Like many other locals wanting to live a more sustainable lifestyle, Gemmell is part of a new wave of ecologically sensitive Canberrans looking to reinvent the typical suburban existence.

Like many other ACT households, there are the solar panels on the roof, a vegetable patch and chickens running around. What separates this backyard from the neighbours, is his poultry sometimes get to eat fish guts cut and pulled from trout and perch grown on the property.

''Our trout are small at the moment but they should be plate-size by December,'' Gemmell, 32, says. ''Then we'll harvest them and stick some in the freezer or have a trout party.''

Gemmell is skilled at aquaponics - an increasingly popular symbiotic cultivation of plants and fish in a recirculating environment - and even teaches others how to do it.

One of his creations is a system made from recycled materials. There's an old bathtub (cost $20) used as a bed for vegetables and a tank ($100), which once held molasses and now holds 1000 litres of water for the fish.

A pump circulates water and moves fish waste from the pond, now home to half a dozen fish, to the vegetables. A more professional set-up with a 3000-litre tank and 50 trout is also in the yard.

''It's organic; you are harnessing a natural ecosystem to recycle waste products to grow your plants,'' he says.

''It is core to the system so you don't want to mess with it. So most organic control methods work in aquaponics, the exception being soap. Soap is a surfactant, which can kill the fish - you need to stay away from using soap sprays.''

But Gemmell is not the only Canberran able to catch an eatable fish from his suburban plot.

Others have trout more than 20 centimetres long that have survived the summer.

Karen Dahl is new to aquaponics but is growing huge trout. ''They're bigger than the trout in the shops, two or three kilograms, and amazingly they're living in harmony with the babies,'' she says. ''It is such a treat to see their compatibility. I have to say that when I left them for a few days without food they did go for the littlies.

''I haven't got the heart to eat them now because they've done so well and are still, of course, feeding some vegies - mainly spinach.''

She kept them alive in summer with a $60 shadecloth and, on really hot days, blocks of ice.

''We [as Australians] have food brought in from very long distances and we need to rethink that,'' she says. ''Do we really need prawns from Thailand or can we just get yabbies? I can grow yabbies in my aquaponics system.''

Australia is one of the world's leading countries in terms of innovation in food production, but this has mainly occurred at commercial agricultural properties.

Now there is more than a grassroots push for the worsening global food shortage to be resisted by individual households. One local group says Canberra needs its own small, intensive commercial enterprises to grow food and ensure greater self-sufficiency for a time when grocery prices skyrocket.

The world must feed 9 billion people by 2050 when at the moment it fails to feed 2 billion fewer than that. And it must achieve this in spite of climate change and the potential instability of future oil crises, according to one group in Canberra.

Fusion Australia, a Christian community organisation, calls for localised intensive food production in the ACT. It says the territory's commercial food-growing sector is not big enough.

''Intensive'' refers to aquaponics as well as hydroponics, where vegetables are, among other techniques, grown using water high in mineral nutrients.

In particular, aquaponics would position fish as the ''food of the future'', in the words of Fusion's John Brummell.

He wants the ACT government to lease small unused plots of land throughout the ACT to farmers who can run an intensive operation. Fusion is already running its own carp farm at Kambah.

The pest fish - pulled from Lake Burley Griffin for the project - was used to get the fish farm started because of its reliability.

Documents from Fusion argue fish eat little more than their body weight up to a certain age, unlike cattle, which need much more feed per kilogram of beef slaughtered.

''Why we aren't being inundated by visitors and business people, I do not know,'' Mr Brummell said.

Fusion Canberra and SEE-Change, a not-for-profit group that aims to reduce Canberra's ecological footprint, have written a discussion paper that identifies emerging threats and proposes a strategy of local food production to counteract their impact.

The publication of the discussion paper will be followed by a free public lecture on food issues by well-known speaker and science journalist Julian Cribb author of The Coming Famine.

According to the ACT government report, Food in the ACT, since 2008 more than half of the world's population has lived in urban environments. Urban sprawl in greenfield sites has reduced the land available for food production in urban and peri-urban areas in Australian cities. This includes the shrinkage of the Sydney Basin, once full of market gardeners.

The report quotes the book Hungry City: How Food Shapes Our Lives, which says the character and culture of cities has in part been produced by freeing people from the constraints of food production.

Becoming increasingly distant from our food sources has required the development of infrastructure, design solutions and global trading networks, but the report notes food has not been a high priority when cities have been planned.

■ Julian Cribb's lecture is at 7.15pm, Tuesday, at Canberra Grammar School, Red Hill.