If subscribing to the adage that age is relative, Bournemouth is your poster community. Jewish leaders talk of 75 as "not old" and the local representative council chairman describes himself as "just a baby" at 51. But when the town's main synagogogue cannot sustain a cheder and bar- and batmitzvahs are a rarity, the future seems less attractive than the sea views that entice many retirees to the resort.

Not that the peaceful surrounds have always bred harmony. Ten years ago, Bournemouth Hebrew Congregation was acrimoniously split over the potential elevation to senior rabbi of assistant minister Yossie Alperowitz, a Lubavitch rabbi. Rabbi Alperowitz eventually quit the congregation and now heads the thriving local Chabad.

More recently, ructions in the Reform community led to breakaway factions establishing Masorti and Liberal groups.

Rep council chair Greg Rubins says things are now "generally friendly" and that it is easy for newcomers to fit in. It is something he can personally attest to after moving to the town from Pinner in 2004 for work reasons. "It is a lovely place to live, by the sea, very healthy. The minuses are obviously that it is a more elderly community with fewer Jewish facilities such as kosher restaurants." There is also a dearth of kosher shops, although the Orthodox shul and Chabad run not-for-profit delis.

Based on the 2011 Census, the Institute for Jewish Policy Research (JPR) reports 1,343 people in the town who identified themselves as Jewish, less than one per cent of the total population. Tellingly, 13 per cent of the identifying Jews were aged 85 or above - the figure within the general population was three per cent - and there were just 119 under-18s. The overall figure represents a fall of almost one-fifth from the 2001 Census total of 1,667.

Given that the shuls draw members from a wide area - and those with holiday homes - Mr Rubins estimates that well over 1,000 people are involved in Bournemouth congregations with many more unaffiliated. Of the latter, "we know there are Israelis who have moved to Bournemouth who don't belong to a synagogue - that's just the way they are. There are also possibly people who are unaware of all the facilities available. We are doing events as a rep council to improve the profile. For example, we recently had Tobias Ellwood, who is our local MP but also Minister of State for the Middle East. He gave a talk which was very well attended."

In membership terms, the biggest shul is Bournemouth Hebrew Congregation, with just over 600 adults. Its new president Brian Lassman - who once ran the local New Ambassador and Normandie hotels and still takes over the Queens Hotel for Pesach trade - says that those lost through death are replaced by retirees moving to the area. A year ago, the shul held a meeting to discuss the sale of its town centre premises and relocating to a more suitable location.

Mr Lassman declines to discuss the current state of play, other than to acknowledge that its "beautiful" Wootton Gardens building requires modernisation and that to vacate it would be sad.

Although others suggest that both its size - the shul can seat 900 - location and proximity to local nightlife make it unsuitable for current needs, Mr Lassman concedes only that "in summer [its surrounds] might be a little bit rowdy" for those walking home after services.

"We hold 21 services a week and get a minyan for every one. And it's not the same people. We get between 120 and 140 on Shabbat." Mr Lassman - who remembers the days when BHC ran a cheder for 120 children - does not view the congregation's predominantly elderly make-up as a problem. He cites the commitment of those in their 70s, 80s and beyond, as well as a social and cultural programme ranging from bridge and opera to table tennis and flower arranging. "We have a 104-year-old who walks to shul on Shabbat. It would be a very nice situation to have young families moving in but we are financially sound."

Over at Reform, its "Bournemouth through and through" chair Deborah Tendler says she has found evidence of unaffiliated young families in her work as a speech and drama teacher. "At one of my schools there are three Jewish children from different families that we didn't know about. I say to members: 'When you meet Jews through work, through being neighbours or through friends, see if they are interested in getting involved.'"

Mrs Tendler enthuses about a "stimulating, exciting time" at the 320-member congregation. "We have a great new rabbi, Maurice Michaels. He's part-time but it feels as though he's full-time."

Although the shul's cheder has 18 chidren, Mrs Tendler says there will not be a bar- or batmitzvah this year. And in an ageing population, members who were active in the congregation in their 70s and 80s 15 years ago are now in their 90s.

She is conscious of the need to cater for the older population and the shul has been holding forums on issues such as bereavement.

The problems of senior citizens from across the community occupy Pat Cravitz on a daily basis. A livewire personality to whom the "not old at 75" tag certainly applies, Mrs Cravitz is team leader of Bournemouth Jewish Social Services, which she established four years ago with Josie Lipsith, Elizabeth Harris and Marcia Goodman-Press. Having worked for Jewish Care in the 1990s, Mrs Cravitz asked the charity for help and was promised practical, if not financial support. Run entirely by volunteers, BJSS has an office in the Bournemouth Hebrew Congregation premises and deals with a constant flow of new referrals, almost exclusively concerning elderly people. Befriending is a big part of its work.

"Loneliness is the biggest difficulty," she says. "So many are old with no family - and their friends have died. They do feel isolated." On the day I visit, Mrs Cravitz fields calls from a Glasgow-based relative of a woman who is seriously ill in the local hospital and a man in rehab care who says he wants to go home but is not well enough. BJSS volunteers also help clients with benefit form-filling. "There are some cases of real hardship."

Susan Feld is the last remaining member of the group of locals which assumed responsibility for the local Jewish residential home, Hannah Levy House, 27 years ago after Jewish Care in London decided that it could no longer afford to administer it. Currently full to its capacity of 32, its residents are a mix of private and council funded. "But we end up subsidising everyone," says Mrs Feld, the senior trustee.

"We fundraise in Bournemouth on a small scale but obviously rely on wills and bequests. I won't say we beg, borrow or steal but we sometimes beg. We make losses every year. Our accountants say: 'What are you going to do?' And we say: 'Talk to us next year.' But we keep most of our residents until end of life because our care is so good."

The most optimistic overview is offered by Rabbi Alperowitz at Chabad, which also operates a cheder. It is very much a family affair as in addition to his wife Chana, Rabbi Alperowitz now has his son and daughter-in-law, Bentzion and Chanchi, involved in a "greatly enhanced programme, working predominantly among students and young people". Around two dozen students are involved in Chabad activities "and we are doing our utmost to encourage other people through festival programmes. Our focus is reaching out to every Jew." Its Water Garden Hotel - established through a supporter's legacy - does a roaring weekend trade.

Definitely a glass half-full man, Rabbi Alperowitz prefers not to dwell on past fall-outs. "We are trying to look to the future. We may be davening in different synagogues but there are events where we come together."

Mr Rubins does not expect his children to remain in Bournemouth. "When we moved down here, there were six or seven couples of our age with similar aged children and those children do mix. But that's not enough. They'll probably go to London."

Mrs Tendler's 23-year-old son Theo has been working as the Reform shul's administrator while he completes his legal training but she doubts if he will stay in the town. "Children go where the jobs are," she reflects.

For Mr Rubins, employment opportunities are crucial. "A big company might move down here and that would bring people with it," he suggests hopefully. "People have taken on roles for a number of years and now we are looking to move them on to the next generation - but that generation isn't really there. It would be such a shame if the community does die out. It's such a nice place to live but we are fighting demographics."