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Effect of the size and density of released Cyprinus carpio juveniles on the restoration of Caspian Sea stocks
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Ziya Kordjazi1   , Hojjat Jafaryan1 , Mohammad Farhangi1 |
| 1- Gonbad Kavous University |
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Abstract: (557 Views) |
| The quality of hatchery reared juvenile fish and their releasing quality to the wild would impact the rate of stock enhancement in the aquatic resource. This study examined the impact of size and density of the hatchery-reared juveniles on the biomass, catch and profit of fishing activities of common carp in the Caspian Sea. Data used in this study was extracted through literatures review, including the number and the size of hatchery reared juveniles of common carp at the releasing time to the wild, annual catch of common carp from 1999 to 2017 in the south-east of the Caspian Sea, and population parameters of common carp estimated using length frequency data in 2019 and 2020. The results indicated that economic rent and biomass decreased in the population without stocking. While, releasing hatchery-reared juveniles at the length of 7 cm (the length equal to the 10% of ) showed that catch profit and relative biomass declined by increasing fishing effort, which was associated with overfishing. Thus, releasing one-gram hatchery-reared, which the length of released juveniles is less than 10% of population asymptotic lengthy , may not increase common carp yield and biomass. In contrast, this may only increase the cost of stock enhancement. In addition, when the size or length of released juveniles increased to the 10% of population asymptotic length, the maximum economic rent (gross revenue) was obtained in the 30% of fishing effort unit. |
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| Keywords: Release of hatchery-reared fish, Stock enhancement, Cyprinus carpio, Caspian Sea |
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Full-Text [PDF 336 kb]
(162 Downloads)
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Type of Study: Research |
Subject:
مديريت و حفاظت منابع آبي
Received: 2023/06/13 | Accepted: 2024/08/31 | Published: 2024/10/2
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