Israel says its six-mile limit around Gaza is a vital security measure. Billy Briggs meets the fishermen targeted by gunboats and the protesters who are sailing from Cyprus to break the siege

SAMY al-Goga walks down to the shore holding his 18'month-old daughter and looks out towards the sea. "It's far too dangerous to go fishing now," the tall Palestinian fisherman says. He is standing on a filthy beach at Gaza City close to an area called Beach Camp that houses refugees. A couple of hundred yards further up the shoreline, raw sewage flows from a pipe into the sea, and on the horizon the grey silhouette of a ship can just be made out through the haze of the summer heat. "That's an Israeli gunboat on patrol," he says, pointing with the stump at the end of his left arm.

Until 17 months ago, Goga was out fishing in his boat nearly every night catching sardines to sell at the hesbeh (market) each day. On the morning of March 5, 2007, however, the 29-year-old's career as a fisherman ended when, he claims, his vessel was attacked and destroyed by an Israeli gunboat.

"We'd been fishing in the south near Rafah and were followed by a boat around 5am on our way back in. As we landed they fired rockets at us. I lost my hand in the attack and my brother was hit by shrapnel," Goga says, lifting his left arm. He has no idea why his boat was targeted, as it had not strayed beyond the six-mile limit.

Earlier, we'd drunk tea with his 73-year-old father, Ali, who, like many other fishermen here in Gaza, spoke in despair of how the industry is being decimated by an economic blockade imposed by Israel after Hamas took control of Gaza in June 2007.

Hamas - a legitimate party of resistance to its supporters but a group branded terrorists by Israel - is committed to removing Israeli forces from the Occupied Territories.

Last year, in response to rocket attacks by Hamas's military wing, and other militant groups targeting Israeli towns near Gaza, Israel tightened economic sanctions imposed 12 months earlier. A year on, the policy has had a devastating impact on Gaza's economy.

According to the United Nations Relief and Rehabilitation Administration, the unemployment rate in the Strip now stands at 45%, one of the highest in the world. The UN says the crisis has left the number of households below the poverty line at an unprecedented 52%.

The fishing industry - which in the 1990s produced an annual income of around £5 million - has been hit particularly hard. Under the Oslo accords, which in 1993 were supposed to herald the coming of an independent Palestinian state, Gazan fishermen were to be allowed 20 nautical miles out to sea, where they could catch sardines. But Israeli naval ships have imposed their own, much-reduced limit as part of the tightening pressure on Gaza that came after the election victory of Hamas.

Oxfam says fishermen are only allowed six miles out to sea, not far enough out to reach the schools of large fish - and fishermen risk being shot or arrested if they breach this limit. For several months in 2007, fishermen were not even allowed out of harbour, and fishermen can no longer export abroad as exports have been prevented for nearly two years.

Fishermen claim they are regularly targeted at sea by the Israeli gunboats that can be seen most days patrolling the horizon.

It's an ominous sight for Gazans and adds to the claustrophobic feel of this densely populated strip of coastal land only 25 miles long and six miles wide.

We meet with several fishermen with similar claims to Goga. At his home in Gaza City, Ibrahim Morad, who has five sons and a daughter, says he was at sea fishing in the Deirbelah area when his boat was targeted and sunk in May 2005.

A colleague was killed in the attack, he claims. Morad was fished from the water, arrested and subsequently sentenced to two years in Ashkelon prison for breaching the limit.

"They the Israelis beat me up and broke my left arm, and for the first two months I was given electric shocks," he claims. Morad shows me a letter sent by Israel to the Fishing Workers Trade Union after his release which states he is banned from fishing for five years. If caught at sea, he faces five years in prison. "What right have they to ban me from fishing in Gaza's waters?" he asks.

His neighbour, Ibrahem al-Naga, who makes nets, tells me that his son, Hane, was shot at sea by a sniper on October 2, 2006. Hane's brothers, Zake and Mohammed, he adds, are both in prison after being arrested at sea in March, 2007.

There are also environmental problems to exacerbate the human misery. As fuel supplies have been cut because of the blockade, some pumps at Gaza's 33 water stations are idle, so an estimated 77 tonnes of raw sewage flows into the sea each day.

The rising cost of diesel is another major issue. As Majed Abu Reyaleh lies asleep on nets after a night shift at sea, his father, Mohammed, explains that the cost of fuel has risen tenfold in 12 months, from around 75p a litre to £7.50. "Most boats are tied up, and if this continues the industry will be dead this time next year," he says.

For its part, Israel says that the six-mile limit imposed on fishermen is a vital security measure to prevent weapons and artillery being smuggled into Gaza. A spokesman for the Israeli embassy in London said the economic blockade was not a collective punishment on the people of Gaza and that it was purely to prevent rockets being fired by militias such as Islamic Jihad and the Izz ad-Din al-Qassam Brigades, Hamas's military wing, who regularly target Israeli civilians in border towns such as Ashkelon and Sderot.

Since the onset of the second intifada in 2000, the Israeli spokesman says, Hamas has perpetrated 425 terrorist attacks in which 377 Israelis died and 2076 people were wounded. These included 52 suicide attacks, in which 288 Israelis were murdered. Despite a ceasefire being in place since June 19, 2008, he added, 11 rockets and 15 mortars have since been fired at Israel. Between January and June 2008, 1075 rockets and more than 1204 mortar bombs were fired at Israel from the Gaza Strip.

As a result of this threat, Israel is faced with a dilemma, in that it must protect its civilians from rockets while not being disproportionate with retaliation.

"Israel completely disengaged from Gaza three years ago", says the spokesman, "and Hamas, a terror organisation who took control over the strip more than a year ago, is fully responsible for the fate of the strip and its people. Israel has been supplying fuel, food, medical supplies and other humanitarian assistance in spite of incessant attacks carried out by Hamas and other organizations on border crossings."

He adds: "It is apparent that Hamas is targeting crossings in order to prevent the transfer of humanitarian aid to the civilian population, thus cynically depriving its own population and causing an artificial crisis in the Gaza Strip. Recent reports indicate that Hamas is allocating these supplies for its own use, thus deepening the deprivation of the public. Clearly, Hamas wants to create a crisis in order that international pressure will be placed on Israel."

Israel's blockade has attracted criticism from groups such as Human Rights Watch and Amnesty International, who say that the nation's rightful defence against unlawful rocket attacks does not justify a blockade that is a policy amounting to collective punishment.

Protests are now increasing across the world and while Gaza's fishermen try to come to terms with a bleak future an attempt will be made at sea this week to break the siege. A group of activists, including Tony Blair's sister-in-law Lauren Booth, plan to sail into the Palestinian territory.

Some 46 campaigners, among them several Britons, a Holocaust survivor and an 81-year-old retired Catholic nun from the US, will make the 241-mile crossing from Cyprus in two wooden vessels carrying medical supplies.

The California-based Free Gaza Movement wants to open unrestricted international access to Gaza while delivering a symbolic shipment of 200 hearing aids, batteries and supplies such as painkillers. Organisers say they will not pass through Israeli waters and have therefore not notified Israeli authorities of their plans, but they are prepared for the 21-metre Free Gaza and 18-metre Liberty to encounter resistance. The captains of the two boats, the Free Gaza and the Liberty, are Irish.

Among the passengers is Scotsman Andrew Muncie, 34, from Glasgow, who has philosophy degrees from Aberdeen and Edinburgh universities. He visited the West Bank in 2003 and says the world is ignoring the "injustice" endured by Palestinians and the "catastrophe" that has befallen them.

Organisers say the boats will be inspected by an independent security service to prove that no weapons or dangerous substances were on board.

One of the Free Gaza organisers, Greta Berlin, said: "We don't underestimate Israel at all, and have done a lot of what ifs' the past few days. We've discussed how to react if they blow up the boat, board us, arrest us, shoot us, hire somebody in Gaza to harm us, tow us or stop us.

"We've been looking at what happens if they say the waters are mined, or they have robot submarines in the area. We can give them our route ahead of time. Our safety is in their hands. They have guns, weapons, mines and robot submarines. All we are carrying is 200 hearing aids and 5000 balloons. There is not a single militant among us," she added.

The group has sought to stress the peaceful nature of the mission, following a number of reports that claim they will be carrying weapons to Hamas.

The Israeli embassy in London declined to comment on the crossing.

In 1988, the Palestinian Liberation Organization tried without success to sail from Cyprus to the Israeli port of Haifa. The ship, the Sol Phryne, was damaged in a mine attack in the Cypriot port of Limassol. PLO officials accused Israel of planting the mine. Israeli officials did not deny the allegation.