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Age and Growth of Brown Trout (Salmo caspius) in Tonekabon River
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Nasim Panian   , Asghar Abdoli |
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Abstract: (445 Views) |
Due to the decline in the population of Caspian salmon (Salmo caspius) in the southern part of the Caspian Sea, the age and growth of this fish were studied in the Dohazar River in Tonekabon to improve conservation programs. In December 2018, 63 fish samples were collected using an electroshocker. Among these, 21 females and 42 males were captured, resulting in a sex ratio of 2:1, with a significant difference between the sexes (p<0.05). The length range of males and females was 7.5–18.5 cm and 6.5–21.5 cm, respectively, while their weight ranges were 3.99–65.5 g for males and 2.51–95.42 g for females. Age determination was conducted using scales. The age range of the population was from +1 to +5, with females distributed across 5 age groups and males across 4 age groups. The highest age frequency in all cases was in the 1+ and 2+year age groups. The von Bertalanffy growth equations for males and females were calculated as Lt = 230.462{1-exp(-0.327(t-(-0.240)))} and Lt = 300{1-exp(-0.213(t-(-0.139)))} respectively. The mean Monro index for the total sample was 2.26, with 2.23 for males and 2.28 for females. The study results show a significant decrease in the growth parameters of the species across all age groups. Both the growth coefficient and the asymptotic length of the species have decreased compared to previous years.
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| Keywords: Salmo caspius, von bertalanffy, age and growth, Age structure, Tonekabon River |
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Full-Text [PDF 1107 kb]
(77 Downloads)
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Type of Study: Research |
Subject:
Special
Received: 2024/08/30 | Accepted: 2024/09/6 | Published: 2024/10/21
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