Oncorhynchus gorbuscha. It’s a mouthful, but you might as well get used to it because most signs point to growing numbers of pink salmon finding their way to Eastern Canada. And not surprisingly, Atlantic salmon rivers will be their main target.
While Salmo salar have earned the royal moniker “the King of Fish,” pinks, also known as humpbacks, can be considered the middle class of the salmon world. O. gorbuscha is the planet’s most successful salmon species. Due to their tremendous reproductive power and short life cycle, they’re able to support lucrative commercial fisheries in the northern Pacific Ocean, earning them one more nickname—bread and butter fish. A pink’s productivity is balanced by a short life span—it lives only two years. Like all anadromous salmon, they hatch and emerge from river gravel in spring. They crush the two-to-four-year freshwater stage of Atlantics into less than a year, and by fall have smoltified and headed for salt water. After just over a year in the ocean, they return to rivers between June and October to spawn and die.
According to Ian Bradbury, a scientist with Fisheries and Oceans Canada at the Northwest Atlantic Fisheries Centre, the coming season will likely see a bump in pink salmon numbers in Eastern Canadian rivers. The Dartmouth, Nova Scotia–based researcher has been using environmental DNA (eDNA) to confirm the presence of pink salmon in Labrador. “In 2019 we found five rivers had pink salmon,” he says. “In 2021, we identified seven.
When Paul Smith reported on the spread of pink salmon (“The Russians are Coming,” ASJ, Summer 2019), this Pacific Ocean species had only begun its western movements from the Barents Sea and White Sea rivers, where they had been transplanted between 1985 and 2001. It’s easy to blame the Russians for being successful. They were the first to figure out that a more northern strain of this Pacific Ocean salmon was needed, and from 1985 onwards, transplants from the Magadan Oblast region established self-sustaining populations in northwest Russia.
This picture of Atlantic salmon spawning in the St.Jean River, Gaspé was captured by Nick Hawkins.
By 2007, pink salmon had established themselves in northern Norwegian rivers. In 2017, an unprecedented expansion of pink salmon was seen in the Atlantic Ocean, including all of Norway, Scotland, Denmark and Sweden. The U.K., Ireland, Germany, and France also reported captures, and some pink salmon were observed even farther west in Iceland, Greenland and Eastern Canada. In his article, Smith reported on one capture of a male in spawning colours in the Gander River in 2017.
In Norway, catches doubled in 2019, and by 2021 pink salmon had become the most common anadromous salmonid in Norwegian rivers, and in the northernmost rivers, they outnumbered the sum total of all Atlantic salmon, anadromous brown trout and anadromous Arctic char. The western movement of the odd-year strain of pink salmon from the original introductions seems undeniable and unstoppable. “What we don’t know is how large numbers of pink salmon will affect Atlantic salmon,” Bradbury says. “There is so much uncertainty on impacts. For one thing they don’t spend a of time in freshwater, leaving for saltwater almost immediately.”
Effects on native salmonids could include interference with returning Atlantics. In the last days of their lives, pink salmon protect their redds aggressively. Perhaps in large numbers, the unwelcome salmon could jam up river habitat, preventing natives from using some spawning areas. Juveniles could compete for prey and prime zones for hiding and resting. Pink salmon may also introduce diseases to which indigenous species have little defence. Bradbury is quick to point out that despite the abundance of O. gorbuscha, there is a paucity of data on interactions with Atlantic salmon. Still, the large numbers of pinks present in rivers in Norway, such as the Teno, may soon begin to shed light on this question.
“There could be positives as well,” Bradbury says. “Pink salmon bring nutrients from the ocean which are left there when they die.” And young could be prey for certain age classes of Atlantics.
“We simply don’t know,” adds Bradbury.
The Fisheries and Oceans scientist is doing his best to learn more, however. He has spent parts of the last few summers at a base camp in the Torngat Mountains in northern Labrador. From there, he and his team travel by helicopter to sample rivers, taking water samples to analyze for environmental DNA. Fish will expel traces of DNA through their feces, shedded skin, scales and carcasses. Environmental DNA (eDNA) is an emerging technology that uses high-throughput sequencing to scan water samples and identify the DNA fingerprint of species present in a watershed. Other more traditional methods of assessment such as electrofishing, beach seining or line fishing can be excessively costly and even dangerous to personnel.
Scientists like Bradbury rely on research like this to formulate suggestions for management. At this point, we know that pink salmon have reached Eastern Canadian rivers. In what numbers and whether they have become established is yet to be revealed. “There is no evidence yet of successful spawning,” he says.
Pink salmon spawn every two years. Fish in odd years do not interbreed with those from even years. The strain headed for Canada is odd-year dominant, which is why you can bet that this coming season, both researchers and anglers across Eastern Canada will be on high alert for any sign of pink salmon.
In Norway, catches doubled in 2019, and by 2021 pink salmon had become the most common anadromous salmonid in Norwegian rivers, and in the northernmost rivers, they outnumbered the sum total of all Atlantic salmon, anadromous brown trout and anadromous Arctic char. The western movement of the odd-year strain of pink salmon from the original introductions seems undeniable and unstoppable. “What we don’t know is how large numbers of pink salmon will affect Atlantic salmon,” Bradbury says. “There is so much uncertainty on impacts. For one thing they don’t spend a of time in freshwater, leaving for saltwater almost immediately.”
Effects on native salmonids could include interference with returning Atlantics. In the last days of their lives, pink salmon protect their redds aggressively. Perhaps in large numbers, the unwelcome salmon could jam up river habitat, preventing natives from using some spawning areas. Juveniles could compete for prey and prime zones for hiding and resting. Pink salmon may also introduce diseases to which indigenous species have little defence. Bradbury is quick to point out that despite the abundance of O. gorbuscha, there is a paucity of data on interactions with Atlantic salmon. Still, the large numbers of pinks present in rivers in Norway, such as the Teno, may soon begin to shed light on this question.
“There could be positives as well,” Bradbury says. “Pink salmon bring nutrients from the ocean which are left there when they die.” And young could be prey for certain age classes of Atlantics.
“We simply don’t know,” adds Bradbury.
The Fisheries and Oceans scientist is doing his best to learn more, however. He has spent parts of the last few summers at a base camp in the Torngat Mountains in northern Labrador. From there, he and his team travel by helicopter to sample rivers, taking water samples to analyze for environmental DNA. Fish will expel traces of DNA through their feces, shedded skin, scales and carcasses. Environmental DNA (eDNA) is an emerging technology that uses high-throughput sequencing to scan water samples and identify the DNA fingerprint of species present in a watershed. Other more traditional methods of assessment such as electrofishing, beach seining or line fishing can be excessively costly and even dangerous to personnel.
Scientists like Bradbury rely on research like this to formulate suggestions for management. At this point, we know that pink salmon have reached Eastern Canadian rivers. In what numbers and whether they have become established is yet to be revealed. “There is no evidence yet of successful spawning,” he says.
Pink salmon spawn every two years. Fish in odd years do not interbreed with those from even years. The strain headed for Canada is odd-year dominant, which is why you can bet that this coming season, both researchers and anglers across Eastern Canada will be on high alert for any sign of pink salmon.
If pink salmon invade eastern Canadian rivers in levels that have been witnessed in Norway, they could crowd out other species from prime spawning areas.
Identifying an Invader
Bradbury is hoping to expand sampling to 60 rivers next season. Samples are drawn from river mouths. At the same time as looking for pink salmon, his team will also be identifying other species. It will be interesting to see, for instance, if Atlantic salmon may be expanding their range northward.
Because these pinks are a dominant, odd-year strain, the progression of movement from the Barents Sea rivers through Norway, Scotland, Iceland and Newfoundland is expected to increase in 2023. Fully mature pink salmon are small, weighing 1.3 to 1.8 kilograms (just under 3–4 pounds) and measuring 50–63 centimetres (20–25 inches) in length. Females and males in the marine phase may be more difficult to differentiate, as they are bright greenish-blue on top and silvery on the sides. On closer examination, however, pink salmon have much smaller scales than Atlantic salmon, white mouths, and black tongues and gums. Close to fresh water, they develop large black spots on their backs and tails. Males develop large humps and hooked jaws closer to spawning. Juvenile pink salmon in their freshwater phase are bright, silvery and shiny with none of the marks that might indicate an Atlantic salmon parr.
If you capture a pink salmon in Newfoundland, Nova Scotia or New Brunswick while angling this season, do not release it. Keep it in the freezer and contact Fisheries and Oceans Canada (number to come). In Quebec, anyone capturing a pink salmon in Nunavik is asked to do one of the following:
email a photo of the fish to observations_eae@mffp.gouv.qc.ca,
phone 1-877-346-6763, or
freeze the entire fish and send it to the Nunavik Research Centre in Kuujjuaq c/o Lilian Tran or Peter May. (They can also be reached email at pmay@makivik.org and ltran@makivik.org or by phone at 819-964-2925.)
ASF aligned with conservation groups, First Nations, and government agencies to rid of the Miramichi of smallmouth bass.
The world turned upside down
Are we doing enough to counter the threat of invasive species?
Pacific salmon in Eastern Canadian rivers and Atlantic salmon spawning in rivers on the west coast. Smallmouth bass in the Miramichi and grass carp in the great lakes. According to the World Conservation Union, invasive alien species are the second most significant threat to biodiversity after habitat loss. We seem to be losing the battle; why isn’t more being done?
You’d think we would have learned from other cases of invasive species on the planet. One of the most famous, or infamous, was the introduction of European rabbits to Australia in the 1800s. The species has caused great damage to the environment, and researchers have introduced counter measures, such as viruses and pathogens, to kill them. There has been some success, but the rabbits continue to be a problem. Take home lesson: it’s much easier to prevent the introduction of an invasive species than to get rid of the species once established.
For this very reason, ASF has been trying to stop the spread of smallmouth bass in the Miramichi, while Fisheries and Oceans Canada is hoping to prevent grass carp from establishing in the Great Lakes. Pink salmon must be treated with a similar urgency.
Are we doing enough to counter the threat of invasive species?
Pacific salmon in Eastern Canadian rivers and Atlantic salmon spawning in rivers on the west coast. Smallmouth bass in the Miramichi and grass carp in the great lakes. According to the World Conservation Union, invasive alien species are the second most significant threat to biodiversity after habitat loss. We seem to be losing the battle; why isn’t more being done?
You’d think we would have learned from other cases of invasive species on the planet. One of the most famous, or infamous, was the introduction of European rabbits to Australia in the 1800s. The species has caused great damage to the environment, and researchers have introduced counter measures, such as viruses and pathogens, to kill them. There has been some success, but the rabbits continue to be a problem. Take home lesson: it’s much easier to prevent the introduction of an invasive species than to get rid of the species once established.
For this very reason, ASF has been trying to stop the spread of smallmouth bass in the Miramichi, while Fisheries and Oceans Canada is hoping to prevent grass carp from establishing in the Great Lakes. Pink salmon must be treated with a similar urgency.
