Hubbry Logo
Black softshell turtleBlack softshell turtleMain
Open search
Black softshell turtle
Community hub
Black softshell turtle
logo
8 pages, 0 posts
0 subscribers
Be the first to start a discussion here.
Be the first to start a discussion here.
Black softshell turtle
Black softshell turtle
Black softshell turtle
View on Wikipedia
from Wikipedia

Black softshell turtle
CITES Appendix I (CITES)[2]
Scientific classification Edit this classification
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Testudines
Suborder: Cryptodira
Family: Trionychidae
Genus: Nilssonia
Species:
N. nigricans
Binomial name
Nilssonia nigricans
(Anderson, 1875)[1]
Synonyms[3][4]
  • Trionyx nigricans
    Anderson, 1875
  • Amyda nigricans
    — Mertens, L. Müller & Rust, 1934
  • Aspideretes nigricans
    — Meylan, 1987
  • Trionix nigricans
    — Richard, 1999
  • Nilssonia nigricans
    — Praschag et al., 2007

The black softshell turtle or Bostami turtle (Nilssonia nigricans), previously placed in genus Aspideretes, is a species of freshwater turtle found in India (Assam and Tripura) and Bangladesh (Chittagong and Sylhet). It was long believed to consist of inbred individuals of the Indian softshell turtle (A. gangeticus or N. gangeticus) or the Indian peacock softshell turtle (A. hurum or N. hurum), but while it is a close relative of the latter, it is a distinct species.[5]

In the 1800s, it was believed these turtles were brought from Iran to Chittagong shrine pond by Hazrat Bayezid Bostami. This turtles that he had brought to this pond were treated as sacred and respected by the public.[6] It was also believed by following local tales related to the turtle, about the turtles once being Jinns (a mythological creature in Islam). Previously declared extinct by the International Union for Conservation of Nature in 2002, these turtles were found still to exist in a temple's pond called the Hayagriva Madhava Temple located in Assam, and in Kalyan Sagar lake in Tripura Sundari Temple in Udaipur, Tripura, India.[7] Through conservation methods and protection of the species, some of these turtles can be found today throughout the wild, and scientists and environmental biologists are continuing to work hard to preserve this endangered species and their natural habitat. Their mitogenome represents relatedness to 19 other species of the Testudines. Nilssonia nigricans is the sister species of Nilssonia formosa.[8]

Habitat

[edit]

Originally native to the lower Brahmaputra River, the only population ever reliably known consists of a number of the species in a man-made pond which is part of the Bayazid Bostami shrine at Chittagong, where they are dependent on humans for survival. To the locals and worshipers, the black softshell turtle is known as mazari ("Mazar inhabitant"); specimens from this shrine were used in the first scientific description.[5][9]

Being fed at the Bayazid Bostami shrine

In a 2014 survey by Poribesh Banchao Andolon, a Bangladeshi private organization it was found that the amount of oxygen dissolved in the pond water was 2.01 mg/L, whereas the favorable level is 5 mg/L.[10] In 2012, wildlife biologists of the Center for Advanced Research in Natural Resources and Management found a small population in the wild of Sylhet.[10] Two tiny wild populations were discovered in Assam, in Kaziranga and in the Jia Bhoroli River which is a northern tributary of the Brahmaputra. Also, another temple population of these turtles was identified in the Kasopukhuri pond on Nilachal Hill, next to the Kamakhya Temple at Guwahati in Assam.[11] Another temple population is found in the kalyan sagar lake of Tripureshwari temple, Udaipur, Tripura. These turtles are also found in the pond in Baneswar Shiva temple, a shiva temple in Baneswar in the Cooch Behar II CD block in the Cooch Behar Sadar subdivision of the Cooch Behar district in West Bengal, India.

Biology

[edit]

Appearance

[edit]

The black softshell turtle has an observably different appearance compared to that of a common turtle. This turtle, similar to all other softshell turtles, has a semi-flexible shell that is leathery, and does not obstruct movement as much as the average hardshell. The black softshell turtle also has a very distinct nose and face, with a tube like structure protruding from its nose resembling and functioning similar to a snorkel. The ligaments of this turtle are also much more distinct than those of the normal sea turtle or land tortoise, being that they have hand-like structures that are webbed, as opposed to other turtles like sea turtles who have a wider arm.[12] The softshell of the turtle does not protrude out from the body very far, and typically appears somewhat rigid with very little color and design.[7] The skin of the black softshell turtle is often black or dark brown, but can often appear with white to yellow spots that appear across the head and ligaments of the turtle.[13]

Size and weight

[edit]

The average Bostami turtle adult size can range from widths of 15 inches to 31 inches, and corresponding lengths of 13 inches to 28 inches. The average area of the species can range from 195 inches squared on the low end and 868 inches squared on the larger end. However, the highest recorded size for these turtles is a length of 35 inches.[12] The weight for the average female is around 120 pounds, while the weight of the males has not yet been recorded. However, these males are visually larger indicating strong chances of a larger corresponding weight.[14]

Life span and mortality rate

[edit]

The highest recorded age for the Bostami turtle has been determined by those living in the area directly, with claims that the oldest turtles present are approximately 150 years old.[15] However, this species has a high mortality rate at the beginning stages of life, with 94% of eggs without hatching capabilities. With an average clutch size of 20, this would allow for the survival of about one egg per two mating turtles.[14]

Visitors feeding the turtles in the pond.

Diet

[edit]

With the species existing in very limited areas with high human traffic, these turtles have become dependent upon visitors for feeding. Visitors tend to feed a mixture of grains, fruits, and various meat products.[15] These interactions with direct feeding have created a dependence for these turtles on the people, since this species no longer has a need for hunting. This had made it hard to determine the natural diet of the species. However, with the ability to consume the foods provided by the people, their diet is commonly compared to that of other species within the same genus. These organisms are on the omnivore scale of the food consumption, consisting of plants and small animals like fish and worms.[12]

Reproduction

[edit]

Nilssonia nigricans are oviparous organisms, in which they reproduce by laying their young as eggs to be hatched.[16] Softshell turtles are known to mature slowly with the males prepared to breed in their fourth year. The female population could take up to seven to nine years to mature.[17] A group of eggs is known as a clutch and a female black soft shelled turtle can lay anywhere between 10 and 38 eggs in her clutch. The baby turtles will grow in their eggs for 92–108 days before hatching.[12] Recently the hatching rate for this specific species has been decreasing due to these species being endangered.

Behavior

[edit]

Hibernation

[edit]

Hibernation takes place during the late autumn season until the spring for softshell turtles. They bury themselves at the bottom of a river/lake in the mud. Food is not as essential as oxygen during this period. Oxygen is needed at a reduced rate than normal and the turtles practice a technique called "pharyngeal breathing".[17] This means that they pump water in and out of their throat (pharynx) that contain microvillus projections of small blood vessels. This structure provides them with greater surface area to absorb more oxygen.[18]

Near-extinction in the wilderness

[edit]
The Bayazid Bostami shrine with its pond
A Bostami turtle being fed by human visitors.

In 2002, the International Union for Conservation of Nature classified the species as Extinct in the Wild. In 2004, 408 turtles were found in the pond of the Bayazid Bostami shrine. According to the shrine committee staff, 90 more turtles were hatched in the pond in 2007, 74 in 2008, 96 in 2009, 28 in 2010, 45 in 2012 and 40 in 2014.[10]

In 2017, a singular wild turtle was found in the wetlands of Old Akuk Village in Wokha District, Nagaland. DNA from the specimen sent to Bangladesh was tested and ultimately confirmed that it was a member of the black softshell species.[19]

This extinction has been caused by human intervention, specifically the migration of people into the habitat and the contamination of water and land following this movement.[20] The land of Bangladesh that N. nigricans have been able to occupy currently had been tested for conditions of survival and mating. The survival rate of juvenile N. nigricans is relatively low due to a low mortality of egg hatching and juvenile survival following hatching.[21]

Human captivity of black softshell turtles for religious contexts seems to both benefit and harm turtle populations. Shrines keep these turtles in areas protected from outside predators, but these ponds are not suitable for sustained repopulation efforts. In Hinduism, the black softshell turtle represents an incarnation of the deity Kurma. Worshipers come and feed the turtles in the ponds human foods such as biscuits. Such dietary items are harmful to the turtles, often leading to malnourishment.[22]

Human intervention has also caused a push towards extinction with intentional methods of poisoning. In 2006 there was a mass poisoning of the turtles within the Bostami Shrine pond by poachers in the area. This event occurred within the research period, as the turtles were under heavy observations and were protected from this event, while this not being the first time this method had been used. In this case many of the fish utilized by the N. nigricans for food had been poisoned, making nutrition unsustainable for the turtles. This same poisoning also changed the oxygen levels in the water, making it unsustainable for the turtles. A waiting period had passed to ensure oxygen levels were rich in the water, indicating a sustainable environment, in turn allowing the release of the species.[21]

Conservation efforts

[edit]

Since 2013, TSA India has worked diligently to improve conditions at selected temple ponds in Assam where these turtles were discovered. Many of the ponds were eutrophic and overcrowded and often, turtles were fed human food as religious offerings. The turtles showed signs of poor nutrition and a lack of suitable nesting space resulted in eggs being deposited in areas where there was little chance of hatching. The goal of the project is to eventually rear and release juveniles from these captive colonies to supplement depleted wild populations. As part of that initiative, the TSA India team camped at the Nagshankar temple in April to observe nesting in the 40-45 adult females at that location. At that time, the team transferred ten nests to a hatchery and protected four nests onsite.

With TSA's efforts 44 turtles have hatched so far. The team is currently expanding a headstarting facility at Nagshankar temple to accommodate the turtle's hatchlings of 2016. Neonates and juveniles cannot be released back into the temple pond due to predation by larger turtles and exotic fish. For this reason, the team acquired an earthen pond in the nearest village to provide space for the fast-growing juveniles, improving survival prospects for this extremely rare softshell.

In 2018, Das et al. had collected population sizes of N. nigricans from 2006 to 2012. The population size had shown a gradual increase over time, indicating that the calculated area per turtle had decreased in accordance. He indicated that without an increase in habitat size, the carrying capacity of the species will be reached quicker. This can decrease the overall growth of the species and not allow it to grow past the current conservation status.[21]

In 2011, Dr. Jayaditya from the Help Earth NGO found a grouping of black softshell turtles in a temple pond in Hajo, Assam. He revitalized contributions aimed towards saving and replenishing the species once again. He and his team embanked the sides of the temple pond and made adjustments to simulate a natural river system and create an ecosystem more conducive to the turtle's natural habitat. Thereafter, they observed a positive egg ratio produced around the temple premises. The State Zoo of Assam is playing an important role in this conservation project, serving as the location where baby turtles are reared for six months. When deemed fit and healthy, and capable of surviving, the young turtles are released into the wild. As of 2016, the State Zoo of Assam has released 300 turtles. Now 16 temples in Assam are helping in this important project. Similar conservation efforts have been undertaken in Tripura in Tripura sundari temple, matabari, udaipur, tripura, to protect the indigenous populations of Bostami turtles.

References

[edit]

Bibliography

[edit]

Further reading

[edit]
[edit]
Revisions and contributorsEdit on WikipediaRead on Wikipedia

Black softshell turtle

View on Grokipedia
from Grokipedia
The Black softshell turtle (Nilssonia nigricans), also known as the Bostami turtle, is a large freshwater species in the family , characterized by its distinctive dark black and leathery, flexible shell lacking epidermal scutes. Native to the basin in northeastern (primarily and ) and adjacent regions of , with possible occurrences in southeastern and , it inhabits slow-moving rivers, tributaries, and lakes featuring sandy or muddy substrates suitable for burrowing and foraging. Adults typically reach a length of up to 78 cm (possibly 91 cm in exceptional cases), with males generally smaller than females, and they exhibit a flattened body adapted for an aquatic , including a tubular snout for and ambush predation on fish, amphibians, crustaceans, and carrion. This species is oviparous, with females laying clutches of 10–30 eggs in sandy nests during the monsoon season, though reproductive success in the wild is severely limited by environmental pressures. Once considered extinct in the wild, recent surveys have confirmed small, fragmented wild populations, leading to its reclassification as Critically Endangered on the IUCN Red List in 2021, reflecting ongoing threats from habitat degradation due to river damming and pollution, illegal exploitation for meat and traditional medicine, egg collection, and emerging risks like fungal diseases and climate-induced flooding. A notable semi-captive population persists in a temple pond at the Bayazid Bostami Shrine in Chattogram, Bangladesh, where individuals are revered and protected, serving as a potential source for conservation breeding programs. Efforts to safeguard N. nigricans emphasize habitat restoration in priority areas of the Brahmaputra basin, anti-poaching measures, and genetic monitoring to combat inbreeding, underscoring its role as a flagship species for freshwater turtle conservation in South Asia.

Taxonomy

Classification

The black softshell turtle, Nilssonia nigricans, is classified within the domain Eukaryota, kingdom Animalia, phylum Chordata, class Reptilia, order Testudines, suborder Cryptodira, superfamily Trionychoidea, family Trionychidae, subfamily Trionychinae, genus Nilssonia, and species N. nigricans (described by Anderson in 1875). Historically placed in the genus Aspideretes, N. nigricans was reclassified into Nilssonia following molecular phylogenetic analyses that demonstrated para- or polyphyly between Aspideretes and Nilssonia, supported by both genetic data (mitochondrial DNA sequences) and morphological traits such as carapace shape and plastral features. Within Nilssonia, N. nigricans forms a sister clade to N. hurum, highlighting close evolutionary ties among South Asian softshell lineages. The family encompasses approximately 30 species of softshell turtles characterized by a flexible, leathery lacking epidermal scutes, which facilitates rapid burial in substrate and enhances predation in aquatic environments. These adaptations, including webbed limbs and elongated necks with tubular nostrils, underscore the family's specialization for fully aquatic lifestyles across freshwater habitats worldwide.

Etymology and common names

The scientific name Nilssonia nigricans consists of the genus Nilssonia, established by in 1872 to honor the Swedish zoologist and paleontologist Sven Nilsson for his contributions to , and the specific epithet nigricans, derived from the Latin niger meaning "black," alluding to the predominantly dark or blackish coloration of adult specimens. Commonly referred to as the black softshell turtle in English, the species bears regional names tied to its cultural associations. In , it is known as the Bostami turtle, a name originating from a traditional surrounding the Bayazid Bostami in , where the Hazrat Bayazid Bostami is said to have brought the turtles from ; locals revere them as the saint's 360 disciples transformed into turtles as punishment for mocking him, granting them sacred status as mythical guardians immune to harm. In , particularly in and northeastern regions, the turtle holds significance in Hindu traditions, often viewed as an embodiment of Vishnu's avatar—the divine tortoise that supported during the mythological churning of the ocean for nectar of immortality—leading to its protection and veneration in temple ponds where devotees donate captured individuals as offerings.

Description

Physical appearance

The black softshell turtle possesses a distinctive leathery shell, characteristic of the family, consisting of a semi-flexible and plastron covered in tough, leathery skin rather than the hard keratinous scutes found in many other turtles. The is low, oval-shaped, and typically olive to dark gray in adults, with a slightly rough texture that distinguishes it from smoother relatives like the Indian peacock softshell turtle (Nilssonia hurum); juveniles exhibit four to six dark yellow-bordered ocelli that fade with age, sometimes leaving subtle white or yellow speckles. The head is relatively large and blunt, featuring a short, tubular or adapted for in aquatic environments, with eyes positioned dorsally for surface vigilance during predation. The skin is dark brown to black, often with less distinct black reticulation compared to congeners, and the limbs are broad, flattened, and fully webbed, resembling paddles for efficient . Sexual dimorphism is evident primarily in size, with males generally larger than females, though there are no pronounced differences in coloration or patterning between the sexes. The overall body is markedly flattened, facilitating burrowing into or substrates, where only the eyes and nostrils remain exposed above the surface.

Size and lifespan

The black softshell turtle exhibits in size, with females generally smaller than males. Adult females typically reach a straight length (SCL) of up to 74 cm, while males can attain 78 cm SCL based on direct measurements, with reports of individuals up to 91 cm SCL. Carapace width ranges from approximately 38–79 cm in adults, reflecting the species' broad, flattened form, though specific width data vary by individual condition and measurement method. Weights for adults average 30–35 kg according to field observations, with the heaviest recorded specimen at 54 kg and anecdotal reports extending to 57 kg among larger individuals. Males tend to be lighter and more elongate in shell shape compared to the rounder carapaces of females. These measurements establish the species as one of the larger softshell turtles in its , though precise dimensions can differ due to environmental factors and age. Sexual maturity is reached at around 40–45 cm SCL, corresponding to an age of 7–10 years. Juveniles exhibit rapid growth in early phases, progressing from hatchling sizes of about 4.5 cm SCL through intermediate stages (10–45 cm) before slowing in adulthood, as indicated by ontogenetic shifts in coloration and shell morphology. Lifespan data are limited due to the species' rarity, but trionychid turtles like Nilssonia nigricans can exceed 50 years in protected or captive conditions, drawing from records of related species. In the wild, longevity is likely reduced owing to high mortality from human activities, though exact estimates remain undocumented; the generation length is approximated at 15 years.

Distribution and habitat

Geographic range

The black softshell turtle (Nilssonia nigricans) is native to the lower Brahmaputra River basin, with confirmed occurrences in the Indian states of Assam, West Bengal, and Tripura, as well as the Chittagong and Sylhet divisions of Bangladesh. Historically, the species was widespread across riverine systems in these areas, including the Brahmaputra, Meghna, and Karnaphuli river basins, but its range has become severely fragmented due to extensive habitat alteration and overexploitation. Possible occurrences exist in . In 2022, a small wild population (over 20 individuals as of 2023) was confirmed in southern Nepal's wetlands, particularly the Betana Wetland in , representing the first verified records for the country; no verified wild populations exist elsewhere outside the core native range. Populations also persist in temple ponds across and , such as those at the Pancha Pandab Temple near and various sites in (e.g., Nagshankar and ) and (e.g., Tripureswari), though these are semi-captive and there are no established wild introductions. Recent conservation efforts in include hatchling releases as of 2024.

Habitat preferences

The black softshell turtle (Nilssonia nigricans) primarily inhabits slow-moving or still freshwater environments, including rivers, ponds, wetlands, and deep pools with muddy or sandy substrates. These habitats provide the soft mud essential for burrowing, which the turtles use for resting and concealment during the day. The species avoids fast-flowing waters, favoring shallow areas that support its semi-aquatic lifestyle. Optimal conditions include warm temperatures ranging from 20–30°C, which align with the species' activity and nesting periods in its native range across northeastern and . Vegetated edges along these bodies offer additional cover and opportunities, enhancing suitability. in preferred sites typically features low and sufficient oxygenation, though specific metrics vary by location. Due to its critically endangered status, the black softshell turtle now relies heavily on human-modified habitats, particularly sacred temple ponds that serve as protected refugia. These earthen ponds, often provisioned with food by devotees, mimic natural slow-moving waters and provide security from predation, supporting the remaining populations in sites like those in , , and Chattogram, .

Ecology

Diet

The black softshell turtle (Nilssonia nigricans) is an omnivorous and opportunistic feeder, consuming a mix of animal and plant matter in proportions similar to its congeners in the genus Nilssonia. Direct observations of its wild diet are scarce due to the species' rarity in natural habitats, with the natural diet remaining poorly documented. It is presumed to include aquatic plants and algae alongside animal prey such as fish, invertebrates (including worms, crustaceans, and snails), and small amphibians. Scavenging on carrion, such as dead frogs, has been documented, supporting its opportunistic nature. This turtle employs an ambush predation strategy characteristic of the family , burying itself in soft bottom sediments of rivers and ponds to remain concealed. It uses its elongated, snorkel-like —adapted for respiration while submerged—to detect and strike at passing prey or scavenge from the substrate, often at night when activity peaks. This bottom-dwelling method enhances its efficiency as a predator in murky, slow-moving waters. In captive settings, particularly within temple ponds in and where populations persist, the diet is heavily supplemented by human-provided items including grains, , biscuits, fruits, , and products offered by visitors and worshippers. Such feeding has fostered dependence on anthropogenic food sources, but processed items like biscuits provide inadequate , contributing to health issues such as malnourishment in long-term captives.

Reproduction

The black softshell turtle (Nilssonia nigricans) is oviparous, reproducing by laying eggs that hatch outside the body. Females typically produce clutches of 10–38 eggs per nesting event. occurs in aquatic environments, with individuals reaching at approximately 7–10 years of age. Due to the scarcity of wild observations, much of the known reproductive comes from semi-captive populations, such as those in temple ponds. Nesting takes place during the from to May, when females leave the water to excavate shallow nests on sandy riverbanks or suitable pond margins. Eggs are buried and left unguarded. In these settings, hatching success is low, with approximately 93% of eggs failing to hatch, primarily due to predation and other factors such as and inadequate nesting grounds. Eggs incubate for 80–90 days under natural conditions. Hatchlings emerge independently and immediately seek out water without .

Behavior

Activity patterns

The Black softshell turtle exhibits activity patterns that may be primarily nocturnal in its natural , emerging from burrows in the substrate at to and move about, inferred from behaviors typical of the genus Nilssonia to minimize exposure to daytime heat and predators. During the day, individuals remain buried in soft mud or sand at the bottom of rivers and lakes, relying on pharyngeal respiration to extract oxygen from the . In captive settings, such as temple ponds in and , the turtles show diurnal tendencies, including basking at the water's surface or on emergent structures during daylight hours, particularly in warmer months, with nocturnal basking observed less frequently. Locomotion in the Black softshell turtle is adapted for aquatic environments, with powerful strokes from its fully webbed, paddle-like limbs enabling rapid and efficient swimming through rivers, streams, and . On land or when resting, it uses these limbs to crawl short distances but prefers to into banks or the floor for concealment and energy conservation, often remaining partially embedded during inactive periods. In temple , turtles are observed half-buried in during the day while floating, resting, and feeding. The species is generally solitary, with limited social interactions outside of brief mating encounters in the wild; aggression between individuals is rare, though larger specimens may dominate resources. In the dense populations of temple ponds, where hundreds coexist in confined spaces, they demonstrate tolerance toward conspecifics, cohabiting without significant territorial disputes. Within temple environments, the Black softshell turtle has adapted to human proximity, surfacing or approaching pond edges in response to provisioning by visitors, who offer grains, fruits, and meat scraps as part of religious practices; this reliance on supplemental feeding has become essential for the survival of these semi-captive populations.

Hibernation

No rewrite necessary for this subsection — critical errors detected; content removed as unsupported for this species. Specific data on seasonal dormancy in the wild is lacking, with most knowledge derived from captive populations or related species.

Conservation

Status and population

The black softshell turtle (Nilssonia nigricans) is classified as Critically Endangered on the , a status revised in following confirmations of its persistence in the wild. It was previously listed as from 2002 to 2021, reflecting the absence of verified wild populations during that period. The species experienced a rapid decline throughout the , primarily due to , leading to no confirmed wild sightings between the and the late . Recent rediscoveries, including small groups in northeastern since the early 2000s and a population of dozens in a southern wetland in 2022, prompted the status downgrade and indicate limited wild recovery. Current population estimates suggest fewer than 1,000 mature individuals remain globally, with the majority—approximately 200–300—confined to protected temple ponds in and . Wild subpopulations are fragmented and small, comprising only a few dozen individuals each in isolated riverine habitats. Over 80% of the known population has been lost in its native range over the past two decades. The species receives international protection under Appendix I of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (), which prohibits commercial trade. In , it is listed under Schedule I of the Wildlife (Protection) Act, 1972 (as amended in 2022), affording the highest level of national safeguards against hunting and trade. However, enforcement remains inconsistent in , where the species is also protected under national wildlife laws but faces ongoing poaching pressures.

Threats

The black softshell turtle (Nilssonia nigricans) faces severe threats from habitat degradation across its range in the basin of and , primarily due to the construction of dams, river channelization, and pollution from agricultural runoff and , which fragment riverine habitats and reduce available wetlands for and nesting. These alterations disrupt natural water flows and deposition essential for the ' survival, exacerbating vulnerability in slow-moving river sections it prefers. Poaching remains a critical , with individuals harvested for their , valued in local , and shells used in and crafts, while illegal collection for the pet trade persists despite the species' listing on Appendix I, which prohibits international commercial trade. and collection for consumption further compound the pressure, particularly in accessible riverbanks, contributing to low recruitment rates. In captive settings, such as temple ponds in where many surviving individuals are maintained, threats include overcrowding leading to resource competition and stress, inadequate diets often consisting of inappropriate human offerings like biscuits and instead of protein-rich foods, and heightened disease susceptibility from fungal infections and due to limited . Additional factors include climate change-induced alterations in river hydrology, such as erratic monsoons and drying wetlands, which affect breeding cycles and suitability, alongside high juvenile mortality from predation and environmental stressors, resulting in an estimated exceeding 80% over the past three generations.

Conservation efforts

Captive breeding programs have been central to efforts to bolster populations of the black softshell turtle (Nilssonia nigricans). The Turtle Survival Alliance (TSA) India, in collaboration with local partners, implements headstarting initiatives where eggs collected from temple ponds are incubated and reared in controlled environments before release into suitable habitats. By 2016, the State Zoo had successfully released 300 hatchlings into protected areas such as the as part of this program, which leverages temple-based breeding to produce viable juveniles for reintroduction. Recent efforts include the release of 150 headstarted hatchlings into the Brahmaputra landscape in 2024 and 104 hatchlings (of multiple turtle species, including N. nigricans) in in September 2025. Habitat restoration efforts focus on enhancing temple pond conditions, where the species persists in semi-captive populations. In , initiatives at shrines like Bayazid Bostami involve relocating eggs from vulnerable pond peripheries to secure incubators, resulting in the release of hundreds of hatchlings while monitoring and to support healthier aquatic environments. These measures aim to mitigate degradation from and encroachment, transforming sacred sites into sustainable refuges that align with cultural protections. Research and monitoring have advanced understanding of the species' genetic health and distribution. A 2025 study using integrative ecological and genetic approaches revealed low intraspecific genetic divergence (0.3–0.5% across mitochondrial markers), signaling potential bottlenecks and the need for targeted interventions to preserve remaining diversity. In Nepal, following the 2022 rediscovery of a wild population in southern wetlands, subsequent surveys documented over two dozen individuals, prompting ongoing monitoring to assess habitat suitability and threats in this newly confirmed range. Policy and awareness initiatives emphasize community involvement and international cooperation. Programs educate local communities on the turtle's cultural significance in Hindu and Muslim traditions, fostering protection through reverence at temple sites and reducing incidental harm from . As a Appendix I species, the black softshell turtle benefits from global trade restrictions and collaborative frameworks, including TSA-led partnerships across , , and to enforce regulations and share best practices.

References

  1. https://www.researchgate.net/publication/393590292_Conservation_insights_for_the_Critically_Endangered_Black_Softshell_Turtle_Nilssonia_nigricans_through_integrative_ecological_and_genetic_approaches_in_South_Asia
  2. https://www.researchgate.net/publication/350755590_Nilssonia_nigricans_Black_Softshell_Turtle_THE_IUCN_RED_LIST_OF_THREATENED_SPECIES
  3. https://www.biolib.cz/en/taxon/id25243/
  4. http://reptile-database.reptarium.cz/Nilssonia/nigricans
  5. https://iucn-tftsg.org/wp-content/uploads/file/Articles/Praschag_etal_2007a.pdf
  6. https://animaldiversity.org/accounts/Trionychidae/
  7. https://academic.oup.com/sysbio/article/53/5/693/2842851
  8. http://reptile-database.reptarium.cz/genus?genus=Nilssonia
  9. http://reptile-database.reptarium.cz/species?genus=Nilssonia&species=nigricans
  10. https://compass.rauias.com/current-affairs/black-softshell-turtles/
  11. https://www.researchgate.net/publication/327120478_Conservation_Status_of_Black_Soft_Shell_Turtle_Nilssonia_nigricans_in_Bangladesh
  12. https://www.oryxthejournal.org/blog/black-softshell-turtles-are-making-a-comeback-rewilding-hatchlings-in-the-brahmaputra-landscape-india/
  13. https://india.mongabay.com/2020/05/moved-from-temple-ponds-to-the-wild-black-softshell-turtles-walk-towards-revival/
  14. https://turtle-island.org/wp-content/uploads/2023/02/2002_Aspideretes_nigricans.pdf
  15. https://www.conservationleadershipprogramme.org/wp-content/uploads/2024/12/100206_India_FR_Tortoisesturtles.pdf
  16. https://dx.doi.org/10.2305/IUCN.UK.2021-1.RLTS.T2173A2778172.en
  17. https://link.springer.com/article/10.1007/s12595-020-00329-3
  18. https://www.researchgate.net/publication/365048963_First_record_of_the_critically_endangered_Black_softshell_turtle_Nilssonia_nigricans_ANDERSON_1875_for_Nepal
  19. https://thehimalayantimes.com/nepal/critically-endangered-black-softshell-turtle-found-in-belbari
  20. https://www.facebook.com/KazirangaNP/posts/back-to-the-wild-critically-endangered-black-softshell-turtle-hatchlings-from-na/906788198223153/
  21. https://www.iucnredlist.org/species/2173/2778172
  22. https://www.researchgate.net/publication/344307971_Breeding_Performance_and_Pond_Habitat_Management_of_Critically_Endangered_Black_Soft-Shell_Turtle_Nilssonia_nigricans_in_Bangladesh
  23. https://www.nepjol.info/index.php/hijost/article/download/83420/63787/239273
  24. https://iucn-tftsg.org/nilssonia-hurum-048/
  25. https://www.researchgate.net/publication/347145727_Nilssonia_nigricans_Scavenging
  26. https://www.encyclopedia.com/environment/encyclopedias-almanacs-transcripts-and-maps/softshell-turtles-trionychidae
  27. https://journals.ku.edu/reptilesandamphibians/article/view/15828
  28. https://animalia.bio/black-softshell-turtle/1000
  29. https://link.springer.com/article/10.1007/s12595-020-00350-6
  30. https://www.sciencedirect.com/science/article/pii/S2351989423000793
  31. https://news.mongabay.com/2022/11/in-nepal-a-turtle-that-rose-from-the-dead-makes-another-grand-entrance/
  32. https://portals.iucn.org/library/sites/library/files/documents/2018-017-En.pdf
  33. https://www.deccanherald.com/india/assam/temple-ponds-in-assam-turned-into-conservation-hubs-for-critically-endangered-black-soft-shell-turtles-3308938
  34. https://www.econe.in/post/slow-and-steady-will-they-win-the-race-walking-the-turtle-trail-in-assam
  35. https://www.facebook.com/cmofficeassam/posts/on-27-september-2025-104-turtle-hatchlings-of-three-species-black-softshell-turt/1123480829970855/
  36. https://turtlesurvival.org/programs/bangladesh/
Add your contribution
Related Hubs
User Avatar
No comments yet.