By Sorrel Hoskin

A whitebait is a whitebait - or is it? Take a closer look next time you haul up your whitebait net - you might be surprised at what you find.

More than just whitebait

Whitebait are the babies of up to six varieties of New Zealand native fish. According to the Department of Conservation (DOC) the three most common species caught are galaxiids: inanga, kōaro and banded kōkopu. Other fish such as giant kokopu, short jawed kōkopu and smelt sometimes turn up in nets along with the young of other fish including eels, trout and cockabullies.

Not much is known about the lifecycle of whitebait - what we do know is that they hatch in rivers during late autumn from where they head out to sea. They spend several months in the ocean growing before making the migration back up river in late winter/early spring. They begin their journey as the tide builds and use the surge of the waves to push them upstream. The whitebait gather together in shoals and make their way up the river.

It's at this stage when whitebaiters get excited and haul out their nets - keen to get a feed of the little fish.

The whitebait that make it upstream settle in bush covered streams and swamps where they grow to adults. All varieties of whitebait like slightly different habitats - some, like the short jawed kōkopu and giant kōkopu live in swampy streams and ditches with muddy bottoms. Inanga prefer to be closer to the sea in lowland waters. Banded kōkopu and kōaro like fast flowing streams that have rocks and tree cover.

DOC researchers think that the start of the migration downstream is influenced by river flows and phases of the moon. Whatever happens, when the moment is right the mature inanga migrate downstream and spawn in grasses along river and estuary edges, covered by water at spring tides. The eggs stay stuck to the grass until the next spring tide comes along when the tiny larvae, half the size of a pin, hatch and are carried out to sea. The adults often die, or are so exhausted they fall prey to birds and larger fish.

Whitebait in trouble

But there's a big problem. Whitebait habitats are being destroyed. Swamplands and streams are being drained, trees chopped down and stock are breaking down riverbanks. Culverts and weirs can prevent whitebait from swimming upstream. This all reduces places for the whitebait to spawn, and for them to live when they are older. And then there're those people who flaunt the rules…

Whitebait protection squad

For DOC programme manager species management, Bryan Williams, the August to November months are the often busiest in his calendar. The New Plymouth-based officer's main role during this time is enforcing the regulations - checking that whitebaiters are following the rules set to protect whitebait numbers.

"Most of the whitebaiters are very good - there're only a small percentage of them, because we are seen as an enforcement agent, who get a bit uptight - they're usually people who are trying to supplement their income by selling whitebait."

It's illegal in New Zealand to sell any native fish without a permit - apart from whitebait. This year whitebait has fetched up to $150 kg in New Plymouth. Whitebaiters sell their catch to the shops for around $65kg. This has been an exceptionally good season for some, says Bryan. One whitebaiter he knows of caught 25kg one day - which would have earned just over $1600. It's all perfectly legal - but not particularly fair. "The people who are trying to supplement their incomes are those we often have problems with," says the DOC officer. "They tend to cheat and make it difficult for everybody else."

These are the people who try and push the limits with the size of their nets, who use larger screens than legally allowed, who fish near culverts and creek entrances where whitebait congregate, and try to hide when DOC rangers come patrolling. And then there's those who jump start the season. Whitebait run all year around - but the months from August through to November are the best. Sometimes the whitebait will run early - heading upstream in July - keen whitebaiters watch the rivers and set their nets, despite it being illegal.

DOC does prosecute illegal whitebaiters - last season six people were fined up to $5000.

Bryan also works in with other Government departments and businesses, including  Taranaki Regional Council and Fonterra, encouraging riparian planting to help protect whitebait habitats, working in with the Resource Management Act to ensure any new developments won't harm habitats, and preserving remaining wetlands.

"We're slowly getting back some of the habitat that was lost - particularly in Taranaki because of a consorted effort - but it's really only spawning habitat - a lot of the wetlands and stream habitats where the adult whitebait like to live have gone."

Check out the DOC regualtions for whitebaiting here.