Demographic patterns of an endemic cichlid, Etroplus suratensis, across five rivers in the Western Ghats Biodiversity Hotspot, India

Chelapurath Radhakrishnan Renjithkumar; Kuttanelloor Roshni

doi:10.3153/AR26007

EN

Demographic patterns of an endemic cichlid, Etroplus suratensis, across five rivers in the Western Ghats Biodiversity Hotspot, India

Abstract

Etroplus suratensis (Cichlidae), a commercially important food fish endemic to the Western Ghats (WG) biodiversity hotspot in India, has shown a marked decline in population due to excessive exploitation. To assess the impacts of overexploitation on E. suratensis, as detailed information on the fishery and current population status is lacking. The study examined the fishery, length-weight relationships (LWRs), growth patterns, mortality rates, and exploitation status of E. suratensis across five major rivers in the Western Ghats of India. The annual catches of E. suratensis ranged from 1.3 to 4.75 tons/year. Total mortality ranged from 0.93 yr-1 to 2.16 yr-1, while fishing mortality varied from 0.36 yr-1 to 1.37 yr-1. The length at first capture (Lc) was lower than the length at first maturity (Lm), indicating that more than half of the E. suratensis population is harvested before attaining reproductive maturity. The stock of E. suratensis in most rivers appears to be approaching full exploitation under the current fishing levels. Implementing management measures such as seasonal fishing closures, mesh size regulations, establishment of fish sanctuaries, and adoption of quota systems could help promote the sustainable utilisation and conservation of E. suratensis populations.

Keywords

Ethical Statement

As Etroplus suratensis is not listed as threatened on the IUCN Red List or under any national or regional legislation, including the Indian Wildlife (Protection) Act, and since no fish were killed explicitly for this study, the research was considered non-invasive. Samples were obtained from commercial catches available at fish landing sites, eliminating the need for specific ethics approval. The study was exempted from ethics review based on institutional guidelines.

Thanks

The authors express their gratitude to the local fishers for their assistance in collecting fish samples.

References

Barry, J.P., Tegner, M.J. (1990). Inferring demographic processes from size–frequency distributions: simple models indicate specific patterns of growth and mortality. Fishery Bulletin US, 88, 13–19.
Beverton, R.J.H., Holt, S.J. (1966). Manual of methods for fish stock assessment. Part 2. Tables of yield functions. Rome: FAO, FAO Fish Technical Paper No 38 (Rev. 1), Rome.
Bindu, L., Padmakumar, K.G. (2014). Reproductive biology of Etroplus suratensis (Bloch) from the Vembanad wetland systems, Kerala. Indian Journal of Geo Marine Science, 43(4), 646–656. https://doi.org/10.21077/ijf.2019.67.2.69586-18
Bindu, L., Padmakumar, K.G. (2020). Catch and size composition of Etroplus suratensis (Bloch, 1790) from Kumarakom region of Vembanad Lake, India. Indian Journal of Fisheries, 67(2), 125-129. https://doi.org/10.1007/BF00005346
Branstetter, S. (1987). Age, growth and reproductive biology of the silky shark, Carcharhinus falciformis, and the scalloped hammerhead, Sphyrna lewini, from the northwestern Gulf of Mexico. Environmental Biology of Fishes, 19(3), 161–173.
Cooke, S.J., Allison, E.H., Beard, T.D., Arlinghaus. R., Arthington, A.H, Bartley, D.M et al. (2016). On the sustainability of inland fisheries: Finding a future for the forgotten. Ambio, 45, 753–764. https://doi.org/10.1007/s13280-016-0787-4
Dahanukar, N., Raghavan, R. (2013). Freshwater fishes of Western Ghats: Checklist v 1.0 August 2013. MIN - Newsletter of IUCN SSC/WI Freshwater Fish Specialist Group - South Asia and the Freshwater Fish Conservation Network of South Asia (FFCNSA).
Dahanukar, N., Raghavan, R., Ali, A., Abraham, R., Shaji, C.P. (2011). The status and distribution of freshwater fishes of the Western Ghats. Chapter 3. In The status and distribution of freshwater biodiversity in the Western Ghats, India. (Eds S Molur, KG Smith, BA Daniel, WRT Darwall) pp. 21–48 (Cambridge, UK and Gland, Switzerland: IUCN, and Coimbatore, India: Zoo Outreach Organisation).

Froese, R. (2006). Cube law, condition factor and weight–length relationships: History, meta-analysis and recommendations. Journal of Applied Ichthyology, 22, 241–253. https://doi.org/10.1111/j.1439-0426.2006.00805.x
Fricke, R., Eschmeyer, W.N., van der Laan, R. (2023). Eschmeyer's Catalog of Fishes: Genera, Species, References. Available at https://researcharchive.calacademy.org/research/ichthyology/catalog/fishcatmain.asp (accessed September 4, 2024).
Gayanilo, F.C., Sparre, P., Pauly, D. (2005). The FAO-ICLARM stock-assessment tools II (FiSAT II). User's guide. Revised version FAO Computerized Information Series (Fisheries) Vol. 8. FAO, Rome.
Gulland, J.A. (1971). The fish resources of the Ocean West Polyfleet Survey. FAO Technical Paper. 97, Rome.
King, A.J, Humphries, P., Lake, P.S. (2003). Fish recruitment on floodplains: The roles of patterns of flooding and life history characteristics. Canadian Journal of Fisheries and Aquatic Sciences, 60, 773–786. https://doi.org/10.1139/f03-057
Kurup, B.M., Sebastian, M.J., Sankaran, T.M., Rabindranath, P. (1993). Exploited Fishery Resources of the Vembanad Lake, Status of Residents and Migrants. Fishery Technology (Special issue: Society of Fishery Technologists, India), Kerala, India.
Kurup, B.M., Sebastian, M.J., Sankaran, T.M., Rabindranath, P. (1995). Exploited fishery resources of Vembanad lake 4: estimates of marketable surplus of production. Journal of Marine Biological Association of India, 37, 1–10.
Jayaprakas, V., Nair, N.B. (1981). Maturation and spawning in the pearl spot Etroplus suratensis (Bloch), Proceedings of the National Academy of Sciences, India Section B: Biological Sciences, 47(6), 828–836.
Le Cren, E.D. (1951). The length-weight relationship and seasonal cycle in gonad weight and condition of perch (Perca fluviatilis). Journal of Animal Ecology, 20, 201–219. https://doi.org/10.2307/1540
Menon, A.G.K. (1999). Check list - freshwater fishes of India. Records of the Zoological Survey of India, Miscellaneous Publication, Occasional Paper No. 175, Kolkata, India.
Ministry of Environment and Forest (MoEF). (2013). Report of the high level working group on Western Ghat, Volume 1. Published by the Government of India. Available at http://uttarakannada.nic.in/docs/Publication/HLWGWESTERNGHATSVOLUME1.pdf (accessed 26 September 2024)
Myers, R.A., Mertz, G. (1998). The limits of exploitation: A precautionary approach. Ecological Application, 8, 165–169. https://doi.org/10.2307/2641375
Padmakumar, K., Bindu, L., Manu, P. (2012). Etroplus suratensis (Bloch), the State Fish of Kerala. Journal of Bioscience, 37, 925–931. https://doi.org/10.1007/s12038-012-9271-x
Pauly, D. (1984). Fish population dynamics in tropical waters: A manual for use with programmable calculators. ICLARM Studies Review, 8, 325.
Pauly, D., Munro, J.L. (1984). Once more on the comparison of growth in fish and invertebrates. Fishbyte, The WorldFish Center, 2(1), 1–21.
Prasad, G., Ali, A., Harikrishnan, M., Raghavan, R. (2012). Population dynamics of an endemic and threatened Yellow Catfish, Horabagrus brachysoma (Gunther) from Periyar River, Southern Western Ghats, India. Journal of Threatened Taxa, 4, 2333–2342. https://doi.org/10.11609/JoTT.o2590.2333-42
Qasim, S.Z., Qayyum, A. (1961). Spawning frequencies and breeding seasons of some freshwater fishes with special reference to those occurring in the plains of Northern India. Indian Journal of Fisheries, 8 (1), 24–43.
Raghavan, R., Prasad, G., Ali, A., Pereira, B. (2008). Fish fauna of River Chalakudy, part of Western Ghats biodiversity hotspot (South India): patterns of distribution, threats and conservation needs. Biodiversity Conservation, 17, 3119–3131. https://doi.org/10.1016/j.fishres.2011.03.008
Raghavan, R., Ali, A., Dahanukar, N., Rosser, A. (2011). Is the Deccan Mahseer, Tor khudree (Sykes) fishery in the Western Ghats Hotspot sustainable? A participatory approach to assessment. Fisheries Research, 110, 29–38. https://doi.org/10.1016/j.fishr es.2011.03.008
Raghavan, R., Das, S., Nameer, P.O., Bijukumar, A., Dahanukar, N. (2016). Protected areas and imperilled endemic freshwater biodiversity in the Western Ghats Hotspot. Aquatic Conservation: Marine and Freshwater Ecosystems, 26, 78-90. https://doi.org/10.1002/aqc.2653
Raghavan, R., Ramprasanth, M.R., Ali, A., Dahanukar, N. (2018). Population dynamics of an endemic cyprinid (Hypselobarbus kurali): Insights from an exploited reservoir fishery in the Western Ghats of India. Lakes & Reservoirs: Science, Policy and Management for Sustainable Use, 23(3), 250–255. https://doi.org/10.1111/lre.12233
Rahman, M.M., Kashmi, M.N.S., Rahman, M.A., Sarwar, M.G., Sujana, F.M., Rahman, O., Hossain, M.S., Abedin, M.J., Laboni, T.A., Khatun, M.S., Hossain, M.Y. (2023). First report on population dynamics and stock status of Badis badis in a wetland ecosystem (NW Bangladesh): Insights from a new recorded maximum length. Heliyon, 9(12), e22777. https://doi.org/10.1016/j.heliyon.2023.e22777
Renjithkumar, C.R. (2015). Fish germplasm and exploited fisheries resources of Kerala and Bionomics of Red Canarese barb, Hypselobarbus thomassi (Day, 1874), PhD Thesis, MG University, India
Renjithkumar, C.R., Roshni, K. (2024). Demographics and reproductive characteristics of threatened Malabar pufferfish (Carinotetraodon travancoricus) from Western Ghats hotspot, India. Marine and Freshwater Research, 5, MF23170. https://doi.org/10.1071/MF23170
Renjithkumar, C.R., Harikrishnan, M., Kurup, B.M. (2011). Exploited fisheries resources of the Pampa River, Kerala, India. Indian Journal of Fisheries 58(3), 13–22.
Renjithkumar, C.R., Roshni, K., Kurup, B.M. (2016). Exploited Fishery Resources of Muvattupuzha River, Kerala, India. Fishery Technology 53, 177–182.
Renjithkumar, C.R., Roshni, K., Harikrishnan, M., Kurup, B.M. (2020). Population dynamics of Hypselobarbus thomassi (Day 1874), an endemic cyprinid fish from a tropical reservoir of Southern Western Ghats, India. Lakes & Reservoirs: Science, Policy and Management for Sustainable Use, 25(4), 388–393. https://doi.org/10.1111/lre.12343
Roshni, K., Renjithkumar, C.R. (2023). Population dynamics of two sympatric native and exotic cichlids in a tropical microtidal estuary, India. International Journal of Aquatic Biology, 11(1), 20–29.
Roshni, K., Renjithkumar, C.R., Kurup, B.M. (2016). Length-weight relationship of two cichlid fish species, Etroplus suratensis (Bloch, 1790) and Etroplus maculatus (Bloch,1795) from Lake Vembanad, Kerala, India. Journal of Applied Ichthyology, 32, 1308-1309. https://doi.org/10.1111/jai.13141
Roshni, K., Renjithkumar, C.R., Kurup, B.M. (2017). The downturn of the state fish, Etroplus suratensis, in Vembanad Lake: a Ramsar site, Kerala, India. In ‘Perspectives Biodiversity in India. Vol. III: Proceedings of Fourth Indian Biodiversity Congress, pp. 352–354 (Pondicherry University, Puducherry, India).
Roshni, K., Renjithkumar, C.R., Sreekanth, G.B., Raghavan, R., Ranjeet, K., Harikrishnan, M., & Kurup, B.M. (2021a). Trophic interactions between native and exotic cichlids in a shallow tropical estuary (Lake Vembanad, India). Marine and Freshwater. Research, 73(3), 411–416. https://doi.org/10.1071/MF21044
Roshni, K., Renjithkumar, C.R., Kurup, B. M. (2021b). Reproductive Biology of the Endemic Fish Etroplus suratensis (Cichlidae) from a Tropical Estuary in Southern India. Journal of Applied Ichthyology, 61, 460–466. https://doi.org/10.1134/S0032945221030097
Samuel, C.T. (1969). Problems and prospects of the estuarine fisheries of Kerala. In ‘First All India Symposium on Estuarine Biology’ (Tambaram, Madras, India). Shaji, C.P., Laladhas, K.P. (2013). Monsoon flood plain fishery and traditional fishing methods in Thrissur District, Kerala. Indian Journal of Traditional Knowledge, 12(1), 102–108.
Suresh, V. (2000). Floating Islands: A Unique Fish Aggregating Method. Naga, the ICLARM Quarterly, 23, 11–13.
Swapna, S. (2009). Fish Diversity in Achenkovil River, Kerala, India. Journal of Bombay Natural History Society, 106, 104–106.
Zar, J.H. (1999). Biostatistical Analysis. 4th Edition. (Prentice-Hall, Englewood Cliffs, New Jersey) ISBN: 013081542X

Details

Primary Language

English

Subjects

Fish Biology , Fisheries Management , Aquaculture and Fisheries Stock Assessment

Journal Section

Research Article

Authors

Chelapurath Radhakrishnan Renjithkumar ^*
0000-0001-6569-5075
India

Kuttanelloor Roshni
0000-0002-2542-2600
India

Early Pub Date

January 16, 2026

Publication Date

January 16, 2026

Submission Date

October 6, 2025

Acceptance Date

January 13, 2026

Published in Issue

Year 2026 Volume: 9 Number: 1

DOI

https://doi.org/10.3153/AR26007

IZ

https://izlik.org/JA67WA69BZ

Cite

RIS / Bibtex

APA

Renjithkumar, C. R., & Roshni, K. (2026). Demographic patterns of an endemic cichlid, Etroplus suratensis, across five rivers in the Western Ghats Biodiversity Hotspot, India. Aquatic Research, 9(1), 63-77. https://doi.org/10.3153/AR26007

Öz

Demographic patterns of an endemic cichlid, Etroplus suratensis, across five rivers in the Western Ghats Biodiversity Hotspot, India

Abstract

Keywords

Ethical Statement

Thanks

References

Details

Primary Language

Subjects

Journal Section

Authors

Early Pub Date

Publication Date

Submission Date

Acceptance Date

Published in Issue

DOI

IZ

Cite