Nile Softshell Turtles19/07/2018
Israeli nature is a home for other species of turtles in addition to sea turtles. In addition to the local spur-thighed tortoise (Testudo graeca), the Balkan pond turtle (Mauremys rivulata) and in some coastal streams – the Nile softshell turtle as well. The shell of the Nile softshell is covered with a smooth layer of skin that gives it the appearance of soft tissue, hence its name.
The flat body of a Nile softeshell turtle is perfectly suited to life in streams, while membranes on its limbs make it an excellent swimmer. It is well camouflaged in murky water and on muddy streambeds, and its long, flexible neck allows it to peek out of the water and survey its surroundings. Like many species of reptiles, the Nile softeshell enjoys sunning itself. Its sharp claws allow it to climb vegetation and smooth rocks on streambanks. It feeds on insects, mollusks and amphibians as well as on various plants and nuts.
The Nile softshell turtle (Trionyx triunguis) that lives in Israel’s streams is a member of an ancient family called Trionychidae. This family once included hundreds of species that thrived throughout the world, but there are now only 13 genera and 22 species left. Most of them live in Africa, Asia and the Middle East, and some on the American continent. The most common species in Israel is considered the largest in Africa (its shell can be as much as 90 cm long) and it can live for decades.
The Nile softshell turtle was first described for science in 1775, when it was found in the Nile River, giving it its popular name Scientists were surprised to discover only a few decades ago, in the 1970s, how broad its distribution actually is – from the Sahara Desert and southward, in river estuaries in West Africa as well as in Kenya, Somalia and elsewhere. The Nile softshell reached Israel via the Nile Delta, into the Mediterranean Sea and from there to various streams. It arrived in Lebanon, Syria and Turkey in the same way.
Scientific surveys have revealed that the population of Nile softshell turtles in the Alexander Stream in Israel is one of the three major populations of this species in the Mediterranean basin (the two others are in the rivers of southwestern Turkey). Still, no one has been able to precisely estimate the number of adult Nile softshells in the Mediterranean basin. Past surveys have calculated their number at about 500 or less.
Nile softshell turtles sunning themselves on the banks of the Alexander Stream. photo: yaniv levi
Various nature conservation organizations and international conventions define the Nile softshell turtle population in Mediterranean countries (Egypt, Israel, Lebanon, Syria and Turkey) as a subspecies in need of special care. In 1996, the International Union for the Conservation of Nature declared the Nile softshell population critically endangered. In a survey carried out in Egypt, Syria and Lebanon, no living individuals were found, but rather only remnants of shells in the hands of local fishermen.
It is no secret that like the green sea turtle, the Nile softshell turtle is in real danger, whether directly threatened by hunting or fishing or indirectly, by development, ongoing pollution, drying up of moist habitats and other factors.
The negative impacts of the indirect factors threatening Nile softshell turtles have grown stronger over the past few decades:
Change, restriction and habitat fragmentation: Among the many threats, these are perhaps the most severe. They include stabilization of riverbanks that prevent access to nesting sites, dams that raise water levels, which restrict some nesting sites and flood others and restriction and even blockage of access to nesting sites on beaches due to development.
Water and beach pollution: Waste and toxins flowing into streams severely damage habitats and cause serious harm to animals, particularly the Nile softshell turtle. Discarded garbage on beaches also significantly reduces potential nesting sites.
Human activities: These include motorboats, which are a clear and present physical danger, noisy crowds and unmonitored feeding. In addition, one of the most complex dangers is entanglement in fishing nets and hooks which injure or choke the turtles. It should be noted that in some parts of the world (mainly Africa and Southeast Asia), Nile softshell turtles are hunted for food or to use their limbs in folk remedies.
Predators in nature: With or without humans, Nile softshell turtles are exposed to predators. But the large quantities of garbage people throw out near nesting sites attract foxes, jackals, mongooses, badgers and dogs that tend to dig into the nests and eat the eggs.
X-ray of fishhooks embedded in the esophagus of a Nile softshell turtle. Photo: Dr. Tsachi Eisenberg, Kol Hai Clinic.
In the not-too-distant past, Nile softshell turtles were abundant in this country. In fact, until the beginning of the twentieth century they could be found in most coastal streams. After Israel was established, researchers still reported hundreds of adult Nile softshell turtles and a few thousand young ones. But as noted, habitat change, restriction and fragmentation over the past few decades as well as other environmental problems like pollution and various human activities, have led to a considerable decline in their population. Today the largest populations are found in the Hula Nature Reserve and Alexander Stream National Park, and with an estimated few dozen individuals in each of those habitats. The western part of the Alexander Stream is considered the main nesting site in Israel for Nile softshell turtles; dozens of nests can be seen there in breeding season.
And what about the other coastal streams? In the Na‘aman, Kishon, Taninim, Ada and Yarkon streams, only a few individuals have been counted since the 1970s. Nile softshell turtles can also be seen in the Jordan River system (including the Hula Nature Reserve) following the transfer of Nile softshells there in the 1960s.
At that time researchers and conservationists believed that moving the turtles would help them proliferate and protect them from extinction. But in the 1980s experts in the Nature Reserves Authority (now the Israel Nature and Parks Authority) determined that an attempt should be made to remove the Nile softshells from the Jordan system and return them to suitable coastal streams, especially streams that would be rehabilitated. This, they said, was because it does not “belong” to the Jordan River system, where it is considered an invasive species that could upset the ecological balance. Today the Israel Nature and Parks Authority is working according to an organized plan to transfer adult Nile softshells from the Hula reserve to coastal streams. However, if not for that initial transfer, Nile softshell turtles would probably be extinct today in Israel.
A conceptual change in the Israel Nature and Parks Authority has led to comprehensive change and real strengthening of the population of Nile softshell turtles in recent years. While in the past the focus was on the Alexander Stream, since 2004 other coastal streams have also been rehabilitated. So what can be done to help the Nile softshell turtle? We can describe the activities on a number of levels.
Stream rehabilitation: The Ministry of Environmental Protection coordinates planning and implementation of streambed rehabilitation among the various agencies involved. Agencies have also been established to rehabilitate specific streams (such as the Yarkon and the Kishon). Improved water quality and quantity has helped the Nile softshell turtle: In projects like these, the Israel Nature and Parks Authority carries out various tasks, such as clearing overly tangled vegetation on streambanks (to create nesting grounds for the turtles). This has been done, for example, along the Yarkon and the Alexander streams and in the Ein Afek Nature Reserve.
Nesting surveys along coastal streams: These surveys, which are carried out once a year during nesting season, provide experts with an updated picture. For example, surveys carried out recently show the presence of Nile softshell turtle nests along all the coastal streams (expect the Poleg Stream). The survey provides a great deal of knowledge about the lives of the Nile softshells that helps researchers learn how to protect them in the future.
Fencing off nests: This work is important in helping prevent predation. Over the years there have been many attempts to find the right kind of fencing for each habitat. Among the methods tried to protect against predators, one is peripheral fencing of the streambank (in the Alexander Stream National Park) and another is placing special dome-shaped fencing over individual nests (the Na‘aman Stream).
Nesting farms: As with sea turtles, Nile softshell turtle nests can be moved from place to place. At a nesting farm, each nest can be individually fenced, and of course, so can the entire farm. Beyond protection, this option allows for precise monitoring of the hatching of the eggs and a fairly easy sendoff of the hatchlings to the stream. An interesting example of this can be seen downstream on the Kishon, where a well-fenced artificial enclosure has been created. Nests collected along the streambank have been moved to this enclosure.
It should be noted that since 2004, transfer has been underway of nests and hatchlings from nesting farms in the Hula Nature Reserve to coastal streams.
Photo: shir rilov
How you can help?
Not only Israel Nature and Parks Authority rangers or scientists can protect the Nile softshell turtle – so can each and every one of us: children, teens and adults. Surprisingly, it’s very easy to do:
- Don’t feed wild animals at all, particularly not Nile softshell turtles, and don’t leave remnants of food behind in nature.
- Don’t discard garbage, such as paper and plastic.
- If you find a turtle that is injured or otherwise in trouble, or if you see illegal activities near streambeds, report them by phoning *3639.