A colony of soft-shelled turtles, an endangered species, has made its home in a particularly surprising place in the Sharon region

Between Hod Hasharon and Kfar Saba, they live in a pleasant green area near the water, about five turtles, who spend their lives in a pleasant peace disturbed only by seagulls and seagulls who come to visit from time to time. Surprisingly, this pastoral habitat that the turtles chose for themselves is none other than the sewage treatment plant - Samaria rivers and the turtles in question are softshell turtles, a species that is in danger of extinction in the world and in Israel
By: Neta Nissim, Zwata - Science and Environment News Agency

Between Hod Hasharon and Kfar Saba, they live in a pleasant green area near the water, about five turtles, who spend their lives in a pleasant peace disturbed only by seagulls and seagulls who come to visit from time to time. Surprisingly, this pastoral habitat that the turtles have chosen for themselves is none other than the sewage treatment plant - Samaria rivers and the turtles in question are softshell turtles, a species that is in danger of extinction in the world and in Israel.

The common softshell turtles (Trionyx triunguis) live in Israel mainly along the coastal streams. In ancient times, the soft turtle family included hundreds of species that thrived around the world, but today only 22 species remain. Most of them live in Africa, Asia and the Middle East, and a minority - in the Americas. The soft-shell turtle is common in the Middle East, in Africa along the Nile and in central and western Africa and is defined as a "vulnerable species" by the IUCN organization - it faces many dangers and threats, whether these are direct impacts such as hunting and fishing or indirectly, in the form of environmental development, continuous pollution and drying The humid habitats where the turtles live.

In the early 70s, the condition of the softshell turtles in Israel was very serious due to the pollution of streams and accelerated development, so the legendary Israeli zoologist Heinrich Mendelsohn initiated their transfer to Lake Hula in order to keep them there. Since then their situation in the coastal streams has improved, but the fact that an entire colony of the species thrives in an unexpected place such as a sewage treatment facility is nevertheless an unusual and very positive event.

The presence of the turtles in the MTS is not a new matter, but recently nests were also found in the area, a sign that the turtles in the colony not only enjoy wading in the purified sewage water but also take care of the continuity of the species.

"Over the years we knew that there were soft-shelled turtles in the Pelagi Sharon Police Department, but only when the Nature and Parks Authority began conducting surveys to monitor the soft-shelled turtles along the coastal streams did we realize that we have an entire colony of turtles right under our nose that is also breeding," says Gadi Burd, an inspector at the Nahal Yarakon Authority . "It's a big deal to me that right here, in a sewage treatment facility, an animal in danger of global extinction has been growing, multiplying and surviving for many years."

The turtles in the MTS are concentrated in one of the purified effluent water pools, where the water is of a quality suitable for use in irrigation ("secondary treatment"). After the water undergoes tertiary treatment that makes it suitable even for irrigating field crops, it is regularly pumped into the Hadas and Cana streams, which are located near the MTS and are part of the sources of the Yarakon stream.

"Before we fenced off a designated place for turtles within the MTS, the turtles would enter empty ponds so that they and their eggs were very exposed to predators such as crows, mongooses and jackals that roam the area," says Itzik Tamm, director of the Sharon Pelgi Purification Institute. "So that the turtles don't go in there anymore, we covered the pool with a net and fenced off a place for them near the wastewater pool."

"In addition to the soft-shell turtles in the MTS, ducks, seagulls and skuas, species of carnivores come to us throughout the year, and you can find aquatic plants here, such as Nahanronit, which is also an indicator of the good quality of the water," adds Tamam. "We have really created a small ecosystem here and it is important for us to maintain it."

jackals against turtles

The soft-shelled turtles in Israel need someone to look after them, not only at the Pelagi Sharon police station. Today, the largest populations in Israel are found in the Hula Reserve and the Nahal Alexander National Park, and in each of these habitats there are only a few dozen turtles. The situation in other coastal streams is even more worrying: in the Naaman, Kishon, Tannin, Ada and Yarkon streams, few details have been counted since the XNUMXs. As mentioned, additional soft-shelled turtles are also found in the Jordan system (including the Hula Reserve) - this is due to the transfer of soft-shelled turtles to this system in the late XNUMXs.

"There are a number of stable populations of softshell turtles in the streams of the country, and we are working in collaboration with various researchers in order to learn about the genetic diversity of these populations so that we can know how to best treat each population," says Dr. Dana Milstein, aquatic habitat ecologist at the Nature and Parks Authority . "One of the main problems of the soft turtles are the predators that destroy their nests. In Nahal Yarkon, for example, predation is very high, and may reach one hundred percent of the nests in a season (in the past the main predators were mongooses and in recent years jackals are the main threat to the turtles, N.N.). The high percentages of predation are problematic since the population in the stream is small."

Over the years, the population of softshell turtles in the Yarkon has been maintained at varying sizes, even during periods when the pollution levels of the Yarkon water were higher than today, and every year between 15-5 nests of softshell turtles are observed in the stream, but most of them are killed.

"Another danger they face is fishing along the length of the Yarakon streams. We have had unpleasant cases where we have found turtles that have swallowed a hook by catching the fishermen's bait. If we are able to find them in time, we try to remove the hook, but this is a serious health injury and a problem that is not so much in the public awareness," adds Yonatan Raz, the ecologist of the Nahal Yarkon Authority.

"In order to preserve the mollusc turtle populations in the coastal streams, we are carrying out nesting surveys to monitor the nests of the mollusk turtles along the length of all the coastal streams, and that is how we arrived at the nests in the Pelagi Sharon MTS," says Milstein. "We also monitor the characteristics of the spawning using cameras and during the breeding season we monitor and map the number of nests on the banks and try to understand what the preferred spawning places are, so that we can protect them, adapt to the turtle population and keep them from getting mad."

"It is important for us to keep these turtles. They are like a kind of cleaners of streams, they clean the streams by eating carcasses and rotten material and it's fun to know that they live in the water," says Raz.

Should the turtles be returned to the stream?

The soft-shelled turtles apparently came to the Pelagi Sharon MTS from one of the streams in the area. "The tributaries of the Yarkon used to be dry, but in the last decades, high-level sewage water is pumped into them from the Metsh. This means that a continuous water connection has been created between the Pelagi Sharon and Yarkon MTS," Raz explains. "This turns these tributaries into a wet ecological corridor, which invites animals such as turtles as well as various plants."

According to Raz, the presence of the soft-shelled turtles in the MTS emphasizes the importance of using streams in Israel as ecological corridors and shows that even wastewater treatment facilities can serve as a refuge for turtles and other animals.

But wouldn't it be better to move the softshell turtles from the MTS to another coastal stream in the area? "We would be happy if the population of turtles in the MTS lived in their natural environment, but since they are doing well there at the moment, we can use them as a breeding nucleus and a great gene pool for the future," says Burd. "It is true that moving them to another place where there is a population of turtles - the Yarkon, for example - can increase the population and perhaps this way a greater genetic diversity will be created that will strengthen the population of softshell turtles that is there," says Milstein, "but for now we have decided not to touch and keep the population in its current location In the MTS because it reproduces and the products of reproduction (nests and eggs) can be moved back to the stream."

By the way, even though the turtles spend most of their time in sewage, unfortunately the professionals who follow them have yet to report that they have developed impressive ninja abilities or a special fondness for pizza.

More of the topic in Hayadan:

• The bacteria that restore the the stream
• Do all streams flow to the sea?
• Researchers from Tel Aviv University found evidence of eating turtles 400 thousand years ago In a magic cave in Rosh Ha'Ain, not far from Yarkon