The 2,000-year-old fishing boat of Galilee in which, the story goes, Jesus may have sailed, is one of the most precious ancient treasures in Israel.

The vessel, which draws thousands of tourists to a kibbutz in Ginosar, was discovered by chance in 1986 when the sea level dropped dramatically because of a severe drought.

"This year it is actually worse. I have been here 54 years and I have never seen the water so low, the situation so bad," said Haim Binstock, an expert on the boat in the museum where it is kept. "I don't think the outside world realises just how dangerous the situation is, not just for Israel but for the whole region."

The waters of the Sea of Galilee are now at their lowest on record and, officials say, are set to fall even lower. The crisis is both natural and man-made. Four successive years of droughts, with rainfall less than half the annual average, has combined with a lack of snow on the peaks of Mount Hermon to lead to the shortage. At the same time,Israel's relentless pumping of water to irrigate farmland and supply homes has been massively worsening the situation.

The Israeli government, environmentalists say, seems oblivious to the damage being caused to the largest lake in the country. Despite the water falling below the lowest red line, which denotes serious hazard, the pumping has continued until it is due to reach an even lower black line, seen previously as a point of no return.

Gidon Bromberg, the Israel director of Friends of the Earth Middle East says: "There is a very real danger that this could lead to over-salination. The lower red line indicates the level at which the sustainability of the lake is threatened. We are certainly very alarmed by the authorities' willingness to go to the black line. This development could well be irreversible."

The main factor driving the unending thirst is Israel's projection of itself is a country of pioneering farmers who made the desert bloom while the previous Palestinian owners of the land were prepared to live in a barren environment without seeking progress.

Attempts by the Israeli government to bring in strict restrictions on water usage would, analysts say, be politically suicidal with an election on the horizon. No party would be willing to put forward such proposals against the powerful farming lobby.

Israeli farmers consume 40 per cent of the country's fresh water using some of it, environmental campaigners point out, to grow fruit such as bananas and types of berries alien to the desert, for export to the West. That leads to the perverse equation, they say, of water being exported from the parched Middle East to wet Europe.

The Sea of Galilee has now also taken on another international strategic dimension. The next round of the fledgling talks between Israel and Syria are due to begin and, according to Walid al-Moualem, the foreign minister in Damascus, control of the Sea's shoreline is a bone of contention.

The late president of Syria, Hafez al-Assad, while stressing that much of Galilee used to belong to his country, once described to Bill Clinton how he used to swim in the waters of the sea before the 1967 war when Israel captured the eastern shore and the plateau.

Israel's unwillingness to relinquish those gains led to Assad refusing to sign a peace accord at the time. His son and heir, President Bashir al-Assad, insists that Israel must withdraw from "every inch" of the Golan, including the eastern shore of Galilee.

At the kibbutz of Ein Gev, beside the sea, from where ferries run to Tiberias, Leon Segal, a guide, sees Syria's hand behind part of the problem. "Our cousins – I say that because the Bible says we are cousins – have been drilling in areas they should not, and this is diverting the water. This is the politics of the Middle East."

Mr Segal did acknowledge, however, that the Israeli government should be doing a lot more to alleviate the situation. "They should be setting up manydesalination plants to get water from other sources. They're using Israeli expertise in these matters all over the world but this is the one country which isn't using it enough. I don't think it would be possible to deprive the farmers of their water, so what is needed is alternative sources, it's that simple."

Temperatures at midday on the Galilee shore rise to a cloying, humid mid-50s Celsius. Faye Statiabou, 52, who arrived at the kibbutz from Australia 30 years ago, described how "quite big cracks are now appearing on the walls of our home, that is due to the heat caused by the drought. This is the hottest I can remember. We desperately need some rain pretty soon. Maybe this is global warming.

"But the pumping out of the water doesn't help. My husband was a fisherman and he has seen how the water has gone over the years, and with it the fishes."

Ms Statiabou and Mr Segal wandered down to a shore of shingle. "This is where the water used to come to," said Ms Statiabou. "Now look how far it has gone." The nearest sunbathers and swimmers were at the new shoreline at least 30 yards away.

The Galilee region had been verdant through the ages with a ribbon of flourishing towns and villages beside the lake. The historian Flavius Josephus, writing in the first century, was so taken with the area that he wrote: "One may call this place the ambition of nature." He reported 230 fishing boats working each day.

Ari Binyamin, a fisherman, said he wished he was living in that time. "We used to say even a few years ago that one place where you couldn't go wrong fishing was Kinneret [Hebrew name for the Sea of Galilee] but now it is getting very, very hard because the stocks are so low. Many fishermen fear for their livelihood and so do I. But it seems no one really cares about us."

At Ginosar, after showing another group of visitors round the Galilee boat – made out of 12 different types of wood -Mr Binstock said: "Of course many of the disciples of Jesus were fishermen at Galilee. If you recall, he said he would make them fishers of men. Well, that wouldn't be possible now, there are hardly any fish left around here.

"This country has found itself, through circumstances, as the keeper of some of the most precious things in the world, both made by man and by nature. It has a responsibility to the rest of mankind to look after these things. They are failing to do this here, at the Sea of Galilee."