- The second Amblyceps fish species has been discovered from the Western Ghats.
- West-flowing rivers are less explored compared to their east-flowing counterparts.
- Despite intensive sampling, very few specimens were found, possibly indicating sparse populations and endemicity.
A new species of freshwater catfish has been described from the northern Western Ghats in Maharashtra and Goa. The species, Amblyceps vayavy, was formally described in the journal Zootaxa and is likely endemic to west-flowing rivers of the northern Western Ghats. Amblyceps is a genus of freshwater catfish with 24 identified species found in moderate to swift-flowing rivers in South and Southeast Asia. The only known congener, or closely related species, from the Western Ghats is A. accari, first described in 2016.
The name vayavy (pronounced vah-yhav-yah) means ‘northwest’ in both Konkani and Marathi, derived from the species’ distribution in the northern Western Ghats. The first reports emerged in 2020, when a Mumbai-based citizen scientist, Neil Soares, found an Amblyceps specimen in the Kundalika River in Kolad, Maharashtra. It was previously unrecorded in the region, as the distribution of A. accari is restricted to the central Western Ghats.
Balaji Vijaykrishnan, the lead author of the study and an independent researcher, said, “This genus was initially thought to be restricted to the northern parts of India. The discovery of A. accari in 2016 and A. crassioris in 2023 from the Western and Eastern Ghats, respectively, revealed that the genus is also present in both the south-western and eastern parts of the country. Amblyceps vayavy is the second species (of this genus) known from the Western Ghats.”
Over five years, between 2020 and 2025, the team, which included Vijaykrishnan along with researchers Tejas Thackeray and Abhishek Shirke of the Thackeray Wildlife Foundation, conducted over 30 surveys across different seasons in the Kundalika river, where the species was first recorded. Only three specimens were found, of which two were released, while the third served as the paratype — a specimen designated to support the species description alongside the primary reference specimen.
“Rivers in the Western Ghats are broadly divided into east-flowing and west-flowing systems,” says Vijaykrishnan. “While the larger east-flowing rivers like the Kaveri, Godavari, and Krishna are well-studied, the smaller west-flowing rivers are less explored. The Kundalika river is a west-flowing river.”
Though surveys were conducted in other west-flowing rivers of Maharashtra, no specimens were recorded.
Between 2021 and 2025, the team conducted over 20 surveys in tributaries of the Mahadayi river in Goa, yielding a single specimen that was designated as the holotype — the reference specimen for the species. Subsequent ichthyological studies confirmed that the species exhibits morphological characteristics distinct from all known congeners, as described in the study.
A. vayavy is currently known only from the Ragada river in Goa and the Kundalika river in Maharashtra.
Low populations and specialised behaviours
“Amblyceps are typically restricted to clear, fast-flowing, well-oxygenated hill streams and are indicators of good water quality,” explains Balaji Vijaykrishnan. “The presence of Amblyceps in rivers of Goa could imply relatively undisturbed habitats in the upper reaches.” He adds that these fish are highly sensitive to pollution, siltation, and flow alterations, and that A. crassioris is now almost extirpated from its type locality due to sand mining.
While Amblyceps species are generally abundant in other regions — an observation noted in the study and confirmed by Vijaykrishnan — they appear to be rare in the Western Ghats. Vijaykrishnan notes that an hour of sampling in north and north-east India can typically yield between three and 30 Amblyceps specimens, depending on the time of year.
In contrast, surveys in the Western Ghats have yielded only four specimens despite over 50 surveys, across seasons, over five years.
He points to the only other species recorded in the region, Amblyceps accari, which was first collected in the 1960s and wrongly recorded as A. mangois. Two specimens collected decades later in 2016 finally led to the description of A. accari. Further surveys are ongoing in Goa and Maharashtra to determine whether these sparse records reflect inadequate sampling or genuinely low population densities.
Vijaykrishnan told Mongabay-India that the continued description of new fish species and genera from the Western Ghats highlights how much remains unknown, emphasising the role of citizen scientists. Discoveries of Amblyceps species in both the Western and Eastern Ghats were possible through citizen science.
The Western Ghats are characterised by a high degree of endemism.
“Most of the river systems in the Western Ghats are west-flowing, which act like isolated habitats with limited connectivity to other rivers. They have evolved into unique systems with highly localised species,” explains Beta Mahatvaraj, a freshwater fish expert.
He adds that some are highly specialised and restricted to very small areas or microhabitats. For instance, Dawkinsia rohani is found only in Kanyakumari, while Rakthamichthys mumba, a subterranean, groundwater-dwelling fish, is found only in Mumbai. “We know very little about how they feed, breed, or live,” he says.
He adds that studying freshwater fish is challenging, as studies rely on sampling. As it is impossible to sample every stretch of a river, researchers select habitats that appear suitable. Moreover, findings can depend on the season and time of day. Amblyceps, being nocturnal, may not be detected if sampling is conducted during the day or in summer, when rivers may shrink. “This makes population estimates difficult,” he explains.
“If intensive sampling yields very few specimens, it could suggest low population density or indicate that these fish are not prolific breeders, possibly because they occupy microhabitats that cannot support large populations. However, we don’t yet know enough about their breeding behaviour to determine whether low numbers are natural or the result of human disturbance.”
Erased before being studied
While new species continue to be discovered in the Western Ghats — including two freshwater fish species described in April 2025 — the biodiversity hotspot is increasingly threatened by anthropogenic pressures.
In Goa, the proposed doubling of an existing railway track that passes through parts of the Western Ghats and the Bhagwan Mahaveer Wildlife Sanctuary, Goa, and Anshi-Dandeli Tiger Reserve, Karnataka, could cause irreversible damage to the ecosystem. An Environment Impact Assessment Report prepared by the project execution agency, Rail Vikas Nigam Limited (RVNL) and the Wildlife Institute of India (WII) mentions that “the railway alignment intersects numerous streams”.
A citizen group from Goa, Amche Mollem, noted that the EIA had “critical gaps”, and “excluded the potential impact on freshwater fish”. In an Instagram post on their page, the group stated, “The proposed railway line intersects several perennial streams, yet the WII’s environmental impact assessment contains no evaluation of impacts on freshwater fish. Construction-related debris deposition can smother the spawning grounds of resident and migratory species such as stream loaches, carps, and catfish. Despite their ecological and conservation significance, freshwater fish — a cornerstone of aquatic biodiversity — are entirely absent from the WII’s assessment.”
Mahatvaraj points out that such specialised fish are particularly vulnerable to habitat disturbances. “Fish that feed or breed in specific niches — such as under rocks — can be severely affected by construction activities. Silt deposition could cut off access to breeding or feeding grounds, and disruptions can block migratory pathways.”
While certain fish may persist in disturbed habitats, the absence of sensitive species indicates ecological degradation, he says. Amblyceps, for instance, are highly sensitive to environmental changes and habitat alterations. If water stagnates and oxygen levels drop, they cannot survive.
Vijaykrishnan says taxonomic studies are significant because they give species a name while highlighting their endemicity and vulnerability — especially at a time of accelerating habitat change driven by anthropogenic activities, when species may go extinct before being discovered.
Banner image: Amblyceps vayavy, a new species of freshwater fish discovered from the Western Ghats. Image by Abhishek Shirke.
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