Whitebait fritter lovers have good news.

A fish breeding breakthrough at Warkworth means factory farming of the delicious little wrigglers is now possible.

Whitebait could soon be picked up at the supermarket and possibly exported too.

Mahurangi Technical Institute has managed to breed giant kokopu - one of the five native fish collectively called whitebait - on a large scale. This comes amid concerns about falling numbers.

But not all are convinced commercial farming will help dwindling supplies.

Calls for tighter restrictions during the whitebait season have come from Massey University freshwater scientist Mike Joy who says commercial fishing of wild stock should be stopped. Four out of five whitebait species are on the official Conservation Department threatened species list. Dr Joy says the overall decline comes from poor water quality.

Researchers at Warkworth's institute don't believe their breeding programme will bring an end to whitebait fishing in the wild. They see it as a business opportunity which will take some pressure off the wild population.

The private institution specialises in the development of freshwater fish breeding techniques for both commercial and conservation purposes.

Years of research under head scientist and eel specialist Tagried Kurwie on the breeding of the New Zealand shortfinned eel as a commercial fish stock has seen it gain some international recognition.

Mahurangi Technical Institute director and founder Paul Decker thought eel breeding research would be his organisation's big success story - rather than whitebait. The institute is close to developing a technique to breed eels in a closed life cycle, something that could also help wild populations which have plummeted internationally.

The breakthrough in giant kokopu breeding has taken five years of research, mostly by aquatic scientist Quentin O'Brien. But the magnitude of Mahurangi's success has left staff stunned.

"They're eating us out of house and home," Mr Decker says. "With one female able to produce 20,000 eggs, which only take 27 days to hatch, we've got hundreds of thousands and are running out of containers to put them all in. We've got a whitebait tsunami on our hands."

Many of the giant kokopu breeding techniques will be transferable to the other whitebait species.

Getting a business plan sorted is next on the list, Mr Decker says.

The institute should be able to start supplying fish farmers properly early next year.

The whitebait season is from August 15 to November 30 for most of New Zealand, and from September 1 until November 14 on the West Coast.

- © Fairfax NZ News