Taxonomic Notes
Trionyx triunguis has been considered a single widespread, relatively uniform species for decades, with no subspecies or other taxonomic units recognized or proposed in recent years. Phylogeographic studies of regional variation have demonstrated different, partly conflicting results, but were based on generally limited sets of specimens and genetic markers (Gidis et al. 2011; Güçlü et al. 2011, 2015; Shanas et al. 2012). However, there is still uncertainty as to whether Mediterranean and African subpopulations may in fact represent genetically definable separate Management Units (O. Türkozan unpubl. data).
Justification
European regional assessment: Not Applicable (NA)
EU 27 regional assessment: Not Applicable (NA)
The African Softshell Turtle is considered Not Applicable for the European Red List (both European and EU Member States levels) as it is of marginal occurrence in the region, with probably vagrant records from Greece only.
Geographic Range Information
Within the European region, this species has a very marginal distribution. The species was first reported in Europe in 1992 from Kos Island in the eastern Aegean, and the authors suggested that the animal, entangled in fishing gear, may have drifted some way from its original range (Taşkavak et al. 1999). Corsini-Foka and Masseti (2008) report that the species is occasionally seen in the open sea off the coast of other Dodecanese islands (Laymnos, Leros, Rhodes), with live specimens "often" caught by fishers near Laymnos, Leros, and Kos. Unfortunately, no quantitative data are reported for the frequency of these captures. Corsini-Foka and Masseti (2008) also reported an earlier record for Greece; a preserved specimen on Rhodes is attributed to the island of Symi, where it was collected in the 1950s. In the European Mediterranean region, the species is only found at sea level.
The species has a mostly a non-European distribution, being widespread in the African continent with fragmented and relatively threatened subpopulations in West and Central Africa and with abundant and continuous subpopulations along the River Nile in East and north-eastern Africa (van Djik et al. 2017). The species ranges widely in Africa, north along the Nile to the Eastern Mediterranean. In West Africa it has recently been observed also in Senegal, thus representing the westernmost area of native occurrence for the species. It formerly occurred more widely in the coastal regions of southern Türkiye, western Lebanon and in the Mediterranean coastal area of Israel from Tel Aviv northwards. The species is recently reported from Lebanon (Carlino et al. 2019) after several decades. It has not been reported from Syria, although vagrants might occur here. It has been introduced into the Jordan River system in the north including Hula Lake. It occurs in the Nile River basin from Egypt, and in river basins in Eritrea, Ethiopia, Somalia and Kenya, and in coastal and inland river systems from the Senegal (Mauritania-Senegal) river to the Cunene (Namibia) (Iverson 1992, Branch 1988, Boycott and Bourquin 2000, Spawls et al. 2002). It ranges from below sea level to possibly over 1,500 m (in Africa).
Population Information
There are no records on its population abundance or trend in Greece. The entire Mediterranean population was tentatively thought to number fewer than 1,000 mature individuals, but this estimate is not very solid and there is some disagreement between specialists. For instance, according to O. Türkozan (unpublished), only in Dalaman almost 400 individuals were reported; the site of Dalyan is under serious protection, and it can be reliably anticipated that there should be more Trionyx individuals out there. Furthermore, Oruç et al. (2001) reported 437 caught individuals in the mouths of the Seyhan and Ceyhan rivers in 1995 and 1996, while both sea turtle bycatch (Caretta caretta and Chelonia mydas) was less than this. In other words, there is much indirect evidence that the population size of this species is much higher than 1,000 mature individuals.
Limited data are available through most of its range, but it seems that the local abundance of this species varies considerably from country to country. In West Africa, it is generally rare, and the population size is small (van Djik et al. 2017). In the River Nile of West Africa, instead, the species is locally very abundant and is in fact targeted as a source of protein by fishers and heavily traded in the markets (Demaya, Luiselli, unpublished data). In the Mediterranean region, its populations are now very small and scattered, with some wandering individuals. Türkiye is the only country in the Mediterranean that holds a significant population. The species occurs along the Mediterranean coast of the Türkiye (Kasparek 2001) but large breeding stocks have been. Reported in two main areas: the Çukurova Delta (Seyhan River mouth) in the south (Yılmaz et al. 2020) and the Dalyan (Türkozan et al. 2006) and the Dalaman Delta in the southwest. In addition, reproduction occurs at eight more sites (Aksu/Acisu, Anamur, Göksu, Berdan River, Tuzla Drainage Channel, Karatas Drainage Channel, Ceyhan River) (van der Winden et al. 1994, Uçar and Ergene 2022), and recent records may indicate small populations exist from at least five more sites (Patara, Fethiye, Köprü Çayi/Acisu, Bozyazi, Orontes (Asi) River). It seems that, as in Türkiye, all subpopulations are under serious threat. In Israel, it is known from seven rivers in the Hula Basin, with reproduction only taking place in two of these. A good population existed until the early 1990s at Nahal Alexander in coastal Israel, but it declined due to drastic habitat changes after heavy storms and the subsequent intrusion of salt water from the sea. Now the population is much scattered, with mostly single individuals appearing at isolated places along the coast, without having a safe area for reproduction. In Egypt, there are few recent records from north of the Aswan High Dam on the Nile, and a survey of the Nile Delta and its lagoons suggests that it might now be extirpated there (with the possible exception of Bardawill Lake) (Nada 2002). South of the dam it is fairly common in Lake Nasser with large specimens frequently caught (S. Baha El Din pers. comm.). There is a recent record from Lebanon suggesting that nesting still occurs (Demirayak et al. 2002) and one from Greece (where it certainly does not breed). A male-biased population structure was reported, with 2.14 males per female. A total of 396 individuals were estimated with mark-recapture studies in the Dalaman region (Türkiye) with 14 turtles per ha (Akçınar and Taşkavak 2017).
Habitat and Ecology Information
There are no quantitative data documenting the habitat preferences of this species in the European region.
This species is a generalist in terms of habitat preferences. In West Africa, it is known to inhabit both rainforest rivers and savannah waterbodies, and it also occurs in marine waters all throughout its range (van Djik et al. 2017). It inhabits relatively deep water in permanent lakes, rivers, estuaries and coastal lagoons. It is tolerant of full seawater conditions for some time (Branch 1988, Baran and Atatur 1998, Taşkavak and Akçınar 2008)), but the populations occurring in brackish and salt waters are never characterized by a high number of individuals, at least in West Africa (Luiselli, Segniagbeto and Akani, unpublished data). In Israel, the quality of the habitat, and availability of nesting sites, varies with river fluctuations. It feeds on a variety of animal prey (molluscs, insects, crustaceans, frogs, fish), carrion, and vegetarian items (palm nuts, fruits) (Branch 1988, Gramentz 1993, Boycott and Bourquin 2000). The females produce clutches of 25-55 eggs in exposed sandbanks and banks with heavier soil (in Israel for example) and narrow slopes of the vegetated sand dunes (Türkozan et al. 2006, Yılmaz et al. 2020) along rivers (Branch 1988, Spawls et al. 2002). The mean number of eggs deposited by each female was 21 along a long-term study spanning 10 years of monitoring (see Yılmaz et al. 2020). However, the mean clutch size (40.7 eggs) in Türkiye was similar to that in the Alexander River in Israel (40.0 eggs; Leshem et al. 1991) but higher than in Dalyan (23.0 eggs; Türkozan et al. 2006), Dalaman (31.2 eggs; Gidiş and Kaska 2004), Belek (32.0 eggs) and Göksu Delta (29.0 eggs) (Candan 2018) and lower than at Burnaz (48.0 eggs) (Candan 2018). Age at maturity and clutch frequency are unreported. Captive animals have reached over 42 years of age (Branch 1988).
Threats Information
There is no information on threats occurring within the European region. As the species is not thought to be resident in the European region, threats acting outside the European region may be relevant.
It is widely collected for consumption, mainly at the local subsistence level, and especially in sub-Saharan Africa (Branch 1988, Spawls et al. 2002). This species is also present in the West African bushmeat trade, but the number of traded individuals is low because the populations are few and poorly numerous in that part of Africa. Animals caught by fishermen may be killed, and nests destroyed, as perceived competitors e.g., in Türkiye (Gramentz 1990, Baran and Atatur 1998). Although the construction of dams has been detrimental to this species in parts of its range (eg. Türkiye), dam construction has been beneficial to the species in Egypt (S. Baha El Din pers. comm.). In the Mediterranean, the chief threats are: habitat destruction (in particular for touristic developments in Greece), accidental mortality in fishing nets (killing hundreds of animals annually off the shore of the Çukurova Delta (Seyhan, Ceyhan and Berdan rivers) in Türkiye, and human disturbance. Natural predation of mammals, especially foxes, to eggs and hatchlings is a serious problem threatening the survival of the species.
Use and Trade Information
This species is widely used by humans throughout its range. In Europe, fishers are reported to take the species incidentally in nets but to release them prevent damage to nets (Corsini-Foka and Masseti 2008). Occurrence within Europe seems to be sporadic and capture for trade seems unlikely.
In other parts of its global range, the species is widely collected for consumption in the Sub-Saharan part of its distribution, mainly at a local subsistence level (Branch 1988, Spawls et al. 2002). It is also hunted by fishermen for the bushmeat trade in West Africa (for instance, in southern Nigeria; Akani et al. 2001), but the trade level remains low because this species is very rarely encountered in the field. Nonetheless, the meat is highly valued, and the prices are considerable (G.C. Akani, E.A. Eniang, L. Luiselli unpubl. data). Bari fishers consume this species very frequently along the White Nile river course in South Sudan (L. Luiselli and Demaya, unpublished data). Large parts of the range are in areas predominantly occupied by Muslim communities, for whom this species is unsuitable for consumption. This species is also used for tradition medicine in various sectors of West Africa.
Hatchlings are occasionally sold as pets. Trade data: 1987-2010: 1,544 traded. 70% declared as wild-captured exported from Ghana and Togo, imported mainly by EU countries, United States and Japan. Peak declared trade volume was 400-500 animals in 1992, in most years about 100 (including in the 2010-2015 years), with up to about 200 in 2009. The number of imported specimens is too low to make any danger to the native populations.
Conservation Actions Information
The species is in Annex 1 and in Annex II (strictly protected fauna species) of the Bern Convention. It is also in Annex II (Endangered or threatened species that the Parties shall manage with the aim of maintaining them in a favourable state of conservation) of the Barcelona Convention Protocol concerning Specially Protected Areas and Biological Diversity in the Mediterranean (SPA/BD Protocol). The species is included in CITES Appendix III, pertaining to the subpopulation of Ghana.
Information on the population status and trend data for the European region is needed. Awareness of the species' ecology may help counteract wanton killing by fishermen.