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Through the Rain and From Dawn to Dusk

Smolt Wheel – Rocky Brook – May 9, 2012

ASF research staff have been working full days, through the rain, and from dawn to dusk and beyond, to keep up with the ambitious Atlantic salmon tracking program underway.

The object is to unravel the mystery of the Atlantic salmon’s migration routes and times, as well as to understand why mortality at sea has been so much higher in the past two decades.

ASF Salmon Tracking Program

Last week Stephen Tinker and Graham Chafe were at Rocky Brook on the Main Southwest Miramichi upstream from Boiestown, assisted on Wednesday by Frances McCurdy, a summer interpreter at the Wilfred M. Carter Atlantic Salmon Interpretive Centre. The object was to gather 80 healthy smolt coming down this fast-flowing stream with the assistance of a smolt wheel anchored near the mouth of the stream. Then it would be two days of surgeries to implant miniaturized transmitters.

The rain held off on Wednesday as the equipment was set up in the morning in a shed at Rocky Brook Camp, and buckets, coolers and the many pieces of equipment were set up in the special way these researchers have developed over the past decade to do this work.

Collecting Salmon Smolts

Then it was down to the smolt wheel to gather some of the dozens of smolt that had been gently trapped in the live box by the smolt wheel. Each smolt had already been measured for the general log when the cooler was brought up to the work area.

The miniature transmitters made by VEMCO of Halifax are turned on by removing an external magnet, and each is carefully noted for its code number, and full notes taken.

Surgically Implanting Transmitter

The Atlantic salmon smolt are carefully anesthetized with clove oil, and in a process that is efficient and has been tuned finely by hundreds of operations in the past, the smolt are individually measured, and quickly a very short incision is made to the abdominal cavity, the transmitter is inserted, and two efficient surgical stitches complete the operation, in a total time of two minutes. As this is taking place, the salmon smolt’s mouth and gills are kept irrigated.

The Atlantic salmon are gently returned to a large aerated cooler and within a short time are swimming around. To make sure that all is well, they are held for an hour or two, and then returned to the river to continue their migration down the Miramichi, out across the river’s estuary full of predators, and out into the Gulf of St. Lawrence.

After an overnight at Rocky Brook Camp, on Thursday the two researchers continued their work, finally packing up after 80 smolt were on their way downstream.

Meanwhile, further down the Miramichi, another ASF researcher had been setting out receivers in carefully chosen locations in the river, and across the mouth of the Miramichi estuary.

Ocean Survival to Strait of Belle Isle

Ocean Survival to Strait of Belle Isle

What has been the past experience with this research?  About 25% to 30% of the smolt from Rocky Brook on the Miramichi generally pass through the Strait of Belle Isle that separates Labrador from Newfoundland, based on results through past several years

What happens to the rest? Predators undoubtedly get many, and perhaps some are remaining within the Gulf of St. Lawrence.

Releasing Smolt with Transmitters to Continue Migration

This week Stephen Tinker and Graham Chafe were on the Kedgwick, a tributary of the Restigouche, repeating the process of gathering smolts, but this time with 105 transmitters to be inserted.

In addition, together with Mike Best, receivers were deployed in the Restigouche and lines of receivers deployed across the Baie des Chaleurs at Dalhousie, and further down the bay, near its mouth as well, from the New Brunswick to the Quebec side of the waters.

In 2012 a number of the receivers are of a new type where there is no buoy at the surface. In the past there have been some receivers going missing – most likely inadvertently being removed by ship traffic.

Cold Waters of Baie des Chaleurs

With these new receivers there is nothing near the surface, and using GPS coordinates the new versions can be triggered from their connection to the anchors on the bottom to rise to the surface to be retrieved.

It will be interesting to see how these smolts of the Restigouche fare in 2012. Each year since 2009 the survival rate of these Restigouche smolt reaching the Strait of Belle Isle has been improving. Sometime between July 10 and 20 they should be passing across the line of receivers at the Strait of Belle Isle, headed towards Greenland feeding grounds.

This pioneering research in unravelling the story of Atlantic salmon at sea relies on partnerships, as everyone wants to solve this puzzle. To begin with there is the assistance provided by VEMCO, who makes the transmitters and receivers, and helps in any way possible to be sure the technology works. Rocky Brook Camp staff including Manley Price help this research happen, just as the the Miramichi Salmon Association has helped with the kelt tagging and other research on the Miramichi. At Kedgwick, DFO staff including Ivan Benwell assist, and in deploying the receivers near Dalhousie Peter Metallic and the Listiguj Rangers have proven to be invaluable partners. And Duncan Bates and the Ocean Tracking Network from Dalhousie University assisted with the new receivers and in their deployment.

There is still much to be done this year. Smolt in other rivers, and the line of receivers across the fog-shrouded and windy Strait of Belle Isle to name just two tasks. And for the research staff, when back in the office, the seemingly endless task of transferring invaluable field notes to digital formats.

All photos copyright Atlantic Salmon Federation

Through the Rain and From Dawn to Dusk

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