Journal of Environmental Biology

Reproductive biology, histomorphometry and annual maturation cycle of Barilius vagra in Ladhia river, a mid-altitudinal Himalayan lotic ecosystem of Uttarakhand, India

R. Riyaz¹, P. Dash³, K. Kunal², R. Tandel³, P.B. Sawant¹ and D. Sarma¹*     

¹Division of Aquaculture, Indian Council of Agricultural Research-Central Institute of Fisheries Education, Versova, Mumbai-400 061, India

²Indian Council of Agricultural Research- Directorate of Coldwater Fisheries Research, Bhimtal-263 136, India

³Indian Council of Agricultural Research- Central Institute of Brackishwater Aquaculture, Navsari-396 450, India

Received: 03 July 2024                   Revised: 20 August 2024                   Accepted: 11 November 2024

*Corresponding Author Email : debajit@cife.edu.in                  *ORCiD: https://orcid.org/0000-0002-2425-7017

Abstract

Aim: To assess the influence of seasonal changes on the reproductive indices and gonadal maturation of Barilius vagra for future management planning in Central Himalayan rivers.

Methodology: A total of 104 specimens (37 males, 67 females), measuring 5-12 cm and weighing 3-17 g, were collected from the Ladhia River, Uttarakhand, between September 2019 and July 2020. Variations in gonadal histology and gonadosomatic index (GSI) were analyzed to assess reproductive status. Other factors, such as sex ratio, size distribution, condition factor, sexual maturity, fecundity and ova diameter were also studied.

Results: The sex ratio favored females (1:1.12), which were generally larger (8-10 cm). Lm₅₀ for males was 6.6 cm and 7.6 cm for females. Fecundity ranged from 1,640 to 3,354 eggs (9.25±0.2 cm, 5.46±0.31 g), and ova diameters from 17 to 887 µm. The condition factor was less than 1 across seasons, indicating poor well-being of Barilius vagra. Gonadal histology revealed five stages of development: spawning capable, regressing, regenerating, developing and immature.

Interpretation: B. vagra is an asynchronous spawner with a spawning period from late monsoon to early autumn. Seasonal variations significantly affect its reproductive biology, influenced by environmental factors in the Ladhia River.

Key words: Barilius vagra, Fecundity, Gonadosomatic index, Maturity, Oocyte frequency, Sex ratio

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