Sobering Results of Salmon Stocking Program in NB



Graham Chafe, left, Jason Daniels and Heather Dixon, biologists with the Atlantic Salmon Federation, conduct an electrofishing survey of Kedron Stream this past summer. Small tributaries to the Magaguadavic provide critical habitat for juvenile salmon. ASF Photo

Only two wild Atlantic salmon returned to the Magaguadavic River in 2016. The chances these fish were male and female, and then met each other on a gravel patch to spawn are extremely low. This means there is no breeding salmon population left in a river that attracted fly fishermen just a few decades ago.

The decline has been meticulously documented and huge effort has been expended to reverse it. Since 1992, biologists with the Atlantic Salmon Federation have been counting every salmon that passes upstream through the dam at St. George, and a stocking program that began in 1998 has put more than 300,000 hatchery raised fry in the Magaguadavic.

However, if the fry grow to become smolts, and eventually make it to the Bay of Fundy, they simply do not return. In a healthy environment, about seven of every 100 smolts that leave a river should return as mature salmon to spawn.

In reality, the Magaguadavic has been a working river for centuries. A sawmill was built on its banks in 1784. In 1903 a local pulp mill dammed the gorge and cut off any hope of fish passage for 25 years. It was the site of a historic granite processing industry, and today a refurbished dam produces 15 megawatts of electricity.

Despite all this human activity, the salmon kept coming. A best estimate is that Magaguadavic salmon runs during the 1980s were around 1,000 fish per year. These were also the early years for open-net pen salmon aquaculture in New Brunswick, and this river was at the centre of the industry.

Three hatcheries were built in the Magaguadavic watershed to stock sea-cages clustered in bays nearby. The industry was made up of many smaller companies and regulators were learning on the fly. There were large escapes from the hatcheries and at sea.

Atlantic Salmon Federation research estimates that by the mid-1990s, 14 per cent of all salmon eggs laid in the Magaguadavic came from aquaculture escapees. Itís possible the brood-stock captured for later stocking efforts were already hybrids, a genetic mix of farmed and wild salmon less able to survive.

Compounded with other serious threats like invasive smallmouth bass and pickerel in the river, a healthy seal population, and changing conditions at sea, the odds of survival for a wild Magaguadavic salmon dropped.

The partners which came together with the intent to fix the problem include the Atlantic Salmon Federation, J.D. Irving, Limited, Cooke Aquaculture, and provincial and federal government departments. Since 2007, Cooke has hosted the program at their Thomaston Corner hatchery on the Magaguadavic.

Why hasnít it worked? If you pour more fish in a river shouldnít more survive? In this case, and with many stocking programs worldwide, mathematical logic gives way to scientific reality. One hatchery fish does not equal a wild fish. Generally, stocked fish are less likely to survive tough wild conditions.

Now the Magaguadavic River salmon recovery program is at a crossroads. This year was the last for the native broodstock. Those fish are being retired and there are none to take their place. Instead, new blood has been brought in from the Hammond, Nashwaak and Canaan rivers to add much needed genetic diversity.

While no one is ready to give up on the Magaguadavic, itís clear some new techniques are needed. The concept of raising wild fish to adult size before release, which is being tested in Fundy National Park, holds potential. But unless we can say definitively what is killing these salmon after theyíre placed in the river, and fix it, the results may not be any better.