UNB – SamwaysMarch 1, 2016
A recent project designed to give a fighting chance to some young wild salmon is paying off in a big way.
Unprecedented results are being seen in follow-up efforts to a successful pilot project involving the release of native adult salmon to Fundy National Park.
The original pilot in 2009-2013 resulted in 20-year highs in adult observations. Building off of that the CRI is looking to determine the cascading positive effects of those releases on the ecosystem integrity and resulting population fitness.
The three year project – “Restoring ecosystem health and increasing progeny fitness through marine reared Atlantic Salmon” – is already showing positive results.
The project, which will receive a total of $84,000 over the three years from the ASCF, includes collecting wild-exposed smolt from the river which are transported to marine cages where they are raised to adulthood before being returned to the river.
“So far this year we saw some unprecedented results, including the release of 400 adult inner Bay of Fundy Atlantic salmon to the Upper Salmon River in Fundy National Park,” says the CRI’s Kurt Samways. “We tagged all released fish with Passive Integrated Transponder (PIT) tags, which allows us to track the movements including out-migration and over-wintering of fish. We also radio tagged 20 adult salmon. Actively tracking these fish provides data regarding where salmon spawn within this river and their survival after spawning. Based on the current movements, adults are migrating up the river to areas known to be historic spawning locations.”
The numbers of Atlantic salmon within many New Brunswick rivers are at historically low levels, with low numbers of smolts and far fewer returning adults. Inner Bay of Fundy Atlantic salmon populations have declined by 90-percent or more in recent years putting these fish at risk of extinction.
This project is anticipated to tag and release a projected 500-1000 native adult salmon into the Upper Salmon River annually from 2015 through 2018. Those adults will be allowed to spawn naturally and produce large numbers of juveniles with an estimated 4900-6000 smolts (over three years) leaving the river in future years.
Samways says returning adult salmon – including the cage reared adults they released- deliver marine-derived nutrients which drives freshwater productivity.
“In addition to monitoring the adult population within the river, we are also monitoring the ecological state of the river to assess the impact of having a large spawning population of salmon in the river again. We have collected all of the baseline (pre-adult) samples which we will then compare samples collected post-spawn to measure any ecological effects.”
Samways says this project will assess the effectiveness of releasing wild, marine pen reared adult Atlantic salmon as a conservation and restoration tool. He notes the general effects are widely applicable to all salmon producing rivers which are increasingly dealing with declining salmon populations.
He adds a more advanced understanding of the role that Atlantic salmon play in freshwater ecosystems is crucial for a comprehensive approach to mitigate the limiting factors associated with salmon production and survival in freshwaters.
“The annual returns of adult Atlantic salmon, both natural and artificial, are critically important for sustaining productivity, both regionally and throughout Atlantic Canada. Carrying capacity for Atlantic salmon depends on properly functioning biogeochemical cycles and diverse food webs, both of which are strongly dependent on Atlantic salmon.”