Fishery-induced Inter-annual Changes in the Mean Trophic Level, the Northern Sea of Oman off the Iranian Coast, 2002–2011
- 20 Downloads
Ecosystem-based management is one of the most important approaches that may lead to reducing the impacts of fishing on ecosystems. In this context, we have assessed the impact of Iranian coastal fishing (using landing data of 49 exploited species) on the ecosystem of the North Sea of Oman (Sistan and Baluchestan Province), during the last decade (2002–2011), with emphasis on testing the occurrence of the “fishing downˮ phenomenon. The Mean Trophic Level (MTL) and Fishing-in-Balance (FiB) index are two indicators that we used for analysis. The data indicated that the increased total landings in this region might be related to the exploitation of marine fishery resources especially with regard to large pelagic fish. Over the past decade, moderate decreasing trends in MTL and an increasing trend in the FiB-index were observed. In this regard, an upward trend in the spatial expansion factor and also a downward trend in the piscivory index and in Primary Production Required (PPR) in the time period could all indicate a spatial expansion toward deep waters, the catching of the large pelagic piscivorous species, such as tuna, and a sign of fishing pressures on the ecosystem. The results suggest a range of fishery exploitation patterns throughout the food web but it seems that these patterns are not a consequence of ʻfishing downʼ. We suggest that the monitoring research be continued in this region and these indicators should be used to make fisheries management decisions and to prevent the continuance of this trend in future.
Keywordsmean trophic level fishing-in-balance fisheries management fishing down marine food web Oman Sea
Unable to display preview. Download preview PDF.
- Alhabsi MS, Malaysia TDI, Mustapha NHN (2011) Fisheries sustainability in Oman. J Econ Sustain Dev 2(7):35–49Google Scholar
- Al-Sabbagh T, Dashti J (2009) Post-invasion status of Kuwait’s fin-fish and shrimp fisheries (1991–1992). World J Fish Mar Sci 1(2):94–96Google Scholar
- Dadzie S, Manyala JO, Abou-Seedo F (2005) Aspects of the population dynamics of Liza klunzingeri in the Kuwait Bay. Cybium 29(1):13–20Google Scholar
- Daliri M, Paighambari SY, Shabani MJ, Pouladi M, Davoodi R (2012) Length-weight and length-girth relationships, relative weight and relative condition factor of four commercial fish species of Northern Persian Gulf. Annu Rev Res Biol 2:15–26Google Scholar
- Hirawake T, Tobita K, Ishimaru T, Satoh H, Morinaga T (1998) Primary production in the ROPME Area. In: Otsuki A, Abdulraheem MY, Reynolds RM (eds) Offshore environment of the ROPME sea area after the war-related oil spill. Terra Scientific, Tokyo, pp 181–191Google Scholar
- Nergi SK (2014) A review of IRAN Fisheries Data & Statistics with emphasis tuna fishes. In: Present to 10th Session of the Working party on Data Collection and Statistics (WPDCS10) Seychelles, Victoria, 2–4 December 2014, IOTC–2014–WPDCS10-12 Rev2Google Scholar
- Pauly D, Palomares ML (2005) Fishing down marine food web: it is far more pervasive than we thought. B Mar Sci 76(2):197–211Google Scholar
- Planning and Programming Department (2003) Fishery statistics yearbook (1992–2002). Iran Fisheries Company, Tehran, 60 pGoogle Scholar
- Rashid Al-Kiyumi F, Al-kharusi L, Nishida T, Al-Siyabi B (2013) Standardization of kawakawa (Euthynnus affinis) catch rates of drift gillnet fisheries in Sultanate of Oman. In: Third Working Party on Neritic Tunas, Bali, Indonesia, 2–5 July 2013, IOTC–WPNT03 31Rev 2Google Scholar
- Willemse N, Pauly D (2004a) Reconstruction and interpretation of marine fisheries catches from Namibian water, 1950–2000. In: Sumaila UR, Steinshamn SI, Boyer D, Skogen MD (eds) Namibia’s fisheries: ecological, economic and social aspects. Eburon, Netherlands, pp 99–112Google Scholar
- Willemse N, Pauly D (2004b) Ecosystem overfishing: a Namibian case study. In: Chavance P, Ba M, Gascuel D, Vakily M, Pauly D (eds) Proceeding of the international symposium on “Marine Fisheries, Ecosystems and Societies in West Africa: Half a Century of Change”, Dakar, 24–28 June 2002, pp 253–260Google Scholar