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Research on Nile soft-shelled turtles

The Nile soft-shelled turtles are returning to the coastal rivers and streams:
Nine (9) nests with eggs of these soft-shelled turtles were located during a survey of the Yarqon River conducted jointly by the Israel Nature and Parks Authority and the Yarqon River Authority, as part of their efforts to rehabilitate the river.
The fact that these turtles are nesting here indicates the presence of a stable adult population in the river.
Surprise! All the nests were found in the river’s (polluted) mid-section.

Nile soft-shelled turtles nested in the past in all Israel’s coastal rivers and streams, but since the establishment of the State the rivers of Israel have suffered from the pumping out of water, pollution and construction, and together with the rivers many species of fauna and flora which the rivers sustained have also been harmed.  Realizing that various species were facing the threat of extinction due to the harm done to the rivers, the late Prof. Heinrich Mendelssohn decided 40 years ago to remove several specimens of the Nile soft-shelled turtles and transfer them to the Hula Nature Reserve.  It has been known for several years now that Mendelssohn’s prediction has not been fully realized as a population of Nile soft-shelled turtles managed to survive during that time in a number of coastal rivers and streams, and the most notable one numbering hundreds of specimens may be found in the Alexander River.  However a survey conducted by the Israel Nature and Parks Authority (INPA) and the Yarqon River Authority in June last discovered that a population of Nile soft-shelled turtles has been living for many years in the Yarqon River too.  Nine nests with eggs were located during the survey, all of them in the river’s middle section where effluents flow.  “In recent years we released young soft-shelled turtles into the Yarqon River and this survey was planned to investigate the status of the adult population in the river, prior to releasing adult turtles there.  We were surprised to find in the river a natural stable population of Nile soft-shelled turtles, which reproduce even in relatively high numbers”, stated Dr. Yariv Malichi, central district ecologist for the INPA.  The survey was conducted by Yoram Malka, an inspector at the Hula Nature Reserve run by the Israel Nature and Parks Authority (INPA) and Yonathan Raz, an ecologist working with the Yarqon River Authority.

In addition to the young turtles which had been already released into the river and the existing population there, this year a nest with soft-shelled turtle eggs was transferred from the Hula Nature Reserve to the Yarqon River.  Dr. Yariv Malichi noted: “The idea behind transferring soft-shelled turtles to the Hula was to establish a population of this species protected from the pollution in the rivers, but these Nile soft-shelled turtles do not naturally belong in the Hula or in the Jordan River’s ecosystem to which they had been moved.  In recent years many surveys are ongoing in the coastal rivers and streams, as part of the rehabilitation works and in cooperation with the various river authorities, drainage authorities and regional councils.  As we went about our efforts to rehabilitate the rivers and streams and also restore the population of Nile soft-shelled turtles, we began to release soft-shelled turtles and young turtles, which originated in the Hula Nature Reserve, into the Soreq and Hadera rivers.  No adult turtles were released into the Yarqon because we had no knowledge about the state of the natural adult population in the river, and therefore, we conducted the survey in the Yarqon, together with the Yarqon River Authority.  The results were certainly surprising and encouraging as although we knew of the existence of Nile soft-shelled turtles in the river we did not expect to find such a stable natural population.  All the nests were located in, of all places, that section of the river where effluents still flow, but I am certain that these turtles also stand to benefit from the rehabilitation works in the river because the survey of the Nile soft-shelled turtles constituted part of those endeavors.”              
 
Yonathan Raz, an ecologist with the Yarqon River Authority added: “In the first survey conducted in the Yarqon in 2007, about 5 nests, which appeared to have been torn to pieces, probably by mongooses, were found.  Happily, this year much to our surprise, the nests remain untouched by predators and the  longer the incubation process in the nest proceeds, the chances of seeing about 300 soft-shelled young turtles emerging into the Yarqon River this coming August increase, even though only a very small number of them will reach adulthood (as nature dictates).”