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The Future Of Whitebait


As another whitebait season draws to a close, it’s time to ponder the future of the five native fish species making up the catch.

WHITEBAIT - frittered in butter with beaten egg and a pinch of flour, served with fresh bread, washed down with cold beer, white wine, or a cup of tea.

No wonder New Zealanders take to estuaries and river mouths between August and November, hoping to fill a punnet, a bucket or even kerosene tins with wriggling, transparent fish.

Whitebaiting can be lucrative too – top stands in the south of the country change hands for up to $80,000. At $60/kg on the riverbank, the stand owner would need to harvest 1.3 tonnes of whitebait to break even. It has been retailing in shops this season for $10 to $15 a 100 grams.

For the Department of Conservation, however, there is more to whitebaiting than enforcing the rules, and more to native galaxiid fish than a fritter. Of the five species making up the whitebait catch, two are classified as threatened and in gradual decline, says DOC Canterbury Conservancy freshwater ecologist Sjaan Charteris.

While inanga form the bulk of the catch nationwide, the less common species – koaro, banded kokopu, shortjaw kokopu and giant kokopu – are also present in the run.

With whitebaiters around the country having enjoyed variable catches, as the season draws to a close, it may be tempting to believe the fishery is fine. But any lack of concern for its future would be misplaced.

Current catches are much reduced from the harvests of 50 to 100 years ago, says Dave Rowe of the National Institute of Water and Atmospheric Research (NIWA).

“We have long thought one of the main problems was habitat destruction and we now have new research to prove it. Many whitebait escape fishers’ nets to move upstream, and most of these fish die before reaching maturity.”

“Inanga can’t negotiate overhanging culverts, dams and other manmade barriers. Nor can they swim against water released from some floodgates. They live mainly in shallow freshwater streams and swamps, of which 94 per cent have been drained in the last 150 years. Nutrient discharge off farms may affect water quality as well, and the fish prefer not to live in badly-polluted streams.”

Farmers, landowners, foresters, roadmakers and local authorities need to better appreciate what happens to whitebait species as they migrate upstream and progress through their life cycle, the Hamilton-based freshwater fish scientist says.

Despite DOC calls for fish-friendly culverts, and cattle-proof fencing along tidal river margins where inanga spawn, more needs to be done around the country, he says. “It’s in whitebaiters’ interests, let alone all of us, to tune into this problem.”

A number of community groups throughout New Zealand, such as the Landcare Trust, whitebaiters’ associations and iwi groups, have started restoring sections of small streams in inanga and taken an interest in their life cycles.

In early autumn, when spring tides are at their highest following the full moon, a keen observer will spot shoals of silvery adult inanga milling at the river’s edge.

As the tide reaches its peak, the fish wriggle into the bases of flooded vegetation, typically tall grasses, flax or rushes. Females lay their eggs, while males turn the water milky with sperm. Most adults die naturally or are eaten by eels immediately after spawning. However, a few inanga may live as long as three years, spawning each year.

The fertilised eggs stick to the moist base of plant cover, where they develop, above the normal tide line, over the next three to six weeks. On the next big tide, they hatch into tiny larvae, and float out to sea on a falling tide. Here they are joined by the larvae of other whitebait species swept from other spawning sites, and drift as part of the marine plankton.

No one knows where whitebait go during their time at sea or what triggers the massing of 50mm juvenile fish in winter and spring every year at river mouths around the country. The study of whitebait falls short of an exact science.

Bearing in mind that four species are no longer common, of which two are threatened with ongoing decline, DOC has fixed the whitebait season from 15 August to 30 November for most of New Zealand.

On the West Coast, the season runs from 1 September to 14 November to improve the chances of giant and shortjaw kokopu which usually run later in the season reaching their preferred habitats. These include coastal wetlands for giant kokopu and forest-covered streams for short-jaw kokopu.

Early next year DOC is due to release a recovery plan to improve protection and knowledge of the four less common whitebait species. The recovery plan calls for more research into the contribution of these species to the whitebait catch, and better understand national population trends.

Whitebaiters may make a few observations of their own while hauling in their catch. Juvenile inanga have the desirable see-through appearance and swim about in the bottom of the whitebait bucket. Late in the season, a golden sheen may appear on some catch. This “goldenbait” is giant kokopu, or banded kokopu, So strong is their instinct to migrate, these species climb the sides of the bucket in an attempt to move upstream.

The young of koaro and short-jaw kokopu are milky in colour and are known as “elephant ears” for their large fins. Koaro and shortjaw kokopu also climb the sides of the whitebait bucket.

Ms Charteris says whitebaiters who discover goldenbait and elephant ears in their catch could return them to the water to help the chances of survival for their species.

In encouraging people to spare a thought for our quirky native galaxiids, the last word belongs to a Mainland Cheese brochure: “Have you ever wondered what becomes of a whitebait when its life isn’t frittered away?”

Panel (326 words): Whitebait facts – the big five galaxiids: (images available, try www.niwa.co.nz/rc/freshwater/fishatlas/species)

In the spotlight: Shining a torch into suitable galaxiid streams and swamps at night is the easiest method of spotting adults of New Zealand whitebait species. In torchlight, koaro sparkle gold, banded kokopu appear blue, short-jawed kokopu, a brownish-pink and giant kokopu, olive-brown with brilliant gold hieroglyphic markings.

Inanga (Galaxias maculatus): The most common whitebait species grows into 9cm silvery cigar-shaped fish, preferring slow-moving coastal streams, swamps and lakes. Most live for a year, spawn in tidal riverside vegetation in autumn and die. Native to New Zealand, Australia, Chile and Argentina, inanga are among the most widely-distributed freshwater fish species in the world.

Koaro (Galaxias brevipinnis): Spectacular climbers, koaro use their large fins to scale steep slopes, even vertical waterfalls, into rocky, tumbling forest or tussock-lined streams. They grow to around 18cm, rarely up to 30cm, with a distinctive greenish-brown patterning, and spawn in late autumn at stream edges in high water flow. Nocturnal. The second most common whitebait species, koaro are also found in Southeast Australia.

Banded kokopu (Galaxias fasciatus): Adults may grow into 20cm fish with numerous pale stripes across the body. Good climbers as juveniles, adult “bandies”, however, prefer small coastal streams with plenty of overhead forest cover. They spawn in heavy rains during flood flows in streamside forest litter and gravels. Mainly nocturnal. Threatened. Endemic.

Short-jaw kokopu (Galaxias postvectis): A drab, brownish fish as adults which may grow to 20cm, rarely to 30cm or more. Like koaro, they climb streams inland. They are restricted to streams, large or small, with native forest cover. Similar spawning habits to banded kokopu. Nocturnal. Threatened and sparsely distributed. Endemic.

Giant kokopu (Galaxias argenteus): aka Maori trout. Adults are olive-green, blunt-nosed heavy-set fish, up to 50cm long. Their golden hieroglyphic markings, reminiscent of the Milky Way galaxy, have given the genus, Galaxias, its name. Giant kokopu prefer overgrown gently flowing streams, swampy lagoons and lake edges near the sea. Mainly nocturnal. Threatened and in gradual decline. Endemic.

ENDS


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