Researchers track salmon’s epic journey from Greenland to Ireland.
Inland Fisheries Ireland (IFI) has successfully tracked a migrating salmon on an extraordinary journey of more than 2,300km, from Greenland to its native river in Co. Mayo. The discovery highlights the remarkable homing instincts of salmon and the critical role of international collaboration in understanding their migration patterns.
Using acoustic tracking technology installed at the entrance to Killary Harbour, IFI scientists detected a salmon that had been tagged near Qaqortoq, southern Greenland. This breakthrough was made possible by advanced sensors that pick up unique signals emitted by tags attached to fish.
Glen Wightman, an IFI Research Officer, explained: “We recorded a mystery fish at Killary Harbour that had been tagged near Qaqortoq. Although it wasn’t tagged in fresh water in Ireland, we know salmon rely on their strong homing instinct to return to their river of origin.”
The town of Qaqortoq lies over 1,242 nautical miles from Co. Mayo, and the fish’s journey underscores the vast distances salmon travel during their lifecycle. IFI sensors recently detected the fish swimming up the River Erriff, the agency’s National Salmonid Index Catchment.
Remarkable Journey
The salmon, originally tagged in September 2023, weighed 3.3kg and measured 64cm in length at the time. According to Wightman, it may now weigh as much as 5kg after spending two winters feeding in the Atlantic. “We believe this feeding visitor to Greenland has now migrated upstream to spawn in the River Erriff, passing on its genes to the next generation of salmon,” he added.
IFI’s acoustic arrays, which record tags pinging a unique code every 60 to 90 seconds, allow researchers to monitor the fish’s movements in real-time as they approach monitored rivers. This data provides valuable insights into migration patterns and the challenges salmon face during their long journeys.
International Collaboration
The identification of the tagged fish involved coordination with organisations including NOAA Fisheries, Fisheries and Oceans Canada, the Atlantic Salmon Federation, and the Association of Fishermen and Hunters in Greenland.
Tim Sheehan of NOAA Fisheries emphasized the importance of such efforts: “This tagging furthers one of our main goals – to develop a better understanding of the factors driving salmon abundance and the challenges they face.”
The findings contribute to a growing body of research on Atlantic salmon migrations, offering critical information for conservation efforts. As salmon populations face increasing pressure from climate change, habitat loss, and overfishing, the ability to track their movements is vital to ensuring their survival.
