November 26, 2011

Montrose Salmon and Trout Hatchery in the Rakaia Gorge is an asset to the future of the South Island fishery. But it faces a number of threats, Guardian reporter
SUSAN SANDYS writes.

North Canterbury Fish and Game has been managing the Montrose Salmon and Trout Hatchery on Blackford Road in the Rakaia Gorge for 13 years. The facility was established in the late 1970s by George Mee, the farmer of the property at the time.
The hatchery is located on the 207-hectare Montrose tourism property, since subdivided from Mr Mee’s original farm.
In the early days of Fish and Game management, staff and volunteers released 30,000 salmon per year.
They have nurtured the facility to the point where, today, it is a crucial source of stock for wild fisheries in the South Island, and release 350,000 salmon per year.
About 60,000 of these are into the Rakaia River itself, with the remainder going to rivers, lakes and streams throughout the mainland.
The hatchery grows and releases trout – about 80,000 rainbows and 30,000 browns each year.
It provides thousands of “catchable” two-year-old fish for popular take-a-kid-fishing events. At the hatchery’s October release day last month, 1200 salmon were released into Christchurch’s Groynes ponds, and 7000 people turned up with their fishing rods and nets.
The hatchery assists organisations with restorative work, for example in a recent project Contact Energy paid Fish and Game for fish to be released into the Clutha, something the power company had to undertake as part of mitigation requirements.
Hatchery manager Dirk Barr, who is based on site, said such work helped the hatchery pay for its work, and be “cost neutral” in its aim of enhancing wild fishing stocks.
The Montrose and Isaacs hatcheries, the latter on the Waimakiriri River and also managed by North Canterbury Fish and Game, are among just a handful of facilities in New Zealand focusing solely on breeding and release work.
The majority of salmon farms raise fish for their meat.
There are two other Fish and Game hatcheries in the South Island – McKinnons Creek on the Rangitata run by Central South Island Fish and Game, which grows salmon only, and a small rainbow trout hatchery at McCraes Flat run by Otago Fish and Game.
The hatchery’s life blood is the pure cold water which filters down from Mt Hutt. The melted snow exits underground aquifers at Avalanche Creek, and an offshoot of this creek naturally runs into the hatchery at a rate of 80 litres per second.
“It’s beautiful, cold, crystal clear filtered water. Even in the summer it’s 10 degrees,” Mr Barr said.
“That’s why salmon like it so much, because it’s perfect for their spawning, they know what temperature they want.”
But the water is being eyed up by surrounding farmers, who are undertaking studies on its potential for an irrigation scheme. Main Power is also interested, and has made approaches to Fish and Game on a potential secondary purpose of hydro-power generation.
North Canterbury Fish and Game environment officer Tony Hawker said there would not be enough water for the hatchery in the event of such a scheme being developed.
“Any reduction in flow, we would see as a concern because we pretty much utilise all of the water coming into the hatchery,” Mr Hawker said.
A Trustpower Water Conservation Order (WCO) variation application for the Rakaia River, while opposed by Fish and Game, is not seen as a threat. While such a variation would reduce flows at certain times, there would be no reduction in salmon passage in the main Rakaia, Mr Hawker said.
A second potential threat faced by the hatchery is any plans future hatchery owners may have.
The Montrose tourism lodge and chalet has been up for mortgagee sale since winter.
Former owner Ad Bruijn allowed North Canterbury Fish and Game to develop and manage the facility. And as his property went up for mortgagee sale, he feared the new buyer could shut it down.
But information indirectly from the potential future owner suggests this will not happen, at least in the short term.
PGG Wrightson real estate agent Alister Moore said this week the property was under offer, and the sale was expected to go through on Monday.
An earlier offer had fallen through, but Mr Moore was “reasonably certain” this one would go through.
He said the person had expressed interest in keeping the hatchery, and this would certainly seem to make sense for the future benefit of the property.
“My understanding is they would (keep it). But who knows,” Mr Moore said.
The hatchery is at risk of natural disasters, as this year showed. It lost stock following earthquake damage in February, and late last month silt from an earthquake landslide washed into waterways and resulted in four-month-old stock developing gill disease, killing 30,000 of them.
Meanwhile, at the downstream end of the fishery is Montrose Stream, which runs off the Rakaia River. In the autumn it is alive with salmon on their way back to the hatchery to spawn.
They are following their homing instincts, having been the same fish that were released as one-year-olds from the hatchery three years earlier. There is usually about 400 of them, that is all that returns from the 60,000 released. Although it varies each year, and one season about 10 years ago, 1000 returned.
Each of the salmon returning each year have plenty to give in terms of breeding capacity. Each hen, or female fish, has up to 5000 eggs, and the milt of good strong jacks can be used over thousands of eggs.
While typically they come back at three years old, the species’ “natural insurance policy” sees precocious jacks come back at the age of two, and some fish not come back until they are four.
As the salmon head upstream, they enter the Montrose salmon trap.
Here Fish and Game staff and volunteers humanely kill each fish and extract their eggs and milt, and a small proportion are taken to a natural stream bed in the hatchery to spawn naturally, the aim of which is to keep the stream in its natural  condition.
In a hatchery building, staff artificially fertilise the eggs, which then go into buckets for about one month, when eyes can be seen. The eggs are then put through an egg-sorting machine which shoots a laser beam through to determine whether they are alive or dead.
The $12,000 machine was paid for by money forwarded from Rakaia Fishing Competition organisers.
The live eggs will hatch in large tray-like tanks inside the hatchery building, before being transferred into the hatchery’s outdoor ponds.
Seventy-five per cent of the salmon live to the age of one year, compared to what would be an estimated 2 per cent in the wild.
Each June the hatchery holds a salmon release day, where members of the public come along and help release the 60,000 one-year-olds.
Mr Barr said salmon are believed to live within 20 to 30km of the shoreline once out at sea, mostly in schools. He said those from Canterbury Rivers probably do not go far, no further north than Banks Peninsula.
“Once they are out of here, it’s in the lap of the gods,” Mr Barr said.