Studying natural reproduction, spawning grounds and spawning period of Vimba vimba persa population in Sefid-roud River, Guilan Province in north Iran

Document Type : Research Paper

Authors

1 Anzali

2 Tehran

3 tehran

Abstract

To evaluate spawning status of Vimba vimba population in Sefid-roud river, 621 breeders, 1136 larvae, fries and fingerlings were caught in the river using beach seine, cast-net and electro-choker over the years 1999-2000. We found that the fish started spawning migration in March and continued it until July with its peak occurring between mid-April to late-May. Fork length was 116 - 208 mm (153.1 ± 17.95) in male specimens and 122 - 222 mm (173.5 ± 16.46) in females. Total body weight ranged 21.1-116.1 g (52.92 19.23) in males and 23.1 - 170.0 g (77.90 ± 22.88) in females. Males aged 2-6 years (3.53±0.86) and females aged 3-7 years (4.19±0.92) participated in the spawning with their maturity age being calculated as 2 and 3 years respectively. In all, breeders were composed of 51.82% males and 48.18% females with the ratio being significantly different only in May. Gonad weight was 1.13-7.92 g (Avg. 2.89±0.29) in males and 3.21-25.47g (Avg. 10.40±1.52) in females. We found the highest gonad weight for the fish in June and that the gonad weight in female breeders increased upwards of the estuary. Gonado-somatic index was 19-21% in 85.7% of the females and 3-8% in 95.5% of the males. Spawning of the species took place during day and night from late May to late June with its peak in May in water temperature ranging 18-29 degrees centigrade on pebble and gravel grounds from 25 to 75kms away from estuary. The Disaam tributary was distinguished as the major spawning area for the species.

Keywords

Iranian Scientific Fisheries Journal
Volume 14, Issue 3
November and December 2005
Pages 113-126

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