Estimating the species diversity and abundance of discarded fish in the commercial catch of shrimp trawlers at the Lifeh fishing ground, Khuzestan province

Document Type : Research Paper

Authors

1 M.Sc. graduated, Department of Fisheries, Faculty of Marine Natural Resources, Khorramshahr University of Marine Science and Technology, Khorramshahr, Iran

2 Associate Professor, Department of Fisheries, Faculty of Marine Natural Resources, Khorramshahr University of Marine Science and Technology, Khorramshahr, Iran

3 Professor, Department of Fisheries, Faculty of Marine Natural Resources, Khorramshahr University of Marine Science and Technology, Khorramshahr, Iran

4 Associate Professor, Department of Fisheries, Faculty of Natural Resources, Isfahan University of Technology, Isfahan 84156-83111, Iran

10.22059/jfisheries.2024.370787.1412

Abstract

The present study aimed to estimate the quantity and composition of discarded fish species in bottom trawl in the Lifeh area of the coastal waters of Khuzestan. Data were collected based on samples obtained from commercial fishing the autumn of 2017 and the summer of 2018. The results of this study indicated that the discarded samples included 21 species from 16 families. Hamilton's thryssa, Sharhosehammer croaker and Orange-fin pony fish species were predominant. Moreover, the results demonstrated that the average length of most discarded species was below 30 centimeters, with the highest average length belonging to the large scale tongues at 3.8±3.23 centimeters and the lowest for the large scale tongues at 8.5±8.10 centimeters. The findings revealed the discard rate per fishing effort unit in autumn as 4.0±6.8 kilograms per hour and in summer as 8.7±2.7 kilograms per hour. The catch per unit area was also calculated at 24.0±16.0 and 7.15±0.0 kilograms per square mile during autumn and summer, respectively. Furthermore, the percentage frequency of commercial and non-commercial discarded species in autumn was calculated as 22.74 and 77.26, respectively, and in summer as 7.7 and 3.92, respectively. Considering the obtained results and the elevated discard rate in this area, it can evidently have negative impacts on fish stocks, potentially posing risks to the fishing industry in the region in the future.

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Aalizadeh, E., Peyghambari, S.Y., 2013. Investigation of catch per unit effort of shrimp in fishing grounds of Hormozgan province, Second National Fisheries and Aquaculture Congress, Bandar Abbas, Islamic Azad University, Bandar Abbas Branch. (In Persian)
Blanco, M., Nos, D., Lombarte, A., Recasens, L., Company, J.B., Galimany, E., 2023. Characterization of discards along a wide bathymetric range from a trawl fishery in the NW Mediterranean. Fisheries Research 258, 106552. DOI:10.1016/j.fishres.2022.106552
Borges, L., Zuur, A.F., Rogan, E., Officer, R., 2005. Choosing the best sampling unit and auxiliary variable for discards estimations. Fisheries Research 75(1-3), 29-39. DOI: 10.1016/j.fishres.2005.05.002
Brewer, D., Heales, D., Milton, D., Dell, Q., Fry, G., Venables, B., Jones, P., 2006. The impact of turtle excluder devices and bycatch reduction devices on diverse tropical marine communities in Australia’s northern prawn trawl fishery. Fisheries Research 81, 176-188. DOI: 10.1016/j.fishres.2006.07.009
Campo, J.A., Burgos, B., Gamboa, C., 1984. Effect of shrimp trawling on the commercial ichthyofauna of the Gulf of Nicoya, Costa Rica. Revista de Biología Tropical 32(2), 203-207.
Cetini, P., Skeljo, F., Ferri, J., 2011. Discards of the commercial boat seine fisheries on Posidonia oceanica beds in the eastern Adriatic Sea. Scientia Marina 75(2), 289-300. DOI: 10.3989/scimar.2011.75n2289
Dehghan Mediseh, S., Eskandari, Gh., Ismaeili, F., Mayahi, Y., Ghasemi, Sh., 2010. Final report of project: Identification and determination of abundanceof Juvenile of Fishes of Khuzestan. Iranian Fisheries Science Research Institute (IFSRI). (In Persian)
Eayrs, S., Buxton, C., McDonald, B., 1997. A guide to bycatch reduction in Australian prawn trawl fisheries. Australian Maritime College, Tasmania, 54 p.
Eskandari, Gh., Koochaknejad, E., Mayahi, Y., Ansari, H., 2016. Rate, ratio and amount of annual discards in commercial trawl net in northwestern part of the Persian Gulf (Khuzestan Coastal Waters). Journal of Marine Science and Technology 15(1), 84-99. (In Persian) DOI: 10.22113/jmst.2016.8576vz
FAO, 2012. The State of World Fisheries and Aquaculture 2012. Rome. 209 p.
FAO, 2022. The State of World Fisheries and Aquaculture 2022. Towards Blue Transformation. Rome, FAO. DOI: 10.4060/cc0461en.
Fischer, W., Hureau, J.C., 1985. FAO species identification sheets for fishery purposes Southern Ocean: Fishing Areas 48, 58 and 88 (CCAMLR Convention Area).
Gilman, E., Passfield, K., Nakamura, K., 2012. Performance Assessment of Bycatch and Discards Governance by Regional Fisheries Management Organizations. IUCN, Gland, Switzerland, ix, 484 p.
Gücü, A.C., 2012. Impact of depth and season on the demersal trawl discard. Turkish Journal of Fisheries and Aquatic Sciences 12(4), 817-830. DOI: 10.4194/1303-2712-v12_4_10
Hashemi, S.A.R., Valinassab, T., 2011. Stock assessment of demersal resources in the west northern of Persian Gulf water. Journal of Marine Science and Technology 3(6), 480-484. (In Persian)
Hoseininezha, S.A., Mohammadi, G.H., Eskandary, G.R., Hashemi, S.A.R., Khodadadi, M., 2012. Determination of Economic and Non-economic Species, Shrimp Trawl Net in North-West of Persian Gulf (Khuzestan Provinces). International Journal of Fisheries and Aquatic Sciences 1(2), 129-133.
Hoveizav, Sh., Doustshenas, B., Eskandari, Gh., Savari, A., Mohammadasgari, H., 2017. A survey of discard fish in Khuzestan fishery grounds. Journal of Marine Science and Technology 16(3), 72-88. (In Persian). DOI: 10.22113/jmst.2016.14845
Isaksen, B., Valdemarsen, J.W., 1994. Bycatch reduction in trawls by utilizing behavior differences. In: marine fish behavior in capture and abundance estimation. (Ed. A. Ferno and S. Olsen). Fishing News Books. pp. 69-83
Kelleher, K., 2005. Discards in the world’s marine fisheries. An update. FAO Fisheries Technical Paper. No. 470. Rome, FAO. 131 p. 
Lively, J.A. McKenzie, J., 2023. Discards and bycatch: A review of wasted fishing. Advances in Marine Biology 95, 1-26.
Mehrabani, K., Khosravizadeh, M., Yavari, V., Hosseini, S.M., Beyraghdar Kashkooli, O., 2022. Discards characteristics of Bottom trawl fishery in Khuzestan coastal waters (case study: Bosif fishing grounds). Journal of Marine Science and Technology 21(4), 1-16. (In Persian) DOI: 10.22113/jmst.2021.275449.2422
Morizur, Y., Caillart, B. Tingley, D., 1999. The problem of discards in fisheries. Encyclopedia of Life Support Systems.
Pinello, D., Gee, J., Accadia, P., Sabatella, E.C., Vitale, S., Polymeros, K., Fiorentino, F., 2018. Efficiency of shallow-and deep-water trawling in the Mediterranean and its implications for discard reduction. Scientia Marina 82(S1), 97-106. DOI:10.3989/scimar.04749.22A
Rochet, M.J., Trenkel, V.M. 2005. Factors for the variability of discards: assumptions and field evidence. Canadian Journal of Fisheries and Aquatic Sciences 62(1), 224-235. DOI: 10.1139/f04-185
Sepahi, A., Gorgin, S., Santos, J., Abbaspour Naderi, R., Azini, M.R., 2016. Composition and diversity of fish species caught using trawler in Chabahar waters. Journal of Applied Ichthyological Research 4(3), 29-42. (In Persian)
Shadi, A, Savari, A, Kochanian, P., Dehghan Mediseh, S., Gandomi, Y., 2011. Identification and Ecological Study of Juvenile Fishes of Khuzestan (North West Persian Gulf). Journal of Oceanography 2(5), 1-9. (In Persian)
Tsagarakis, K., Palialexis, A., Vassilopoulou, V., 2014. Mediterranean fishery discards: review of the existing knowledge. ICES Journal of Marine Science 71(5), 1219-1234. DOI:10.1093/icesjms/fst074
Valinassab, T., Zarshenas, Gh. and Fatemi, M., Otobideh, M. 2006. By-catch composition of small-scale shrimp trawlers in the Persian Gulf (Hormuzgan Province), Iran. Iranian Scientific Fisheries Journal 15(2), 129-138.
Yıldız, T., Karakulak, F.S., 2017. Discards in bottom‐trawl fishery in the western Black Sea (Turkey). Journal of Applied Ichthyology 33(4), 689-698. DOI: 10.1111/jai.13362