Bhartiya Krishi Anusandhan Patrika, volume 39 issue 1 (march 2024) : 39-45

Indian Freshwater Elasmobranchs: Ongoing Threats along with IUCN Current Status and Conservation of Protecting Hidden Treasures: A Review

Devarshi Ranjan1,*, Ashish Sahu2, Shivaji Kanoujiya3, Preeti Maurya4, Mohiadeen Shajia Banu5, Anjana A.6, Vipul Singh Badguzar6
1College of Fisheries, Dr. Rajendra Prasad Central Agricultural University, Dholi, Muzaffarpur-843 121, Bihar, India.
2Faculty of Fisheries, Kerala University of Fisheries and Ocean Studies, Panangad, Cochin-682 506, Kerala, India.
3College of Fisheries, Acharya Narendra Deva University of Agriculture and Technology, Kumarganj- 224 229, Ayodhya, Uttar Pradesh, India.
4College of Fisheries, G.B. Pant University of Agriculture and Technology, Pantnagar-263 145, Uttarakhand, India.
5College of Fisheries, Central Agricultural University (Imphal), Lembucherra-799 210, Tripura, India.
6ICAR-Central Institute of Fisheries Education, Panch Marg, Yari Road, Mumbai-400 061, Maharashtra, India.
  • Submitted09-02-2024|

  • Accepted02-04-2024|

  • First Online 03-05-2024|

  • doi 10.18805/BKAP713

Cite article:- Ranjan Devarshi, Sahu Ashish, Kanoujiya Shivaji, Maurya Preeti, Banu Shajia Mohiadeen, A. Anjana, Badguzar Singh Vipul (2024). Indian Freshwater Elasmobranchs: Ongoing Threats along with IUCN Current Status and Conservation of Protecting Hidden Treasures: A Review . Bhartiya Krishi Anusandhan Patrika. 39(1): 39-45. doi: 10.18805/BKAP713.

We always thought that elasmobranchs inhabit marine environments, but this is only partially true. About 5% of known elasmobranch species are the freshwater compared to 40% of teleost species. A systematic checklist is available for Indian freshwater elasmobranches with names and IUCN status. A total of 13 species belonging to 3 orders, 3 families and 10 genera were enlisted from secondary data. Euryhaline and obligate species include sharks as Carcharhinus, Glyphis (Carcharhinidae),  Chiloscyllium  (Hemiscylliidae), sawfishes or Pristis (Pristidae), stingrays or Himantura (whiprays) and Pastinachus (cowtailed rays) (Dasyatidae). We focus on distribution, feeding habits, threats and conservation. Freshwater excursions are relatively rare in extant elasmobranchs than other groups of fish. The low growth rate is probably due to late age at maturity and low fecundity, long gestation periods, slow growth and productivity (small, infrequent litters), high natural survivorship for all age classes and long life. Despite this, some species of freshwater elasmobranchs can tolerate and even thrive in freshwater. 

Elasmobranchs, also known as chondrichthyans, are marine vertebrate with a cartilagenous skeleton (Nair et al., 2015). It is one of the largest marine fish resources consisting sharks, skates, sawfishes and rays (Kumar et al., 2022).  Importantly, compared with other marine vertebrates, elasmobranchs are highly evolutionary distinct and are greatly threatened by human activities (for uses of various body parts such as the meat, fins, liver and teeth), especially by overfishing (Pimiento et al., 2023). These fishes are distinguished from their sister group of bony fishes (teleost) by traits such as a cartilaginous skeleton, the lack of swim bladders and the presence of 5 to 7 pairs of gill slits not covered by an operculum (Compagno, 2002). However, elasmobranchs occur regularly in low-salinity water, often beyond the tidal region. These comprise about 5% of all live elasmobranchs (approximately 60 out of 1154 described species). Although the reasons are unknown, marine elasmobranchs maintain a high requirement for urea in their bodies (Ballantyne and Robinson, 2010). They have two groups: 1. Euryhaline elasmobranch 2. Obligate freshwater elasmobranch.
1. Euryhaline elasmobranch
Those fishes that can tolerate a wide range of salinities, from freshwater to brackish, are termed ‘euryhaline elasmobranch’. Euryhaline chondrichthyans include sawfishes (Pristidae), several whaler sharks (Carcharhinidae), one skate (Rajidae) and several stingrays (Dasyatidae), which are primarily marine fishes that can enter and stay in freshwater (Lucifora et al., 2015).
2. Obligate freshwater elasmobranch
These fishes confine to freshwater and comprise all the freshwater stingrays (family-Potamotrygonidae) and several stingrays (Dasyatidae), which complete their whole life, cycle exclusively in freshwater (Lucifora et al., 2015).
According to the IUCN, freshwater elasmobranchs are typically at high risk of extinction but least evaluated. The IUCN Red List of Threatened Species is increasingly used to reveal the health of ocean biodiversity. Dulvy et al., (2021) assessed 1,199 chondrichthyans and demonstrated the need for fishing limits on target and incidental catch and spatial protection to avoid further extinctions and allow for food security and ecosystem functions.
1. More than one-third of chondrichthyan fish species are threatened by overfishing.
2. A disproportionate threat in the tropics risks the loss of ecosystem functions and services.
3. Three species not seen in >80 years are Critically Endangered (Possibly Extinct).
4. The depletion of these species has a continuous demand for human food.
Diversity distribution of freshwater elasmobranches in the world
According to IUCN, 1,199 species were reported in Class Chondrichthyes-sharks, rays and chimeras (Dulvy et al., 2021). The first global assessment (2014) concluded that one-quarter (24%) of species were threatened. Now, 391 (32.6%) species are threatened with extinction.
The seven freshwater obligate chondrichthyans comprised a single West African species (Smooth Stingray-Fontitry gongaurouensis) and six Southeast Asian species (Roughback-Whipray Fluvitry gonkittipongi, Marbled Whipray- F. oxyrhynchus, White-edge Whipray- F. signifer, Mekong Stingray- Hemitry gonlaosensis, Chindwin Cowtail Ray- Makararaja chindwinensis and Giant Freshwater- Whipray (Urogymn uspolylepis).
Distribution and freshwater elasmobranches in India
Indian waters support a diverse chondrichthyan group consisting of more than 110 species of elasmobranch, which comprises 66 species of sharks and 44 species of batoides (Raje et al., 2002). Later description of new records and new species may bring to this sum to about 150-170 species from the Indian coast only, of which 3% are Critically Endangered (CR), 5% are Endangered (EN), 26% are Vulnerable (VU), 21% are Near Threatened (NT), 8% are of Least Concern (LC), 27% are Data Deficient (DD) and 10% are Not Evaluated (NE) (Joshi, 2022; IUCN, 2024). However, there is no correct information on freshwater elasmobranchs. 

In the present report, we have listed 13 species belonging to 3 orders, 3 families and 10 genera from secondary data. We assessed the IUCN status also (Table 1)  and provide a systematic checklist of Indian freshwater elasmobranches with their taxonomic position, distribution and IUCN Red List status (Table 2).

Table 1: Current IUCN red list status.

Table 2: Systematic Checklist of Indian freshwater elasmobranches, their taxonomic position, common, Distribution along with IUCN Red List status.

Habit and habitats
The freshwater elasmobranches occupy a wide range of habitats, including freshwater riverine (but not land-locked water systems) and lake systems, inshore estuaries and lagoons, coastal waters, the open sea and the deep ocean. Most elasmobranchs are mid-level or top predators and play a key role in trophic food webs (Yeldan, 2018)
Socio-economic significance of elasmobranch
Chondrichthyans groups are one of the most versatile/ valuable fisheries resources, providing meat and shark fins for human consumption (Shark fin soup); gills (as a tonic), leather (Purse, belt); shark liver oil used to produce lubricants, for medicine, fuel, cosmetics and vitamin A; live specimens for aquaria; and shark teeth (Ornamental) and jaws sold as tourist curios (Fig 1) (Dent and Clarke, 2015). More recently, shark cartilage has been exploited to treat cancer and other ailments and sharks and rays have become an attraction to scuba divers.

Fig 1: Sharks and rays landed at cochin fisheries harbour, Kochi, Kerala (Photo credit: Ashish Sahu).

Major emerging threats to elasmobranches
Threats posed to elasmobranchs habitats by humans are directly proportional to the habitat’s proximity to land. Elasmobranch fishes (sharks, rays and skates) face several major emerging threats to their survival and well-being (Fig 2) (Bornatowski et al., 2014). These threats contribute to declining populations and endanger many species. Some of the emerging threats to elasmobranchs are:

Fig 2: Major emerging threats to elasmobranches ((Illustration by Ashish Sahu).

It is one of the threats to elasmobranchs driven by the demand for shark fins, meat and other products. They are caught by bottom trawls, longlines and gillnet fishing gears (Dulvy et al., 2021). Many species have slow growth rates and reproduce infrequently, making them particularly vulnerable to overexploitation.
Elasmobranchs are often caught unintentionally as by catch in commercial fishing operations targeting other species. It can lead to high mortality rates for elasmobranchs, especially when discarded at sea.
Habitat loss
Habitat degradation and loss, primarily caused by coastal development, pollution and climate change, impact elasmobranchs’ breeding and feeding grounds. Mangroves, estuaries and coral reefs are crucial habitats for many species.
Climate change
Climate change poses several threats to elasmobranchs. Rising ocean temperatures can alter their distribution and affect prey availability. Ocean acidification can harm their calcium-based skeletons and eggs and changing currents can impact migration patterns.
Illegal fishing
Illegal, unreported and unregulated (IUU) fishing operations often target elasmobranchs for their valuable fins and meat. These activities can undermine conservation efforts and exacerbate population declines.

Trade and shark finning
The global trade in shark fins for use in shark fin soup and traditional medicines is a cause of elasmobranch exploitation. Shark finning, the practice of removing fins and discarding the rest of the carcass at sea, is wasteful and unsustainable.
Shark mislabeling
Shark mislabeling refers to the fraudulent practice of misidentifying or misrepresenting shark species in the seafood supply chain. It can occur at various stages, including fishing, processing and distribution. The mislabeling of shark products has consequences for consumers and the marine environment (Bornatowski et al., 2013).
Pollution from plastic debris, chemical pollutants and heavy metals can harm elasmobranchs directly or indirectly by contaminating their prey and habitats.
Invasive species
Invasive species introduction in freshwater habitats can disrupt elasmobranchs’ ecosystems and reduce prey availability.
Lack of conservation measures
Many elasmobranch species lack adequate protection under national and international conservation agreements. Stronger regulations and enforcement are needed to safeguard these animals (Fischer et al., 2012).
Scientific knowledge gaps
Limited scientific understanding of elasmobranch biology, population dynamics and behavior can hinder conservation efforts. More research is needed to fill these knowledge gaps.
Conservation status of Indian freshwater elasmobranches
International conservation and management initiatives for elasmobranches fish
● United Nations Convention on the Law of the Sea (UNCLOS), 1982.
● UN Fish Stocks Agreement, 1995.
● FAO Code of Conduct for Responsible Fisheries (CCRF),1995.
● Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), 1973.
● Convention on Migratory Species (Bonn Convention), 1979.
● Convention on Biological Diversity, 1992.
● The International Union for Conservation of Nature.
In 2013, the Ministry of Environment and Forests, Government of India implemented shark finning. The Indian Wildlife (Protection) Act, 1972 lists ten elasmobranchs in Schedule I part 2(A) in MoEF, 2001, which are identified accurately in the field to ensure their protection (Table 3).

Table 3: Freshwater elasmobranchs protected under schedule I of (Indian) Wildlife (Protection) Act, 1972.

Approximately 5% of all chondrichthyans are found in the freshwater ecosystem far beyond tidal influences, inhabiting the tropical and subtropical freshwater environment (river and lakes) where prolonged isolation has led to speciation and specialization to freshwater habitats. There are gaps in knowledge of the biology and status of obligate freshwater and euryhaline elasmobranchs. The total diversity of elasmobranchs utilizing reduced salinity habitats is not known. Compagno and Cook (1995) documented 44 species in the river mouths and an additional 25 species penetrate estuarine waters. 
This 21st century has been called the century of extinction. Over-exploitation and habitat degradation/ alteration are major concerns causing loss of biodiversity. There is an urgent need to catalog biodiversity before several species become extinct without humans knowing their existence. This study suggests awareness to conserve these valuable species among all levels of people involved in the fishery and trade of elasmobranchs. We suggest that a systematic review of fishery trades, importance, distribution, biology and the migration pattern of this group in Indian waters, with regional sampling and molecular investigations would identify a greater diversity of this group. We recommend conservation and management, as well as priorities for future work.
All authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

  1. Ballantyne, J.S. and Robinson, J.W. (2010). Freshwater elasmobranchs: A review of their physiology and biochemistry. Journal of Comparative Physiology B. 180: 475-493.

  2. Bornatowski, H., Braga, R.R. and Vitule, J.R.S. (2014). Threats to sharks in a developing country: The need for effective simple conservation measures. Natureza and Conservação.  12(1): 11-18.

  3. Bornatowski, H., Braga, R.R. andVitule, J.R.S. (2013). Shark mislabeling threatens biodiversity. Science. 340(6135): 923-923.

  4. Compagno, L.J.V. (2002). Freshwater and Estuarine Elasmobranch Surveys in the Indo-Pacific Region: Threats, Distribution. In Elasmobranch Biodiversity, Conservation and Management: Proceedings of the International Seminar and Workshop, Sabah, Malaysia, July 1997 (No. 25, p. 168). IUCN.

  5. Compagno, L.J.V. and Cook, S.F. (1995). the exploitation and conservation of freshwater elasmobranchs: Status of taxa and prospects for the future. J. Aquaric. Aquat. Sci. 7: 62-90.

  6. Dent, F. and Clarke, S. (2015). State of the global market for shark products. FAO Fisheries and Aquaculture Technical Paper No. 590. Rome, FAO. 187 pp.

  7. Dulvy, N.K., Pacoureau, N., Rigby, C.L., Pollom, R.A., Jabado, R.W., Ebert, D.A. and Simpfendorfer, C.A. (2021). Overfishing drives over one-third of all sharks and rays toward a global extinction crisis. Current Biology. 31(21): 4773-4787.

  8. Fischer, J., Erikstein, K., D’Offay, B., Guggisberg, S. and Barone, M. (2012). Review of the implementation of the international plan of action for the conservation and management of sharks. FAO Fisheries and Aquaculture Circular. No. 1076. Rome, FAO. 120 pp.

  9. IUCN. Red List of Threatened Species: Retrieved from www.iucn. on 25/02/2024.

  10. Joshi, K.K. (2022). Ichthyofaunal diversity of India. In: ICAR-CMFRI- Winter School on Recent Development in Taxonomic Techniques of Marine Fishes for Conservation and Sustainable Fisheries Management. ICAR-Central Marine Fisheries Research Institute, Kochi, pp. 23-38.

  11. Kumar, M.K., Jayakumar, N., Karuppasamy, K., Manikandavelu, D. and Uma, A. (2022). An annotated checklist of elasmobranchs along the coromandel coast of Tamil Nadu, Southeast Coast of India. Indian Journal of Animal Research. 56(9): 1164-1169. doi: 10.18805/IJAR.B-4281.

  12. Lucifora, L.O., de Carvalho, M.R., Kyne, P.M. and White, W.T. (2015). Freshwater sharks and rays. Current Biology.  25(20): 971-R973.

  13. Nair, R.J. and Zacharia, P.U. (2015). Introduction to the classification of elasmobranchs. CMFRI-Summer School on Recent Advances in Marine Biodiversity Conservation and Management. 118-133.

  14. Pimiento, C., Albouy, C., Silvestro, D., Mouton, T.L., Velez, L., Mouillot, D., Judah, A.B., Griffin, J.N. and Leprieur, F. (2023). Functional diversity of sharks and rays is highly vulnerable and supported by unique species and locations worldwide. Nature Communications. 14(1): 7691. https:/ /

  15. Raje, S.G.G. Mathew, K.K. Rekha, J., Nair, J., Raj, G.M., Srinath, M., Gomathy, S. and Rudramurthy, N. (2002). Elasmobranch fisheries of India-An appraisal. CMFRI., Spl. Publn. No. 71: 76 pp. 

  16. Yeldan, H. (2018). Estimating some population parameters and stock assesment of spiny butterfly ray, Gymnura altavela (Linnaeus, 1758) the Levant Basin coast (Northeastern Mediterranean). Indian Journal of Animal Research. 52(12): 1790-1796. doi: 10.18805/ijar.B-917.

Editorial Board

View all (0)