics for fish populations. Fisheries Research Bulletin 191: 2-6.

Salthaug, A. & Aanes, S. 2003. Catchability and the spatial distribution of fishing vessels. Canadian Journal of Fisheries and Aquatic Science 60: 259–268.

Seber, G.A.F. & Le Cren, E.D. 1967. Estimating population parameters from catches large relative to the population. Journal of Animal Ecology 36: 631-643.

Swain, D.P. & Sinclair, A.F. 1994. Fish distribution and catchability: what is the appropriate measure of distribution? Canadian Journal of Fisheries and Aquatic Sciences 51: 1046–1054.

Tonn, W.M. & Magnuson, J.J. 1982. Patterns in the species composition and richness of fish assemblages in northern Wisconsin lakes. Ecology 63: 1149–1166.

Winters, G.H. & Wheeler, J.P. 1985. Interaction Between stock area, stock abundance, and catchability coefficient. Canadian Journal of Fisheries and Aquatic Sciences 42: 989-998.

Wright, I.; Caputi, N. & Penn, J. 2006. Depletion-based population estimates for western rock lobster (Panulirus Cygnus) fishery in Western Australia. Journal of Marine and Freshwater Research 40(1): 107–122.

Young, I.A.G.; Pierce, G.J.; Daly, H.I.; Santos, M.B.; Key, L.N.; Bailey, N.; Robin, J.P.; Bishop, A.J.; Stowasser, G.; Nyegaard, M.; Cho, S.K.; Rasero, M. & Pereira, J.M.F. 2004. Application of depletion methods to estimate stock size in the squid, Loligo forbesi, in Scottish waters (UK). Fisheries Research 69(2): 211-227.

Zhou, S.; Dichmont, C.; Burridge, C.Y.; Venables, W.; Toscas, P. & Vance, D. 2007. Is catchability density-dependent for schooling prawns? Fisheries Research 85(1): 23–36.

Zhou, S.; Vance, D.; Dichmont, C.; Burridge, C. & Toscas, P.J. 2008. Estimating prawn abundance and catchability from catch-effort data: comparison of fixed and random effects models using maximum likelihood and hierarchical Bayesian methods. Journal of Marine and Freshwater Research 59: 1–9.


  • There are currently no refbacks.