Batagur baska (Gray 1830) – Northern River Terrapin

Abstract

SuMMary. -The northern river terrapin, Batagur baska (Family Geoemydidae), is a large (carapace length to 59 cm) critically endangered river turtle that previously occupied most rivers and estuaries of South Asia (India, Bangladesh, and Myanmar). Populations of river terrapins occurring in Southeast Asia (Thailand, Cambodia, Malaysia, and Indonesia) previously referred to this species are now considered a separate closely-related species, the southern river terrapin, Batagur affinis. Exceptionally large concentrations of this species that resided in the Hugli River of West Bengal in India and the Ayeryawady Delta in Myanmar during the 19th and early 20th centuries are now extirpated. Nesting throughout the northern river terrapin's former range is now extremely rare and the product of only a few scattered survivors. The terrapin's demise has resulted from extensive exploitation of its flesh and eggs, exacerbated by indirect factors, including habitat alteration and destruction (e.g., sand-mining, dam building, water projects, and pollution) that have degraded the turtle's nesting areas and feeding habitat. Recently, remnant populations have also suffered from the introduction of efficient mechanized fishing craft with lethal wide-area nets throughout much of the remaining habitat. Conservation action for the terrapin has been woefully inadequate. Ideally, the species and its eggs require complete protection throughout its range. In India and Bangladesh, extant terrapins now appear to be so few that unless some previously unknown viable population is discovered, the only recourse may be to capture as many of the remaining wild individuals as possible to keep in captive breeding facilities until such time as it is feasible to re-establish a wild population in one or more sanctuaries. Less is known about the species' status in Myanmar. Additional surveys are needed for estuarine habitats in the poorly-known eastern and southeastern river systems in Myanmar to determine if viable populations survive, and if so, to identify nesting sites and critical feeding areas.diStributiOn. Gray, at times, was guilty of describing the same species under more than one name; the river terrapin is an example. In the same year, he published two other names for the terrapin, Trionyx (Tetraonyx) cuvieri and Emys batagur (1830b).

Optimal Background Color for Head-Starting Northern River Terrapins (Batagur baska Gray, 1831)

“…At the end of the 12 week trial, the terrapins were fasted for 12 h prior to collecting the specimens (feces, carapace, and blood). The parameters relating to growth and feed utilization were calculated as described below: Survival (%) = (Final terrapin number/initial terrapin number) × 100 (1) Body condition index (BCI, kg cm −3 ) = (Body weight (kg)/straight carapace length (cm) 3 ) × 10 4 (2)…”

“…The northern river terrapin (Batagur baska Gray, 1831) is a riverine turtle native to Southeast Asian countries (i.e. India, Bangladesh, Myanmar, Thailand, Cambodia, Malaysia, and Indonesia) [1]. It prefers freshwater habitats but also moves to brackish water or estuaries in the breeding season.…”

Optimal Salinity for Head-Starting Northern River Terrapins (Batagur baska Gray, 1831)

“…Northern river terrapin ( Batagur baska Gray, 1831) is Asia’s largest turtle, and is native to southeast Asian countries [1]. Due to consumption as food, this species is listed in the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), and is also classified as critically endangered by the International Union for Conservation of Nature and Natural Resources (IUCN).…”

“…Due to consumption as food, this species is listed in the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), and is also classified as critically endangered by the International Union for Conservation of Nature and Natural Resources (IUCN). In order to conserve the population in the wild, captive breeding and hatchery projects were established in Vawal National Park in Bangladesh and at Sajnekhali Forest Station in India [1]. In Thailand, an ex situ head-starting program of this species before release to natural habitat has been conducted by the Department of Fisheries and the Department of Marine and Coastal Resources [2,3].…”

Batagur affinis (Cantor 1847) – Southern River Terrapin, Tuntong.

“…Historic distribution of Batagur affinis in Southeast Asia. Purple lines = boundaries delimiting major watersheds (level 3 hydrologic unit compartments -HUCs); red dots = museum and literature occurrence records based on Iverson (1992) plus more recent data, and the authors' personal data; green shading = projected historic native distribution based on GIS-defined level 10 HUCs constructed around verified localities and then adding HUCs that connect known point localities in the same watershed or physiographic region, and similar habitats and elevations as verified HUCs (Buhlmann et al 2009;TTWG 2014), and adjusted based on authors' subsequent data; broad gray line = approximate boundary between the two subspecies, with B. a. affinis (1) in the southwest and B. a. edwardmolli (2) in the northeast.…”