Mean Trophic Level and Fishing in Balance index of fisheries landings in the Persian Gulf and Oman Sea

Seyed Ahmadreza HASHEMI, Javad GHASEMZA

Abstract

This study examined the changes in Mean Trophic Level (MTL) and Fishing in Balance index (FiB) of the Iranian fisheries harvested from the Persian Gulf and Oman Sea during the period from 1997 to 2016. The MTL was initially increased significantly followed by a consistent decline for two decades (R=0.45, P<0.05). The MTL demonstrated a declining process that might be attributed to over exploitation of fish stocks. The FiB index also illustrated an intermittent process and positive values from 1998 to 2016, that could be related to the unbalanced condition in this ecosystem (R=0.92, P<0.05). The analysis and interpretation of the MTL and FiB patterns suggest that the fish stocks in the regional Iranian waters of the Persian Gulf and Oman Sea have been over-exploited, which might have been due to fishing down (FD) in this area. The results revealed that the fishery management strategies which were implemented during this period had not been appropriate and should be replaced with new policies and regulations based on the stock assessment, fishing effort, and other effective factors.

Keywords

Mean trophic level, Persian Gulf, Overexploited, Fishing in balance index.

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References

Bhathal, B. & Pauly, D. 2008. Fishing down marine food webs, and spatial expansion of coastal fisheries in India, 1950-2000. Fisheries Research 91(1): 26-34.

Branch, T.A.; Watson, R.; Fulton, E.A.; Jennings, S.; McGilliard, G.R.; Pablico, G.T.; Ricard, D. & Tracey, S.T. 2010. The trophic fingerprint of marine fisheries. Nature 468 (7322): 431-435.

Carpenter, K.E.; Krupp, F.; Jones, D.A. & Zajonz, U. 1997. Living marine resources of Kuwait, Eastern Saudi Arabia, Bahrain, Qatar and UAE, FAO species identification field guide for fishery purposes. FAO Publication. Rome.

Cheung, W.W.L.; Pitcher, T.J. & Pauly, D. 2005. A fuzzy logic expert system to estimate intrinsic extinction vulnerabilities of marine fishes to fishing. Biological Conservation, 124(1): 97-111.

Christensen, V. & Pauly, D. 1992. ECOPATH II-a software for balancing steady-state ecosystem models and calculating network characteristics. Ecological Modelling 61(3-4): 169-185.

Eagderi, S.; Fricke, R.; Esmaeili, H.R. & Jalili P. 2019. Annotated checklist of the fishes of the Persian Gulf: Diversity and conservation status. Iranian Journal of Ichthyology 6: 1-171

IFO. 2017. Report of fishery landing on Persian Gulf and Oman Sea, Iranian Fishery Organization. 75 p.

Jones, M.C. & Cheung, W.W.L. 2017. Using fuzzy logic to determine the vulnerability of marine species to climate change. ICES Journal of Marine Science 72(3): 741-752.

Mashjoor, S. & Kamrani, E. 2015. Evaluation of the “fishing down marine food web” process in the north-west of Persian Gulf (Khuzestan Province) during the period of 2002-2011. Acta Oceanologica Sinica 34: 103-110.

Mashjoor, S.; Heidary Jamebozorgi, F. & Kamrani, E. 2018. Fishery-induced Inter-annual Changes in the Mean Trophic Level, the Northern Sea of Oman off the Iranian Coast, 2002–2011. Ocean Science Journal 2-12.

Milessi, A.C. & Defeo, O. 2002. Long-term impact of incidental catches by tuna longlines: the black escolar (Lepidocybium flavobrunneum) of the southwestern Atlantic Ocean. Fisheries Research, 58(2): 203-213.

Milessi, A. C.; Arancibia, H. & Neira, S. 2005. The mean trophic level of Uruguayan landings during the period 1990–2001. Fisheries Research 74(1-3): 223-231.

Pauly, D.; Christensen, V.; Dalsgaard, J.; Froese, R. & Torres, J.F. 1998. Fishing down marine food webs. Science 279(5352): 860-863.

Pauly, D.; Christensen, V.; Froese, R. & Palomares M. 2000a. Fishing down aquatic food webs. American Scientist 88(1): 46-51.

Pauly, D.; Christensen, V. & Walters, C. 2000b. Ecopath, Ecosim, and Ecospace as tools for evaluating ecosystem impact of fisheries. ICES Journal of Marine Science 57(3): 697-706.

Pauly, D.; Palomares, M.L.; Froese, R.; Saa, P.; Vakily, M.; Preikshot, D. & Wallace, S. 2001. Fishing down Canadian aquatic food webs. Canadian Journal of Fisheries and Aquatic Sciences 58(1): 51-62.

Pauly, D.; Christensen, V.; Guénette, S.; Pitcher, T.J.; Sumaila, U.R.; Walters, C.J.; Watson, R. & Zeller, D. 2002. Towards sustainability in world, fisheries. Nature 418(6898): 689-695.

Pauly, D. & Palomares, M.L. 2005. Fishing down marine food web: it is far more pervasive than we thought. Bulletin of Marine Science 76(2): 197-212.

Rajaei, M.; Poorbagher, H.; Farahmand, H., Mortazavi M.S. & Eagderi, S. 2014. Interpopulation differences in shell forms of the pearl oyster, Pinctada imbricata radiata (Bivalvia: Pterioida), in the northern Persian Gulf inferred from principal component analysis and elliptic Fourier analysis. Turkish Journal of Zoology 38(1): 42-48

Razzaghi, M.; Mashjoor, S. & Kamarani, E. 2017. Mean trophic level of coastal fisheries landings in the Persian Gulf (Hormozgan Province), 2002–2011. Chinese Journal of Oceanology and Limnology 35(3): 528-536.

Reynolds, R.M. 1993. Physical Oceanography of the Gulf, Strait of Hormuz, and the Gulf of Oman, results from the Mitchell expedition. Marine Pollution Bulletin 27: 35-60.

Shannon, L.; Coll, M.; Bundy, A.; Gascuel, D.; Heymans, J.J.; Kleisner, K.; Lynam, C.P.; Piroddi, C.; Tam, J.; Travers-Trolet, M. & Shin, Y. 2014. Trophic level-based indicators to track fishing impacts across marine ecosystems. Marine Ecology Progress Series 512: 115-140.

Swift, S.A.; & Bower, A.S. 2003. Formation and circulation of dense water in the Persian/Arabian Gulf. Journal of Geophysics Research 108(C1): 3004-3012.

Valinassab, T.; Daryanabard, R.; Dehghani, R. & Pierce, G.J. 2006. Abundance of demersal resources in the Persian Gulf and Oman Sea. Journal of Marine Biological Association of the United Kingdom 86: 1455-1462.

Willemse, N.E. & Pauly, D. 2004. Reconstruction and interpretation of marine fisheries catches from Namibian waters, 1950 to 2000. In: U.R. Sumaila, D. Boyer, M. Skog et al. (eds). Namibia's Fisheries: Ecological, Economic and Social Aspects. The Netherlands, Eburon, Delft. pp: 99-112.

DOI: http://dx.doi.org/10.22034/iji.v6i4.340

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