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Changes in demographic indicators based on length of common dolphinfish (Coryphaena hippurus Linnaeus, 1758) over the past decades in the northern waters of the Sea of Oman (Sistan and Baluchistan Province)
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Mastooreh Doustdar    , Seyed Ahmadreza Hashemi , Ashkan Azhdari , Sayemeh Jadgal |
| Iranian fishery science reserch institute & agricultural Research,Education and Extension Organization (AREEO , mastooreh.doustdar@gmail.com |
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Abstract: (142 Views) |
Background and Objectives: The Galit fish has high commercial value, and its catch has experienced significant fluctuations in recent years. The catch in the Persian Gulf and the Sea of Oman has increased from approximately 1.2 thousand tons in 1381 (2002-2003) to about 10 thousand tons in 1402 (2023-2024) (Figure 1). Sistan and Baluchestan Province accounts for over 90% of the catch of this species in the southern waters of the country. This research is about the exploitation status of the Galit fish in the northern waters of the Oman Sea (Sistan and Baluchestan Province). Its objective is to provide fundamental information for understanding and implementing proper and systematic management of its exploitation, as well as gaining a better understanding of the biological and population characteristics of this species, whose catch has been increasing in recent years.
Methods: Four fishing discharge zones in the ports of Pozm (with geographical coordinates longitude 60°28' and latitude 25°14'), Konarak (longitude 26°60' and latitude 25°60'), Beris (longitude 61°15' and latitude 25°16'), and Pasabandar (longitude 61°20' and latitude 25°12') in Sistan and Baluchestan Province were selected as sampling stations for the fish species Gallit.
Findings: During the years 1994 and 2024, more than 2 thousand fish were biometrically measured, and the average length (range) of the common dolphinfish in 1994 was 86±14 (52-127) cm and in 2024 it was 36±8 (58-17) cm.The average weight (range) of the common dolphinfish in 1994 was 5777 (19500-12000) grams and in 2024 it was 1310 (200-4100) grams. The relationship between fork length and body weight was obtained for 1994, W=0.058 L^2.56 (R2=0.89, N=331) and for 2024, W=0.098 L^2.52 (R2=0.85, N=291), and the b value of the length-weight relationship was indicative of allometric (asymmetric) growth. The Van Bertalanffy equation for this species in Sistan and Baluchestan province in 1994 and 2024 was calculated as: Lt = 153 (1- exp (-0.28 (t +0.38)) and Lt = 143 (1- exp (-0.36 (t +0.31)) respectively.
Conclusion: The ratio of B/BMSY and the ratio of F/FMSY in 1994 and 2024 were estimated to be 1.49, 1.37 and 2.55, 2.38, respectively. The ratio of LBSPR in 1994 was 0.45 (0.51-0.39) and in 1994 was 0.50 (0.54-0.46). Decrease Average length, average weight, exploitation rate, fishing mortality index to maximum sustainable yield (F/FMSY >1) can be evidence of overfishing. Based on the results obtained, there are signs of overfishing and for this reason, a precautionary approach should be considered in the management and exploitation of this species. |
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| Keywords: Coryphaena hippurus, LBSPR ratio, B/BMSY, F/FMSY. |
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Full-Text [PDF 2772 kb]
(81 Downloads)
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Type of Study: Research/ Original/ Regular Article |
Subject:
Fisheries and Aquaculture
Received: 2025/05/10 | Revised: 2025/09/21 | Accepted: 2025/09/6 | ePublished: 2025/09/7
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