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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